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Aim: Pancreatic carcinoma is an aggressive cancer that progresses without many symptoms. The difficulty of early diagnosis and an inadequate response to traditional treatments also cause the survival rate of pancreatic cancer to be low. Current research is focusing on methods of diagnosis and treatment, such as gene therapy, to increase survival rates. Small interfering ribonucleic acid (siRNA) has emerged as a promising advanced therapeutic strategy for cancer treatment. This study sought to silence the KRAS gene in the human pancreatic carcinoma cell line using a complex of small interfering ribonucleic acid (siRNA) and gold nanoparticles (AuNP). Methods: In this study, 25 nM siRNA and gold nanoparticles at 0.5 mg/ml, 0.25 mg/ml, and 0.125 mg/ml concentrations were used to silence the KRAS gene in the CAPAN-1 cell line. Real-time PCR analysis, agarose gel electrophoresis, and double staining were carried out, and xCelligence real-time cell analysis (RTCA) was used to measure proliferation. Results: The PCR analysis revealed crossing point (CP) values of actin beta (ACTB) ranging from 33.04 to 35.98, which was in the expected range for all samples. The interaction between the gold nanoparticle/siRNA complex in the double staining analysis revealed that the most effective concentration of gold nanoparticle was 0.125 mg/ml. The WST-1 technique showed that siRNA/AuPEI cells in application groups had a viability rate of over 90%, indicating no toxicity or side effects. The xCELLigence RTCA® showed that at hour 72, there was a significant difference in proliferation in the 0.5 mg/mL PEI/AuNP-siRNA, 0.25 mg/mL PEI/AuNP-siRNA, and 0.125 mg/mL PEI/AuNP-siRNA application groups compared to the control and siRNA groups (p < 0.05). By hour 96, all three groups were statistically different from the control and siRNA groups in terms of proliferation (p < 0.05). Conclusions: The results of this analysis suggest that the AuPEI/siRNA complex can be effectively used to silence the target gene, but more studies are needed to verify these results. [ABSTRACT FROM AUTHOR]

Glutamate is the most important excitatory neurotransmitter, which is relevant for the study of several diseases such as amyotrophic lateral sclerosis and Alzheimer. It is the form L-glutamic acid (Glu) takes at physiologically relevant pHs. The surface-enhanced Raman spectra of Glu obtained at pH values ranging from 3.3 to 12 are collected in the presence of silver and gold colloids and on solid substrates. The observed bands are compared with the positions of calculated normal modes for free neutral glutamic acid, glutamic acid monohydrate, glutamic acid bound to gold and silver atoms, and sodium glutamate. Although gold atoms prefer to bind to the NH2 group as compared to carbonyl groups, silver atoms prefer binding to hydroxyl groups more than binding to the amino group. SERS spectra of glutamic acid solutions with a pH value of 12, in which both carboxylic groups are deprotonated, indicate a complexation of the glutamic acid dianion with the sodium cation, which was introduced into the solution to adjust the pH value. Further research towards an optimal substrate is needed. [ABSTRACT FROM AUTHOR]

Purpose: Waterborne pathogens pose a significant threat to public health, emphasizing the continuous necessity for advancing robust detection techniques, particularly in preventing outbreaks associated with these pathogens. This study focuses on cholera, an infectious disease caused by Vibrio cholerae, serogroups O1 and O139, often transmitted through contaminated water and food, raising significant public health concerns in areas with poor sanitation and limited access to clean water. Methods: We developed a colorimetric biosensor using aptamer-functionalized gold nanoparticles to identify Vibrio cholerae O139 and address this issue. The detection mechanism relies on the color change of gold nanoparticles (AuNPs) from red to blue-purple induced by NaCl after the pathogen incubation and aptamer-target binding. Initial steps involved synthesizing and characterizing AuNPs, then exploring the impact of aptamer and NaCl concentrations on AuNP agglomeration. Optimization procedures for aptamer concentration and salt addition identified the optimal conditions for detection as 120 pM aptamers and 1 M NaCl. Results: The aptasensor demonstrated a robust linear relationship, detecting V. cholerae concentrations from 103 to 108 CFU/mL, with a limit of detection (LOD) of 587 CFU/mL. Specificity tests and accurate sample analyses confirmed the efficiency of the AuNPs aptasensor, showcasing its reliability and speed compared to traditional culture examination methods. Moreover, we extended the aptasensor to a paper-based sensing platform with similar detection principles. Conclusion: The change in color upon target binding was captured with a smartphone and analyzed using image processing software. The paper-based device detected the target in less than 2 min, demonstrating its convenience for on-field applications. [ABSTRACT FROM AUTHOR]

Aim Pancreatic carcinoma is an aggressive cancer that progresses without many symptoms. The difficulty of early diagnosis and an inadequate response to traditional treatments also cause the survival rate of pancreatic cancer to be low. Current research is focusing on methods of diagnosis and treatment, such as gene therapy, to increase survival rates. Small interfering ribonucleic acid (siRNA) has emerged as a promising advanced therapeutic strategy for cancer treatment. This study sought to silence the KRAS gene in the human pancreatic carcinoma cell line using a complex of small interfering ribonucleic acid (siRNA) and gold nanoparticles (AuNP). Methods In this study, 25 nM siRNA and gold nanoparticles at 0.5 mg/ml, 0.25 mg/ml, and 0.125 mg/ml concentrations were used to silence the KRAS gene in the CAPAN-1 cell line. Real-time PCR analysis, agarose gel electrophoresis, and double staining were carried out, and xCelligence real-time cell analysis (RTCA) was used to measure proliferation. Results The PCR analysis revealed crossing point (CP) values of actin beta (ACTB) ranging from 33.04 to 35.98, which was in the expected range for all samples. The interaction between the gold nanoparticle/siRNA complex in the double staining analysis revealed that the most effective concentration of gold nanoparticle was 0.125 mg/ml. The WST-1 technique showed that siRNA/AuPEI cells in application groups had a viability rate of over 90%, indicating no toxicity or side effects. The xCELLigence RTCA® showed that at hour 72, there was a significant difference in proliferation in the 0.5 mg/mL PEI/AuNP-siRNA, 0.25 mg/mL PEI/AuNP-siRNA, and 0.125 mg/mL PEI/AuNP-siRNA application groups compared to the control and siRNA groups (p

Fibrin clots are crucial for hemostasis and the healing of wounds; nevertheless, excessive blood clotting plays an important role in many chronic diseases, including cardiovascular disease. In this study, we demonstrated the effect of the prepared AuNPs@PANI core/shell on the formed fibrin network. The synthesis of nanoparticles combining electrically conducting polymers polyaniline (PANI) and gold nanoparticles (AuNPs) is an appealing field of research currently because of their physical features and prospective applications in biochemistry. AuNPs showed surface plasmonic resonance (SPR) properties in the visible region at 520 nm then, after coating with PANI, there was a dramatic red shift to 610 nm. The morphological conformation was confirmed by characterization at the microscopic (TEM, SEM, EDX). The PANI shell plays a crucial role in this system, first enhances the stability of AuNPs core; also, the surface of the PANI shell has positive charges (zeta potential = +17.8 mV), leading to electrostatic interactions with fibrin clots that have negatively charged surfaces. The synthesized core/shell AuNPs@PANI showed good efficiency for degrading fibrin networks under 1:30 h of irradiation by an external source of laser light, which is a result of AuNPs’ ability to absorb light at 520 nm. The degradation of fibrin was observed using a scanning electron microscope (SEM), which showed a clear change in the shape of the network. The appearance of fibrous endings and gaping indicates the beginning of the degradation and melting of the fibrin network in different sites of the clot. Overall, this method could have a major influence on disease states, for example, deep vein thrombosis, through a localized, catheter-based approach.

The highly tunable surface chemistry of gold nanoparticles (AuNPs) makes them ideal candidates for cancer treatments. Modification of AuNP surface chemistry creates linkage points for different surface coatings whose chemical structure regulates AuNP interactions with cells and thus plays a key role in AuNP cytotoxicity. This study looked at AuNPs functionalized with three polyethylene glycol (PEG) coatings, differing in end group functionality: PEG methyl terminated thiol (PEGCH3), PEG amine terminated thiol (PEGNH2), and PEG carboxylic acid terminated thiol (PEGCOOH). Cytotoxic effects were compared across three cell lines: human embryonic kidney (HEK293T/17), prostate cancer (PC-3), and ovarian cancer (SKOV3). Biochemical assays measured the effect AuNPs elicit on the ability of single cells to form colonies, metabolize thiazolyl blue tetrazolium bromide (MTT), or produce reactive oxygen species (ROS) using 2′,7′-dichlorofluorescein. Overall, AuNP-PEG particles were minimally toxic. HEK293T/17 colony formation was significantly decreased with all but PEGCOOH particle types, and PEGNH2 treatments significantly decreased colony formation for all three tested cell lines. ROS production was significantly increased when treated with 100 µg mL−1 AuNP PEGNH2 in all three cell lines, with PEGCH3 also showing increased ROS in PC-3 cells. PEGCH3 reduced metabolic function (MTT metabolism) in only SKOV3 cells, while PEGCOOH was toxic to HEK293T/17 cells at 100 µg mL−1. These results suggest that differing end group chemistry leads to modest cytotoxic profiles for each AuNP that are cell line and coating dependent. Elucidation of AuNP mechanisms of toxicity is a critical step in the evaluation of the future therapeutic potential for these particles. [ABSTRACT FROM AUTHOR]

Glutamate is the most important excitatory neurotransmitter, which is relevant for the study of several diseases such as amyotrophic lateral sclerosis and Alzheimer. It is the form L-glutamic acid (Glu) takes at physiologically relevant pHs. The surface-enhanced Raman spectra of Glu obtained at pH values ranging from 3.3 to 12 are collected in the presence of silver and gold colloids and on solid substrates. The observed bands are compared with the positions of calculated normal modes for free neutral glutamic acid, glutamic acid monohydrate, glutamic acid bound to gold and silver atoms, and sodium glutamate. Although gold atoms prefer to bind to the NH2 group as compared to carbonyl groups, silver atoms prefer binding to hydroxyl groups more than binding to the amino group. SERS spectra of glutamic acid solutions with a pH value of 12, in which both carboxylic groups are deprotonated, indicate a complexation of the glutamic acid dianion with the sodium cation, which was introduced into the solution to adjust the pH value. Further research towards an optimal substrate is needed.

ABSTRACT: Melamine (MEL), enrofloxacin (ENR), sulfamethazine (SMZ), tetracycline (TC), and aflatoxin M1 (AFM1) are the main chemical contaminants in milk. It is necessary to detect these miscellaneous chemical contaminants in milk synchronously to ensure the safety of the milk. In this study, a multiple lateral flow immunoassay (LFIA) was developed for the detection of MEL, ENR, SMZ, TC, and AFM1 in milk. Under optimal experimental conditions, the cutoff values were 25 ng/mL for MEL, 1 ng/mL for ENR, 2.5 ng/mL for SMZ, 2.5 ng/mL for TC, and 0.25 ng/mL for AFM1 in milk samples. The limits of detection of LFIA were 0.173 ng/mL for MEL, 0.078 ng/mL for ENR, 0.059 ng/mL for SMZ, 0.082 ng/mL for TC, and 0.0064 ng/mL for AFM1. The recovery rates of LFIA in milk were 83.2–104.4% for MEL, 76.5–127.3% for ENR, 96.8–113.5% for SMZ, 107.1–166.6% for TC, and 93.5–130.3% for AFM1. The coefficients of variation were all less than 15%. As a whole, the developed multiple lateral flow immunoassay showed potential as a highly reliable and excellent tool for the rapid and sensitive screening of MEL, ENR, SMZ, TC, and AFM1 in milk.

2024 ECS Joseph W. Richards Research Fellowship – Summary Report [ABSTRACT FROM AUTHOR]

In this work, a gold nanoparticle (AuNP)-embedded composite polymer membrane for dip-catalysis is developed. Primarily, a polyvinylpyrrolidone-stabilized AuNP (PVP-AuNP) with an average size of 6.50 nm was synthesized by the reduction of a composite solution of Au salt and PVP. Next, the composite membrane was fabricated by simply depositing the PVP-AuNP on the Nylon membrane followed by UV cross-linking. The composite membrane having the cross-linked PVP-AuNP was utilized as a dip-catalyst for the aerobic oxidation of alcohols to carbonyl compounds under oxygen and clean reaction conditions. The catalyst was further tested for performing cross-aldol reactions. The PVP-AuNP-catalyzed oxidation reaction also has other noteworthy characteristics, such as a low catalyst loading (Au, 1.2 mol %), high yield, and selectivity with a broad substrate scope (aliphatic, aromatic, biphenyl, and heterocyclic alcohols). The turnover number (TON) and turnover frequency (TOF) for the oxidation reaction of the alcohol are calculated to be 74.5 and 12.41 h–1, respectively. The P4VP-AuNP dip-catalysts are highly stable under the reaction conditions without significant leaching of Au into the solution. The dip-catalyst demonstrates outstanding reusability up to 10 catalytic cycles while maintaining high catalytic performance and structural features. It can be easily recovered by simply pulling it out from the reaction mixture once the reaction is complete, followed by washing and drying. The practical usefulness of the suggested method was further demonstrated by the PVP-AuNP-catalyzed gram-scale synthesis of high-value chemicals like acetophenone. Although the AuNPs are already used for different reactions, their integration into dip-catalysts for oxidation of alcohols and cross-aldol reactions with a wide substrate scope is rare. Overall, these findings demonstrate that developing composite dip-catalyst systems is a realistic strategy for creating high-value chemicals in a sustainable and environmentally friendly way. [ABSTRACT FROM AUTHOR]

A fluorescence off-on method for the detection of Sorghum mosaic virus (SrMV) based on fluorescence resonance energy transfer (FRET) was developed in this study. The biosensor was realized by the adsorption of SrMV coat protein (CP) on gold nanoparticle (AuNP) and conjugation of anti-SrMV antibody (Ab) on cadmium telluride quantum dot (CdTe QD). The optimum quenching efficiency was about 50% obtained at a CdTe QD-Ab/AuNP-CP ratio of 1:7. Moreover, the feasibility of the developed biosensor was verified by the detection of purified CP and the limit of detection was estimated as 0.02 μg/mL. This strategy was also successfully applied to monitor SrMV CP in plant sap with a recovery rate between 97.7 and 107.4%. The developed biosensor is a simple, rapid, and efficient technique which does not need excessive washing and separation steps.

Electrochemical biosensors are used to detect adenosine triphosphate (ATP) levels, which are involved in a variety of biological processes, such as regulating cellular metabolism and biochemical pathways. Therefore, this research aims to develop an aptamer-based electrochemical biosensor with Screen Printed Carbon Electrode/gold nanoparticles (SPCE/AuNP) and collect data as well as information related to ATP detection. The modification of SPCE with AuNP increased the analyte’s binding sensitivity and biocompatibility. The aptamer was selected based on its excellent bioreceptor characteristics. Furthermore, aptamer–SH (F1) and aptamer-NH2 (F2) were immobilized on the SPCE/AuNP surface, which had been characterized using SEM, EIS, and DPV. Also, the ATP-binding aptamers were electrochemically characterized using the K3[Fe(CN)6] redox system and Differential Pulse Voltammetry (DPV). According to the optimization results using the Box-Behnken experimental design, the ideal conditions obtained from the factors influencing the experiment were the F1 concentration and incubation time of 4 µM and 24 h, respectively, as well as F1/F2/ATP incubation time of 7.5 min. Meanwhile, for the range of 0.1 to 100 µM, the detection (LoD) and quantification (LoQ) limits were 7.43 and 24.78 µM, respectively. Therefore, this aptasensor method can be used to measure ATP levels in real samples.

In the present paper, a colorimetric method for the determination of tazobactam and piperacillin based on plasmonic nanoparticles (AuNPs) is suggested. Plasmonic nanoparticles have gained interest for application in the creation of sensitive analytical techniques because of their unique features. The localized surface plasmon resonance (LSPR) absorption band for AuNPs with a wavelength 543.5 (A543.5) nm was used for analysis. The working parameters such as the amount of AuNPs and pH were optimized to obtain the optimum experimental conditions. The calibration curve for the colorimetric method was prepared with tazobactam and piperacillin concentrations ranging from 2.25-30.04 mg/L and0.52-10.33 mg/L, respectively. The detection limits were found to be 1.01 mg/L for tazobactam and 0.29 mg/L for piperacillin The AuNPs-based colorimetric method suggested in this work can use as an alternative analytical method for routine analysis of tazobactam and piperacillin because it is quick, simple, and affordable. [ABSTRACT FROM AUTHOR]

The study's main objective is to limit bacterial biofilm formation on fixed orthodontic appliances. Bacterial biofilm formation on such devices (e.g., brackets) causes enamel demineralization, referred to as white spot lesions (WSL). WSL is significant health, social and economic problem. We provide a nanotechnology‐based solution utilizing a nanocomposite of gold nanoparticles embedded in a polyoxoborate matrix (BOA: B—boron, O—oxygen, A—gold, Latin aurum). The nanocomposite is fully inorganic, and the coating protocol is straightforward, effective, and ecologically friendly (low waste and water‐based). Prepared coatings are mechanically stable against brushing with a toothbrush (up to 100 min of brushing). Bacteria adhesion and antibacterial properties are tested against Streptococcus mutans—common bacteria in the oral cavity. BOA reduces the adhesion of bacteria by around 78%, that is, from around 7.99 × 105 ± 1.33 × 105 CFU per bracket to 1.69 × 105 ± 3.07 × 104 CFU per bracket of S. mutans detached from unmodified and modified brackets, respectively. Modified fixed orthodontic brackets remain safe for eukaryotic cells and meet ISO 10993‐5:2009 requirements for medical devices. The gathered data show that BOA deposited on orthodontic appliances provides a viable preventive measure against bacteria colonization, which presents frequent and significant complications of orthodontic treatment. [ABSTRACT FROM AUTHOR]

Introduction: In clinical work, the realization of an early diagnosis of Subarachnoid hemorrhage (SAH) is primarily based on conventional computed tomography (CT), MR angiography, transcranial Doppler (TCD) ultrasound, and neurological assessments. However, the association between imaging manifestations and clinical findings is insufficiently perfect, particularly in SAH patients in acute phases with a lower amount of blood. The establishment of a direct, rapid and ultra-sensitive detection method based on electrochemical biosensors has emerged as a new competitive challenge in disease biomarkers research.Methods: In this study, a novel free-labeled electrochemical immunosensor for rapidly and sensitively detecting IL-6 in subarachnoid hemorrhage (SAH) blood has been developed using Au nanospheres-thionine composites (AuNPs/THI) as the interface modified on the electrode. Then, we detected IL-6 in blood samples from SAH patients by (enzyme-linked immunosorbent assay) ELISA and electrochemical immunosensor.Results: Under the best conditions, the developed electrochemical immunosensor exhibited a wide linear range from 10−2 ng/mL to 102 ng/mL with a low detection limit of 1.85 pg/mL. Furthermore, when the immunosensor was employed in the analysis of IL-6 in 100% serum, the results obtained by electrochemical immunoassay were consistent with those obtained by ELISA without suffering from other significant biological interference.Discussion: The designed electrochemical immunosensor realizes the detection of IL-6 in actual serum samples with high accuracy and sensitivity, and could potentially become a promising technique for applications in the clinical diagnosis of SAH.

A fluorescence off-on method for the detection of Sorghum mosaic virus (SrMV) based on fluorescence resonance energy transfer (FRET) was developed in this study. The biosensor was realized by the adsorption of SrMV coat protein (CP) on gold nanoparticle (AuNP) and conjugation of anti-SrMV antibody (Ab) on cadmium telluride quantum dot (CdTe QD). The optimum quenching efficiency was about 50% obtained at a CdTe QD-Ab/AuNP-CP ratio of 1:7. Moreover, the feasibility of the developed biosensor was verified by the detection of purified CP and the limit of detection was estimated as 0.02 μg/mL. This strategy was also successfully applied to monitor SrMV CP in plant sap with a recovery rate between 97.7 and 107.4%. The developed biosensor is a simple, rapid, and efficient technique which does not need excessive washing and separation steps. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (AuNPs) were synthesized using citrate reduction, also known as the Turkevich method. The AuNPs were compared with the commercially available product and later subjected to characterization. The AuNPs were 13 nm in diameter with a 2.7 × 108 M−1cm−1 extension coefficient. The calculated concentration was 5.1 nM through the Beer–Lambert law using UV–vis absorbance spectra. Further detailed characterization was applied, such as scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), elemental analysis using electro and DLS instruments, energy-dispersive X-ray spectroscopy (EDS), XRD, and Zeta potential. The synthesized AuNPs had a higher UV-absorbance peak of 0.93 in comparison to commercially available nanoparticles at 5.8 identical conditions. The characterization confirmed successful fabrication of colloidal-citrate-capped AuNPs and their dispersed and aggregated state with induced salt concentration. The shape and morphology were confirmed through XRD, showing a face-centered cubic lattice of {111}, confirmed at 38.1 round shape, and a crystalline lattice. AuNPs tend to be applied in sensing, detection, drug delivery, pharmaceuticals, and other applications in the environment and materials. Other applications include environmental contaminant detection, colorimetric sensors, antimicrobial applications, biosensing and drug delivery, tissue engineering, nanomedicines, optoelectronics, and catalysts. [ABSTRACT FROM AUTHOR]

Due to their unique chemical and physical properties, nanobiomaterials (NBMs) are extensively studied for applications in medicine and drug delivery. Despite these exciting properties, their small sizes also make them susceptible to toxicity. Whilst nanomaterial immunotoxicity and cytotoxicity are studied in great depth, there is still limited data on their potential genotoxicity or ability to cause DNA damage. In the past years, new medical device regulations, which came into place in 2020, were developed, which require the assessment of long-term NBM exposure; therefore, in recent years, increased attention is being paid to genotoxicity screening of these materials. In this article, and through an interlaboratory comparison (ILC) study conducted within the Horizon 2020 REFINE project, we assess five different NBM formulations, each with different uses, namely, a bio-persistent gold nanoparticle (AuNP), an IR-780 dye-loaded liposome which is used in deep tissue imaging (LipImage™815), an unloaded PACA polymeric nanoparticle used as a drug delivery system (PACA), and two loaded PACA NBMs, i.e. the cabazitaxel drug-loaded PACA (CBZ-PACA) and the NR668 dye-loaded PACA (NR668 PACA) for their potential to cause DNA strand breaks using the alkaline comet assay and discuss the current state of genotoxicity testing for nanomaterials. We have found through our interlaboratory comparison that the alkaline comet assay can be suitably applied to the pre-clinical assessment of NBMs, as a reproducible and repeatable methodology for assessing NBM-induced DNA damage. Workflow for assessing the applicability of the alkaline comet assay to determine nanobiomaterial (NBM)-induced DNA strand breaks, through an interlaboratory comparison study (ILC) [ABSTRACT FROM AUTHOR]

Bijon Kumar Sil,1 Mohd Raeed Jamiruddin,2 Md Ahsanul Haq,1 Mohib Ullah Khondoker,3 Nowshin Jahan,1 Shahad Saif Khandker,1 Tamanna Ali,1 Mumtarin Jannat Oishee,1 Taku Kaitsuka,4 Masayasu Mie,5 Kazuhito Tomizawa,6 Eiry Kobatake,5 Mainul Haque,7 Nihad Adnan8 1Gonoshasthaya-RNA Molecular Diagnostic and Research Center, Dhaka, 1205, Bangladesh; 2Department of Pharmacy, BRAC University, Dhaka, 1212, Bangladesh; 3Gonoshasthaya Samaj Vittik Medical College, Savar, Dhaka, 1344, Bangladesh; 4School of Pharmacy, International University of Health and Welfare, Okawa, Fukuoka, 831-8501, Japan; 5School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Kanagawa, 226-8502, Japan; 6Department of Molecular Physiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, 860-0811, Japan; 7The Unit of Pharmacology, Faculty of Medicine and Defence Health Universiti Pertahanan, Nasional Malaysia (National Defence University of Malaysia), Kuala Lumpur, 57000, Malaysia; 8Department of Microbiology, Jahangirnagar University, Savar, Dhaka, 1342, BangladeshCorrespondence: Nihad AdnanDepartment of Microbiology, Jahangirnagar University, Savar, Dhaka, 1342, BangladeshTel +8801705709910Email nihad@juniv.eduMainul HaqueThe Unit of Pharmacology, Faculty of Medicine and Defence Health, Universiti Pertahanan, Nasional Malaysia (National Defence University of Malaysia), Kem Perdana Sungai Besi, Kuala Lumpur, 57000, MalaysiaTel +60109265543Email runurono@gmail.comBackground: Serological tests detecting severe acute respiratory syndrome coronavirus− 2 (SARS-CoV-2) are widely used in seroprevalence studies and evaluating the efficacy of the vaccination program. Some of the widely used serological testing techniques are enzyme-linked immune-sorbent assay (ELISA), chemiluminescence immunoassay (CLIA), and lateral flow immunoassay (LFIA). However, these tests are plagued with low sensitivity or specificity, time-consuming, labor-intensive, and expensive. We developed a serological test implementing flow-through dot-blot assay (FT-DBA) for SARS-CoV-2 specific IgG detection, which provides enhanced sensitivity and specificity while being quick to perform and easy to use.Methods: SARS-CoV-2 antigens were immobilized on nitrocellulose membrane to capture human IgG, which was then detected with anti-human IgG conjugated gold nanoparticle (hIgG-AuNP). A total of 181 samples were analyzed in-house. Within which 35 were further evaluated in US FDA-approved CLIA Elecsys SARS-CoV-2 assay. The positive panel consisted of RT-qPCR positive samples from patients with both < 14 days and > 14 days from the onset of clinical symptoms. The negative panel contained samples collected from the pre-pandemic era dengue patients and healthy donors during the pandemic. Moreover, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of FT-DBA were evaluated against RT-qPCR positive sera. However, the overall efficacies were assessed with sera that seroconverted against either nucleocapsid (NCP) or receptor-binding domain (RBD).Results: In-house ELISA selected a total of 81 true seropositive and 100 seronegative samples. The sensitivity of samples with < 14 days using FT-DBA was 94.7%, increasing to 100% for samples > 14 days. The overall detection sensitivity and specificity were 98.8% and 98%, respectively, whereas the overall PPV and NPV were 99.6% and 99%. Moreover, comparative analysis between in-house ELISA assays and FT-DBA revealed clinical agreement of Cohen’s Kappa value of 0.944. The FT-DBA showed sensitivity and specificity of 100% when compared with commercial CLIA kits.Conclusion: The assay can confirm past SARS-CoV-2 infection with high accuracy within 2 minutes compared to commercial CLIA or in-house ELISA. It can help track SARS-CoV-2 disease progression, population screening, and vaccination response. The ease of use of the assay without requiring any instruments while being semi-quantitative provides the avenue of its implementation in remote areas around the globe, where conventional serodiagnosis is not feasible.Keywords: COVID-19, SARS-CoV-2, dot-blot immunoassay, AuNP, gold nanoparticle, serosurveillance, nucleocapsid, receptor binding domain

[Display omitted] Fibrin clots are crucial for hemostasis and the healing of wounds; nevertheless, excessive blood clotting plays an important role in many chronic diseases, including cardiovascular disease. In this study, we demonstrated the effect of the prepared AuNPs@PANI core/shell on the formed fibrin network. The synthesis of nanoparticles combining electrically conducting polymers polyaniline (PANI) and gold nanoparticles (AuNPs) is an appealing field of research currently because of their physical features and prospective applications in biochemistry. AuNPs showed surface plasmonic resonance (SPR) properties in the visible region at 520 nm then, after coating with PANI, there was a dramatic red shift to 610 nm. The morphological conformation was confirmed by characterization at the microscopic (TEM, SEM, EDX). The PANI shell plays a crucial role in this system, first enhances the stability of AuNPs core; also, the surface of the PANI shell has positive charges (zeta potential = +17.8 mV), leading to electrostatic interactions with fibrin clots that have negatively charged surfaces. The synthesized core/shell AuNPs@PANI showed good efficiency for degrading fibrin networks under 1:30 h of irradiation by an external source of laser light, which is a result of AuNPs' ability to absorb light at 520 nm. The degradation of fibrin was observed using a scanning electron microscope (SEM), which showed a clear change in the shape of the network. The appearance of fibrous endings and gaping indicates the beginning of the degradation and melting of the fibrin network in different sites of the clot. Overall, this method could have a major influence on disease states, for example, deep vein thrombosis, through a localized, catheter-based approach. [ABSTRACT FROM AUTHOR]

Oncolytic adenoviruses (OAd) can be employed to efficiently eliminate cancer cells through multiple mechanisms of action including cell lysis and immune activation. Our OAds, AdΔΔ and Ad-3∆-A20T, selectively infect, replicate in, and kill adenocarcinoma cells with the added benefit of re-sensitising drug-resistant cells in preclinical models. Further modifications are required to enable systemic delivery in patients due to the rapid hepatic elimination and neutralisation by blood factors and antibodies. Here, we show data that support the use of coating OAds with gold nanoparticles (AuNPs) as a possible new method of virus modification to help augment tumour uptake. The pre-incubation of cationic AuNPs with AdΔΔ, Ad-3∆-A20T and wild type adenovirus (Ad5wt) was performed prior to infection of prostate/pancreatic cancer cell lines (22Rv, PC3, Panc04.03, PT45) and a pancreatic stellate cell line (PS1). Levels of viral infection, replication and cell viability were quantified 24–72 h post-infection in the presence and absence of AuNPs. Viral spread was assessed in organotypic cultures. The presence of AuNPs significantly increased the uptake of Ad∆∆, Ad-3∆-A20T and Ad5wt in all the cell lines tested (ranging from 1.5-fold to 40-fold), compared to virus alone, with the greatest uptake observed in PS1, a usually adenovirus-resistant cell line. Pre-coating the AdΔΔ and Ad-3∆-A20T with AuNPs also increased viral replication, leading to enhanced cell killing, with maximal effect in the most virus-insensitive cells (from 1.4-fold to 5-fold). To conclude, the electrostatic association of virus with cationic agents provides a new avenue to increase the dose in tumour lesions and potentially protect the virus from detrimental blood factor binding. Such an approach warrants further investigation for clinical translation. [ABSTRACT FROM AUTHOR]

In recent years, infectious diseases caused by drug-resistant bacteria have been expanding worldwide. Methicillin-resistant Staphylococcus aureus (MRSA) is a type of drug-resistant bacterium that causes nosocomial infections. To detect nosocomial infections at an early stage, it is important to develop a rapid and simple method to detect MRSA. In this study, we developed a simple colorimetric biosensor that separates target DNA-probe-modified gold nanoparticles (AuNPs) using a freeze-dried Ca2+-cross-linked 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO)- oxidized cellulose nanofiber (TOCN) filter. First, the AuNP probe was hybridized with the target ssDNA to form a complex. Because of the large size of the DNA–AuNP probe complex, it was trapped by the filter and showed the red color characteristic of AuNPs. The color intensity of the AuNPs increased with the DNA concentration. The color filter sensor was able to quantify the target DNA in the range of 10–1000 pM without polymerase chain reaction (PCR) amplification (3.0 × 108–3.0 × 1010 copies). The sensor we developed can filter out unreacted AuNP probes, thus eliminating the need for bond/free (B/F) separation. Our sensing system was able to finish detection in 1 min and was selective enough to distinguish between MRSA and S. aureus (SA). [ABSTRACT FROM AUTHOR]

Malignant pleural effusion is one of the most common complications of advanced lung cancer and there is no effective clinical treatment at present. Here, we constructed an aptamer-siRNA chimeras/PEI/PEG/gold nanoparticle (AuNP)/collagen membrane that can progressively activate T cells by layer by layer assembly. Electron microscope showed this collagen membrane could be divided into 10 layers with a total thickness of 50–80μm, and AuNPs could be observed. Aptamer-siRNA chimeras could bind specifically to OX40+ cells and silencing programmed death receptor-1 (PD-1) gene. In vitro experiments demonstrated that chimeras/PEI/PEG/AuNPs gradually activated T cells to continuously kill lung adenocarcinoma cells in malignant pleural effusion. Animal experiments showed that chimeras/PEI/PEG/AuNP/collagen membrane effectively treated malignant pleural effusion. Compared with PD-1 inhibitor group, the number of cancer cells, ki-67 proliferation index and CD44 expression in the pleural effusion was significantly decreased and the lymphocyte/cancer cell ratio was significantly increased in the chimeras/AuNP-CM group. Flow cytometry showed that compared with PD-1 inhibitor group, T cell number in the chimeras/AuNP-CM group was significantly increased, while the proportion of PD-1+ T cells was markedly decreased. In conclusion, we constructed an chimeras/PEI/PEG/AuNP/collagen membrane, which was more effective in the treatment of malignant pleural effusion, and had less side effects than PD-1 inhibitors.

Carbapenemase-producing Gram-negative bacteria have been increasingly reported. Simple and sensitive methods for carbapenemase detection are still needed. In this study, a gold nanoparticle (AuNP) solution was modified by the addition of zinc sulfate (ZnSO4) for improving the conventional GoldNano Carb (cGoldC) test, and the modified GoldC (mGoldC) test was then evaluated for phenotypic detection of carbapenemase production in Gram-negative bacilli clinical isolates. ZnSO4 was added to give final concentrations of 0.25, 0.5, 0.75, and 1 mM. The performance of the mGoldC test was evaluated in Enterobacterales, Acinetobacter spp., and Pseudomonas aeruginosa isolates from six hospitals in different regions using polymerase chain reaction (PCR) as a gold standard. The AuNP solution with 0.25 mM ZnSO4 was used for the mGoldC test. Evaluation of the mGoldC test in 495 Enterobacterales, 212 Acinetobacter spp., and 125 P. aeruginosa isolates (including 444 carbapenemase producers and 388 non-carbapenemase producers) revealed sensitivity, specificity, a positive likelihood ratio, and a negative likelihood ratio of 98.6%, 98.2%, 54.7, and 0.01, respectively. This test is fast, easy to perform, cost-effective (~0.25 USD per test), and highly sensitive and specific for routine carbapenemase detection, thus leading to effective antimicrobial therapy and infection control measures. [ABSTRACT FROM AUTHOR]

Background: Gold nanoparticles (AuNP) may be useful in precision radiotherapy and disease monitoring as theragnostic agents. In diagnostics, they can be detected by computerized tomography (CT) because of their higher atomic number. AuNP may also improve the treatment results in radiotherapy due to a higher cross-section, locally improving the physically absorbed dose. Methods: Key parameters values involved in the use of AuNP were imposed to be optimal in the clinical scenario. Mass concentration of AuNP as an efficient contrast agent in clinical CT was found and implemented in a Monte Carlo simulation method for dose calculation under different proposed therapeutic beams. The radiosensitization effect was determined in irradiated cells with AuNP. Results: an AuNP concentration was found for a proper contrast level and enhanced therapeutic effect under a beam typically used for image-guided therapy and monitoring. This lower energetic proposed beam showed potential use for treatment monitoring in addition to absorbed dose enhancement and higher radiosensitization at the cellular level. Conclusion: the results obtained show the use of AuNP concentration around 20 mg Au·mL−1 as an efficient tool for diagnosis, treatment planning, and monitoring treatment. Simultaneously, the delivered prescription dose provides a higher radiobiological effect on the cancer cell for achieving precision radiotherapy. [ABSTRACT FROM AUTHOR]

An electrochemiluminescence (ECL) aptasensor for the detection of the milk protein allergen β-lactoglobulin (β-LG) using nanocomposite as luminophore was fabricated. The Ru-AuNPs/GNP/Naf complex was formed by combining the Rubpy32+-AuNPs complex (Ru-AuNPs), prepared by modifying the negatively charged surface of gold nanoparticles (AuNPs) with positively charged Rubpy32+ through electrostatic interactions and the graphene nanoplatelets-Nafion (GNP/Naf) at a ratio of 2:1. The nanocomposite was coated on the surface of the screen-printed electrode (SPCE) through the film-forming properties of Nafion. A layer of chitosan (CS) was coated onto this modified electrode, and later amine-terminated β-LG aptamers were covalently attached to the CS/Ru-AuNP/GNP/Naf via glutaraldehyde (GLUT) cross-linking. When β-LG was incubated with the aptasensor, a subsequent decrease in ECL intensity was recorded. Under the optimal conditions, the ECL intensity of the aptasensor changed linearly with the logarithmic concentration of β-LG, in the range 0.1 to 1000 pg/ml, and the detection limit was 0.02 pg/mL (3σ/m). The constructed aptasensor displayed simple and fast determination of β-LG with excellent reproducibility, stability, and high specificity. Additionally, the proposed ECL aptasensor displayed high recoveries (92.5–112%) and low coefficients of variation (1.6–7.8%), when β-LG fortified samples were analyzed. Integrating Ru-AuNPs/GNP/Naf nanocomposite in the ECL aptasensor paves the way towards a cost-effective and sensitive detection of the milk allergen β-LG. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (AuNP) are promising anti-cancer agents because of their modifiable properties and high biocompatibility. This study used multiple parallel analyses to investigate the cytotoxic properties of 5 nm AuNP conjugated to four different ligands with distinct surface chemistry: polyethylene glycol (PEG), trimethylammonium bromide (TMAB), 4-dimethylaminopyridine (DMAP), and carboxyl (COOH). We used a range of biochemical and high-content microscopy methods to evaluate the metabolic function, oxidative stress, cell health, cell viability, and cell morphology in SKOV3 ovarian cancer cells. Each AuNP displayed a distinct cytotoxicity profile. All AuNP species assessed exhibited signs of dose-dependent cytotoxicity when morphology, clonogenic survival, lysosomal uptake, or cell number were measured as the marker of toxicity. All particles except for AuNP-COOH increased SKOV3 apoptosis. In contrast, AuNP-TMAB was the only particle that did not alter the metabolic function or induce significant signs of oxidative stress. These results demonstrate that AuNP surface chemistry impacts the magnitude and mechanism of SKOV3 cell death. Together, these findings reinforce the important role for multiparametric cytotoxicity characterization when considering the utility of novel particles and surface chemistries. [ABSTRACT FROM AUTHOR]

Lipid membrane containing cholesterol gold nanoparticle and cationic, neutral and anionic lipid was prepared on gold electrode using mixed monolayer cushion for ultrasensitive electrochemical label-free DNA and unprocessed whole E. coli bacterial cell detection in the presence of K3[Fe(CN)6]/K4[Fe(CN)6] in physiological buffer. Cholesterol and gold nanoparticles interactions were characterized by dynamic light scattering (DLS) technique, cyclic voltammetry (CV), electrochemical impedance (EIS), Fourier infrared transform (FTIR) and transmission electron microscope (TEM) techniques. Insulation property of mixed monolayer towards K3[Fe(CN)6]/K4[Fe(CN)6] is influenced by the presence of lipid–gold nanoparticles. DNA hybridization studies indicate higher discrimination efficiency (75 ± 3%) between the unhybridized ssDNA and hybridized dsDNA for the binary cationic/cationic lipid–gold composite compared to the discrimination efficiencies 20 ± 3% and 5% noticed for other composite membranes cationic/anionic, cationic/neutral and anionic/neutral membranes constructed on thiol monolayer cushion. The sensor showed a wide linear range from 10–9 to 10–19 M with lowest detection limit (LOD) of 10–19 M and limit of quantification (LOQ) 10–17 M. E. coli DNA was used as a model system. For cross-reactivity validation, Staphylococcus, Enterococcus and E. coli were isolated and used for the direct and selective sensing of whole E. coli cell at 106 CFU/mL by label-free impedance technique. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (AuNPs) were synthesized using citrate reduction, also known as the Turkevich method. The AuNPs were compared with the commercially available product and later subjected to characterization. The AuNPs were 13 nm in diameter with a 2.7 × 108 M−1cm−1 extension coefficient. The calculated concentration was 5.1 nM through the Beer–Lambert law using UV–vis absorbance spectra. Further detailed characterization was applied, such as scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), elemental analysis using electro and DLS instruments, energy-dispersive X-ray spectroscopy (EDS), XRD, and Zeta potential. The synthesized AuNPs had a higher UV-absorbance peak of 0.93 in comparison to commercially available nanoparticles at 5.8 identical conditions. The characterization confirmed successful fabrication of colloidal-citrate-capped AuNPs and their dispersed and aggregated state with induced salt concentration. The shape and morphology were confirmed through XRD, showing a face-centered cubic lattice of {111}, confirmed at 38.1 round shape, and a crystalline lattice. AuNPs tend to be applied in sensing, detection, drug delivery, pharmaceuticals, and other applications in the environment and materials. Other applications include environmental contaminant detection, colorimetric sensors, antimicrobial applications, biosensing and drug delivery, tissue engineering, nanomedicines, optoelectronics, and catalysts.

Alpha-fetoprotein (AFP) is a fetal protein that can indicate congenital anomalies such as Down syndrome and spinal canal blockage when detected at abnormal levels in pregnant women. Current AFP detection methods rely on invasive blood or serum samples, which require sophisticated equipment. From the many solutions proposed, colorimetric paper-based assays excel in point-of-care settings. The concept of paper-based ELISA (p-ELISA) enhances traditional methods, aligning with the ASSURED criteria for diagnostics in resource-limited regions. Despite success in microfluidic paper-based assay devices, laser printing remains underexplored for p-ELISA. Additionally, modifying the paper surface provides an additional layer of sensitivity enhancement. In this study, we developed a novel laser-printed paper-based ELISA (LP-pELISA) for rapid, sensitive, and noninvasive detection of AFP in saliva samples. The LP-pELISA platform was fabricated by printing hydrophobic barriers on filter paper using a laser printer, followed by depositing hydroxyapatite (HAp) as an immobilization material for the antibodies. The colorimetric detection was achieved using AuNPs functionalized with anti-AFP antibodies and silver nitrate enhancement. The LP-pELISA exhibited a linear response for AFP detection in both buffer and saliva samples over a range of 1.0–800 ng mL−1, with a limit of detection (LOD) reaching 1.0 ng mL−1. The assay also demonstrated good selectivity, repeatability, reproducibility, and stability. The LP-pELISA was further validated by testing spiked human saliva samples, showing its potential for point-of-care diagnosis of congenital disabilities. The LP-pELISA is a noninvasive platform showcasing simplicity, cost-effectiveness, and user-friendliness, utilizing laser printing, hydroxyapatite modification, and saliva samples to efficiently detect AFP. Beyond its application for AFP, this method's versatility extends to other biomarkers, positioning it as a catalyst for the evolution of paper-based biosensors. The LP-pELISA holds promise as a transformative tool for point-of-care diagnostics, fostering advancements in healthcare with its innovative technology. [Display omitted] • The study introduces laser printing to create paper-based ELISA. • Hydroxyapatite was used to immobilize antibody binding and enhance assay performance. • Colorimetric detection using silver-enhanced AuNPs for rapid and sensitive readout. • The LP-pELISA shows a high Greenness score aligning with ecofriendly practices. [ABSTRACT FROM AUTHOR]

Plant‐mediated nanoparticle synthesis is an eco‐friendly method designed to reduce toxicity. This research reports the effects of gold nanoparticle green synthesis on immune modulation for the first time, using aqueous extract from Turnera diffusa. First, the chemical composition showed that T. diffussa is abundant in compounds, such as oplopanone, γ‐eudesmol, hydroquinone‐β‐d‐glucoside (arbutin) and inositol. The synthesized gold nanoparticles (AuNPDam) were confirmed by ultraviolet visible (UV‐Vis) spectrophotometry; the micro‐graphical analysis confirmed the average size that was estimated about 24 nm, which were mostly spherical in shape. The Fourier transform infrared spectroscopy (FTIR) technique helped to confirm the functional groups of the synthesized AuNPDam. Its antioxidant capability was analysed using 2,2‐diphenyl‐1‐picrylhydarzyl (DPPH), superoxide radical scavenging and fluorescence recovery after photobleaching (FRAP) methods. These results indicated a worthy antioxidant activity. The synthesized AuNPDam showed strong antibacterial activity against Vibrio parahaemolyticus and Aeromonas hydrophila. Interestingly, AuNPDam were nontoxic to Longfin yellowtail head kidney leukocytes after 24 h. The phagocytosis activity, production of reactive oxygen species and nitric oxide were also enhanced in leukocytes treated with AuNPDam. Overall, the results suggested that AuNPDam is non‐cytotoxic, displays strong bactericidal activity and has therapeutic properties by enhancing the immune system. [ABSTRACT FROM AUTHOR]

Purpose: Intrinsic radioresistance and increased proliferation rates in head and neck cancers (HNCs) are associated with negative radiotherapy (RT) treatment responses. The use of gold nanoparticles (AuNPs) as radiosensitizers could enable total radiation dose reduction and lowered radiation toxicity. AuNP radiosensitization may overcome hypoxia‐induced radioresistance and treatment‐induced accelerated repopulation of cancer cells in HNCs, improving radiotherapy outcomes. Methods: Tumor control was determined by considering individual cancer cell responses in probabilistic computational simulations using HYP‐RT software for clinical radiotherapy doses and fractionation schedules along with three different nanoparticle administration schedules. Antagonistic tumor hypoxia and rapid tumor regrowth due to accelerated repopulation of cancers cells were taken into consideration. Results: Simulations indicate that tumors that are conventionally uncontrollable can be controlled with AuNP radiosensitization. In simulations where the absence of AuNPs required radiotherapy doses above standard clinical prescriptions, reoccurring AuNP administration allowed for radiation dose reductions below standard clinical dose prescriptions. For example, considering a 2 Gy per fraction radiotherapy schedule, tumor control was achieved with 57.2 ± 5.1 Gy (P = <0.0001) for weekly AuNP administration and 53.0 ± 4.0 Gy (P = <0.0001) for biweekly AuNP administration compared to 69.9 ± 5.8 Gy with no radiosensitization. Conclusions: AuNPs decreased the predicted RT total doses required to achieve tumor control via total stem cell elimination, offering an optimistic prediction and method for which hypoxia‐induced and rapidly growing radioresistant tumors are treated more effectively. Outcomes are also shown to be sensitive to the RT schedule with data for hyperfractionated RT indicating the greatest benefits from radiosensitization. [ABSTRACT FROM AUTHOR]

Nanogels (Ng) are crosslinked polymer-based hydrogel nanoparticles considered to be next-generation drug delivery systems due to their superior properties, including high drug loading capacity, low toxicity, and stimuli responsiveness. In this study, dually thermo-pH-responsive plasmonic nanogel (AuNP@Ng) was synthesized by grafting poly (N-isopropyl acrylamide) (PNIPAM) to chitosan (CS) in the presence of a chemical crosslinker to serve as a drug carrier system. The nanogel was further incorporated with gold nanoparticles (AuNP) to provide simultaneous drug delivery and photothermal therapy (PTT). Curcumin's (Cur) low water solubility and low bioavailability are the biggest obstacles to effective use of curcumin for anticancer therapy, and these obstacles can be overcome by utilizing an efficient delivery system. Therefore, curcumin was chosen as a model drug to be loaded into the nanogel for enhancing the anticancer efficiency, and further, its therapeutic efficiency was enhanced by PTT of the formulated AuNP@Ng. Thorough characterization of Ng based on CS and PNIPAM was conducted to confirm successful synthesis. Furthermore, photothermal properties and swelling ratio of fabricated nanoparticles were evaluated. Morphology and size measurements of nanogel were determined by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Nanogel was found to have a hydrodynamic size of ~167 nm and exhibited sustained release of curcumin up to 72 h with dual thermo-pH responsive drug release behavior, as examined under different temperature and pH conditions. Cytocompatibility of plasmonic nanogel was evaluated on MDA-MB-231 human breast cancer and non-tumorigenic MCF 10A cell lines, and the findings indicated the nanogel formulation to be cytocompatible. Nanoparticle uptake studies showed high internalization of nanoparticles in cancer cells when compared with non-tumorigenic cells and confocal microscopy further demonstrated that AuNP@Ng were internalized into the MDA-MB-231 cancer cells via endosomal route. In vitro cytotoxicity studies revealed dose-dependent and time-dependent drug delivery of curcumin loaded AuNP@Ng/Cur. Furthermore, the developed nanoparticles showed an improved chemotherapy efficacy when irradiated with near-infrared (NIR) laser (808 nm) in vitro. This work revealed that synthesized plasmonic nanogel loaded with curcumin (AuNP@Ng/Cur) can act as stimuli-responsive nanocarriers, having potential for dual therapy i.e., delivery of hydrophobic drug and photothermal therapy.

Carbapenemase-producing Gram-negative bacteria have been increasingly reported. Simple and sensitive methods for carbapenemase detection are still needed. In this study, a gold nanoparticle (AuNP) solution was modified by the addition of zinc sulfate (ZnSO4) for improving the conventional GoldNano Carb (cGoldC) test, and the modified GoldC (mGoldC) test was then evaluated for phenotypic detection of carbapenemase production in Gram-negative bacilli clinical isolates. ZnSO4 was added to give final concentrations of 0.25, 0.5, 0.75, and 1 mM. The performance of the mGoldC test was evaluated in Enterobacterales, Acinetobacter spp., and Pseudomonas aeruginosa isolates from six hospitals in different regions using polymerase chain reaction (PCR) as a gold standard. The AuNP solution with 0.25 mM ZnSO4 was used for the mGoldC test. Evaluation of the mGoldC test in 495 Enterobacterales, 212 Acinetobacter spp., and 125 P. aeruginosa isolates (including 444 carbapenemase producers and 388 non-carbapenemase producers) revealed sensitivity, specificity, a positive likelihood ratio, and a negative likelihood ratio of 98.6%, 98.2%, 54.7, and 0.01, respectively. This test is fast, easy to perform, cost-effective (~0.25 USD per test), and highly sensitive and specific for routine carbapenemase detection, thus leading to effective antimicrobial therapy and infection control measures.

Background: Gold nanoparticles (AuNP) may be useful in precision radiotherapy and disease monitoring as theragnostic agents. In diagnostics, they can be detected by computerized tomography (CT) because of their higher atomic number. AuNP may also improve the treatment results in radiotherapy due to a higher cross-section, locally improving the physically absorbed dose. Methods: Key parameters values involved in the use of AuNP were imposed to be optimal in the clinical scenario. Mass concentration of AuNP as an efficient contrast agent in clinical CT was found and implemented in a Monte Carlo simulation method for dose calculation under different proposed therapeutic beams. The radiosensitization effect was determined in irradiated cells with AuNP. Results: an AuNP concentration was found for a proper contrast level and enhanced therapeutic effect under a beam typically used for image-guided therapy and monitoring. This lower energetic proposed beam showed potential use for treatment monitoring in addition to absorbed dose enhancement and higher radiosensitization at the cellular level. Conclusion: the results obtained show the use of AuNP concentration around 20 mg Au·mL−1 as an efficient tool for diagnosis, treatment planning, and monitoring treatment. Simultaneously, the delivered prescription dose provides a higher radiobiological effect on the cancer cell for achieving precision radiotherapy.

Huey-Ming Lo,1,2 Ming-Chieh Ma,1 Jiunn-Min Shieh,3,4 Hui-Ling Chen,5 Wen-Bin Wu1 1School of Medicine, Fu-Jen Catholic University, New Taipei City, Taiwan; 2Section of Cardiology, Department of Internal Medicine, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan; 3Department of Internal Medicine, Chi-Mei Medical Center, Tainan, Taiwan; 4Department of Recreation and Healthcare Management, Chia Nan University of Pharmacy and Science, Tainan, Taiwan; 5Holistic Education Center, Fu-Jen Catholic University, New Taipei City, Taiwan Introduction: Vascular smooth muscle cells (VSMCs) play an important role in the development and progression of atherosclerosis and vascular injuries in terms of proliferation and migration. Therefore, the aim of this study was to investigate the anti-migratory and proliferative effects of naked gold nanoparticles (AuNPs) on VSMCs. Materials and methods: One set of physically synthesized AuNPs (pAuNPs) and three sets of chemically synthesized AuNPs (cAuNPs) were tested. Results and discussion: Among them, the pAuNPs were found to significantly and markedly inhibit platelet-derived growth factor (PDGF)-induced VSMC migration. Transmission electron microscopy revealed that the pAuNPs were ingested and aggregated in the cytoplasm at an early stage of treatment, while the viability of VSMCs was not affected within 24 hours of treatment. The pAuNP treatment enhanced cellular mitochondrial activity but inhibited basal and PDGF-induced VSMC proliferation, as determined by MTT, WST-1, and BrdU cell proliferation assays. Furthermore, the pAuNPs did not interfere with PDGF signaling or matrix metalloproteinase-2 expression/activity. Unlike the cAuNPs, the pAuNPs could markedly reduce VSMC adhesion to collagen, which was supported by the findings that the pAuNPs could inhibit collagen-induced tyrosine protein and focal adhesion kinase (FAK) phosphorylation and actin cytoskeleton reorganization during cell adhesion. The in vitro effects of the pAuNPs were confirmed in the in vivo rat balloon-injured carotid artery model by diminishing the proliferating VSMCs. Conclusion: Taken together, the present study provides the first evidence that naked pAuNPs can reduce VSMC migration and compromise cell adhesion by affecting FAK and tyrosine-protein activation. The pAuNPs also have an inhibitory effect on PDGF-induced VSMC proliferation and can reduce proliferating/migrating VSMC expression in vivo. Keywords: adhesion, AuNP, cardiovascular disease, FAK, platelet-derived growth factor, VSMC, TEM

The electrochemical DNA biosensor has been developed for the detection of Listeria monocytogenes in raw milk samples. The electrochemical studies of the developed biosensor was recorded by cyclic voltammetry (CV) and electrochemical impedance (EI) using methylene blue (MB) and potassium ferricyanide K3Fe(CN)−6 as redox indicators. The selectivity of the developed biosensor was demonstrated using complementary and mismatch oligonucleotide sequences. The sensitivity (S) of the developed sensor was recorded as 3461 (μA/cm2)/ng and limit of detection (LOD) was found to be 82 fg/6 µl with the regression coefficient (R2) 0.941 using CV. The sensor was characterized by field emission scanning electron microscopy (FE-SEM). The electrode was found to be stable for six months, with only 10% loss in the initial CV current. [ABSTRACT FROM AUTHOR]

The in-situ detection of nanoplastics (NP) has attracted a great deal of attention due to their poisonous properties for both human beings or marine organism. Surface Enhanced Raman Scattering (SERS) is utilized to distinguish a typical NP, polystyrene (PS). However, PS NPs in aqueous solution could barely be detected through SERS. In this research, a SERS detection strategy based on the electric charge adsorption of the designed hetero-charged PS NPs and AuNPs was brought out. Under this strategy, the intensity of the Raman signal in aqueous solution was strong enough to identify PS NPs, and the lowest detection line was 0.08 wt%. All result indicated that once the spacing distance lower than 2 nm would have a great SERS performance. Moreover, the particles relationship of this SERS detection discovered by the FETEM results was different from the traditional SERS detection strategy. The SERS performance was related to the number of the PS NPs surrounded the AuNPs, and the intensity of the superposition electric field would have a progressive linear relationship with the number of the charged surrounded PS NPs. All these principle and phenomena would suit for further research of the MPs/NPs in marine pollution or detection biomarker in vivo directly. [Display omitted] • A strategy based on electric charge adsorption to support for enhanced SERS detection signal of the PS NPs. • The SERS detection in situ and in an aqueous solution utilized AuNPs for detecting the PS NPs. • Strong Raman signal intensity related to a particle spacing distance is below than 2 nm. • Once a strong electric field in an aqueous solution formed, the Raman signal is capable for SERS detection. [ABSTRACT FROM AUTHOR]

Using silicon-on-insulator MOSFET as the platform for RNA detection, the impact of Au nanoparticle (AuNP) distribution on sensitivity is investigated in this work. For the first time it is revealed that the AuNP formed by 2 nm as-deposited Au film (AuNP (2nm)) enables the largest amount of effective immobilization probe DNA, which enhances the capture efficiency of target microRNA-375, thus improving the sensitivity by 55% and 100%, compared to AuNP (1 nm) and AuNP (3 nm) case, respectively. It provides a new way to improve the microRNA detection sensitivity for sensors in which Au is used as the linker based on FET platform. [ABSTRACT FROM AUTHOR]

The generation of PNA-decorated gold nanoparticles (AuNPs) has revealed to be more difficult as compared to the generation of DNA-functionalized ones. The less polar nature of this artificial nucleic acid system and the associated tendency of the neutral poly-amidic backbone to aspecifically adsorb onto the gold surface rather than forming a covalent bond through gold-thiol interaction, combined with the low solubility of PNAs itself, form the main limiting factors in the functionalization of AuNP. Here, we provide a convenient methodology that allows to easily conjugate PNAs to AuNP. Positively charged PNAs containing a masked furan moiety were immobilized via a double exchange Diels-Alder cycloaddition onto masked maleimide-functionalized AuNPs in a one-pot fashion. Conjugated PNA strands retain their ability to selectively hybridize with target DNA strands. Moreover, the duplexes resulting from hybridization can be detached through a retro-Diels-Alder reaction, thus allowing straightforward catch-and-release of specific nucleic acid targets.

Sensitive detection of cancerous exosomes is critical to early diseases diagnosis and prognosis. Herein, a sensitive aptasensor was demonstrated for exosomes detection by surface plasmon resonance (SPR) with dual gold nanoparticle (AuNP)-assisted signal amplification. Dual nanoparticle amplification was achieved by controlled hybridization attachment of AuNPs resulting from electronic coupling between the Au film and AuNPs, as well as coupling effects in plasmonic nanostructures. By blocking the Au film surface with 11-Mercapto-1 -undecanol (MCU), nonspecific adsorption of AuNPs onto the SPR chip surface was suppressed and regeneration of the SPR sensor was realized. This method was highly sensitive and we have achieved the limit of detection (LOD) down to 5 × 103 exosomes/mL, which showed a 104-fold improvement in LOD compared to commercial ELISA. Moreover, the SPR sensor had the capability to differentiate the exosomes secreted by MCF-7 breast cancer cells and MCF-10A normal breast cells. Furthermore, the SPR sensor could effectively detect the exosomes in 30% fetal bovine serum. The work provides a sensitive and efficient quantification approach to detect cancerous exosomes and offers an avenue toward future diagnosis and comprehensive studies of exosomes. • High sensitive SPR sensor for exosomes detection was introduced. • Dual gold nanoparticle-assisted signal amplification was used to enhance the signal. • The limit of detection of exosomes was lowered to 5 × 103 exosomes/mL. • The work has great promise for exosomes-based disease diagnosis and prognosis.. [ABSTRACT FROM AUTHOR]

Abstract Marine bio-resources are being widely studied as an invaluable source of compounds with therapeutic applicability. In particular, macroalgae contain an extended variety of bioactive compounds with different structures and promising biological applications. In this work, Ulva lactuca L. (hereafter UL) was utilyzed for the synthesis of gold and silver nanoparticles. Full characterization by UV–Vis spectroscopy, TEM, HRTEM and STEM miscroscopies, Z Potential and FTIR spectroscopy was performed. The first time in the scientific literature, the composition of carbohydrates of UL extract and their changes observed after nanoparticles synthesis were explored in order to investigate their possible role in the biosynthetic process. The reducing power, total phenolic content and DPPH scavenging activity of UL extract, Au@UL and Ag@UL nanoparticles were determined. The effects of UL extract, Au@UL and Ag@UL were tested in vitro on the colon cancer cell lines HT-29 and Caco-2, on normal primary neonatal dermal fibroblast cell line PCS-201-010, as well as on normal colon cell line CCD-112CoN. Lastly, the apoptotic activity and cellular uptake evaluation was determined for Au@UL and Ag@UL. Highlights • Aqueous extract of Ulva lactuca served to synthesize gold and silver nanoparticles. • The composition of the extract before and after the synthesis was determined. • This provided new information about the possible role of sugars during the synthesis. • The effects of UL extract, Au@UL and Ag@UL were tested in vitro on colon cancer cells. • Apoptotic activity and cellular uptake evaluation was determined for Au@UL and Ag@UL. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Nanostructured surfaces made of immobilized gold nanoparticles. • Short and long-lasting anti-oxidant capacity against free-radical species. • Enhancement of reduced thiol half-life. • High density of immobilized gold nanoparticles may form an intelligent packaging. Abstract The development of new packaging able to preserve sensitive biomolecules against oxidative stress is an important field. Several studies refer to antioxidant properties carried out by colloidal gold nanoparticles (AuNP). Herein, the purpose was to check whether this property is preserved when AuNP are immobilized on a glass support. After nanostructured film preparation, the physicochemical characterization proved that AuNP were well-individualized in the films with a high density of immobilization. Two radicals: ABTS•+ and DPPH• were used to investigate their antioxidant capacity. The results showed that immobilized AuNP had a preserved antioxidant capacity characterized by a different kinetic: more controlled and more prolonged but with the same efficiency (vs the same quantity of colloidal AuNP). The AuNP films demonstrated a capacity to prevent from degradation a molecule containing a thiol function. A 10-fold increase of N-acetylcysteine half-life was measured using the immobilized AuNP, highlighting the interest of the developed and adaptable support. [ABSTRACT FROM AUTHOR]