Utilizing Gold Nanoparticles Research Articles

Ultrasound-Driven Nanomachine for Enhanced Sonodynamic Therapy of Non-Small-Cell Lung Cancer.

Non-small-cell lung cancer (NSCLC) is the most prevalent type of lung cancer, and there is an urgent need for developing novel therapies. Sonodynamic therapy exhibits exceptional tissue penetration and minimal harm to healthy tissue, making it extremely promising for cancer treatment. The efficacy of SDT is limited by the intricate immunological microenvironment and the resistance to tumor treatment. This study developed targeted nanoparticles that use ultrasound to concentrate on treating NSCLC. The hybrid targeted nanoparticles utilize gold nanoparticles as their fundamental component, with the outside modified with engineered macrophage exosomes and the aptamer S11e to specifically target NSCLC. Ultrasound could effectively eliminate tumors in NSCLC cells by destroying lysosomes via targeted nanoparticles. Simultaneously, fragmented tumor antigens could effectively activate dendritic cell cells to recruit T cells. This method has significant efficacy in suppressing the development of NSCLC and exhibits potential for therapeutic application.

Optimizing Electron‐Beam Photothermal Pyrolysis Parameters for Enhanced Molecular Biodegradability of Polyvinyl Chloride Plastics

AbstractPolyvinyl chloride (PVC), a synthetic plastic notable for harmful emissions during deterioration, has potential to be molecularly adjusted by photo‐oxidative ultraviolet degradation. This research investigates the influence of electron beam irradiation and near‐infrared photothermal treatment utilizing gold nanoparticles to establish the optimized molecular weight and beam time exposure for biodegradable PVC properties while maintaining a minimum tensile strength as measured through the ratio of peak tension force by cross sectional area. PVC powder samples with number‐average molecular weights ranging from 20.0 to 90.0 kDa and varying exposure times of a 100 kGy electron beam from 80 to 115 ms are employed for the study. Outcomes from PVC irradiation reveal the optimal parameters for inducing biodegradability in samples: an e‐beam exposure duration of 95 ms applied to PVC powder with a sample molecular weight of 20.0 kDa. Analysis of the ratio of number average molecular weight and weight average molecular weight demonstrates that shorter irradiation durations result in lower molecular weights and molecular weight is directly proportional to Tg and crystallinity. Future work aims to scale up the procedure to industrial applications and investigate the treatment's applicability to a variety of thermoplastics.

One-step copper deposition-induced signal amplification for multiplex bacterial infection diagnosis on a lateral flow immunoassay device

The lateral flow immunoassay (LFIA) is predominant in rapid diagnostic tests owing to its cost-effectiveness and operational simplicity. However, the conventional LFIA exhibits limited sensitivity and is susceptible to human variance for the result readout, impacting result interpretation. In this study, we introduced a novel one-step copper deposition-induced signal amplification lateral flow immunoassay (osa-LFIA) that markedly enhances the detection sensitivity for Staphylococcus aureus (protein A) and Pseudomonas aeruginosa (exotoxin A). Utilizing gold nanoparticles (AuNPs) as a catalyst, this approach employs ascorbic acid to reduce Cu2+ to Cu0, depositing on AuNPs at the test line and amplifying the signal. A user-friendly design features a three-dimensional paper structure incorporating pre-dried reagents, enabling a streamlined, efficient testing process. The osa-LFIA significantly lowers detection limits to 3 ng mL−1 for protein A and 10 ng mL−1 for exotoxin A, offering a tenfold improvement over conventional LFIA. Additionally, we developed a portable grayscale detection device, achieving less than 10% error in quantitative analysis compared to the data acquired and analyzed in the lab. This entire process, from detection to signal amplification, is completed in just 20 min. For the clinical trial, we utilized the osa-LFIA to test synovial fluid samples infected with Staphylococcus aureus. We also successfully detected different concentrations of the exotoxin A in parallel, with a recovery value of 96%–110%. Our findings demonstrate the osa-LFIA's potential as a rapid, highly sensitive, and simple-to-use diagnostic tool for detecting various pathogens, significantly advancing the field of rapid diagnostic testing.

Electrochemical immunosensor based on gold nanoparticles for the detection of creatine kinase as a cardiac marker

This study presents the development of an electrochemical immunosensor utilizing gold nanoparticles for the detection of creatine kinase (CK), a crucial cardiac marker. Gold nanoparticles with an average diameter of 18.3 ± 2.1 nm were synthesized and characterized, exhibiting a characteristic surface plasmon resonance peak at 520 nm. The construction of the immunosensor was observed through cyclic voltammetry and electrochemical impedance spectroscopy, showing notable alterations in electron transfer rates during each step of the assembly process. Optimal performance was achieved at pH 7.4, with an antibody concentration of 100 μg/mL and an incubation time of 45 minutes. The sensor demonstrated a sensitivity of 152.6 Ω/(ng/mL) and maintained its response in the presence of common interfering substances, with maximum signal deviation of 7.2 %. Testing with spiked human serum samples yielded recovery rates between 96.5 % and 103.8 %. Comparison with ELISA using clinical samples further validated the sensor's accuracy. This AuNP-based immunosensor offers a promising platform for rapid and sensitive CK detection in cardiac health assessment.

Biosynthesis of gold nanoparticles from Martynia annua aqueous leaves extract, its antioxidant potential and antimicrobial ability against selected wound pathogens

The field of nanotechnology has great potential within the realm of modern nanoscience and technology. Ecologically responsible nanoparticle production requires the careful selection of a solvent that is ecologically acceptable, together with the use of reducing and stabilizing chemicals that are also environmentally beneficial. The utilization of gold nanoparticles has been widely investigated in the fields of separation sciences and illness diagnosis for biological purposes. The objective of this study is to synthesize gold nanoparticles utilizing a Water-based Leaf Extract from the Martynia annua Plant in an ecologically sustainable manner. X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were employed to analyze the morphological characteristics, stability, and crystalline structure of the produced nanoparticles. The experimental results validate the commencement of the gold ion reduction process by the detected change in color of the reaction mixture to a deep purple colour. Moreover, the synthesis was confirmed by the use of UV–visible spectrometry, within the wavelength region of 584 nm. The zeta potential of the produced nanoparticles is reported to be −31 mV, while the average diameter of the particles is about 21 nm. The synthesized particles exhibit significant antioxidant capacity in comparison to the standard. Further AuNPs shows strong antibacterial potential against Escherichia coli, Staphylococcus aureus, Streptococcus sp, Bacillus subtilis, and Enterococcus sp was 53.94 µg/mL, 78.02 µg/mL, 55.47 µg/mL, 55.83 µg/mL, and 95.24 µg/mL respectively Synthesized particles demonstrate substantial cytotoxicity against A549 human lung cancer cells and it shows the inhibitory concentration at 20 µg/ml. The results indicated a significant decrease in cell viability, which was directly linearly related to the dosage of particles. The Martynia annua plant mediated gold nanoparticles exhibit potent antioxidant and antibacterial properties effectively combating specific wound infections.

Microfluidic Detection Platform for Determination of Ractopamine in Food.

A novel microfluidic ractopamine (RAC) detection platform consisting of a microfluidic RAC chip and a smart analysis device is proposed for the determination of RAC concentration in meat samples. This technology utilizes gold nanoparticles (AuNPs) modified with glutamic acid (GLU) and polyethyleneimine (PEI) to measure RAC concentration in food products. When RAC is present, AuNPs aggregate through hydrogen bonding, causing noticeable changes in their optical properties, which are detected using a self-built UV-visible micro-spectrophotometer. Within the range of 5 to 80 ppb, a linear relationship exists between the absorbance ratio (A693nm/A518nm) (Y) and RAC concentration (X), expressed as Y = 0.0054X + 0.4690, with a high coefficient of determination (R2 = 0.9943). This method exhibits a detection limit of 1.0 ppb and achieves results within 3 min. The practical utility of this microfluidic assay is exemplified through the evaluation of RAC concentrations in 50 commercially available meat samples. The variance between concentrations measured using this platform and those determined via liquid chromatography-tandem mass spectrometry (LC-MS/MS) is less than 8.33%. These results underscore the viability of the microfluidic detection platform as a rapid and cost-effective solution for ensuring food safety and regulatory compliance within the livestock industry.

Chitosan-coated iron(III) oxide nanoparticles and tungsten disulfide quantum dots-immobilized Fiber-based WaveFlex Biosensor for Staphylococcus Aureus bacterial detection in real food samples

The research proposes and investigates an extraordinarily sensitive, label-free WaveFlex biosensor utilizing optical fiber technology for the detection of Staphylococcus aureus (S. aureus), a common foodborne bacterium. The WaveFlex biosensor (plasmon Wave based Flexible optical fiber Biosensor) is based on a novel flexible tapered single-mode fiber structure, utilizing gold nanoparticles (AuNPs) to trigger the phenomenon of localized surface plasmon resonance (LSPR). Additionally, the sensitivity is further enhanced using chitosan-coated iron(III) oxide nanoparticles (Fe3O4–CS NPs) and tungsten disulfide quantum dots (WS2-QDs). The optical fiber surface is functionalized with antibodies to achieve specific detection of S. aureus. For S. aureus concentrations at 1 × 108 CFU/mL (colony-forming units per milliliter), the sensor's maximum sensitivity of 2.74 nm/lg (CFU/mL), and a detection limit (LOD) of 6.67 CFU/mL. This ultra-sensitive biosensor holds great potential for widespread applications in various fields, including disease detection, medical diagnostics, and food safety inspection.

Ultrasensitive detection of water pollutant PFOA based on AuNPs decorated NiOScZ screen-printed electrode

This study focuses on the development of a highly sensitive and on-site detection method for the water pollutant perfluorooctanoic acid (PFOA). The method utilizes gold nanoparticles (AuNPs) decorated on a screen-printed electrode and nickel oxide-scandium zirconium (NiOScZ). The newly developed electrode demonstrates outstanding analytical performances in a wide linear range between 0.001 nM and 100 nM, a remarkable detection limit of 0.3 pM, and a high sensitivity of 3.76 μA/nM cm2. The method's applicability for detecting PFOA in water samples was verified by achieving spiked recovery results ranging from 96.5 % to 105.6 %, with RSD (%) values below 5 %.

A label-free fluorescence sensing strategy based on gold nanoparticles assisted copper nanoclusters for the detection of aflatoxin B1 in cereals and peanuts

To effectively monitor the degree of aflatoxin B1 (AFB1) contamination in food and mitigate potential health risks to consumers eating food contaminated with AFB1, a label-free fluorescence aptamer-sensing strategy utilizing gold nanoparticles (AuNPs) was developed. Polyvinylpyrrolidone-copper nanoclusters (PVP-CuNCs) and AuNPs were selected as donor/acceptor pairs to convert the color signal change of AuNPs into fluorescence signal changes in PVP-CuNCs via the inner filter effect (IFE). In the presence of AFB1, the aptamer preferentially adsorbed with AFB1, and the AuNPs without aptamer protection changed color from red to blue under NaCl-induced aggregation. The green fluorescence of PVP-CuNCs recovered gradually. The developed strategy offers high sensitivity for the detection of AFB1, with a linear range of 0.02–20 μg L−1, and a low detection limit of 0.69 μg L−1. In addition, the strategy was successfully applied to real samples such as corn, rice, oats and peanuts, and the recovery rate was 93.4–106.2 %, which verified the reliability and applicability of this strategy. This strategy has the advantages of cost-effectiveness, high sensitivity, low detection limit and easy operation, providing a reference for sensitive and selective detection of mycotoxins contamination in food.

Fluorescent probe for imaging intercellular tension: molecular force approach.

Cellular mechanical force plays a crucial role in numerous biological processes, including wound healing, cell development, and metastasis. To enable imaging of intercellular tension, molecular tension probes were designed, which offer a simple and efficient method for preparing Au-DNA intercellular tension probes with universal applicability. The proposed approach utilizes gold nanoparticles linked to DNA hairpins, enabling sensitive visualization of cellular force in vitro. Specifically, the designed Au-DNA intercellular tension probe includes a molecular spring flanked by a fluorophore-quencher pair, which is anchored between cells. As intercellular forces open the hairpin, the fluorophore is de-quenched, allowing for visualization of cellular force. The effectiveness of this approach was demonstrated by imaging the cellular force in living cells using the designed Au-DNA intercellular tension probe.

Comparative analysis of the application efficiency of gold nanoparticles-based SERS in four foodborne pathogenic microbes

It has been widely reported that SERS can detect foodborne pathogenic bacteria, but SERS has only been limited to the detection of purified single bacteria. However, there’s few single bacterial infections in the natural state were found at the most time, and rare comparative investigations of different Gram-negative and Gram-positive bacteria by SERS exist. At the present study, we are aiming at the comparative analysis of the detection efficiency toward different foodborne pathogenic microbes by a conventional citrate-reduced gold colloid, including Escherichia coli, Salmonella enteritidis, Staphylococcus aureus and Listeria monocytogenes. The SERS spectra of samples were collected with sterile 0.5% NaCl solution as aggregating compound. First, the stability of each bacterial were detected with gold nanoparticles. Afterward, SERS signals of the four bacteria were compared at different concentrations, and it was found that Gram-positive and Gram-negative bacteria have different minimum sensitivity and detection stability. Next, the mixed bacterial SERS detection was applied to classify and identify the similar Raman spectra. Spectral data were analyzed using multivariate data analysis methods, including principal component analysis (PCA) and hierarchical cluster analysis (HCA). The SERS procedure we proposed, which utilized gold nanoparticles adsorbing on bacteria and multivariate analysis, allowed differentiation of species. The results of this pilot study demonstrate the potential of SERS to rapidly identify Gram-negative and Gram-positive foodborne pathogens.

Selective Amperometric Sensor for the Determination of Hydrazine at a Gold Nanoparticle Decorated Poly(Brilliant Blue) Modified Electrode

There is a pressing requirement to synthesize stable electrode components that possess enhanced capabilities for creating electrochemical sensors, which are sensitive and discerning, to swiftly detect dangerous noxious substances. A sensitive electrochemical sensor has been developed in this study for hydrazine (HY) oxidation, utilizing gold nanoparticles (AuNPs) and poly(brilliant blue) (p(BB)) modifiers on the surface of the pencil graphite electrode (PGE). The features of the sensor for detecting hydrazine were characterized by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). Additionally, when examined under optimal parameters using CV and amperometry, the proposed hydrazine sensor presents favorable electrochemical and analytical figures of merit. The AuNPs/p(BB)/PGE provides the determination of low levels of hydrazine in water samples with a detection limit of 0.14 µM. A wide linear range from 1.0 to 800 μM was obtained. The findings indicate that the AuNPs/p(BB)/PGE sensor exhibits good stability, repeatability, and reproducibility for hydrazine. The proposed sensor was effectively used to determine hydrazine in both water and mineral water samples.

Photothermal biosensing integrated with microfluidic paper-based analytical device for sensitive quantification of sarcosine

This article presents the development of a photothermal biosensing integrated with microfluidic paper-based analytical device (PT-μPAD) as a quantitative biosensor method for monitoring sarcosine in human control urine, plasma, and serum samples. The device utilizes gold nanoparticles (AuNPs) as both a peroxidase-like nanozyme and a photothermal substrate to enable sarcosine detection. In our PT-μPAD, hydrogen peroxide (H2O2) is generated through the oxidation of sarcosine by a sarcosine oxidase (SOx) enzyme. Subsequently, the H2O2 flows through the paper microchannels to the detection zone, where it etches the pre-deposited AuNPs, inducing a temperature change upon exposure by a 532 nm laser. The temperature variation is then measured using a portable and inexpensive infrared thermometer. Under optimized conditions, we obtained a linear range between 10.0 and 40.0 nmol L−1 (R2 = 0.9954) and a detection limit (LOD) of 32.0 pmol L−1. These values fall within the clinical range for sarcosine monitoring in prostate cancer diagnostics in humans. Moreover, our approach exhibits high selectivity without interfering effects. Recovery studies in various human control samples demonstrated a range of 99.05–102.11 % with the highest RSD of 2.25 %. The PT-μPAD was further validated for sarcosine determination in human control urine and compared with a commercial ELISA assay, revealing no significant difference between these two methods at a 95 % confidence level. Overall, our proposed sarcosine biosensor is well-suited for prostate cancer monitoring, given its affordability, sensitivity, and user-friendliness, even for unskilled individuals. Moreover, this strategy has promising prospects for broader applications, potentially detecting various biomarkers as a point-of-care (POC) diagnostic tool.

Streptomyces monashensis MSK03-mediated synthesis of gold nanoparticles: characterization and antibacterial activity.

Nanotechnology is a cutting-edge field with diverse applications, particularly in the utilization of gold nanoparticles (AuNPs) due to their stability and biocompatibility. AuNPs serve as pivotal components in medical applications, with a specific emphasis on their significant antibacterial efficacy. This study focuses on synthesizing AuNPs using the cell-free supernatant of Streptomyces monashensis MSK03, isolated from terrestrial soil in Thailand. The biosynthesis process involved utilizing the cell-free supernatant of S. monashensis MSK03 and hydrogen tetrachloroauric acid (HAuCl4) under controlled conditions of 37 °C and 200 rpm agitation. Characterization studies revealed spherical AuNPs with sizes ranging from 7.1 to 40.0 nm (average size: 23.2 ± 10.7 nm), as confirmed by TEM. UV-Vis spectroscopy indicated a localized surface plasmon resonance (LSPR) band at 545 nm, while XRD analysis confirmed a crystalline structure with characteristics of cubic lattice surfaces. The capping molecules on the surface of AuNPs carry a negative charge, indicated by a Zeta potential of -26.35 mV, and FTIR analysis identified functional groups involved in reduction and stabilization. XANES spectra further confirmed the successful reduction of Au3+ to Au0. Moreover, the synthesized AuNPs demonstrated antibacterial activity against drug-resistant strains of Pseudomonas aeruginosa and Acinetobacter baumannii. Interestingly, the AuNPs showed non-toxicity to Vero cell lines. These significant antibacterial properties of the produced nanoparticles mean they hold great promise as new antimicrobial treatments for tackling the increasing issue of antibiotic resistance.

The impact of pH and temperature on the green gold nanoparticles preparation using Jeju Hallabong peel extract for biomedical applications.

The utilization of gold nanoparticles (AuNPs) has garnered significant attention in recent times, particularly in the field of biomedical research. The utilization of AuNPs in chemical synthesis procedures raises apprehensions regarding their potential toxicity in living organisms, which is inconsistent with their purported eco-friendly and cost-effective aspects. In this investigation, AuNPs were synthesized via the green synthesis approach utilizing Jeju Hallabong peel extract (HPE), a typical fruit variety indigenous to South Korea. The visible-range absorption spectrum of gold nanoparticles from green synthesis (HAuNPs) that are red wine in color occurs at a wavelength of λ = 517 nm. The morphology and particle size distribution were analysed using transmission electron microscopy (TEM) and ImageJ software. The TEM images reveal that the HAuNPs exhibit a high degree of dispersion and uniformity in their spherical shape, with an average size of approximately 7 nm. Moreover, elevating the initial pH level of the mixed solution has an impact on the decrease in particle dimensions, as evidenced by the blue shift observed in the UV-visible spectroscopy absorbance peak. Elevating the reaction temperature may accelerate the synthesis duration. However, it does not exert a substantial impact on the particle dimensions. The outcomes of an avidin-biocytin colorimetric assay provide preliminary analyses of possible sensor tunability using HAuNPs. The cytotoxicity of HAuNPs was evaluated through in vitro studies using the MTT assay on RAW 264.7 cell lines. The results indicated that the HAuNPs exhibited lower cytotoxicity compared to both chemically reduced gold nanoparticles (CAuNPs).

Electrochemical performance of gold nanoparticles decorated on Multi-walled Carbon Nanotube (MWCNT) Screen-printed Electrode (SPE)

The modification of the multi-walled carbon nanotube screen-printed electrode (MWCNT/SPE) with gold nanoparticles (AuNP) was achieved through drop-casting method utilizing gold nanoparticles synthesized via the Turkevich method. The combination of nanomaterial based on carbon (multi-walled carbon nanotubes) and the noble metal (gold nanoparticles) aims to exploit the synergistic benefits of the two materials in electrochemical measurement. Electrochemical performance was evaluated through techniques including cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The results indicated an increase in the electroactive surface area of the modified working electrodes compared to the unmodified ones. This increase in electroactive surface area can be attributed to the successful decoration of AuNP, which facilitates greater surface interactions and improved electron transfer kinetics, crucial for efficient catalytic reactions. The decoration of AuNP also makes sure that the electrode will have good biocompatibility for future bioanalytical applications. This investigation’s main goal was to determine the effects of the AuNP modification methods to the carbon electrode’s electroactive surface area for further contributing to the development of efficient label-free sensing platforms for diverse applications in biosensing.

Identification of acetaldehyde based on plasmonic patterns of a gold nanostructure conjugated with chromophore and H2O2: a new platform for the rapid and low-cost analysis of carcinogenic agents by colorimetric affordable test strip (CATS).

Acetaldehyde, a prevalent carbonyl compound in fermented foods, poses challenges in various applications due to its reactivity. This study addresses the need for efficient acetaldehyde detection methods across biotechnological, environmental, pharmaceutical, and food sectors. Herein, we present a novel colorimetric/UV spectrophotometric approach utilizing gold nanoparticles (AuNPs), particularly gold nano-flowers (AuNFs), for sensitive acetaldehyde identification. The method exhibits a notable sensitivity, detecting acetaldehyde at concentrations as low as 0.1 μM. The mechanism involves the interaction of acetaldehyde molecules with AuNFs, leading to a significant change in the absorbance spectrum, which serves as the basis for detection. Moreover, its applicability extends to human biofluids, notably urine samples. Integration with a cost-effective one-drop microfluidic colorimetric device (OD-μPCD) enables the development of an affordable test strip (CATS). This semi-analytical device, employing a multichannel OD-μPCD, facilitates real-time analysis of acetaldehyde in human samples. Our findings demonstrate the pioneering utilization of AuNPs for selective and sensitive acetaldehyde detection, promising advancements in environmental and occupational safety standards, and laying a foundation for enhanced detection and monitoring of related volatile organic compounds (VOCs).

Gold Nanoparticle-Based Colorimetric Biosensing for Foodborne Pathogen Detection.

Ensuring safe high-quality food is an ongoing priority, yet consumers face heightened risk from foodborne pathogens due to extended supply chains and climate change in the food industry. Nanomaterial-based assays are popular and have recently been developed to ensure food safety and high quality. This review discusses strategies for utilizing gold nanoparticles in colorimetric biosensors. The visible-signal biosensor proves to be a potent sensing technique for directly measuring targets related to foodborne pathogens in the field of food analysis. Among visible-signal biosensors, the localized surface plasmon resonance (LSPR) biosensor has garnered increasing attention and experienced rapid development in recent years. This review succinctly introduces the origin of LSPR theory, providing detailed insights into its fundamental principles. Additionally, this review delves into the application of nanotechnology for the implementation of the LSPR biosensor, exploring methods for utilizing gold nanoparticles and elucidating the factors that influence the generation of visible signals. Several emerging technologies aimed at simple and rapid immunoassays for onsite applications have been introduced in the food industry. In the foreseeable future, field-friendly colorimetric biosensors could be adopted in food monitoring systems. The onsite and real-time detection of possible contaminants and biological substances in food and water is essential to ensure human health and safety.

A novel dual-mode aptasensor based colorimetry and electrochemical detection of norovirus in fecal sample

Norovirus is a leading cause of acute gastroenteritis in humans. This paper presents the development of a novel dual-mode aptasensor for detecting norovirus using colorimetry and electrochemical methods. The initial colorimetric method utilizes gold nanoparticles (AuNPs) and sodium chloride to establish a positive correlation between the concentration of norovirus in a solution and the absorbance ratio A650/A520. The naked eye can detect concentrations as low as 0.1 μg/mL, corresponding to a Ct value of 33 (2.2 copies/μL, CT = 34.102–3.2185·lgX), allowing for qualitative and semi-quantitative analysis. For more accurate trace analysis, a gold electrode is modified with a thiol-modified aptamer and closed with 6-Mercapto-1-hexanol. After incubation with norovirus, the virus specifically binds to the aptamer, causing changes in its spatial structure and distance from the electrode surface. These changes can then be detected using electrochemical square wave voltammetry (SWV). Under optimal reaction conditions, the peak current from SWV exhibits a strong linear relationship with the logarithm of norovirus concentrations between 10−9 μg/mL and 10−2 μg/mL. The regression equation Y = 14.76789 + 1.03983·lgX, with an R2 value of 0.987, accurately represents this relationship. The limit of detection was determined to be 1.365 × 10−10 μg/mL. Furthermore, the aptasensor demonstrated high specificity for norovirus in fecal samples, making it a promising tool for detecting norovirus in various sample types.

Gold nanoparticle-powered screening of membrane protein-specific lipids from complex lipid mixtures

Membrane proteins (MPs) are affected by binding of specific lipids. We previously developed a methodology for systematically analyzing MP-lipid interactions leveraging surface plasmon resonance (SPR). In this method, the gold sensor chip surface was modified with a self-assembled monolayer (SAM), which allowed for a larger amount of MP-immobilization. However, the laborious lipid purification step remained a bottleneck. To address this issue, a new strategy has been developed utilizing gold nanoparticles (AuNPs) instead of the gold sensor chip. AuNPs were coated with SAM, on which MP was covalently anchored. The MP-immobilized AuNPs were mixed with a lipid mixture, and the recovered lipids were quantified by LC–MS. Bacteriorhodopsin (bR) was used as an MP to demonstrate this concept. We optimized immobilization conditions and confirmed the efficient immobilization of bR by dynamic light scattering and electron micrographs. Washing conditions for pulldown experiments were optimized to efficiently remove non-specific lipids. A new binding index was introduced to qualitatively reproduce the known affinity of lipids for bR. Consequently, the low-abundant and least-studied lipid S-TeGD was identified as a candidate for bR-specific lipids. This technique can skip the laborious lipid purification process, accelerating the screening of MP-specific lipids from complex lipid mixtures.