Search Results (182)

Background/Objectives: Extracellular vesicles (EVs) are involved in cell-to-cell communication and delivery of signaling molecules and represent an interesting approach in targeted therapy. This project focused on EV-mediated facilitation and cell-specific delivery of effector antimiR molecules carried by biologically produced gold nanoparticles (AuNPs). Methods: First, we loaded EVs derived from cancer cells 4T1 with AuNPs-antimiR. The AuNPs were also decorated with or without transferrin (Tf) molecules. We examined parental cell-specific delivery of the AuNPs-Tf-antimiR within monocultures as well as co-cultures in vitro. Subsequently, we used autologous EVs containing AuNPs-Tf-antimiR to target tumor cells in a xenograft tumor model in vivo. Efficacy of the antimir transfer was assessed by qPCR and apoptosis assessment. Results: In vitro, EVs loaded with AuNPs-antimiR were internalized only by the parental cells and the AuNPs-antimiR transfer was successful and effective only in EVs that were decorated with Tf. We achieved effective delivery of the antimiR molecule into cancer cells in vivo, which was proved by specific silencing of the target oncogenic miRNA as well as induction of cancer cells apoptosis. Conclusions: EVs represent an interesting and potent way for targeted cargo delivery and personalized medicine. On the other hand, there are various safety and efficacy challenges that remain to be addressed. Full article

The detection of trace chemicals at low and ultra-low concentrations is critical for applications in environmental monitoring, medical diagnostics, food safety and other fields. Conventional detection techniques often lack the required sensitivity, specificity, or cost-effectiveness, making real-time, in situ analysis challenging. Surface-enhanced Raman spectroscopy (SERS) is a powerful analytical tool, offering improved sensitivity through the enhancement of Raman scattering by plasmonic nanostructures. While noble metals such as Ag and Au are currently the reference choices for SERS substrates, fabrication methods should balance enhancement efficiency, reproducibility and scalability. In this study, we propose a novel approach for SERS substrate fabrication using reactive Aerosol Jet Printing (r-AJP) as an innovative additive manufacturing technique. The r-AJP process enables in-flight Ag seed reduction and nucleation of Ag nanoparticles (NPs) by mixing silver nitrate and ascorbic acid aerosols before deposition, as suggested by computational fluid dynamics (CFD) simulations. The resulting coatings were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses, revealing the formation of nanoporous crystalline Ag agglomerates partially covered by residual matter. The as-prepared SERS substrates exhibited remarkable SERS activity, demonstrating a high enhancement factor (10⁶) for rhodamine (R6G) detection. Our findings highlight the potential of r-AJP as a scalable and cost-effective fabrication strategy for next-generation SERS sensors, paving the way for the development of a new additive manufacturing tool for noble metal material deposition. Full article

Creatinine serves as a crucial diagnostic biomarker for assessing kidney disease. This work developed portable non-enzymatic and multienzyme-modified electrochemical biosensors for the detection of creatinine based on commercial screen-printed carbon electrodes (SPCEs). The non-enzymatic creatinine sensor was constructed by the electrochemical deposition of AuNPs onto the surface of a pre-activated SPCE by electrochemical activation, followed by the surface modification of a Nafion membrane. The developed AuNPs/SCPE exhibited excellent reproducibility, and the proposed Nafion/AuNPs/SPCE sensor showed excellent detection sensitivity and selectivity toward creatinine. In comparison, the enzymatic creatinine biosensor was gradually established by the electrodeposition of a Prussian blue (PB) membrane on the optimal AuNPs/SCPE surface, followed by multi-enzyme cascade modification (which consisted of creatinine amidohydrolase (CA), creatine oxidase (CI) and sarcosine oxidase (SOx)) and drop-casting the Nafion membrane to stabilize the interface. The introduction of a PB interlayer acted as the redox layer to monitor the generation of hydrogen peroxide (H₂O₂) produced by the enzymatic reaction, while the Nafion membrane enhanced the detection selectivity toward creatine, and the multi-enzyme cascade modification further increased the detection specificity. Both non-enzymatic and enzymatic creatinine sensors could detect the lowest concentrations of less than or equal to 10 μM. In addition, the efficiency and reproducibility of the proposed composite biosensor were also confirmed by repetitive electrochemical measurements in human serum, which showed a positive linear calibration relation of peak currents versus the logarithm of the concentration between 10 μM and 1000 μM, namely, i_p (μA) = −7.06 lgC (μM) −5.30, R² = 0.996. This work offers a simple and feasible approach to the development of enzymatic and non-enzymatic creatinine biosensors. Full article

Alzheimer’s disease (AD) early screening requires non-invasive, high-sensitivity detection of low-abundance biomarkers in complex biofluids like saliva. In this study, we present a miniaturized, silicon-based electrochemical sensor for sequential detection of two AD salivary biomarkers, lactoferrin (Lf) and amyloid β-protein 1-42 (Aβ_1-42), on a single reusable electrode. The sensor features a three-electrode system fabricated by sputter-coating a quartz substrate with gold (Au) sensing electrodes, which are further modified with gold nanoparticles (AuNPs) to form 3D dendritic structures that enhance surface area and electron transfer. To improve specificity, immunomagnetic beads (MBs) are employed to selectively capture and isolate target biomarkers from saliva samples. These MB–biomarker complexes are introduced into a polydimethylsiloxane chamber aligned with Au sensing electrodes, where a detachable magnet localizes the complexes onto the electrode surface to amplify redox signals. The AuNPs/MBs sensor achieves detection limits of 2 μg/mL for Lf and 0.1 pg/mL for Aβ_1-42, outperforming commercial ELISA kits (37.5 pg/mL for Aβ_1-42) and covering physiological salivary concentrations. After the MBs capture the biomarkers, the sensor can output the result within one minute. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements confirm enhanced electron transfer kinetics on AuNP-decorated surfaces, while linear correlations (R² > 0.95) validate quantitative accuracy across biomarker ranges. The compact and integrated design eliminates reliance on bulky instrumentation and enables user-friendly operation, establishing a promising platform for portable, cost-effective AD screening and monitoring. Full article

Background/Objectives: Lactic acid bacteria produce biofilms in meat products that contribute to the products’ deterioration, reduction in quality, and shortened shelf life. Although LAB are generally considered benign, certain strains create slime and cause significant drops in pH. The study’s goal was to identify and characterize LAB strains from sausage products that are capable of biofilm formation, and to evaluate the inhibitory effects of E. bicyclis methanol extract, its ethyl acetate fraction, and phloroglucinol, as well as to synthesize AuNPs, and assess their efficacy in controlling biofilm formation. Methods: Slime or biofilm-producing LAB bacteria were isolated from commercial sausages and identified using 16S rRNA gene sequencing. Lactobacillus sakei S10, which can tolerate high salt concentrations and cold temperatures, was chosen as a representative strain. The isolates were subsequently tested for hemolytic activity, salt and temperature tolerance, and carbohydrate consumption patterns. To evaluate antibiofilm potential, marine-derived compounds from Eisenia bicyclis, such as phloroglucinol (PG), crude methanolic extracts, ethyl acetate fractions, and gold nanoparticle (AuNP) formulations, were tested in situ on sausage surfaces against L. sakei S10 and common pathogens (Pseudomonas aeruginosa and Staphylococcus aureus). The biofilm-inhibitory effects of the extracts, PG, and PG-AuNPs were estimated using the colony-counting method. Results: The PG-AuNPs had an average particle size of 98.74 nm and a zeta potential of −29.82 mV, indicating nanoscale dimensions and considerable colloidal stability. Structural analysis confirmed their spherical form and crystalline structure, as well as the presence of phenolic groups in both reduction and stabilization processes. Among the studied treatments, the PG and PG-AuNPs had the strongest antibiofilm activities, dramatically lowering biofilm biomass, particularly for P. aeruginosa and L. sakei S10. However, the inhibitory effects were less prominent in in situ conditions than in in vitro testing, highlighting the complexity of real food matrices. Conclusions: The results of this study indicate that polyphenolic compounds obtained from marine sources, particularly in nano-formulated forms, have a great deal of potential as natural antibiofilm products. Enhancing the microbiological safety of processed meat products and extending their shelf life could be accomplished through the application of these polyphenolic compounds in food packaging or surface treatments. Full article

Norovirus (NoV), a leading cause of acute gastroenteritis worldwide, imposes significant morbidity and economic burdens across all age groups. Timely and accurate laboratory diagnosis is crucial for effective outbreak control and patient management. However, current diagnostic methods often require specialized equipment, technical expertise, and considerable time. To address these challenges, we developed a visual detection method utilizing gold nanoparticles (AuNPs) functionalized with the SMV25 aptamer specific to the NoV capsid protein. Detection relies on MgCl₂-induced changes in the color and absorbance of these aptamer-functionalized AuNPs. The assay exhibited a good linear relationship between the A630/A520 absorbance ratio and NoV capsid protein concentration. Specifically, in a buffer system, this linearity (R² = 0.9026) was observed over a 0–32 ng/µL range with a limit of detection (LOD) of 9.65 ng/µL. Similarly, for NoV spiked into stool suspensions, a strong linear correlation (R² = 0.9170) was found across a 0–100 ng/µL range, with an LOD of 37.11 ng/µL. Evaluation with real stool samples yielded 77% sensitivity and 65% specificity. Notably, the assay demonstrated the highest sensitivity towards NoV GII.2 (100%), followed by GII.4 (78%). Scanning transmission electron microscopy confirmed the underlying aggregation and dispersion patterns of the aptamer-functionalized AuNPs. This colorimetric assay provides a simple, rapid, and visual method for NoV detection. Nevertheless, further enhancements are necessary to improve its performance in the direct testing of complex specimens, paving the way for future on-site detection applications, especially in resource-limited settings. Full article

In this study, we developed a novel SERS-active magnetic substrate (MBs@CS@AuNPs) for detecting malachite green (MG) in aquatic products, including shrimp, cod, and aquaculture water. The substrate combines chitosan-functionalized magnetic nanobeads with dense gold nanoparticles. It efficiently enriches MG through electrostatic and π–π interactions, generates high-density plasmonic hotspots for stable signals, and utilizes a superparamagnetic core to concentrate MG molecules. This design achieved an ultralow detection limit of 10⁻⁹ M for MG in aquaculture samples, with a linear range spanning from 10⁻³ to 10⁻¹⁰ M (R² = 0.999). The substrate demonstrated superior performance in untreated, complex food matrices (e.g., shrimp, cod), outperforming conventional magnetic mass spectrometry systems that are prone to matrix interference. This work introduces an innovative approach for detecting harmful residues in food during environmental safety monitoring. Full article

Gold nanoparticles–cuprous oxide/reduced graphene oxide/polypyrrole (AuNPs-Cu₂O/rGO/PPy) hybrid nanocomposites were synthesized for surface acoustic wave (SAW) sensors, achieving high sensitivity (2 Hz/ppb), selectivity, and fast response (~2 min) at room temperature. The films, deposited via spin-coating, were characterized by SEM, EDS, and XRD, revealing a rough, wrinkled morphology beneficial for gas adsorption. The sensor showed significant frequency shifts to NH₃, enhanced by AuNPs, Cu₂O, rGO, and PPy. It had a 6.4-fold stronger response to NH₃ compared to CO₂, H₂, and CO, confirming excellent selectivity. The linear detection range was 12–1000 ppb, with a limit of detection (LOD) of 8 ppb. Humidity affected performance, causing negative frequency shifts, and sensitivity declined after 30 days due to resistivity changes. Despite this, the sensor demonstrated excellent NH₃ selectivity and stability across multiple cycles. In simulated breath tests, it distinguished between healthy and patient-like samples, highlighting its potential as a reliable, non-invasive diagnostic tool. Full article

Carcinoembryonic antigen (CEA) is an important tumor biomarker for the early clinical diagnosis of various cancers, and, therefore, the accurate and sensitive quantitative determination of CEA is of vital significance. In this study, we demonstrated the in situ growth of Au nanoparticles (AuNPs) on nitrogen-doped graphene quantum dots (N-GQDs) decorated reduced graphene oxide (rGO) nanocomposites by using simple drop-coating and electrochemical deposition methods. N-GQDs@rGO can be formed through the π–π stacking interaction and possesses a high specific surface area and many functional groups, providing lots of anchor sites (amino moieties in NGQDs) for the in situ electrochemical growth of AuNPs without the addition of reductants and protective agents. Such AuNPs/N-GQDs@rGO ternary nanocomposites combine the characteristics of three nanomaterials, showing a large surface area, excellent solubility, good conductivity, catalytic activity, a simple fabrication process, and notable stability, which are further used to construct a label-free electrochemical immunosensor for the determination of CEA. Under the optimized experimental conditions, the AuNPs/N-GQDs@rGO-based electrochemical immunosensor achieves a broad linear response, ranging from 1 pg/mL to 0.5 μg/mL and a low detection limit of 0.13 pg/mL. Moreover, the AuNPs/N-GQDs@rGO-based electrochemical immunosensor shows exceptional selectivity, anti-interference, and anti-fouling capabilities for the direct analysis of CEA amounts in fetal bovine serum samples, showing vast potential in the clinical screening of cancer. Full article

Dopamine (DA) is a neurotransmitter that works in the brain. It plays several important roles in executive functions, including motor control, memory, mood, motivation, and reward. DA imbalances are associated with diseases in the nervous system such as Parkinson’s disease, schizophrenia, Alzheimer’s disease, and attention deficit hyperactivity disorder (ADHD). Therefore, the development of a biosensor for the detection of precise amounts of DA is of great interest. In this research, polypyrrole-3-carboxylic acid/polypyrrole/gold nanoparticle (PP3C/PPy/AuNPs) composites were developed for the electrochemical detection of DA. Firstly, a PP3C/PPy/AuNPs composite thin film was synthesized by electropolymerization on a fluorine-doped tin oxide (FTO)-coated glass substrate. Subsequently, cyclic voltammetry (CV), scanning electron microscopy (SEM), and differential pulse voltammetry (DPV) were used for the characterization and study of the efficiency of the obtained conducting polymer–gold nanoparticle composite thin film for the detection of DA. The proposed electrochemical sensor showed good sensitivity and selectivity for the detection of DA with a wide detection linear range from 5 to 180 μM (R² = 0.9913). The limit of detection (LOD) and limit of quantitation (LOQ) values were 9.72 nM and 0.032 μM, respectively. Therefore, it can be concluded that the electrochemically fabricated PP3C/PPy/AuNPs composite thin film can be applied as an electrochemical biosensor for the detection of dopamine for the early diagnosis of various neurological disorders in the future. Full article

(1) Context: Cancer is still a major problem worldwide, and traditional therapies like radiation and chemotherapy often fail to alleviate symptoms because of side effects, systemic toxicity, and mechanisms of resistance. Beneficial anticancer effects that spare healthy tissues are made possible by the distinctive redox characteristics of noble metal complexes, especially those containing palladium, gold, silver, and platinum. (2) Methods: The redox processes, molecular targets, and therapeutic uses of noble metal complexes in cancer have been the subject of much study over the last 20 years; novel approaches to ligand design, functionalization of nanoparticles, and tumor-specific drug delivery systems are highlighted. (3) Results: Recent developments include Pt(IV) prodrugs and terpyridine-modified Pt complexes for enhanced selectivity and decreased toxicity; platinum complexes, like cisplatin, trigger reactive oxygen species (ROS) production and DNA damage. Functionalized gold nanoparticles (AuNPs) improve targeted delivery and theranostic capabilities, while gold complexes, particularly Au(I) and Au(III), inhibit redox-sensitive processes such as thioredoxin reductase (TrxR). (4) Conclusions: Ag(I)-based compounds and nanoparticles (AgNPs) induce DNA damage and mitochondrial dysfunction by taking advantage of oxidative stress. As redox-based anticancer medicines, noble metal complexes have the ability to transform by taking advantage of certain biochemical features to treat cancer more effectively and selectively. Full article

Transition-metal ion copper(II) (Cu(II)) has drawn increasing attention as a small-molecular cancer theranostic agent. However, delivering a sufficient dosage of Cu(II) to the tumor site and integrating multiple imaging modalities to achieve precise and effective cancer theranostics remains a critical challenge. Herein, an emerging Cu(II)-based nanocomposite has been synthesized for targeted tumor computed tomography (CT)/magnetic resonance (MR) dual-mode imaging and chemodynamic therapy (CDT). Briefly, 2-picolinic acid (PA-COOH), polyethylene glycol (PEG)-linked folic acid (FA), and fluorescein isothiocyanate (FI) were sequentially conjugated with polyethylenimine (PEI.NH₂) and then in situ fabrication of gold nanoparticles (Au NPs) occurred within the PEI.NH₂ internal cavity. After acetylation of PEI.NH₂ terminal amines and Cu(II) complexation, the Cu(II)-based nanocomposites FA-Au/Cu(II) PENPs with a mean diameter of 2.87 nm were generated. The synthesized FA-Au/Cu(II) PENPs showed favorable stability of colloidal dispersion, sustainable Cu(II) release properties in a pH-dependent manner, and Fenton-like catalytic activity specifically. With the FA-mediated targeting pathway, FA-Au/Cu(II) PENPs can specifically accumulate in cancer cells with high expression of FA receptors. Meanwhile, the complementary CT/MR dual-mode imaging in vitro and in vivo can be afforded by FA-Au/Cu(II) PENPs based on the excellent X-ray attenuation properties of Au NPs and the applicable r₁ relaxivity (0.7378 mM⁻¹s⁻¹) of Cu(II). Notably, the Cu(II)-mediated CDT mechanism enables FA-Au/Cu(II) PENPs to elicit the generation of toxic hydroxyl radicals (·OH), depletion of glutathione (GSH), promotion of lipid peroxidation (LPO), and induction of cancer cell apoptosis in vitro, and further demonstrates remarkable anti-tumor efficacy in a xenograft tumor model. With the illustrated targeted theranostic capacity of FA-Au/Cu(II) PENPs towards tumors, this Cu(II)-based nanocomposite paradigm inspires the construction of advanced theranostic nanoplatforms incorporating alternative transition metal ions. Full article

Functionalized plasmonic nanostructure platforms are widely used for developing optical biosensors and SERS assays. In this work, we present a low-cost and scalable surface-enhanced Raman scattering (SERS) system based on an innovative optical transducer comprising gold nanoparticles (AuNPs) embedded in nano-fibrillated bacterial cellulose (BC). The AuNPs@BC composite leverages the unique nanofibrillar architecture of bacterial cellulose, which provides a high surface area, flexibility, and uniform nanoparticle distribution, enabling the formation of numerous electromagnetic “hot spots”. This structure excites localized surface plasmon resonance (LSPR), as demonstrated by a bulk sensitivity of 72 nm/RIU, and supports enhanced Raman signal amplification. The eco-friendly and disposable AuNPs@BC platform was tested for agrifood applications, focusing on the detection of thiram pesticide. The system achieved a detection limit of 0.24 ppm (1 µM), meeting the sensitivity requirements for regulatory compliance in food safety. A strong linear correlation (R² ≈ 0.99) was observed between the SERS peak intensity at 1370 cm⁻¹ and thiram concentrations, underscoring its potential for quantitative analysis. The combination of high sensitivity, reproducibility, and environmental sustainability makes the AuNPs@BC platform a promising solution for developing cost-effective, flexible, and portable sensors for pesticide monitoring and other biosensing applications. Full article

MicroRNA122 (miR-122) is a microRNA that is highly expressed in hepatocytes and has been identified as a prospective therapeutic target and biomarker for liver injury. An expanding body of research has demonstrated that miR-122 is a critical regulator in both the initiation and progression of a wide range of liver diseases. Traditional methods for detecting miR-122 mainly include Northern blotting and qRT-PCR, but they are technically complex and cumbersome, requiring expensive instruments and high technical requirements. In this paper, we present a novel rapid testing method utilizing a lateral flow nucleic acid biosensor (LFNAB) for the sensitive and time-efficient detection of miR-122. This approach offers several advantages, including a high specificity for miR-122, the ability to detect low concentrations of the target molecule, and a significantly reduced testing time compared to conventional detection methods. In this study, a thiol-modified single-stranded detection DNA probe (Det-DNA), a biotinylated single-stranded capture DNA probe (Cap-DNA), and a biotinylated single-stranded control DNA probe (Con-DNA) are used to construct the LFNAB. A gold nanoparticle (AuNP) is a colored tag, which is used to label the Det-DNA probe. The principle of detecting miR-122 is based on dual DNA-miRNA hybridization reactions on the LFNAB to form sandwich-type AuNP-Det-DNA-miR-122-Cap-DNA complexes, which are captured on the test area of LFNAB for visualization and quantification. After systematic optimization of conditions of experiment, the response of LFNAB was highly linear within the scope of 0 pM-100 pM miR-122, and the detection limit in 15 min was 3.90 pM. The use of LFNAB to detect miR-122 in serum and fingertip blood has yielded satisfactory results. This successful application indicates the effectiveness of LFNAB in detecting miR-122 in both serum and fingertip blood samples, showcasing its potential utility in clinical and research settings for assessing miR-122 levels in different biological samples. Full article

The highly selective and sensitive determination of pesticide residues in food is critical for human health protection. Herein, the specific selectivity of molecularly imprinted polymers (MIPs) was proposed to construct an electrochemical sensor for the detection of carbendazim (CBD), one of the famous broad-spectrum fungicides, by combining with the synergistic effect of bioelectrocatalysis and nanocomposites. Gold nanoparticle-reduced graphene oxide (AuNP-rGO) composites were electrodeposited on a polished glassy carbon electrode (GCE). Then the MIP films were electropolymerized on the surface of the nanolayer using CBD as the template molecule and o-phenylenediamine (OPD) as the monomer. The detection sensitivity of CBD on the heterogeneous structure films was greatly amplified by AuNP-rGO composites and the bioelectrochemical oxidation of glucose, which was catalyzed by glucose oxidase (GOD) with the help of mediator in the underlying solution. The developed sensor showed high selectivity, good reproducibility, and excellent stability towards CBD with the linear range from 2.0 × 10⁻⁹ to 7.0 × 10⁻⁵ M, and the limit of detection (LOD) of 0.68 nM (S/N = 3). The expected system would provide a new idea for the development of simple and sensitive molecularly imprinted electrochemical sensors (MIESs). Full article