Chemosensors

33 pages, 4028 KiB

Open AccessEditor’s ChoiceReview

3D Printing Technologies in Biosensors Production: Recent Developments

by Giulia Remaggi, Alessandro Zaccarelli and Lisa Elviri

Chemosensors 2022, 10(2), 65; https://doi.org/10.3390/chemosensors10020065 - 7 Feb 2022

Cited by 56 | Viewed by 10241

Recent advances in 3D printing technologies and materials have enabled rapid development of innovative sensors for applications in different aspects of human life. Various 3D printing technologies have been adopted to fabricate biosensors or some of their components thanks to the advantages of [...] Read more.

Recent advances in 3D printing technologies and materials have enabled rapid development of innovative sensors for applications in different aspects of human life. Various 3D printing technologies have been adopted to fabricate biosensors or some of their components thanks to the advantages of these methodologies over the traditional ones, such as end-user customization and rapid prototyping. In this review, the works published in the last two years on 3D-printed biosensors are considered and grouped on the basis of the 3D printing technologies applied in different fields of application, highlighting the main analytical parameters. In the first part, 3D methods are discussed, after which the principal achievements and promising aspects obtained with the 3D-printed sensors are reported. An overview of the recent developments on this current topic is provided, as established by the considered works in this multidisciplinary field. Finally, future challenges on the improvement and innovation of the 3D printing technologies utilized for biosensors production are discussed. Full article

(This article belongs to the Section (Bio)chemical Sensing)

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26 pages, 29132 KiB

Open AccessEditor’s ChoiceReview

Nanostructured Metal Oxide Semiconductors towards Greenhouse Gas Detection

by Mehran Dadkhah and Jean-Marc Tulliani

Chemosensors 2022, 10(2), 57; https://doi.org/10.3390/chemosensors10020057 - 30 Jan 2022

Cited by 24 | Viewed by 4670

Abstract

Climate change and global warming are two huge current threats due to continuous anthropogenic emissions of greenhouse gases (GHGs) in the Earth’s atmosphere. Accurate measurements and reliable quantifications of GHG emissions in air are thus of primary importance to the study of climate [...] Read more.

Climate change and global warming are two huge current threats due to continuous anthropogenic emissions of greenhouse gases (GHGs) in the Earth’s atmosphere. Accurate measurements and reliable quantifications of GHG emissions in air are thus of primary importance to the study of climate change and for taking mitigation actions. Therefore, the detection of GHGs should be the first step when trying to reduce their concentration in the environment. Throughout recent decades, nanostructured metal oxide semiconductors have been found to be reliable and accurate for the detection of many different toxic gases in air. Thus, the aim of this article is to present a comprehensive review of the development of various metal oxide semiconductors, as well as to discuss their strong and weak points for GHG detection. Full article

(This article belongs to the Special Issue Functional Nanomaterials for the Detection of Greenhouse Gases)

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20 pages, 5898 KiB

Open AccessEditor’s ChoiceArticle

Introducing Graphene–Indium Oxide Electrochemical Sensor for Detecting Ethanol in Aqueous Samples with CCD-RSM Optimization

by Ramin Boroujerdi and Richard Paul

Chemosensors 2022, 10(2), 42; https://doi.org/10.3390/chemosensors10020042 - 24 Jan 2022

Cited by 13 | Viewed by 4280

Abstract

There is significant demand for portable sensors that can deliver selective and sensitive measurement of ethanol on-site. Such sensors have application across many industries, including clinical and forensic work as well as agricultural and environmental analysis. Here, we report a new graphene–indium oxide [...] Read more.

There is significant demand for portable sensors that can deliver selective and sensitive measurement of ethanol on-site. Such sensors have application across many industries, including clinical and forensic work as well as agricultural and environmental analysis. Here, we report a new graphene–indium oxide electrochemical sensor for the determination of ethanol in aqueous samples. Graphene layers were functionalised by anchoring In₂O₃ to its surface and the developed composite was used as a selective electrochemical sensor for sensing ethanol through cyclic voltammetry. The detection limit of the sensor was 0.068 mol/L and it showed a linear response to increasing ethanol in the environment up to 1.2 mol/L. The most significant parameters involved and their interactions in the response of the sensor and optimization procedures were studied using a four-factor central composite design (CCD) combined with response surface modelling (RSM). The sensor was applied in the detection of ethanol in authentic samples. Full article

(This article belongs to the Special Issue Recent Advances in Biosensors for Healthcare Applications)

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13 pages, 2071 KiB

Open AccessEditor’s ChoiceArticle

In Situ Detection of Hydrogen Sulfide in 3D-Cultured, Live Prostate Cancer Cells Using a Paper-Integrated Analytical Device

by Jae-Hyung Kim, Young-Ju Lee, Yong-Jin Ahn, Minyoung Kim and Gi-Ja Lee

Chemosensors 2022, 10(1), 27; https://doi.org/10.3390/chemosensors10010027 - 10 Jan 2022

Cited by 10 | Viewed by 3327

Abstract

In this study, a paper-integrated analytical device that combined a paper-based colorimetric assay with a paper-based cell culture platform was developed for the in situ detection of hydrogen sulfide (H₂S) in three-dimensional (3D)-cultured, live prostate cancer cells. Two kinds of paper [...] Read more.

In this study, a paper-integrated analytical device that combined a paper-based colorimetric assay with a paper-based cell culture platform was developed for the in situ detection of hydrogen sulfide (H₂S) in three-dimensional (3D)-cultured, live prostate cancer cells. Two kinds of paper substrates were fabricated using a simple wax-printing methodology to form the cell culture and detection zones, respectively. LNCaP cells were seeded directly on the paper substrate and grown in the paper-integrated analytical device. The cell viability and H₂S production of LNCaP cells were assessed using a simple water-soluble tetrazolium salt colorimetric assay and H₂S-sensing paper, respectively. The H₂S-sensing paper showed good sensitivity (sensitivity: 6.12 blue channel intensity/μM H₂S, R² = 0.994) and a limit of quantification of 1.08 μM. As a result, we successfully measured changes in endogenous H₂S production in 3D-cultured, live LNCaP cells within the paper-integrated analytical device while varying the duration of incubation and substrate concentration (L-cysteine). This paper-integrated analytical device can provide a simple and effective method to investigate H₂S signaling pathways and drug screening in a 3D culture model. Full article

(This article belongs to the Section Analytical Methods, Instrumentation and Miniaturization)

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20 pages, 9733 KiB

Open AccessEditor’s ChoiceReview

Recent Development of Optofluidics for Imaging and Sensing Applications

by Jiukai Tang, Guangyu Qiu and Jing Wang

Chemosensors 2022, 10(1), 15; https://doi.org/10.3390/chemosensors10010015 - 1 Jan 2022

Cited by 24 | Viewed by 5543

Abstract

Optofluidics represents the interaction of light and fluids on a chip that integrates microfluidics and optics, which provides a promising optical platform for manipulating and analyzing fluid samples. Recent years have witnessed a substantial growth in optofluidic devices, including the integration of optical [...] Read more.

Optofluidics represents the interaction of light and fluids on a chip that integrates microfluidics and optics, which provides a promising optical platform for manipulating and analyzing fluid samples. Recent years have witnessed a substantial growth in optofluidic devices, including the integration of optical and fluidic control units, the incorporation of diverse photonic nanostructures, and new applications. All these advancements have enabled the implementation of optofluidics with improved performance. In this review, the recent advances of fabrication techniques and cutting-edge applications of optofluidic devices are presented, with a special focus on the developments of imaging and sensing. Specifically, the optofluidic based imaging techniques and applications are summarized, including the high-throughput cytometry, biochemical analysis, and optofluidic nanoparticle manipulation. The optofluidic sensing section is categorized according to the modulation approaches and the transduction mechanisms, represented by absorption, reflection/refraction, scattering, and plasmonics. Perspectives on future developments and promising avenues in the fields of optofluidics are also provided. Full article

(This article belongs to the Special Issue Nanophotonic Biosensors: Challenges and Development)

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19 pages, 2042 KiB

Open AccessEditor’s ChoiceReview

Molecularly Imprinted Polymers for Chemical Sensing: A Tutorial Review

by Nadja Leibl, Karsten Haupt, Carlo Gonzato and Luminita Duma

Chemosensors 2021, 9(6), 123; https://doi.org/10.3390/chemosensors9060123 - 26 May 2021

Cited by 144 | Viewed by 11821

Abstract

The field of molecularly imprinted polymer (MIP)-based chemosensors has been experiencing constant growth for several decades. Since the beginning, their continuous development has been driven by the need for simple devices with optimum selectivity for the detection of various compounds in fields such [...] Read more.

The field of molecularly imprinted polymer (MIP)-based chemosensors has been experiencing constant growth for several decades. Since the beginning, their continuous development has been driven by the need for simple devices with optimum selectivity for the detection of various compounds in fields such as medical diagnosis, environmental and industrial monitoring, food and toxicological analysis, and, more recently, the detection of traces of explosives or their precursors. This review presents an overview of the main research efforts made so far for the development of MIP-based chemosensors, critically discusses the pros and cons, and gives perspectives for further developments in this field. Full article

(This article belongs to the Section Materials for Chemical Sensing)

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26 pages, 8544 KiB

Open AccessEditor’s ChoiceReview

Current Trends in Polymer Based Sensors

by Giancarla Alberti, Camilla Zanoni, Vittorio Losi, Lisa Rita Magnaghi and Raffaela Biesuz

Chemosensors 2021, 9(5), 108; https://doi.org/10.3390/chemosensors9050108 - 13 May 2021

Cited by 80 | Viewed by 8526

Abstract

This review illustrates various types of polymer and nanocomposite polymeric based sensors used in a wide variety of devices. Moreover, it provides an overview of the trends and challenges in sensor research. As fundamental components of new devices, polymers play an important role [...] Read more.

This review illustrates various types of polymer and nanocomposite polymeric based sensors used in a wide variety of devices. Moreover, it provides an overview of the trends and challenges in sensor research. As fundamental components of new devices, polymers play an important role in sensing applications. Indeed, polymers offer many advantages for sensor technologies: their manufacturing methods are pretty simple, they are relatively low-cost materials, and they can be functionalized and placed on different substrates. Polymers can participate in sensing mechanisms or act as supports for the sensing units. Another good quality of polymer-based materials is that their chemical structure can be modified to enhance their reactivity, biocompatibility, resistance to degradation, and flexibility. Full article

(This article belongs to the Section Materials for Chemical Sensing)

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19 pages, 5198 KiB

Open AccessEditor’s ChoiceReview

Recent Development in Nanomaterial-Based Electrochemical Sensors for Cholesterol Detection

by Hemraj Mahipati Yadav, Jong-Deok Park, Hyeong-Cheol Kang and Jae-Joon Lee

Chemosensors 2021, 9(5), 98; https://doi.org/10.3390/chemosensors9050098 - 29 Apr 2021

Cited by 38 | Viewed by 6761

Abstract

Functional nanomaterials have attracted significant attention in a variety of research fields (in particular, in the healthcare system) because of the easily controllable morphology, their high chemical and environmental stability, biocompatibility, and unique optoelectronic and sensing properties. The sensing properties of nanomaterials can [...] Read more.

Functional nanomaterials have attracted significant attention in a variety of research fields (in particular, in the healthcare system) because of the easily controllable morphology, their high chemical and environmental stability, biocompatibility, and unique optoelectronic and sensing properties. The sensing properties of nanomaterials can be used to detect biomolecules such as cholesterol. Over the past few decades, remarkable progress has been made in the production of cholesterol biosensors that contain nanomaterials as the key component. In this article, various nanomaterials for the electrochemical sensing of cholesterol were reviewed. Cholesterol biosensors are recognized tools in the clinical diagnosis of cardiovascular diseases (CVDs). The function of nanomaterials in cholesterol biosensors were thoroughly discussed. In this study, different pathways for the sensing of cholesterol with functional nanomaterials were investigated. Full article

(This article belongs to the Special Issue Microfluidic Biosensing Platform)

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22 pages, 2707 KiB

Open AccessEditor’s ChoiceReview

Metal Nanoparticle and Quantum Dot Tags for Signal Amplification in Electrochemical Immunosensors for Biomarker Detection

by Anton Popov, Benediktas Brasiunas, Asta Kausaite-Minkstimiene and Almira Ramanaviciene

Chemosensors 2021, 9(4), 85; https://doi.org/10.3390/chemosensors9040085 - 18 Apr 2021

Cited by 33 | Viewed by 6216

Abstract

With the increasing importance of healthcare and clinical diagnosis, as well as the growing demand for highly sensitive analytical instruments, immunosensors have received considerable attention. In this review, electrochemical immunosensor signal amplification strategies using metal nanoparticles (MNPs) and quantum dots (Qdots) as tags [...] Read more.

With the increasing importance of healthcare and clinical diagnosis, as well as the growing demand for highly sensitive analytical instruments, immunosensors have received considerable attention. In this review, electrochemical immunosensor signal amplification strategies using metal nanoparticles (MNPs) and quantum dots (Qdots) as tags are overviewed, focusing on recent developments in the ultrasensitive detection of biomarkers. MNPs and Qdots can be used separately or in combination with other nanostructures, while performing the function of nanocarriers, electroactive labels, or catalysts. Thus, different functions of MNPs and Qdots as well as recent advances in electrochemical signal amplification are discussed. Additionally, the methods most often used for antibody immobilization on nanoparticles, immunoassay formats, and electrochemical methods for indirect biomarker detection are overviewed. Full article

(This article belongs to the Special Issue Electrochemical Immunosensor)

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39 pages, 3803 KiB

Open AccessEditor’s ChoiceReview

Microneedle Arrays for Sampling and Sensing Skin Interstitial Fluid

by Navid Kashaninejad, Ahmed Munaz, Hajar Moghadas, Sharda Yadav, Muhammad Umer and Nam-Trung Nguyen

Chemosensors 2021, 9(4), 83; https://doi.org/10.3390/chemosensors9040083 - 16 Apr 2021

Cited by 79 | Viewed by 14293

Abstract

Dermal interstitial fluid (ISF) is a novel source of biomarkers that can be considered as an alternative to blood sampling for disease diagnosis and treatment. Nevertheless, in vivo extraction and analysis of ISF are challenging. On the other hand, microneedle (MN) technology can [...] Read more.

Dermal interstitial fluid (ISF) is a novel source of biomarkers that can be considered as an alternative to blood sampling for disease diagnosis and treatment. Nevertheless, in vivo extraction and analysis of ISF are challenging. On the other hand, microneedle (MN) technology can address most of the challenges associated with dermal ISF extraction and is well suited for long-term, continuous ISF monitoring as well as in situ detection. In this review, we first briefly summarise the different dermal ISF collection methods and compare them with MN methods. Next, we elaborate on the design considerations and biocompatibility of MNs. Subsequently, the fabrication technologies of various MNs used for dermal ISF extraction, including solid MNs, hollow MNs, porous MNs, and hydrogel MNs, are thoroughly explained. In addition, different sensing mechanisms of ISF detection are discussed in detail. Subsequently, we identify the challenges and propose the possible solutions associated with ISF extraction. A detailed investigation is provided for the transport and sampling mechanism of ISF in vivo. Also, the current in vitro skin model integrated with the MN arrays is discussed. Finally, future directions to develop a point-of-care (POC) device to sample ISF are proposed. Full article

(This article belongs to the Section Analytical Methods, Instrumentation and Miniaturization)

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26 pages, 5315 KiB

Open AccessEditor’s ChoiceReview

Application of PEDOT:PSS and Its Composites in Electrochemical and Electronic Chemosensors

by Nan Gao, Jiarui Yu, Qingyun Tian, Jiangfan Shi, Miao Zhang, Shuai Chen and Ling Zang

Chemosensors 2021, 9(4), 79; https://doi.org/10.3390/chemosensors9040079 - 13 Apr 2021

Cited by 104 | Viewed by 15257

Abstract

Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) is a highly important and attractive conducting polymer as well as commercially available in organic electronics, including electrochemical and electronic chemosensors, due to its unique features such as excellent solution-fabrication capability and miscibility, high and controllable conductivity, excellent chemical and [...] Read more.

Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) is a highly important and attractive conducting polymer as well as commercially available in organic electronics, including electrochemical and electronic chemosensors, due to its unique features such as excellent solution-fabrication capability and miscibility, high and controllable conductivity, excellent chemical and electrochemical stability, good optical transparency and biocompatibility. In this review, we present a comprehensive overview of the recent research progress of PEDOT:PSS and its composites, and the application in electrochemical and electronic sensors for detecting liquid-phase or gaseous chemical analytes, including inorganic or organic ions, pH, humidity, hydrogen peroxide (H₂O₂), ammonia (NH₃), CO, CO₂, NO₂, and organic solvent vapors like methanol, acetone, etc. We will discuss in detail the structural, architectural and morphological optimization of PEDOT:PSS and its composites with other additives, as well as the fabrication technology of diverse sensor systems in response to a wide range of analytes in varying environments. At the end of the review will be given a perspective summary covering both the key challenges and potential solutions in the future research of PEDOT:PSS-based chemosensors, especially those in a flexible or wearable format. Full article

(This article belongs to the Special Issue Chemical and Biosensors: A Theme Issue in Honor of Professor Otto S. Wolfbeis)

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11 pages, 2129 KiB

Open AccessEditor’s ChoiceArticle

Electrochemical Detection of Prostate Cancer Biomarker PCA3 Using Specific RNA-Based Aptamer Labelled with Ferrocene

by Alexei Nabok, Hisham Abu-Ali, Sarra Takita and David P. Smith

Chemosensors 2021, 9(4), 59; https://doi.org/10.3390/chemosensors9040059 - 24 Mar 2021

Cited by 30 | Viewed by 5922

Abstract

This paper reports on a feasibility study of electrochemical in-vitro detection of prostate cancer biomarker PCA3 (prostate cancer antigen 3) in direct assay with specific RNA aptamer labelled with a redox group (ferrocene) and immobilized on a screen-printed gold electrode surface. The cyclic [...] Read more.

This paper reports on a feasibility study of electrochemical in-vitro detection of prostate cancer biomarker PCA3 (prostate cancer antigen 3) in direct assay with specific RNA aptamer labelled with a redox group (ferrocene) and immobilized on a screen-printed gold electrode surface. The cyclic voltammograms and electrochemical impedance spectroscopy methods yield encouraging results on the detection of PCA3 in a range of concentrations from 1 μg/mL down to 0.1 ng/mL in buffer solutions. Both anodic and cathodic current values in cyclic voltammograms measurements and charge transfer resistance values in electrochemical impedance spectroscopy experiments correlate with the PCA3 concentration in the sample. Kinetics studies of the binding of the PCA3 to our aptamer demonstrated high specificity of the reaction with a characteristic affinity constant of approximately

4 \cdot 10^{- 10}

molar. The results of this work provide a background for the future development of novel, highly sensitive and cost-effective diagnostic methodologies for prostate cancer detection. Full article

(This article belongs to the Special Issue Electrochemical Immunosensor)

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26 pages, 1908 KiB

Open AccessEditor’s ChoiceReview

A Review of Microfluidic Detection Strategies for Heavy Metals in Water

by Annija Lace and John Cleary

Chemosensors 2021, 9(4), 60; https://doi.org/10.3390/chemosensors9040060 - 24 Mar 2021

Cited by 54 | Viewed by 10335

Abstract

Heavy metal pollution of water has become a global issue and is especially problematic in some developing countries. Heavy metals are toxic to living organisms, even at very low concentrations. Therefore, effective and reliable heavy metal detection in environmental water is very important. [...] Read more.

Heavy metal pollution of water has become a global issue and is especially problematic in some developing countries. Heavy metals are toxic to living organisms, even at very low concentrations. Therefore, effective and reliable heavy metal detection in environmental water is very important. Current laboratory-based methods used for analysis of heavy metals in water require sophisticated instrumentation and highly trained technicians, making them unsuitable for routine heavy metal monitoring in the environment. Consequently, there is a growing demand for autonomous detection systems that could perform in situ or point-of-use measurements. Microfluidic detection systems, which are defined by their small size, have many characteristics that make them suitable for environmental analysis. Some of these advantages include portability, high sample throughput, reduced reagent consumption and waste generation, and reduced production cost. This review focusses on developments in the application of microfluidic detection systems to heavy metal detection in water. Microfluidic detection strategies based on optical techniques, electrochemical techniques, and quartz crystal microbalance are discussed. Full article

(This article belongs to the Special Issue Colorimetric Sensors and Biosensors for Healthcare, Food Safety, Environmental Monitoring and Biosecurity Applications)

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20 pages, 658 KiB

Open AccessEditor’s ChoiceReview

Gas Sensors Based on Copper Oxide Nanomaterials: A Review

by Stephan Steinhauer

Chemosensors 2021, 9(3), 51; https://doi.org/10.3390/chemosensors9030051 - 5 Mar 2021

Cited by 173 | Viewed by 13924

Abstract

Metal oxide semiconductors have found widespread applications in chemical sensors based on electrical transduction principles, in particular for the detection of a large variety of gaseous analytes, including environmental pollutants and hazardous gases. This review recapitulates the progress in copper oxide nanomaterial-based devices, [...] Read more.

Metal oxide semiconductors have found widespread applications in chemical sensors based on electrical transduction principles, in particular for the detection of a large variety of gaseous analytes, including environmental pollutants and hazardous gases. This review recapitulates the progress in copper oxide nanomaterial-based devices, while discussing decisive factors influencing gas sensing properties and performance. Literature reports on the highly sensitive detection of several target molecules, including volatile organic compounds, hydrogen sulfide, carbon monoxide, carbon dioxide, hydrogen and nitrogen oxide from parts-per-million down to parts-per-billion concentrations are compared. Physico-chemical mechanisms for sensing and transduction are summarized and prospects for future developments are outlined. Full article

(This article belongs to the Section Nanostructures for Chemical Sensing)

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41 pages, 15347 KiB

Open AccessEditor’s ChoiceReview

Metal–Oxide Nanowire Molecular Sensors and Their Promises

by Hao Zeng, Guozhu Zhang, Kazuki Nagashima, Tsunaki Takahashi, Takuro Hosomi and Takeshi Yanagida

Chemosensors 2021, 9(2), 41; https://doi.org/10.3390/chemosensors9020041 - 22 Feb 2021

Cited by 32 | Viewed by 7664

Abstract

During the past two decades, one–dimensional (1D) metal–oxide nanowire (NW)-based molecular sensors have been witnessed as promising candidates to electrically detect volatile organic compounds (VOCs) due to their high surface to volume ratio, single crystallinity, and well-defined crystal orientations. Furthermore, these unique physical/chemical [...] Read more.

During the past two decades, one–dimensional (1D) metal–oxide nanowire (NW)-based molecular sensors have been witnessed as promising candidates to electrically detect volatile organic compounds (VOCs) due to their high surface to volume ratio, single crystallinity, and well-defined crystal orientations. Furthermore, these unique physical/chemical features allow the integrated sensor electronics to work with a long-term stability, ultra-low power consumption, and miniature device size, which promote the fast development of “trillion sensor electronics” for Internet of things (IoT) applications. This review gives a comprehensive overview of the recent studies and achievements in 1D metal–oxide nanowire synthesis, sensor device fabrication, sensing material functionalization, and sensing mechanisms. In addition, some critical issues that impede the practical application of the 1D metal–oxide nanowire-based sensor electronics, including selectivity, long-term stability, and low power consumption, will be highlighted. Finally, we give a prospective account of the remaining issues toward the laboratory-to-market transformation of the 1D nanostructure-based sensor electronics. Full article

(This article belongs to the Special Issue Nanomaterials-Based Sensors)

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17 pages, 1161 KiB

Open AccessEditor’s ChoiceReview

Recent Advances in Optical, Electrochemical and Field Effect pH Sensors

by Federico Vivaldi, Pietro Salvo, Noemi Poma, Andrea Bonini, Denise Biagini, Lorenzo Del Noce, Bernardo Melai, Fabio Lisi and Fabio Di Francesco

Chemosensors 2021, 9(2), 33; https://doi.org/10.3390/chemosensors9020033 - 5 Feb 2021

Cited by 54 | Viewed by 9361

Abstract

Although its first definition dates back to more than a century ago, pH and its measurement are still studied for improving the performance of current sensors in everyday analysis. The gold standard is the glass electrode, but its intrinsic fragility and need of [...] Read more.

Although its first definition dates back to more than a century ago, pH and its measurement are still studied for improving the performance of current sensors in everyday analysis. The gold standard is the glass electrode, but its intrinsic fragility and need of frequent calibration are pushing the research field towards alternative sensitive devices and materials. In this review, we describe the most recent optical, electrochemical, and transistor-based sensors to provide an overview on the status of the scientific efforts towards pH sensing. Full article

(This article belongs to the Collection pH Sensors, Biosensors and Systems)

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12 pages, 4168 KiB

Open AccessEditor’s ChoiceArticle

Development of an ImmunoFET for Analysis of Tumour Necrosis Factor-α in Artificial Saliva: Application for Heart Failure Monitoring

by Daiva Vozgirdaite, Hamdi Ben Halima, Francesca G. Bellagambi, Albert Alcacer, Francisio Palacio, Nicole Jaffrezic-Renault, Nadia Zine, Joan Bausells, Abdelhamid Elaissari and Abdelhamid Errachid

Chemosensors 2021, 9(2), 26; https://doi.org/10.3390/chemosensors9020026 - 29 Jan 2021

Cited by 29 | Viewed by 6154

Abstract

Assessing tumour necrosis factor-α (TNF-α) levels in the human body has become an essential tool to recognize heart failure (HF). In this work, label-free, rapid, easy to use ImmunoFET based on an ion-sensitive field effect transistor (ISFET) was developed for the detection of [...] Read more.

Assessing tumour necrosis factor-α (TNF-α) levels in the human body has become an essential tool to recognize heart failure (HF). In this work, label-free, rapid, easy to use ImmunoFET based on an ion-sensitive field effect transistor (ISFET) was developed for the detection of TNF-α protein. Monoclonal anti-TNF-α antibodies (anti-TNF-α mAb) were immobilized on an ISFET gate made of silicon nitride (Si₃N₄) after salinization with 11-(triethoxysilyl) undecanal (TESUD). The obtained ISFET functionalized with the mAbs (ImmunoFET) was used to detect TNF-α protein in both phosphate buffer saline (PBS) and artificial saliva (AS). The change in the threshold voltage of the gate (∆V_T) showed approximately linear dependency on the concentration of the antigens in the range 5–20 pg/mL for both matrixes. The cross-selectivity study showed that the developed ImmunoFET demonstrated to be selective towards TNF-α, when compared to other HF biomarkers such as N-terminal pro-brain natriuretic peptide (NT-proBNP), interleukin-10 (IL-10), and cortisol, even if further experiments have to be carried out for decreasing possible unspecific absorption phenomena. To the best of our knowledge, this is the first ImmunoFET that has been developed based on Si₃N₄ for TNF-α detection in AS by electrical measurement. Full article

(This article belongs to the Section Applied Chemical Sensors)

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13 pages, 3027 KiB

Open AccessEditor’s ChoiceArticle

Carbon Dots Fluorescence-Based Colorimetric Sensor for Sensitive Detection of Aluminum Ions with a Smartphone

by Wei Wei, Juan Huang, Wenli Gao, Xiangyang Lu and Xingbo Shi

Chemosensors 2021, 9(2), 25; https://doi.org/10.3390/chemosensors9020025 - 29 Jan 2021

Cited by 37 | Viewed by 5712

Abstract

In this work, blue emission carbon dots (CDs) are synthesized in the one-pot solvothermal method using naringin as precursor. The CDs are used to develop a ratiometric fluorescence sensor for the sensitive analysis of Al³⁺ with a detection limit of 113.8 nM. [...] Read more.

In this work, blue emission carbon dots (CDs) are synthesized in the one-pot solvothermal method using naringin as precursor. The CDs are used to develop a ratiometric fluorescence sensor for the sensitive analysis of Al³⁺ with a detection limit of 113.8 nM. A fluorescence emission peak at 500 nm gradually appears, whereas the original fluorescence peak at 420 nm gradually decreases upon the increase in the Al³⁺ concentration. More importantly, the obvious color change of the CDs probe from blue to green under a 360 nm UV lamp can be identified by a smartphone and combined with the RGB (red/green/blue) analysis. This results in a visual and sensitive analysis of Al³⁺ with a detection limit of 5.55 μM. Moreover, the high recovery is in the 92.46–104.10% range, which demonstrates the high accuracy of this method for actual samples’ analysis. The use of a smartphone and the RGB analysis greatly simplifies the operation process, saves equipment cost, shortens the detection time, and provides a novel method for the instant, on-site, visual detection of Al³⁺ in actual samples. Full article

(This article belongs to the Special Issue Near-Infrared Fluorophores for Biomedical Research)

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21 pages, 5499 KiB

Open AccessEditor’s ChoiceReview

Electrochemical Impedance Spectroscopy on 2D Nanomaterial MXene Modified Interfaces: Application as a Characterization and Transducing Tool

by Juvissan Aguedo, Lenka Lorencova, Marek Barath, Pavol Farkas and Jan Tkac

Chemosensors 2020, 8(4), 127; https://doi.org/10.3390/chemosensors8040127 - 7 Dec 2020

Cited by 55 | Viewed by 9674

Abstract

This review presents the basic characteristics of MXene, a novel 2D nanomaterial with many outstanding properties applicable to electrochemical sensing and biosensing. The second part deals with electrochemical impedance spectroscopy (EIS) and its beneficial features applicable to ultrasensitive electrochemical sensing and label-free biosensing. [...] Read more.

This review presents the basic characteristics of MXene, a novel 2D nanomaterial with many outstanding properties applicable to electrochemical sensing and biosensing. The second part deals with electrochemical impedance spectroscopy (EIS) and its beneficial features applicable to ultrasensitive electrochemical sensing and label-free biosensing. The main part of the review presents recent advances in the integration of MXene to design electrochemical interfaces. EIS was used to evaluate the effect of anodic potential on MXene and the effect of the MXene preparation route and for characterization of MXene grafted with polymers. It also included the application of EIS as the main transducing tool for antibody- and aptamer-based biosensors or biosensors integrating molecularly imprinted polymers. Full article

(This article belongs to the Special Issue Analytical (Chem and Bio)sensors Based on EIS Measurements)

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17 pages, 4881 KiB

Open AccessEditor’s ChoiceArticle

Graphene Oxide as a Sensing Material for Gas Detection Based on Nanomechanical Sensors in the Static Mode

by Gaku Imamura, Kosuke Minami, Kota Shiba, Kissan Mistry, Kevin P. Musselman, Mustafa Yavuz, Genki Yoshikawa, Koichiro Saiki and Seiji Obata

Chemosensors 2020, 8(3), 82; https://doi.org/10.3390/chemosensors8030082 - 2 Sep 2020

Cited by 28 | Viewed by 7400

Abstract

Graphene is a key material for gas sensing applications owing to its high specific surface area and vast chemical modification potential. To fully utilize the potential of graphene, a sensing platform independent of conductive properties is required. In this study, we employed membrane-type [...] Read more.

Graphene is a key material for gas sensing applications owing to its high specific surface area and vast chemical modification potential. To fully utilize the potential of graphene, a sensing platform independent of conductive properties is required. In this study, we employed membrane-type surface stress sensors (MSS)—A kind of nanomechanical sensor operated in the static mode—As a sensing platform and utilized graphene oxide (GO) as a gas sensing material. MSS detect surface stress caused by gas sorption; therefore, chemically modified graphene with low conductivity can be utilized as a gas sensing material. We evaluated the sensing performance of a GO-coated MSS by measuring its responses to five gases. We demonstrated with the GO-coated MSS the feasibility of GO as a gas sensing material for static mode nanomechanical sensors and revealed its high selectivity to water vapor. Moreover, we investigated the sensing mechanism of the GO-coated MSS by comparing it with the sensing performance of MSS coated with reduced graphene oxide and graphite powder and deduced key factors for sensitivity and selectivity. Considering the high sensitivity of the GO-coated MSS and the compact measurement system that MSS can realize, the present study provides a new perspective on the sensing applications of graphene. Full article

(This article belongs to the Section Materials for Chemical Sensing)

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11 pages, 2388 KiB

Open AccessEditor’s ChoiceArticle

Molecular Imprinted Based Quartz Crystal Microbalance Sensors for Bacteria and Spores

by Usman Latif, Serpil Can, Hermann F. Sussitz and Franz L. Dickert

Chemosensors 2020, 8(3), 64; https://doi.org/10.3390/chemosensors8030064 - 4 Aug 2020

Cited by 18 | Viewed by 4197

Abstract

A molecular imprinting strategy was combined with mass-sensitive transducers to generate robust and reliable biomimetic sensor systems for the detection of bioparticles. The patterning of polymers with bioanalytes enabled us to detect Escherichia coli (E. coli) bacteria with quartz crystal microbalance [...] Read more.

A molecular imprinting strategy was combined with mass-sensitive transducers to generate robust and reliable biomimetic sensor systems for the detection of bioparticles. The patterning of polymers with bioanalytes enabled us to detect Escherichia coli (E. coli) bacteria with quartz crystal microbalance (QCM). The QCM sensor results were compared with direct Atomic Force Microscopy (AFM) measurements—bacteria cells adhering to the sensor coatings were counted. The recognition sites generated by Bacillus subtilis (B. subtilis) spores could successfully and reversibly recognize the template analyte and ensured rapid sensing. Cross sensitive measurements clearly showed the advantage of the molecular imprinting strategy, by which spores of Bacillus species (subtilis and thuringiensis) could easily be differentiated and selectively detected. The growth of B. subtilis from its spores was observed at 42 °C in appropriate nutrient solution of glucose and ammonium sulfate over a period of 15 h. Moreover, the growth of B. subtilis bacteria from its respective spores was studied by increasing the glucose concentration until saturation effect of the sensor. The polymeric sensor coatings were patterned to fix the B. subtilis in order to investigate osmotic effects according to a frequency response of 400 Hz by altering the ionic strength of 0.1 M. Full article

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23 pages, 9902 KiB

Open AccessEditor’s ChoiceReview

Macrocyclic Arenes Functionalized with BODIPY: Rising Stars among Chemosensors and Smart Materials

by Jianjun Huang, Yuyu Fang and Wim Dehaen

Chemosensors 2020, 8(3), 51; https://doi.org/10.3390/chemosensors8030051 - 6 Jul 2020

Cited by 18 | Viewed by 6797

Abstract

Macrocycles play a crucial role in supramolecular chemistry and the family of macrocyclic arenes represents one of the most important types of hosts. Among them, calixarenes, resorcinarenes and pillararenes are the most commonly encountered macrocyclic arenes, and they have received considerable attention. Boron-dipyrromethene [...] Read more.

Macrocycles play a crucial role in supramolecular chemistry and the family of macrocyclic arenes represents one of the most important types of hosts. Among them, calixarenes, resorcinarenes and pillararenes are the most commonly encountered macrocyclic arenes, and they have received considerable attention. Boron-dipyrromethene (BODIPY) dyes are fascinating compounds with multiple functionalization sites and outstanding luminescence properties including high fluorescence quantum yields, large molar absorption coefficients and remarkable photo- and chemical stability. The combination of macrocyclic arenes and BODIPY dyes has been demonstrated to be an effective strategy to construct chemosensors for various guests and smart materials with tailored properties. Herein, we firstly summarize the recent advances made so far in macrocyclic arenes substituted with BODIPY. This review only focuses on the three macrocyclic arenes of calixarenes, resorcinarenes and pillararenes, as there are no other macrocyclic arenes substituted BODIPY units at the present time. Hopefully, this review will not only afford a guide and useful information for those who are interested in developing novel chemosensors and smart materials, but also inspire new opportunities in this field. Full article

(This article belongs to the Special Issue Organic Fluorescent Materials as Chemical Sensors)

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18 pages, 3230 KiB

Open AccessEditor’s ChoiceArticle

Chemical and Temperature Sensors Based on Functionalized Reduced Graphene Oxide

by Esteban Araya-Hermosilla, Matteo Minichino, Virgilio Mattoli and Andrea Pucci

Chemosensors 2020, 8(2), 43; https://doi.org/10.3390/chemosensors8020043 - 21 Jun 2020

Cited by 6 | Viewed by 4848

Abstract

In this work, we investigated the functionalization of reduced graphene oxide (rGO) with 2-(dodecen-1-yl) succinic anhydride (TPSA) to increase the rGO effective interactions with organic solvents both in liquid and vapor phases. Thermogravimetric analysis, STEM, XPS, FTIR-ATR, and Raman spectroscopy confirmed the effective [...] Read more.

In this work, we investigated the functionalization of reduced graphene oxide (rGO) with 2-(dodecen-1-yl) succinic anhydride (TPSA) to increase the rGO effective interactions with organic solvents both in liquid and vapor phases. Thermogravimetric analysis, STEM, XPS, FTIR-ATR, and Raman spectroscopy confirmed the effective functionalization of rGO with about the 30 wt% of grafted TPSA without affecting the structural characteristics of graphene but successfully enhancing its dispersibility in the selected solvent except for the apolar hexane. Solid TPSA-rGO dispersions displayed a reproducible semiconducting (activated) electrical transport with decreased resistance when heated from 20 °C to 60 °C and with a negative temperature coefficient of 10⁻³ K⁻¹, i.e., comparable in absolute value with temperature coefficient in metals. It is worth noting that the same solid dispersions showed electrical resistance variation upon exposure to vapors with a detection limit in the order of 10 ppm and sensitivity α of about 10⁻⁴ ppm⁻¹. Full article

(This article belongs to the Section Materials for Chemical Sensing)

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11 pages, 1811 KiB

Open AccessEditor’s ChoiceArticle

Electrochemical Aptasensor for Detection of Dopamine

by Hisham Abu-Ali, Cansu Ozkaya, Frank Davis, Nik Walch and Alexei Nabok

Chemosensors 2020, 8(2), 28; https://doi.org/10.3390/chemosensors8020028 - 15 Apr 2020

Cited by 31 | Viewed by 7628

Abstract

This work presents a proof of concept of a novel, simple, and sensitive method of detection of dopamine, a neurotransmitter within the human brain. We propose a simple electrochemical method for the detection of dopamine using a dopamine-specific aptamer labeled with an electrochemically [...] Read more.

This work presents a proof of concept of a novel, simple, and sensitive method of detection of dopamine, a neurotransmitter within the human brain. We propose a simple electrochemical method for the detection of dopamine using a dopamine-specific aptamer labeled with an electrochemically active ferrocene tag. Aptamers immobilized on the surface of gold screen-printed gold electrodes via thiol groups can change their secondary structure by wrapping around the target molecule. As a result, the ferrocene labels move closer to the electrode surface and subsequently increase the electron transfer. The cyclic voltammograms and impedance spectra recorded on electrodes in buffer solutions containing different concentration of dopamine showed, respectively, the increase in both the anodic and cathodic currents and decrease in the double layer resistance upon increasing the concentration of dopamine from 0.1 to 10 nM L⁻¹. The high affinity of aptamer-dopamine binding (KD ≈ 5 nM) was found by the analysis of the binding kinetics. The occurrence of aptamer-dopamine binding was directly confirmed with spectroscopic ellipsometry measurements. Full article

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29 pages, 5419 KiB

Open AccessEditor’s ChoiceReview

Silver Nanoparticles as Colorimetric Sensors for Water Pollutants

by Paolo Prosposito, Luca Burratti and Iole Venditti

Chemosensors 2020, 8(2), 26; https://doi.org/10.3390/chemosensors8020026 - 31 Mar 2020

Cited by 168 | Viewed by 18576

Abstract

This review provides an up-to-date overview on silver nanoparticles-based materials suitable as optical sensors for water pollutants. The topic is really hot considering the implications for human health and environment due to water pollutants. In fact, the pollutants present in the water disturb [...] Read more.

This review provides an up-to-date overview on silver nanoparticles-based materials suitable as optical sensors for water pollutants. The topic is really hot considering the implications for human health and environment due to water pollutants. In fact, the pollutants present in the water disturb the spontaneity of life-related mechanisms, such as the synthesis of cellular constituents and the transport of nutrients into cells, and this causes long / short-term diseases. For this reason, research continuously tends to develop always innovative, selective and efficient processes / technologies to remove pollutants from water. In this paper we will report on the silver nanoparticles synthesis, paying attention to the stabilizers and mostly used ligands, to the characterizations, to the properties and applications as colorimetric sensors for water pollutants. As water pollutants our attention will be focused on several heavy metals ions, such as Hg(II), Ni(II),Cu(II), Fe(III), Mn(II), Cr(III/V) Co(II) Cd(II), Pb(II), due to their dangerous effects on human health. In addition, several systems based on silver nanoparticles employed as pesticides colorimetric sensors in water will be also discussed. All of this with the aim to provide to readers a guide about recent advanced silver nanomaterials, used as colorimetric sensors in water. Full article

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19 pages, 2174 KiB

Open AccessEditor’s ChoiceReview

Heavy Metal/Toxins Detection Using Electronic Tongues

by Flavio M. Shimizu, Maria L. Braunger and Antonio Riul

Chemosensors 2019, 7(3), 36; https://doi.org/10.3390/chemosensors7030036 - 2 Aug 2019

Cited by 53 | Viewed by 6352

Abstract

The growing concern for sustainability and environmental preservation has increased the demand for reliable, fast response, and low-cost devices to monitor the existence of heavy metals and toxins in water resources. An electronic tongue (e-tongue) is a multisensory array mostly based on electroanalytical [...] Read more.

The growing concern for sustainability and environmental preservation has increased the demand for reliable, fast response, and low-cost devices to monitor the existence of heavy metals and toxins in water resources. An electronic tongue (e-tongue) is a multisensory array mostly based on electroanalytical methods and multivariate statistical techniques to facilitate information visualization in a qualitative and/or quantitative way. E-tongues are promising analytical devices having simple operation, fast response, low cost, easy integration with other systems (microfluidic, optical, etc) to enable miniaturization and provide a high sensitivity for measurements in complex liquid media, providing an interesting alternative to address many of the existing environmental monitoring challenges, specifically relevant emerging pollutants such as heavy metals and toxins. Full article

(This article belongs to the Special Issue Chemical Sensors for Heavy Metals/Toxin Detection)

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14 pages, 2239 KiB

Open AccessEditor’s ChoiceArticle

Development of Novel and Highly Specific ssDNA-Aptamer-Based Electrochemical Biosensor for Rapid Detection of Mercury (II) and Lead (II) Ions in Water

by Hisham Abu-Ali, Alexei Nabok and Thomas J. Smith

Chemosensors 2019, 7(2), 27; https://doi.org/10.3390/chemosensors7020027 - 4 Jun 2019

Cited by 54 | Viewed by 9480

Abstract

In this work, we report on the development of an electrochemical biosensor for high selectivity and rapid detection of Hg²⁺ and Pb²⁺ ions using DNA-based specific aptamer probes labeled with ferrocene (or methylene blue) and thiol groups at their 5′ and [...] Read more.

In this work, we report on the development of an electrochemical biosensor for high selectivity and rapid detection of Hg²⁺ and Pb²⁺ ions using DNA-based specific aptamer probes labeled with ferrocene (or methylene blue) and thiol groups at their 5′ and 3′ termini, respectively. Aptamers were immobilized onto the surface of screen-printed gold electrodes via the SH (thiol) groups, and then cyclic voltammetry and impedance spectra measurements were performed in buffer solutions with the addition of HgCl₂ and PbCl₂ salts at different concentrations. Changes in 3D conformation of aptamers, caused by binding their respective targets, e.g., Hg²⁺ and Pb²⁺ ions, were accompanied by an increase in the electron transfer between the redox label and the electrode. Accordingly, the presence of the above ions can be detected electrochemically. The detection of Hg²⁺ and Pb²⁺ ions in a wide range of concentrations as low as 0.1 ng/mL (or 0.1 ppb) was achieved. The study of the kinetics of aptamer/heavy metal ions binding gave the values of the affinity constants of approximately 9.10⁻⁷ mol, which proved the high specificity of the aptamers used. Full article

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23 pages, 1386 KiB

Open AccessEditor’s ChoiceReview

Thin Films Sensor Devices for Mycotoxins Detection in Foods: Applications and Challenges

by Andréia O. Santos, Andreia Vaz, Paula Rodrigues, Ana C. A. Veloso, Armando Venâncio and António M. Peres

Chemosensors 2019, 7(1), 3; https://doi.org/10.3390/chemosensors7010003 - 4 Jan 2019

Cited by 27 | Viewed by 7236

Abstract

Mycotoxins are a group of secondary metabolites produced by different species of filamentous fungi and pose serious threats to food safety due to their serious human and animal health impacts such as carcinogenic, teratogenic and hepatotoxic effects. Conventional methods for the detection of [...] Read more.

Mycotoxins are a group of secondary metabolites produced by different species of filamentous fungi and pose serious threats to food safety due to their serious human and animal health impacts such as carcinogenic, teratogenic and hepatotoxic effects. Conventional methods for the detection of mycotoxins include gas chromatography and high-performance liquid chromatography coupled with mass spectrometry or other detectors (fluorescence or UV detection), thin layer chromatography and enzyme-linked immunosorbent assay. These techniques are generally straightforward and yield reliable results; however, they are time-consuming, require extensive preparation steps, use large-scale instruments, and consume large amounts of hazardous chemical reagents. Rapid detection of mycotoxins is becoming an increasingly important challenge for the food industry in order to effectively enforce regulations and ensure the safety of food and feed. In this sense, several studies have been done with the aim of developing strategies to detect mycotoxins using sensing devices that have high sensitivity and specificity, fast analysis, low cost and portability. The latter include the use of microarray chips, multiplex lateral flow, Surface Plasmon Resonance, Surface Enhanced Raman Scattering and biosensors using nanoparticles. In this perspective, thin film sensors have recently emerged as a good candidate technique to meet such requirements. This review summarizes the application and challenges of thin film sensor devices for detection of mycotoxins in food matrices. Full article

(This article belongs to the Special Issue Thin Film Based Sensors)

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14 pages, 5514 KiB

Open AccessEditor’s ChoiceArticle

Real-Time Frequency Tracking of an Electro-Thermal Piezoresistive Cantilever Resonator with ZnO Nanorods for Chemical Sensing

by Andi Setiono, Jiushuai Xu, Michael Fahrbach, Maik Bertke, Wilson Ombati Nyang’au, Hutomo Suryo Wasisto and Erwin Peiner

Chemosensors 2019, 7(1), 2; https://doi.org/10.3390/chemosensors7010002 - 3 Jan 2019

Cited by 20 | Viewed by 7156

Abstract

The asymmetric resonance response in electro-thermal piezoresistive cantilever resonators causes a need of an optimization treatment for taking parasitic actuation-sensing effects into account. An electronic reference circuit for signal subtraction, integrated with the cantilever resonator has the capability to reduce the effect of [...] Read more.

The asymmetric resonance response in electro-thermal piezoresistive cantilever resonators causes a need of an optimization treatment for taking parasitic actuation-sensing effects into account. An electronic reference circuit for signal subtraction, integrated with the cantilever resonator has the capability to reduce the effect of parasitic coupling. Measurement results demonstrated that a symmetric amplitude shape (Lorentzian) and an optimized phase characteristic (i.e., monotonically decreasing) were successfully extracted from an asymmetric resonance response. With the monotonic phase response, real-time frequency tracking can be easier to implement using a phase-locked loop (PLL) system. In this work, an electro-thermal piezoresistive cantilever resonator functionalized with self-assembled monolayers of chitosan-covered ZnO nanorod arrays as sensitive layers has been investigated under different relative humidity (rH) levels. Enhancement of resonance phase response has been demonstrated by implementing the reference signal subtraction. Subsequently, a lock-in amplifier integrated with PLL system (MFLI, Zurich Instruments, Zurich, Switzerland) was then employed for continuously tracking the resonant frequency. As a result, we find a good correlation of frequency shift (∆f₀) with change in rH monitored using a commercial reference sensor. Full article

(This article belongs to the Special Issue Nanotechnology Efforts for Chemical Sensors)

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17 pages, 3173 KiB

Open AccessEditor’s ChoiceReview

Advances on Sensors Based on Carbon Nanotubes

by Luca Camilli and Maurizio Passacantando

Chemosensors 2018, 6(4), 62; https://doi.org/10.3390/chemosensors6040062 - 6 Dec 2018

Cited by 142 | Viewed by 10632

Abstract

Carbon nanotubes have been attracting considerable interest among material scientists, physicists, chemists, and engineers for almost 30 years. Owing to their high aspect ratio, coupled with remarkable mechanical, electronic, and thermal properties, carbon nanotubes have found application in diverse fields. In this review, [...] Read more.

Carbon nanotubes have been attracting considerable interest among material scientists, physicists, chemists, and engineers for almost 30 years. Owing to their high aspect ratio, coupled with remarkable mechanical, electronic, and thermal properties, carbon nanotubes have found application in diverse fields. In this review, we will cover the work on carbon nanotubes used for sensing applications. In particular, we will see examples where carbon nanotubes act as main players in devices sensing biomolecules, gas, light or pressure changes. Furthermore, we will discuss how to improve the performance of carbon nanotube-based sensors after proper modification. Full article

(This article belongs to the Special Issue Carbon Nanotube Sensors)

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13 pages, 2568 KiB

Open AccessEditor’s ChoiceArticle

Nanostructured Nickel on Porous Carbon-Silica Matrix as an Efficient Electrocatalytic Material for a Non-Enzymatic Glucose Sensor

by Nassim Zahmouli, Silvia Marini, Mouna Guediri, Nabil Ben Mansour, Mokhtar Hjiri, Lassaad El Mir, Claudia Espro, Giovanni Neri and Salvatore Gianluca Leonardi

Chemosensors 2018, 6(4), 54; https://doi.org/10.3390/chemosensors6040054 - 16 Nov 2018

Cited by 19 | Viewed by 4871

Abstract

Nanostructured nickel on porous carbon-silica matrix (N-CS) has been synthesized using a sol gel process and subsequent pyrolysis treatment at a temperature of 650 °C. The morphology and microstructure of the N-CS sample has been investigated using XRD (X-ray Diffraction), SEM-EDS (Scanning Electron [...] Read more.

Nanostructured nickel on porous carbon-silica matrix (N-CS) has been synthesized using a sol gel process and subsequent pyrolysis treatment at a temperature of 650 °C. The morphology and microstructure of the N-CS sample has been investigated using XRD (X-ray Diffraction), SEM-EDS (Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy), and BET (Brunauer-Emmett-Teller) analysis. The synthesized nanocomposite has been used for developing NCS-modified screen-printed electrodes (NCS-SPCEs) and was applied in the electrochemical monitoring of glucose. After electrochemical activation, via cycling the modified electrode in a potential window from 0 to 0.8 V in 0.1 M KOH solution, the fabricated NCS-SPCEs electrodes were evaluated for the voltammetric and amperometric determination of glucose. The developed sensors showed good sensing performance towards glucose, displaying a sensitivity of 585 µA/mM cm⁻¹ in the linear range from 0.05 to 1.5 mM, a detection limit lower than 30 µM with excellent selectivity. Full article

(This article belongs to the Special Issue Nanotechnology Efforts for Chemical Sensors)

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16 pages, 1295 KiB

Open AccessEditor’s ChoiceReview

From Gas Sensors to Biomimetic Artificial Noses

by Paolo Pelosi, Jiao Zhu and Wolfgang Knoll

Chemosensors 2018, 6(3), 32; https://doi.org/10.3390/chemosensors6030032 - 7 Aug 2018

Cited by 47 | Viewed by 7355

Abstract

Since the first attempts to mimic the human nose with artificial devices, a variety of sensors have been developed, ranging from simple inorganic and organic gas detectors to biosensing elements incorporating proteins of the biological olfactory system. In order to design a device [...] Read more.

Since the first attempts to mimic the human nose with artificial devices, a variety of sensors have been developed, ranging from simple inorganic and organic gas detectors to biosensing elements incorporating proteins of the biological olfactory system. In order to design a device able to mimic the human nose, two major issues still need to be addressed regarding the complexity of olfactory coding and the extreme sensitivity of the biological system. So far, only 50 of the approximately 300–400 functioning olfactory receptors have been de-orphanized, still a long way from breaking the human olfactory code. On the other hand, the exceptional sensitivity of the human nose is based on amplification mechanisms difficult to reproduce with electronic circuits, and perhaps novel approaches are required to address this issue. Here, we review the recent literature on chemical sensing both in biological systems and artificial devices, and try to establish the state-of-the-art towards the design of an electronic nose. Full article

(This article belongs to the Special Issue Electronic nose’s, Machine Olfaction and Electronic Tongue’s)

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21 pages, 8255 KiB

Open AccessEditor’s ChoiceReview

Metal Oxide Nanostructures in Food Applications: Quality Control and Packaging

by Vardan Galstyan, Manohar P. Bhandari, Veronica Sberveglieri, Giorgio Sberveglieri and Elisabetta Comini

Chemosensors 2018, 6(2), 16; https://doi.org/10.3390/chemosensors6020016 - 14 Apr 2018

Cited by 103 | Viewed by 11917

Abstract

Metal oxide materials have been applied in different fields due to their excellent functional properties. Metal oxides nanostructuration, preparation with the various morphologies, and their coupling with other structures enhance the unique properties of the materials and open new perspectives for their application [...] Read more.

Metal oxide materials have been applied in different fields due to their excellent functional properties. Metal oxides nanostructuration, preparation with the various morphologies, and their coupling with other structures enhance the unique properties of the materials and open new perspectives for their application in the food industry. Chemical gas sensors that are based on semiconducting metal oxide materials can detect the presence of toxins and volatile organic compounds that are produced in food products due to their spoilage and hazardous processes that may take place during the food aging and transportation. Metal oxide nanomaterials can be used in food processing, packaging, and the preservation industry as well. Moreover, the metal oxide-based nanocomposite structures can provide many advantageous features to the final food packaging material, such as antimicrobial activity, enzyme immobilization, oxygen scavenging, mechanical strength, increasing the stability and the shelf life of food, and securing the food against humidity, temperature, and other physiological factors. In this paper, we review the most recent achievements on the synthesis of metal oxide-based nanostructures and their applications in food quality monitoring and active and intelligent packaging. Full article

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13 pages, 2632 KiB

Open AccessEditor’s ChoiceReview

Spectroscopic Chemical Sensing and Imaging: From Plants to Animals and Humans

by Pietro Strobbia, Ren A. Odion and Tuan Vo-Dinh

Chemosensors 2018, 6(1), 11; https://doi.org/10.3390/chemosensors6010011 - 26 Feb 2018

Cited by 21 | Viewed by 5712

Abstract

Chemical sensing and imaging technologies are of great importance in medical diagnostics and environmental sensing due to their ability to detect and localize chemical targets and provide valuable information in real-time. Biophotonic techniques are the most promising for in vivo applications due to [...] Read more.

Chemical sensing and imaging technologies are of great importance in medical diagnostics and environmental sensing due to their ability to detect and localize chemical targets and provide valuable information in real-time. Biophotonic techniques are the most promising for in vivo applications due to their minimal invasivity. Our laboratory has introduced various biophotonics-based technologies for chemical sensing and imaging for biochemical sensing, medical diagnostics, and fundamental research. Over the years, we have developed a wide variety of fluorescence and surface-enhanced Raman scattering (SERS)-based technologies for the detection of biomarkers for cancer and other diseases. This paper provides an overview of the research on chemical and biological sensors developed in our laboratory, highlighting our work on in vivo imaging and sensing, including minimally invasive detection of endogenous fluorophores associated with malignant tissue, SERS-tag localization of cancer cells and tissues, and SERS-based detection of nucleic acid biotargets and its feasibility for in vivo applications. This manuscript also presents new development on the use of Raman imaging of SERS-labeled nanoprobes incubated in leaves for use in biofuel research, laying the foundation for studies on functional imaging of nucleic acid biomarkers in plants. Full article

(This article belongs to the Special Issue Advances in Chemical Imaging and its Applications)

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24 pages, 3220 KiB

Open AccessEditor’s ChoiceReview

Recent Advances in the Detection of Neurotransmitters

by Bo Si and Edward Song

Chemosensors 2018, 6(1), 1; https://doi.org/10.3390/chemosensors6010001 - 4 Jan 2018

Cited by 157 | Viewed by 21039

Abstract

Neurotransmitters are chemicals that act as messengers in the synaptic transmission process. They are essential for human health and any imbalance in their activities can cause serious mental disorders such as Parkinson’s disease, schizophrenia, and Alzheimer’s disease. Hence, monitoring the concentrations of various [...] Read more.

Neurotransmitters are chemicals that act as messengers in the synaptic transmission process. They are essential for human health and any imbalance in their activities can cause serious mental disorders such as Parkinson’s disease, schizophrenia, and Alzheimer’s disease. Hence, monitoring the concentrations of various neurotransmitters is of great importance in studying and diagnosing such mental illnesses. Recently, many researchers have explored the use of unique materials for developing biosensors for both in vivo and ex vivo neurotransmitter detection. A combination of nanomaterials, polymers, and biomolecules were incorporated to implement such sensor devices. For in vivo detection, electrochemical sensing has been commonly applied, with fast-scan cyclic voltammetry being the most promising technique to date, due to the advantages such as easy miniaturization, simple device architecture, and high sensitivity. However, the main challenges for in vivo electrochemical neurotransmitter sensors are limited target selectivity, large background signal and noise, and device fouling and degradation over time. Therefore, achieving simultaneous detection of multiple neurotransmitters in real time with long-term stability remains the focus of research. The purpose of this review paper is to summarize the recently developed sensing techniques with the focus on neurotransmitters as the target analyte, and to discuss the outlook of simultaneous detection of multiple neurotransmitter species. This paper is organized as follows: firstly, the common materials used for developing neurotransmitter sensors are discussed. Secondly, several sensor surface modification approaches to enhance sensing performance are reviewed. Finally, we discuss recent developments in the simultaneous detection capability of multiple neurotransmitters. Full article

(This article belongs to the Special Issue Polymers Based Chemical Sensors)

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