Use Of Gold Nanoparticles Research Articles

Interaction of Colloidal Gold Nanoparticles with Urine and Saliva Biofluids: An Exploratory Study.

The use of gold nanoparticles for drug delivery, photothermal or photodynamic therapy, and biosensing enhances the demand for knowledge about the protein corona formed on the surface of nanoparticles. In this study, gold nanospheres (AuNSs), gold nanorods (AuNRs), and gold nanoflowers (AuNFs) were incubated with saliva or urine. After the interaction, the surface of gold nanoparticles was investigated using UV-VIS spectroscopy, zeta potential, and dynamic light scattering. The shifting of the localized surface plasmon resonance (LSPR) band, the increase in hydrodynamic diameter, and the changes in the surface charge of nanoparticles indicated the presence of biomolecules on the surface of AuNSs, AuNRs, and AuNFs. The incubation of AuNFs with saliva led to nanoparticle aggregation and minimal protein adsorption. AuNSs and AuNRs incubated in saliva were analyzed through liquid chromatography with tandem mass spectrometry (LC-MS/MS) to identify the 96 proteins adsorbed on the surface of the gold nanoparticles. Among the 20 most abundant proteins identified, 14 proteins were common in both AuNSs and AuNRs. We hypothesize that the adsorption of these proteins was due to their high sulfur content, allowing for their interaction with gold nanoparticles via the Au-S bond. The presence of distinct proteins on the surface of AuNSs or AuNRs was also investigated and possibly related to the competition between proteins present on the external layers of corona and gold nanoparticle morphology.

Gold nanoparticles in painted miniatures on ivory: Non-invasive evidence and characterisation

To document the use of gold nanoparticles (also known as “Purple of Cassius” pigment) in miniature painting, seven 19th century portraits from Czech collections containing purple colour were studied. The research was performed non-invasively, as it was not possible to sample the small-sized and delicate paintings. Large area X-ray fluorescence scanning indicated the presence of Purple of Cassius in four paintings, while in the three of them, the desired shade was achieved by mixing red and blue pigments, for example vermillion and Prussian blue. The detected gold nanoparticles were characterised in detail by X-ray powder diffraction and via innovative use of environmental scanning electron microscopy. The obtained diffraction patterns enabled the calculation of average size of the particles, which equalled to 8–14 nm. Based on available historical recipes, the pigment preparation was replicated in laboratory, yielding analogous pigment with similar particle size. For the first time, Purple of Cassius was identified and characterised in portrait miniatures.

Prospects in the use of gold nanoparticles as cancer theranostics and targeted drug delivery agents

Prospects in the use of gold nanoparticles as cancer theranostics and targeted drug delivery agents

Enhanced cytotoxic effect of doxorubicin conjugated gold nanoparticles on breast cancer model

BackgroundThe difficulty of achieving targeted drug delivery following administration of presently marketed anticancer therapeutics is still a concern. Metallic nanoparticles (NPs) appear to be promising in this regard. The present study focused on the use of gold nanoparticles (AuNPs) as a drug carrier for anticancer Doxorubicin (DOX) forming DOX–AuNPs nanocomposite. The anticancer effect of the prepared nanocomposite was evaluated using SRP essay on breast cancer cell line (MCF7) for different incubation times (24 h,48, and72hr). The prepared DOX–AuNPs nanocomposite was investigated by UV–visible spectroscopy, TEM, fluorescence spectroscopy, and FTIR spectroscopy.ResultsOur results showed that the prepared AuNPs and DOX–AuNPs nanocomposite have spherical and small size10 ± 2 nm and 12 ± 2 nm respectively. The potential cytotoxicity of the DOX-AuNPs nanocomposite on the MCF7 cell line was significantly increased compared to free DOX. The 20 µM DOX- AuNPs nanocomposite produced a similar decrease in cell survival as 80 µM free DOX.ConclusionFuture work is in progress to investigate the positive effects of the prepared nanocomposite for chemo-photothermal combination treatment.

Biosynthesis and Characterization of Gold Nanoparticles Produced Using Rhodococcus Actinobacteria at Elevated Chloroauric Acid Concentrations.

The growing industrial and medical use of gold nanoparticles (AuNPs) requires environmentally friendly methods for their production using microbial biosynthesis. The ability of actinobacteria of the genus Rhodococcus to synthesize AuNPs in the presence of chloroauric acid (HAuCl4) was studied. The effect of elevated (0.8-3.2 mM) concentrations of HAuCl4 on bacterial viability, morphology, and intracellular accumulation of AuNPs by different Rhodococcus species was shown. An increase in surface roughness, a shift of the zeta potential to the positive region, and the formation of cell aggregates of R. erythropolis IEGM 766 and R. ruber IEGM 1135 during nanoparticle synthesis were revealed as bacterial adaptations to toxic effects of HAuCl4. The possibility to biosynthesize AuNPs at a five times higher concentration of chloroauric acid compared to chemical synthesis, for example, using the citrate method, suggests greater efficiency of the biological process using Rhodococcus species. The main parameters of biosynthesized AuNPs (size, shape, surface roughness, and surface charge) were characterized using atomic force microscopy, dynamic and electrophoretic light scattering, and also scanning electron microscopy in combination with energy-dispersive spectrometry. Synthesized by R. erythropolis spherical AuNPs have smaller (30-120 nm) dimensions and are positively (12 mV) charged, unlike AuNPs isolated from R. ruber cells (40-200 nm and -22 mV, respectively). Such differences in AuNPs size and surface charge are due to different biomolecules, which originated from Rhodococcus cells and served as capping agents for nanoparticles. Biosynthesized AuNPs showed antimicrobial activity against Gram-positive (Micrococcus luteus) and Gram-negative (Escherichia coli) bacteria. Due to the positive charge and high dispersion, the synthesized by R. erythropolis AuNPs are promising for biomedicine, whereas the AuNPs formed by R. ruber IEGM 1135 are prone to aggregation and can be used for biotechnological enrichment of gold-bearing ores.

Conjugation of Hypericin to Gold Nanoparticles for Enhancement of Photodynamic Therapy in MCF-7 Breast Cancer Cells.

Breast cancer, among the different types of cancer, is one of the most diagnosed cancers and the leading cause of mortalities amongst women. Factors, including genetic and epigenetic alterations in tumors, make it resistant to therapies, which results in treatment failures and/or recurrence. Furthermore, the existing therapies have many unfavorable side effects leading to poor prognosis and reduced therapeutic outcomes. Photodynamic therapy (PDT) is one of the most effective cancer therapies with increased selectivity and specificity toward cancer cells. As a result, the use of gold nanoparticles (AuNP) further improves the effectiveness of PDT by increasing the drug loading capacity into the cells. In this study, hypericin (Hyp) photosensitizer (PS) was adsorbed on gold nanoparticles (AuNPs) by sonication to achieve physical adsorption of the PS to AuNP. The resulting compound was characterized by FTIR, Zeta potential, UV-Vis spectroscopy, and TEM. The compound was used for the PDT treatment of MCF-7 human breast cancer in vitro. Cellular responses at 12 h post-PDT at 10 J/cm2 were observed. Cellular morphology, LDH membrane integrity, ATP luminescence assay, and Annexin V/PI staining were performed. The results demonstrated typical cell death morphological features while the biochemical responses indicated increased LDH and decreased ATP levels. In conclusion, this study presents an insight into the application of advanced PDT in breast cancer cells by inducing cancer cell death in vitro via apoptosis.

Low-Tech Test for Mercury Detection: A New Option for Water Quality Assessment

Mercury pollution is a global environmental problem, especially in low-resource areas where artisanal iron mining is taking place and industrialization is on the rise. Therefore, there is a demand for simple methods for the determination of toxic metals at low. In this study, an on-field membrane lateral flow test system for sensitive and specific detection of Hg2+ in natural waters matrix is proposed. For this purpose, mercaptosuccinic acid (MSA) conjugated with protein-carrier (bovine serum albumin) was pre-impregnated in the test zone of the strip and used as a capping agent for mercury complexation. Quantitative evaluation of the analyte was provided by the use of gold nanoparticles stabilized with Tween-20 as a detecting agent. The sensing principle relies on the formation of Au–Hg nanoalloy during the migration of a solution containing Hg2+ along the strip, followed by capture in the test zone with the formation of a colored complex. Under optimum conditions, the proposed lateral flow test exhibited the linear correlation between color intensity in the test zone from the concentration of Hg2+ in the range of 0.04–25 ng/mL. The total analysis time was 11 min, without the need for the usage of additional instrumentation. The detection limit was estimated to be 0.13 ng/mL, which is 45 times lower than the WHO guidelines. The applicability of the proposed lateral flow test was confirmed by the analysis of natural waters, with the recoveries ranging from 70 to 120%. Due to the high affinity of Au to Hg and the use of a capping agent for mercury complexing, the developed system demonstrates high selectivity toward Hg2+. Compared to existing analytical methods, the proposed approach can be easily implemented and is characterized by economy and high analytical performance.

Label-free miniaturized electrochemical nanobiosensor triaging platform for swift identification of the bacterial type

In chronic wounds, rapid identification of the bacterial type is critical for immediate clinical assessment. A novel, cost-effective, and label-free electrochemical nanobiosensor was developed with the help of an indigenously fabricated carbon paste working electrode to rapidly identify the bacterial type. The proposed platform made use of gold nanoparticles (AuNPs) to boost electrochemical activity, and the strong affinity of boronic acid moieties for diols allowed for detection and differentiation of gram + ve and gram -ve bacteria on the same platform. A scalable and robust miniaturized Electrochemical Cell (E-Cell) designed for the developed electrodes assisted in reducing sample waste, detection time, and Limit of Detection (LOD). Within 15 min, the proposed nano biosensing platform identified Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria with an excellent recovery rate for the blind samples. Because of its size and the extra lipopolysaccharides (LPS) layer containing diols, the bioelectrode demonstrated a superior response to E. coli, effectively distinguishing it from S. aureus. Furthermore, the proposed biosensing platform demonstrated an excellent shelf-life and reproducibility with acceptable selectivity and exhibited an excellent specificity towards bacteria, making it an ideal candidate for rapid identification of the bacterial type.

Decalepis hamiltonii derived gold nanoparticles and photodynamic cytotoxic evaluation on skin melanoma (B16F10) cells as an effective drug delivery vehicle

The present work describes the use of gold nanoparticles as an efficient drug delivery vehicle to target skin melanoma cells B16F10 by photodynamic cancer therapy. For the first time, gold nanoparticles were synthesized from medicinally important plant Decalepis hamiltonii. The nanoparticles were further conjugated with an anticancer drug 5-aminolevulinic acid (5-ALA) and subsequently activating the photosensitizer molecule protoporphyrin IX (PpIX) through irradiation which resulted in the formation of reactive oxygen species. The roots of Decalepis hamiltonii was used for the synthesis of gold nanoparticles by a simple technique of reduction reaction and the morphology like size, shape, charge were evaluated using SEM (Scanning Electron Microscopy), DLS (Dynamic Light Scattering) and Zeta potential analysis. The cytotoxicity of nanoparticles were tested on RBCs and buccal cells which showed there was negligible damage to the cells. The photodynamic therapy was tested on skin melanoma cells and the results were compared with the standard drug 5-ALA and production of ROS molecules was evaluated using 2,7 dichlorofluorescein-diacetate (DCFH-DA) probe. The results indicated that the gold-5ALA conjugates had a deleterious effect on cancer cells specially after activation of protoporphyrin IX and showed a two fold increase in cytotoxic level post irradiation. Interestingly, the gold nanoparticles and conjugates which showed high cytotoxicity against cancer cells had no significant effect on normal RBCs and buccal cells indicating there was a specific target on cancer cells.

Biogenic green synthesis of gold nanoparticles and their applications – A review of promising properties

• The revolution of biogenic AuNPs in various fields have been explored. • Fabrication of AuNPs with improved properties by simple, efficient, and eco-friendly alternatives is explored. • Comparison of conventional chemical and biogenic synthesis of gold nanoparticle was clarified. • Research articles on the use of phyto-based AuNPs in medical applications have been critically discussed. • This review will be an eye-opener for the future researchers to explore the role of green AuNPs in other fields. There has been extensive research on the synthesis and use of gold nanoparticles (AuNPs) for medical applications due to their biocompatibility, oxide-free surface, easy bioconjugation, size- and shape-related optical properties. However, conventional methods for synthesizing AuNPs involve the use of toxic chemicals and high energy consumption and are not environmentally friendly. Due to the overwhelming advantages of the biogenic green methods, phyto-based AuNPs may become worthy materials for improved biomedical, sensor, catalysis, diagnostic and pharmaceutical applications. In this review, research articles concerning the use of phyto-based AuNPs in medical applications over the past decade are critically discussed as the green synthesis of AuNPs is continually explored for researchers to identify facile, efficient, and eco-friendly synthetic routes for improved AuNPs properties. In addition, this review will be useful for the future role that green AuNPs play in medicine as it recognizing obvious uses and the challenges currently faced during synthesis.

Field-deployable aptasensor with automated analysis of stain patterns for the detection of chlorpyrifos in water

Organophosphorus compounds such as chlorpyrifos (CPS) are causing serious environmental problems worldwide. Efficient monitoring of the CPS levels in water resources demands portable devices for on-field testing. Here we report the development of a CPS sensor coupled with smartphones for automated reading and data analysis. The sensing mechanism makes use of gold nanoparticles stabilized by a CPS-specific aptamer, where colloidal destabilization occurs in presence of competing CPS molecules. In particular, an innovative readout is proposed: quantitative analysis of the stain patterns left by evaporating drops of the test solutions. We have found that the CPS-induced destabilization suppresses the typical coffee-ring stain of the colloidal gold, and then exploited the phenomenon to quantitatively determine the CPS concentration in water samples. A strong correlation between CPS level in samples and the alteration of the stain patterns was established for a wide range of CPS concentrations (0.048 μM–482 μM). The limit of detection of the sensor was 0.2 μM. The assay was implemented on Whatman filter paper cards that were specially patterned by wax-printing. A smartphone-based Python program was written for fully automated image capture and processing. Notably, as we analyze the spatial configuration of the stains, the reading system is independent of external illumination. The system also enables data management and traceability, which are highly desirable attributes for environmental monitoring.

Sodium Alginate/Chitosan Scaffolds for Cardiac Tissue Engineering: The Influence of Its Three-Dimensional Material Preparation and the Use of Gold Nanoparticles.

Natural biopolymer scaffolds and conductive nanomaterials have been widely used in cardiac tissue engineering; however, there are still challenges in the scaffold fabrication, which include enhancing nutrient delivery, biocompatibility and properties that favor the growth, maturation and functionality of the generated tissue for therapeutic application. In the present work, different scaffolds prepared with sodium alginate and chitosan (alginate/chitosan) were fabricated with and without the addition of metal nanoparticles and how their fabrication affects cardiomyocyte growth was evaluated. The scaffolds (hydrogels) were dried by freeze drying using calcium gluconate as a crosslinking agent, and two types of metal nanoparticles were incorporated, gold (AuNp) and gold plus sodium alginate (AuNp+Alg). A physicochemical characterization of the scaffolds was carried out by swelling, degradation, permeability and infrared spectroscopy studies. The results show that the scaffolds obtained were highly porous (>90%) and hydrophilic, with swelling percentages of around 3000% and permeability of the order of 1 × 10−8 m2. In addition, the scaffolds proposed favored adhesion and spheroid formation, with cardiac markers expression such as tropomyosin, troponin I and cardiac myosin. The incorporation of AuNp+Alg increased cardiac protein expression and cell proliferation, thus demonstrating their potential use in cardiac tissue engineering.

Green synthesis and characterization of bisphosphonate conjugated gold nanoparticle with cissus quadrangularis extract to enhance orthodontic anchorage

Bisphosphonates are increasingly being used to treat several skeletal disorders such as osteoporosis. Several studies have shown that localized bisphosphonates improve orthodontic anchorage. Adverse reactions of the drug can be further avoided through more targeted drug delivery of this drug. The use of gold nanoparticles in bone tissue regeneration has shown promising results. The combination of bisphosphonate and gold nanoparticles has been shown to produce more targeted action through systemic administration in osteoporosis. The Adverse Effects of the Gold nanoparticle such as toxicity can be reduced through green synthesis. Cissus Quadrangularis is a green edible medicinal plant used in Ayurvedic preparations to treat osteoporosis, general inflammatory conditions, ulcers, menstrual disorders, hemorrhoids, and a variety of other ailments. The purpose of this study was to green synthesize Bisphosphonate conjugated gold nanoparticles with Cissus quadrangularis extract and test their antimicrobial and cytotoxic activity. Green synthesis of Bisphosphonate conjμgated gold nanoparticles using cissus quadrangularis extract was achieved and is characterised using visual colour change, uv spectrophotometer, TEM analysis. Gold nanoparticles have good antibacterial activity against Streptococcus mutans (150 ug/ml – 17 mm zone of Inhibition) & Lactobacillus (150 ug/ml – 20 mm zone of Inhibition) and showed 20% lethality at 50 ul concentration.

PEGylated Gold Nanoparticle Toxicity in Cardiomyocytes: Assessment of Size, Concentration, and Time Dependency.

Gold Nanoparticles (GNPs) have shown promising capabilities for use in many in-vivo applications such as gene and drug delivery, photothermal ablation of tumors, and tracking in many imaging modalities. Yet GNPs have thus far had limited use in cardiovascular medicine. Polyethylene glycol functionalized (PEGylated) GNPs have been extensively studied in a wide array of in vitro and in vivo models with results showing no apparent toxicity, but to our knowledge an investigation has never been performed to determine direct cardiomyocyte toxicity. In this study, we assessed if PEGylated GNPs exhibited direct toxicity to a primary culture of neonatal rat cardiomyocytes in order to establish PEGylated GNPs for potential future use in cardiovascular medicine applications. We present novel results that demonstrate both a particle size and concentration dependent relationship on cell viability. Cell viability was found to be significantly enhanced for many concentrations and sizes as compared to the control and increased linearly as a function of particle diameter. Additionally, viability increased in a parabolically dependent manner as a function of decreasing particle concentration. These new results could advance understanding of nanoparticle-cell interactions and lead to the development of new applications involving the use of gold nanoparticles in cardiovascular medicine.

Semiconductor Metal Oxides Doped with Gold Nanoparticles for Use in Acetone Gas Sensors

The effect of nanosized gold particles on the adsorption-sensitive properties of SnO2–Au sensors under the detection of acetone vapors has been studied. Different techniques for the preparation of SnO2–Au nanocomposites with an average Au particle size of 2 nm were applied. It has been found that a fivefold increase in the sensor response to acetone vapors and threshold sensitivity (C lim) of 0.1 ppm are achieved by adding gold to tin dioxide in the colloidal form during synthesis. While adding gold in ion form (Au (III)) leads to a growth of the sensor response to acetone vapors by 2.7 times and defines C lim of 0.2 ppm. The slope of the calibration curves of the SnO2–Au sensors allows registering acetone vapors at concentrations ranging from C lim to 5 ppm. This concentration range can be used for express diagnostics in diabetes. The enhanced sensitivity of SnO2–Au sensors to acetone vapors can be explained by an increase in the adsorption-catalytic activity of tin ions as a result of the modifying effect of sulfate groups and the envolving of highly dispersed gold in the adsorption – catalytic process of oxidation of acetone molecules.

Microalgae Peptide-Stabilized Gold Nanoparticles as a Versatile Material for Biomedical Applications.

Microalgae peptides have many medical and industrial applications due to their functional properties. However, the rapid degradation of peptides not naturally present in biological samples represents a challenge. A strategy to increase microalgae peptide stability in biological samples is to use carriers to protect the active peptide and regulate its release. This study explores the use of gold nanoparticles (AuNPs) as carriers of the Chlorella microalgae peptide (VECYGPNRPQF). The potential of these peptide biomolecules as stabilizing agents to improve the colloidal stability of AuNPs in physiological environments is also discussed. Spectroscopic (UV-VIS, DLS) and Microscopic (TEM) analyses confirmed that the employed modification method produced spherical AuNPs by an average 15 nm diameter. Successful peptide capping of AuNPs was confirmed with TEM images and FTIR spectroscopy. The stability of the microalgae peptide increased when immobilized into the AuNPs surface, as confirmed by the observed thermal shifts in DSC and high zeta-potential values in the colloidal solution. By optimizing the synthesis of AuNPs and tracking the conferred chemical properties as AuNPs were modified with the peptide via various alternative methods, the synthesis of an effective peptide-based coating system for AuNPs and drug carriers was achieved. The microalgae peptide AuNPs showed lower ecotoxicity and better viability than the regular AuNPs.

Sensing Soluble Immune Checkpoint Molecules and Disease-Relevant Cytokines in Cancer: A Novel Paradigm in Disease Diagnosis and Monitoring

Conventional detection of cancer involves highly invasive and expensive diagnostic procedures, often leading to non-compliance from patients. Therefore, there is a strong requirement for the development of non-invasive techniques that can facilitate rapid and timely diagnosis of the disease. The tumor-immune interaction often leads to anomalous expression of different soluble immune signaling molecules like cytokines and chemokines, thus making them promising candidates for sensing disease development and progression. Furthermore, differential expression of soluble isoforms of several immune-checkpoint molecules like PD-L1, CTLA-4 etc., has been found to have strong correlation with tissue-specific tumor development, disease progression and in many cases, disease prognosis. Therefore, development of biosensors, to rapidly detect and analyze the levels of these soluble immune molecules in different body fluids, requiring minimal sample volume, has the potential to be a game-changer in the field of cancer diagnosis. In addition, real time monitoring of these soluble immune checkpoint molecules in patient-derived biofluids may serve as decision support tools for patient selection for immunotherapeutic interventions. Majority of the biosensors designed to detect the soluble immune biomarkers, have used a two-antibody based sandwich system to capture the target analyte. However, new technologies using bioreceptors like the aptamers or nano-yeast scFv antibody fragments have made possible multiplexed detection of several analytes simultaneously. The use of gold nanoparticles or carbon nanotubes on the electrode surface serves to increase the sensitivity of detection, due to their high electrical conductivity. Further, fabrication of the biosensors on microfluidic platforms enable the detection of these analytes at ultra-low levels. This review discusses the recent advances made in the development of biosensors for specific and selective detection of these immune-markers that can be successfully translated to the clinics as a new paradigm in disease diagnosis and monitoring.

Extracellular Vesicle (EV) Dot Blotting for Multiplexed EV Protein Detection in Complex Biofluids.

Extracellular vesicles (EVs) are nanoscale vesicles secreted from cells, carrying biomolecular cargos similar to their cells of origin. Measuring the protein content of EVs in biofluids can offer a crucial insight into human health and disease. For example, detecting tumor-derived EVs' protein markers can aid in early diagnosis of cancer, which is life-saving. In order to use these EV proteins for diagnosis, sensitive and multiplexed methods are required. The current methods for EV protein detection typically require large sample consumption due to challenges with sensitivity and often need an EV isolation step for complex biofluid samples such as blood plasma. In this work, we have developed a simple and sensitive method for multiplexed detection of protein markers on EV membrane surfaces, which we call "EV dot blotting", inspired by conventional dot blotting techniques. After optimization of multiple factors such as antibody concentration, blocking reagent, type of 3D membranes, and use of gold nanoparticles for signal enhancement, cancer-cell-derived EVs were spiked in pooled normal human plasma for conducting a multiplexed assay in a microarray format. Without the need of isolating EVs from blood plasma, a limit of detection of 3.1 × 105 EVs/mL or 1863 EVs/sample was achieved for CD9 protein, 4.7 × 104 EVs/mL or 281 EVs/sample for CD24, and 9.0 × 104 EVs/mL or 538 EVs/sample for EpCAM, up to 4 orders of magnitude lower than those of conventional ELISA. This platform offers sensitive, multiplexed, simple, and low-cost EV protein detection directly from complex biofluids with minimal sample consumption, providing a useful tool for multiplexed EV protein quantification for a variety of applications.

Sensitive recognition of prostate-specific antigen using biotinylated antibody encapsulated on D-penicillamine decorated wrinkled silicate nanoparticles (WSN): An innovative sandwich-type biosensor toward diagnosis of prostate cancer.

In this study, a new sandwich-type biosensor was developed to specific recognition of prostate-specific antigen (PSA) and early-stage diagnosis of prostate cancer using encapsulation of biotinylated antibody (Ab1) of prostate-specific antigen on D-penicillamine decorated wrinkled silicate nanoparticles (WSN). For the first time, KCC-1-NH-DPA was synthesized and used to immobilization of biomacromolecules. So, fabricated immunosensor was performed by on sandwich-type strategy. After fabrication of immunosensor, cyclic voltammetry, differential pulse voltammetry, and square wave voltammetry techniques were used to electrochemical evaluation of immune-platform for PSA detection. The proposed biocompatibility immune-platform provided a novel interface toward sensitive bioanalysis of PSA biomarker in human plasma samples. Due to the use of gold nanoparticles functionalized Cysteamine (Cys A) in the structure of the secondary antibody (Ab2 [HRP-Ab2]), the intensity of the electrochemical signal has increased, resulting in a more accurate detection of the target molecules. Under the right conditions, the engineering immunosensor provides good bioanalytical performance for determining the PSA biomarker in the linear range of 0.002 to 60 μg L-1 which low limit of quantification was 0.002 μg L-1 . As a result, it is suggested to use these immune-devices in the clinical pre-diagnosis of prostate cancer.

Convex fiber-tapered seven core fiber-convex fiber (CTC) structure-based biosensor for creatinine detection in aquaculture.

The purpose of this article is to propose an optical fiber sensor probe based on the localized surface plasma resonance (LSPR) technique for the detection of creatinine in aquaculture. The sensing probe is functionalized through the use of gold nanoparticles (AuNPs), niobium carbide (Nb2CTx) MXene, and creatinase (CA) enzyme. The intrinsic total internal reflection (TIR) mechanism is modified to increase the evanescent field intensity using a heterogeneous core mismatch and tapering probe structure (i.e., convex fiber-tapered seven core fiber-convex fiber (CTC) structure). Strong evanescent fields can stimulate AuNPs and induce the LSPR effect, thereby increasing probe sensitivity. The specific recognition is enhanced by Nb2CTx MXene adsorbing more active CA enzymes. The developed sensor probe has a sensitivity and limit of detection of 3.1 pm/µM and 86.12 µM, respectively, in the linear range of 0-2000µM. Additionally, the sensor probe's reusability, reproducibility, stability, and selectivity were evaluated, with satisfactory results obtained with impact for areas like food protein, marine life and healthcare.