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12 pages, 7256 KiB

Open AccessArticle

Development of a Smartphone-Integrated Reflective Scatterometer for Bacterial Identification

by Iyll-Joon Doh, Brianna Dowden, Valery Patsekin, Bartek Rajwa, J. Paul Robinson and Euiwon Bae

Sensors 2022, 22(7), 2646; https://doi.org/10.3390/s22072646 - 30 Mar 2022

Cited by 6 | Viewed by 2297

Abstract

We present a smartphone-based bacterial colony phenotyping instrument using a reflective elastic light scattering (ELS) pattern and the resolving power of the new instrument. The reflectance-type device can acquire ELS patterns of colonies on highly opaque media as well as optically dense colonies. [...] Read more.

We present a smartphone-based bacterial colony phenotyping instrument using a reflective elastic light scattering (ELS) pattern and the resolving power of the new instrument. The reflectance-type device can acquire ELS patterns of colonies on highly opaque media as well as optically dense colonies. The novel instrument was built using a smartphone interface and a 532 nm diode laser, and these essential optical components made it a cost-effective and portable device. When a coherent and collimated light source illuminated a bacterial colony, a reflective ELS pattern was created on the screen and captured by the smartphone camera. The collected patterns whose shapes were determined by the colony morphology were then processed and analyzed to extract distinctive features for bacterial identification. For validation purposes, the reflective ELS patterns of five bacteria grown on opaque growth media were measured with the proposed instrument and utilized for the classification. Cross-validation was performed to evaluate the classification, and the result showed an accuracy above 94% for differentiating colonies of E. coli, K. pneumoniae, L. innocua, S. enteritidis, and S. aureus. Full article

(This article belongs to the Special Issue Label-Free Sensor/Biosensors for Biomedical and Environmental Monitoring)

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14 pages, 3219 KiB

Open AccessEditor’s ChoiceArticle

Photonic Label-Free Biosensors for Fast and Multiplex Detection of Swine Viral Diseases

by Maribel Gómez-Gómez, Carles Sánchez, Sergio Peransi, David Zurita, Laurent Bellieres, Sara Recuero, Manuel Rodrigo, Santiago Simón, Alessandra Camarca, Alessandro Capo, Maria Staiano, Antonio Varriale, Sabato D’Auria, Georgios Manessis, Athnasios I. Gelasakis, Ioannis Bossis, Gyula Balka, Lilla Dénes, Maciej Frant, Lapo Nannucci, Matteo Bonasso, Alessandro Giusti and Amadeu Griol Show full author list Hide full author list

Sensors 2022, 22(3), 708; https://doi.org/10.3390/s22030708 - 18 Jan 2022

Cited by 10 | Viewed by 3603

Abstract

In this paper we present the development of photonic integrated circuit (PIC) biosensors for the label-free detection of six emerging and endemic swine viruses, namely: African Swine Fever Virus (ASFV), Classical Swine Fever Virus (CSFV), Porcine Reproductive and Respiratory Syndrome Virus (PPRSV), Porcine [...] Read more.

In this paper we present the development of photonic integrated circuit (PIC) biosensors for the label-free detection of six emerging and endemic swine viruses, namely: African Swine Fever Virus (ASFV), Classical Swine Fever Virus (CSFV), Porcine Reproductive and Respiratory Syndrome Virus (PPRSV), Porcine Parvovirus (PPV), Porcine Circovirus 2 (PCV2), and Swine Influenza Virus A (SIV). The optical biosensors are based on evanescent wave technology and, in particular, on Resonant Rings (RRs) fabricated in silicon nitride. The novel biosensors were packaged in an integrated sensing cartridge that included a microfluidic channel for buffer/sample delivery and an optical fiber array for the optical operation of the PICs. Antibodies were used as molecular recognition elements (MREs) and were selected based on western blotting and ELISA experiments to ensure the high sensitivity and specificity of the novel sensors. MREs were immobilized on RR surfaces to capture viral antigens. Antibody–antigen interactions were transduced via the RRs to a measurable resonant shift. Cell culture supernatants for all of the targeted viruses were used to validate the biosensors. Resonant shift responses were dose-dependent. The results were obtained within the framework of the SWINOSTICS project, contributing to cover the need of the novel diagnostic tools to tackle swine viral diseases. Full article

(This article belongs to the Special Issue Label-Free Sensor/Biosensors for Biomedical and Environmental Monitoring)

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15 pages, 4274 KiB

Open AccessArticle

A Label-Free Impedimetric Genosensor for the Nucleic Acid Amplification-Free Detection of Extracted RNA of Dengue Virus

by Ching-Chou Wu, Hao-Yu Yen, Lu-Ting Lai, Guey-Chuen Perng, Cheng-Rei Lee and Shuenn-Jue Wu

Sensors 2020, 20(13), 3728; https://doi.org/10.3390/s20133728 - 3 Jul 2020

Cited by 19 | Viewed by 3481

Abstract

Developing rapid and sensitive diagnostic methods for dengue virus (DENV) infection is of prime priority because DENV infection is the most prevalent mosquito-borne viral disease. This work proposes an electrochemical impedance spectroscopy (EIS)-based genosensor for the label-free and nucleic acid amplification-free detection of [...] Read more.

Developing rapid and sensitive diagnostic methods for dengue virus (DENV) infection is of prime priority because DENV infection is the most prevalent mosquito-borne viral disease. This work proposes an electrochemical impedance spectroscopy (EIS)-based genosensor for the label-free and nucleic acid amplification-free detection of extracted DENV RNA intended for a sensitive diagnosis of DENV infection. A concentration ratio of 0.04 mM 6-mercaptohexanoic acid (MHA) to 1 mM 6-mercapto-1-hexanol (MCH) was selected to modify thin-film gold electrodes as a link to control the coverage of self-designed probe DNA (pDNA) at a density of 4.5 ± 0.4 × 10¹¹ pDNA/cm². The pDNA/MHA/MCH-modified genosensors are proven to improve the hybridization efficiency of a synthetic 160-mer target DNA (160mtDNA) with a 140-mer electrode side overhang as compared to other MHA/MCH ratio-modified genosensors. The MHA(0.04 mM)/MCH(1 mM)-modified genosensors also present good hybridization efficiency with the extracted DENV serotype 1 (DENV1) RNA samples, having the same electrode side overhangs with the 160mtDNA, showing a low detection limit of 20 plaque forming units (PFU)/mL, a linear range of 10²–10⁵ PFU/mL and good selectivity for DENV1. The pDNA density-controlled method has great promise to construct sensitive genosensors based on the hybridization of extracted DENV nucleic acids. Full article

(This article belongs to the Special Issue Label-Free Sensor/Biosensors for Biomedical and Environmental Monitoring)

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11 pages, 2750 KiB

Open AccessArticle

A Graphene-PEDOT:PSS Modified Paper-Based Aptasensor for Electrochemical Impedance Spectroscopy Detection of Tumor Marker

by Yi-Kuang Yen, Chen-Hsiang Chao and Ya-Shin Yeh

Sensors 2020, 20(5), 1372; https://doi.org/10.3390/s20051372 - 2 Mar 2020

Cited by 65 | Viewed by 7766

Abstract

A graphene and poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) modified conductive paper-based electrochemical impedance spectroscopy (EIS) aptasensor has been successfully fabricated by a simple and continuous coating process. A graphene/PEDOT:PSS modified paper electrode forms the nanocomposite providing a conductive and sensitive substrate for further aptamer functionalization [...] Read more.

A graphene and poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) modified conductive paper-based electrochemical impedance spectroscopy (EIS) aptasensor has been successfully fabricated by a simple and continuous coating process. A graphene/PEDOT:PSS modified paper electrode forms the nanocomposite providing a conductive and sensitive substrate for further aptamer functionalization of the biosensor. This low-cost paper-based aptasensor exhibits its sensitivity to carcinoembryonic antigens (CEA) in standard buffer solutions and human serum samples in a linear range of 0.77–14 ng·mL⁻¹. The limit of detection (LOD) is found to be 0.45 ng·mL⁻¹ and 1.06 ng·mL⁻¹ for CEA in both samples, separately. This aptamer-based sensing device was also evaluated and received a good correlation with the immunoassay detection method. The proposed paper-based aptasensor has demonstrated its potential as a rapid simple point-of-care analytical platform for early cancer diagnosis in less developed areas where manufacturing facilities, analytical instruments, and trained specialists are limited. Full article

(This article belongs to the Special Issue Label-Free Sensor/Biosensors for Biomedical and Environmental Monitoring)

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16 pages, 2426 KiB

Open AccessArticle

Dark Field Microscopy-Based Biosensors for the Detection of E. coli in Environmental Water Samples

by Rita La Spina, Diana C. António, Cloe Desmet, Andrea Valsesia, Radoslaw Bombera, Hedvig Norlén, Teresa Lettieri and Pascal Colpo

Sensors 2019, 19(21), 4652; https://doi.org/10.3390/s19214652 - 26 Oct 2019

Cited by 8 | Viewed by 4616

Abstract

Development of sensitive methods for the determination of E. coli bacteria contamination in water distribution systems is of paramount importance to ensure the microbial safety of drinking water. This work presents a new sensing platform enabling the fast detection of bacteria in field [...] Read more.

Development of sensitive methods for the determination of E. coli bacteria contamination in water distribution systems is of paramount importance to ensure the microbial safety of drinking water. This work presents a new sensing platform enabling the fast detection of bacteria in field samples by using specific antibodies as the biorecognition element and dark field microscopy as the detection technique. The development of the sensing platform was performed using non-pathogenic bacteria, with the E. coli DH5α strain as the target, and Bacillus sp. 9727 as the negative control. The identification of the captured bacteria was made by analyzing the dark field microscopy images and screening the detected objects by using object circularity and size parameters. Specificity tests revealed the low unspecific attachment of either E. coli over human serum albumin antibodies (negative control for antibody specificity) and of Bacillus sp. over E. coli antibodies. The system performance was tested using field samples, collected from a wastewater treatment plant, and compared with two quantification techniques (i.e., Colilert-18 test and quantitative polymerase chain reaction (qPCR)). The results showed comparable quantification capability. Nevertheless, the present method has the advantage of being faster, is easily adaptable to in-field analysis, and can potentially be extended to the detection of other bacterial strains. Full article

(This article belongs to the Special Issue Label-Free Sensor/Biosensors for Biomedical and Environmental Monitoring)

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8 pages, 2385 KiB

Open AccessCommunication

Microcapsule-Based Signal Amplification Method for Biomolecules

by Masaki Yamaguchi

Sensors 2019, 19(12), 2711; https://doi.org/10.3390/s19122711 - 17 Jun 2019

Viewed by 4064

Abstract

The direct signal amplification of target molecules could be an effective means of increasing the sensitivity and reducing the size of biosensors. The purpose of this study was to propose a novel signal amplification method suitable for the detection of biomolecules using microcapsules [...] Read more.

The direct signal amplification of target molecules could be an effective means of increasing the sensitivity and reducing the size of biosensors. The purpose of this study was to propose a novel signal amplification method suitable for the detection of biomolecules using microcapsules that can quickly respond to concentration variation. This microcapsule-based amplification method consists of two elements—microcapsules and a well-array. The microcapsules consist of (i) an inner shell fabricated through layer-by-layer assembly, (ii) a lipid bilayer, and (iii) loaded target molecules. In this method, the inner surface of the well-array was modified using TiO₂ as a photocatalyst. The diameter and thickness of the fabricated micro-capsules for biomarker loading were shown to be 2.7 μm and 78 nm, respectively. An ultraviolet (UV) irradiation time of 5 min was needed when the change in optical density reached 90% saturation of the optical density change. Dye molecules were incorporated into the microcapsules and were subsequently released, and the concentration of the released solution changed in proportion with the encapsulated dye concentration. This demonstrates the proof of concept for this novel signal amplification method based on microcapsules. Full article

(This article belongs to the Special Issue Label-Free Sensor/Biosensors for Biomedical and Environmental Monitoring)

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10 pages, 4362 KiB

Open AccessArticle

Multifunctional UV and Gas Sensors Based on Vertically Nanostructured Zinc Oxide: Volume Versus Surface Effect

by Leonidas E. Ocola, Yale Wang, Ralu Divan and Junhong Chen

Sensors 2019, 19(9), 2061; https://doi.org/10.3390/s19092061 - 2 May 2019

Cited by 29 | Viewed by 5209

Abstract

This article reports that it is possible to make multifunctional sensing devices with ZnO infiltrated polymers while the sensing interactions could occur throughout the polymer. As such, we find that infiltrated devices with SU-8 polymer can result in highly sensitive UV sensors. Mesh [...] Read more.

This article reports that it is possible to make multifunctional sensing devices with ZnO infiltrated polymers while the sensing interactions could occur throughout the polymer. As such, we find that infiltrated devices with SU-8 polymer can result in highly sensitive UV sensors. Mesh dielectric core devices were found to make sensitive gas sensors with a better than 5 ppm sensitivity for formaldehyde and NO₂. A new type of p-n junction device is further demonstrated that is sensitive to UV illumination, thus making it an enhanced UV sensor. Sensing devices relying on volume interactions, such as light absorption, can significantly benefit from the infiltrated polymer. In contrast, devices that rely on surface interactions, such as gas sensors, do not gain performance in any significant way with or without the infiltrated polymer. Full article

(This article belongs to the Special Issue Label-Free Sensor/Biosensors for Biomedical and Environmental Monitoring)

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Review

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16 pages, 2213 KiB

Open AccessReview

Label-Free Bioelectrochemical Methods for Evaluation of Anticancer Drug Effects at a Molecular Level

by Francesco Tadini-Buoninsegni and Ilaria Palchetti

Sensors 2020, 20(7), 1812; https://doi.org/10.3390/s20071812 - 25 Mar 2020

Cited by 16 | Viewed by 3645

Abstract

Cancer is a multifactorial family of diseases that is still a leading cause of death worldwide. More than 100 different types of cancer affecting over 60 human organs are known. Chemotherapy plays a central role for treating cancer. The development of new anticancer [...] Read more.

Cancer is a multifactorial family of diseases that is still a leading cause of death worldwide. More than 100 different types of cancer affecting over 60 human organs are known. Chemotherapy plays a central role for treating cancer. The development of new anticancer drugs or new uses for existing drugs is an exciting and increasing research area. This is particularly important since drug resistance and side effects can limit the efficacy of the chemotherapy. Thus, there is a need for multiplexed, cost-effective, rapid, and novel screening methods that can help to elucidate the mechanism of the action of anticancer drugs and the identification of novel drug candidates. This review focuses on different label-free bioelectrochemical approaches, in particular, impedance-based methods, the solid supported membranes technique, and the DNA-based electrochemical sensor, that can be used to evaluate the effects of anticancer drugs on nucleic acids, membrane transporters, and living cells. Some relevant examples of anticancer drug interactions are presented which demonstrate the usefulness of such methods for the characterization of the mechanism of action of anticancer drugs that are targeted against various biomolecules. Full article

(This article belongs to the Special Issue Label-Free Sensor/Biosensors for Biomedical and Environmental Monitoring)

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