Nanocomposite Platform Research Articles

Development of a Photothermal Regenerative Plasmonic Platform as a Light-Controlled Interface.

This study introduces a novel plasmonic nanocomposite platform, where gold nanoparticles (AuNPs) are synthesized in situ within a polydimethylsiloxane (PDMS) film. The innovative fabrication process leverages ethyl acetate swelling to achieve a uniform distribution of AuNPs, eliminating the need for additional reagents. The resulting nanocomposite film exhibits exceptional photothermal conversion capabilities, efficiently converting absorbed light into heat and rapidly reaching high temperatures. Furthermore, the platform is biofunctionalized with the phosphotriesterase enzyme, not only enabling the degradation of organophosphate pesticides but also showcasing the potential for multifunctional applications. The platform's ability to be regenerated after use underscores its sustainability for repeated applications.

Detection of H. pylori VacA protein using a graphene-Au nanoparticle electrochemical sensing platform

This study presents a novel electrochemical biosensor for the detection of Helicobacter pylori VacA protein using a graphene-Au nanocomposite platform. The nanocomposite was synthesized via a one-pot reduction method and characterized using SEM, XRD, and FTIR. The biosensor fabrication process was monitored through cyclic voltammetry and electrochemical impedance spectroscopy. Optimization studies revealed ideal conditions of pH 7.4, 30-minute incubation time, and 100 μg/mL antibody concentration. The biosensor exhibited a linear response range of 0.1–100 ng/mL with a detection limit of 0.03 ng/mL. Selectivity tests against common interfering substances showed minimal cross-reactivity (<5 % signal change). The sensor demonstrated good reproducibility (3.8 % RSD) and stability (95 % signal retention after 30 days). In spiked serum samples, recoveries ranged from 96.5 % to 103.2 % with RSDs below 4.5 %. Compared to traditional methods, this biosensor offers improved sensitivity and shorter analysis time for VacA detection, potentially enhancing early diagnosis of H. pylori infections and monitoring treatment efficacy.

Tailoring of Novel Amorphous RuS2/ZrS2/MWCNT Nanocomposite Platform as a Dual Sensor for the Detection for Water Pollutant Indigo Carmine

The present study focuses on synthesizing amorphous nanocomposites of RuS2/ZrS2/MWCNT and exploring their potential for modifying electrodes and detecting indigo carmine dyestuff. Amorphous materials have recently garnered significant attention due to their ability to control material properties through their distinct nature. Transition metal dichalcogenides, or TMDs, are being extensively used in various applications such as catalysis, dye degradation, and so on. Amorphous transition metal sulphides, due to their heightened active sites, exhibit higher performance. This study presents the first-ever successful production of two amorphous metal sulphides that are doped with multi-walled carbon nanotubes. The resulting novel material was used to detect indigo carmine with high efficiency. The detection range was wide, spanning from 0.1 μM to 300.0 μM, and the limit of detection was 0.08 μM. These results demonstrate that the material outperforms most previously reported studies in this field. The technique employed was both simple and innovative, and it was used on both Glassy Carbon Electrode (GCE) and Screen-Printed Electrode (SPE) systems. It was effectively evaluated for the detection of the dye in water samples as well as food and pharmaceutical samples.

Single Mesenchymal Stromal Cell Migration Tracking into Glioblastoma Using Photoconvertible Vesicles.

Reliable cell labeling and tracking techniques are imperative for elucidating the intricate and ambiguous interactions between mesenchymal stromal cells (MSCs) and tumors. Here, we explore fluorescent photoconvertible nanoengineered vesicles to study mMSC migration in brain tumors. These 3 μm sized vesicles made of carbon nanoparticles, Rhodamine B (RhB), and polyelectrolytes are readily internalized by cells. The dye undergoes photoconversion under 561 nm laser exposure with a fluorescence blue shift upon demand. The optimal laser irradiation duration for photoconversion was 0.4 ms, which provided a maximal blue shift of the fluorescent signal label without excessive laser exposure on cells. Vesicles modified with an extra polymer layer demonstrated enhanced intracellular uptake without remarkable effects on cell viability, motility, or proliferation. The optimal ratio of 20 vesicles per mMSC was determined. Moreover, the migration of individual mMSCs within 2D and 3D glioblastoma cell (EPNT-5) colonies over 2 days and in vivo tumor settings over 7 days were traced. Our study provides a robust nanocomposite platform for investigating MSC-tumor dynamics and offers insights into envisaged therapeutic strategies. Photoconvertible vesicles also present an indispensable tool for studying complex fundamental processes of cell-cell interactions for a wide range of problems in biomedicine.

Simultaneous immunodetection of multiple cervical cancer biomarkers based on a signal-amplifying redox probes/polyethyleneimine-coated gold nanoparticles/2D tungsten disulfide/graphene oxide nanocomposite platform

To advance cervical cancer diagnostics, we propose a state-of-the-art label-free electrochemical immunosensor designed for the simultaneous detection of multiple biomarker proteins (p16INK4a, p53, and Ki67). This immunosensor is constructed using a polyethyleneimine-coated gold nanoparticles/2D tungsten disulfide/graphene oxide (PEI-AuNPs/2D WS2/GO) composite-modified three-screen-printed carbon electrode (3SPCE) array. The 2D WS2/GO hybrid provides a large specific surface area for supporting well-dispersed PEI-AuNPs and adsorbed redox-active species, enhancing overall performance. The PEI-AuNPs-decorated 2D WS2/GO composite not only improves electrode conductivity but also increases the antibody loading capacity. Redox-active species, including Cd2+ ions, 2,3-diaminophenazine (DAP), and methylene blue (MB), serve as distinct signaling compounds to quantitatively detect the cervical cancer biomarkers p16INK4a, p53, and Ki67, respectively. Additionally, the immunosensor demonstrates the detection with high sensitivity, good storage stability, high selectivity, and acceptable reproducibility. This immunosensor demonstrates a good linear relationship with the logarithm of protein concentrations. Additionally, the immunosensor also demonstrates high sensitivity, good storage stability, high selectivity, and acceptable reproducibility. Our promising results and the successful application of the immunosensor in detecting three tumor markers in human serum highlight its potential for clinical diagnosis of cervical cancer.

Advancements in Metal‐Organic, Enzymatic, and Nanocomposite Platforms for Wireless Sensors of the Next Generation

AbstractAdvanced wireless sensors, incorporating metal‐organic frameworks (MOFs), enzymatic systems, and nanocomposites, offer unparalleled solutions for monitoring analytes and human physiological signals. These cutting‐edge sensors, when used with external devices, enable real‐time monitoring of analytes and physicochemical processes within the human body, thereby enhancing the understanding of complex biological systems. This study presents advancements in sensor development, fabrication techniques, and user‐friendly protocols. The performance of these sensors is evaluated based on their selectivity, sensitivity, and detection limits. Moreover, this article explores limitations, challenges, and key strategies to enhance analyte recognition from onsite environmental and biological species, ensuring human point‐of‐care safety.

Synthesis and Characterization of Palladium/Silver Modified Reduced Graphene Oxide–Nanocomposite Platform for Electrochemical Sensors

AbstractMetal nanoparticles incorporated into carbon nanostructures have tremendous applications in the field of nanosensors and other technologies. Herein, a nanohybrid of reduced graphene oxide modified with silver and/or palladium nanoparticles (Ag/Pd/rGO) was prepared by impregnation of Pd and Ag into the rGO platform and deposited on a glass carbon electrode. Palladium and silver nanoparticles improve the stability and durability of the sensor platform by preventing the agglomeration of graphene oxide sheets and providing chemical stability against environmental factors. This ensures long‐term reliability and repeatability of the sensor performance. The morphologies and microstructures of the as‐prepared nanohybrid were characterized by X‐ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, UV–visible and infrared spectroscopy. The average crystallite size of PdAgNPs was found to be between 12 and 15 nm and demonstrated good dispersion across reduced graphene oxide sheets with high‐loading capacities. Thorough investigation of the electrochemical properties of the nanomaterial surfaces through cyclic voltammetry (CV) experiments, revealed distinct redox peaks for Ag+/Ag0 and Pd2+/Pd0 processes and demonstrated the excellent electrochemical properties of the prepared nanocomposites. The rGO‐PdAgNPs‐GCE had a diffusion coefficient value of 1.14×10−14 cm2 s−1 which is acceptable for electrochemical sensors as it is indicative of a fast response time and enhanced sensitivity to changes in gas concentration. The results obtained through thorough characterizations contributes to the novelty of the research by offering a deeper understanding of the material properties and the potential of the nanohybrid material for a broad application scope.

In Vitro Evaluation and Characterization of Double Emulsion Based on Polyvinylpyrrolidone/Agarose/ZIF-8 Hydrogel Nanocomposite Platform for Quercetin Delivery to Breast Cancer Cells

In Vitro Evaluation and Characterization of Double Emulsion Based on Polyvinylpyrrolidone/Agarose/ZIF-8 Hydrogel Nanocomposite Platform for Quercetin Delivery to Breast Cancer Cells

FeS2-modified MXene nanocomposite platform for efficient PTT/CDT/TDT integration through enhanced GSH consumption.

Hypoxic microenvironment and glutathione (GSH) accumulation in tumours limit the efficacy of cytotoxic reactive oxygen species (ROS) anti-tumour therapy. To address this challenge, we increased the consumption of GSH and the production of ROS through a novel nanoplatform with the action of inorganic nanoenzymes. In this study, we prepared mesoporous FeS2 using a simple template method, efficiently loaded AIPH, and assembled Ti3C2/FeS2-AIPH@BSA (TFAB) nanocomposites through self-assembly with BSA and 2D Ti3C2. The constructed TFAB nanotherapeutic platform enhanced chemodynamic therapy (CDT) by generating toxic hydroxyl radicals (˙OH) via FeS2, while consuming GSH to reduce the loss of generated ˙OH via glutathione oxidase-like (GSH-OXD). In addition, TFAB is able to stimulate the decomposition of AIPH under 808 nm laser irradiation to produce oxygen-independent biotoxic alkyl radicals (˙R) for thermodynamic therapy (TDT). In conclusion, TFAB represents an innovative nanoplatform that effectively addresses the limitations of free radical-based treatment strategies. Through the synergistic therapeutic strategy of photothermal therapy (PTT), CDT, and TDT within the tumor microenvironment, TFAB nanoplatforms achieve controlled AIPH release, ROS generation, intracellular GSH consumption, and precise temperature elevation, resulting in enhanced intracellular oxidative stress, significant apoptotic cell death, and notable tumor growth inhibition. This comprehensive treatment strategy shows great promise in the field of tumor therapy.

Enzyme-mediated fabrication of nanocomposite hydrogel microneedles for tunable mechanical strength and controllable transdermal efficiency

Microneedles (MNs) are increasingly used in transdermal drug delivery due to high bioavailability, simple operation, and improved patient compliance. However, further clinical applications are hindered by unsatisfactory mechanical strength and uncontrolled drug release. Herein, an enzyme-mediated approach is reported for the fabrication of nanocomposite hydrogel-based MNs with tunable mechanical strength and controllable transdermal efficiency. As a proof-of-concept, tetrakis(1-methyl-4-pyridinio)porphyrin (TMPyP) was chosen as a model drug for photodynamic therapy of melanoma. TMPyP-loaded PLGA nanoparticles (NP/TMPyP) served as an inner phase of MNs for controlled release of photosensitizers, and enzyme-mediated hyaluronic acid-tyramine (HAT) hydrogels served as an external phase for optimizing the mechanical strength of MNs. By changing the concentration of HRP and H2O2, three types of MNs were fabricated for transdermal delivery of TMPyP, which demonstrated different cross-linking densities and various mechanical strength. Among the three MNs, the HAT-Medium@NP/TMPyP-MN with a medium mechanical strength exhibited the highest values of transdermal efficiency in vitro and the longest retention time in vivo. As compared to pure TMPyP and TMPyP-loaded nanoparticles, the HAT-Medium@NP/TMPyP-MN demonstrated higher anticancer efficacy in both melanoma A375 cells and a xenografted tumor mouse model. Therefore, the enzyme-mediated nanocomposite hydrogel MNs show great promise in the transdermal delivery of therapeutic drugs with enhanced performance. Statement of SignificanceThis study reports an enzyme-mediated approach for the fabrication of photodynamically-active microneedles (HAT@NP/TMPyP-MNs) with tunable mechanical strength and controllable transdermal efficiency. On one hand, HAT hydrogels that bear different cross-linking densities, facilitate tunable mechanical strength and optimized transdermal performances of MNs; on the other hand, NP/TMPyP and HAT network contribute to sustained release of photosensitizers. Comparing to other formulation (i.e., NP/TMPyP or TMPyP), the HAT-Medium@NP/TMPyP-MN exhibited excelling anticancer efficacy in photodynamic therapy in vitro and in vivo. We believe that the combination of enzyme-mediated polymeric cross-linking and slow-releasing nano-vehicles in a single nanocomposite platform provides a versatile approach for the fabrication of MNs with enhanced therapeutic efficacy, which holds great promise in the transdermal delivery of various therapeutic drugs in future.

An injectable nanocomposite hydrogel prevents postoperative tumor recurrence and wound infection via synergistic photothermal-chemo-therapy

HypothesisTumor recurrence, bacterial infection, and wound healing remain significant clinical challenges after skin-tumor resection. In this study, we tested the hypothesis that a multifunctional nanocomposite platform containing nanoparticles (NPs) with the photothermal agent IR820 and bioactive drug curcumin (Cur) would be able to prevent tumor recurrence, limit bacterial wound infections, and promote wound healing. ExperimentsIn this study, we developed a near-infrared light-activated nanocomposite hydrogel system (Hydrogel/Cur@IR820) by incorporating self-assembled NPs (Cur@IR820) in solutions containing Pluronic F127 modified with aldehyde groups (F127-CHO) and polyethyleneimine-grafted F127 (F127-PEI). FindingsThe Hydrogel/Cur@IR820 platform exhibited inherent multifunctional properties, including superior injectability, self-healing behavior, photothermal effects, and free radical scavenging ability. The Cur@IR820 NPs led to photonic hyperthermia and near-infrared (NIR)-triggered Cur release, which drove synergistic therapeutic effects against bacteria and tumor cells. Furthermore, the Hydrogel/Cur@IR820 system promoted wound repair and tissue regeneration by reducing inflammation through the antioxidant properties of Cur. Overall, the results of this study have clinical implications for inhibiting tumor growth, treating bacterial infections, and accelerating tissue regeneration.

A label-free sensor based on a carbon nanotube-graphene platform for the detection of non-Hodgkin lymphoma genes

Early diagnosis of non-Hodgkin lymphoma (NHL) is crucial for effective management. We report an ultrasensitive electrochemical genosensor using multi-walled carbon nanotube (MWCNT)-graphene nanocomposite for detection of lymphoma biomarker gene. MWCNTs were dispersed over graphene nanoplatelets to form a conductive nanocomposite platform. The high surface area and π-π stacking ability enabled efficient immobilization of lymphoma probe DNA. Detailed materials characterization was performed using microscopy and spectroscopy techniques. The sensor was fabricated by drop-casting probe-conjugated nanocomposite suspension onto a glassy carbon electrode. The genosensor exhibited a wide dynamic range of 1 fM to 1 nM with a sensitivity of 0.895 kΩ per decade of target concentration. The sensor showed excellent selectivity for fully complementary target sequence over even single base mismatch. Hybridization detection by electrochemical impedance spectroscopy was further validated using differential pulse voltammetry which showed drastic reduction in redox peak current after incubating with target. The nanocomposite genosensor demonstrated good reproducibility with relative standard deviation of 3.72 % among five independently prepared electrodes. Clinical applicability was tested by spiking lymphoma gene biomarker in 10 % serum and recoveries of 93–99 % were obtained. The proposed MWCNT-graphene nanocomposite genosensor provides a simple, specific and ultrasensitive platform for point-of-care diagnosis of NHL.

Paper-based colorimetric detection of COVID-19 using aptasenor based on biomimetic peroxidase like activity of ChF/ZnO/CNT nano-hybrid

Corona Virus Disease 2019 (COVID-19) as the infectious disease caused the pandemic disease around the world through infection by SARS-CoV-2 virus. The common diagnosis approach is Quantitative RT-PCR (qRT-PCR) which is time consuming and labor intensive. In the present study a novel colorimetric aptasensor was developed based on intrinsic catalytic activity of chitosan film embedded with ZnO/CNT (ChF/ZnO/CNT) on 3,3′,5,5′-tetramethylbenzidine (TMB) substrate. The main nanocomposite platform was constructed and functionalized with specific COVID-19 aptamer. The construction subjected with TMB substrate and H2O2 in the presence of different concentration of COVID-19 virus. Separation of aptamer after binding with virus particles declined the nanozyme activity. Upon addition of virus concentration, the peroxidase like activity of developed platform and colorimetric signals of oxidized TMB decreased gradually. Under optimal conditions the nanozyme could detect the virus in the linear range of 1–500 pg mL and LOD of 0.05 pg mL. Also, a paper-based platform was used for set up the strategy on applicable device. The paper-based strategy showed a linear range between 50 and 500 pg mL with LOD of 8 pg mL. The applied paper based colorimetric strategy showed reliable results for sensitive and selective detection of COVID-19 virus with the cost-effective approach.

A Direct Immunoassay Based on Surface-Enhanced Spectroscopy Using AuNP/PS-b-P2VP Nanocomposites

A biosensor was developed for directly detecting human immunoglobulin G (IgG) and adenosine triphosphate (ATP) based on stable and reproducible gold nanoparticles/polystyrene-b-poly(2-vinylpyridine) (AuNP/PS-b-P2VP) nanocomposites. The substrates were functionalized with carboxylic acid groups for the covalent binding of anti-IgG and anti-ATP and the detection of IgG and ATP (1 to 150 μg/mL). SEM images of the nanocomposite show 17 ± 2 nm AuNP clusters adsorbed over a continuous porous PS-b-P2VP thin film. UV–VIS and SERS were used to characterize each step of the substrate functionalization and the specific interaction between anti-IgG and the targeted IgG analyte. The UV–VIS results show a redshift of the LSPR band as the AuNP surface was functionalized and SERS measurements showed consistent changes in the spectral features. Principal component analysis (PCA) was used to discriminate between samples before and after the affinity tests. Moreover, the designed biosensor proved to be sensitive to different concentrations of IgG with a limit-of-detection (LOD) down to 1 μg/mL. Moreover, the selectivity to IgG was confirmed using standard solutions of IgM as a control. Finally, ATP direct immunoassay (LOD = 1 μg/mL) has demonstrated that this nanocomposite platform can be used to detect different types of biomolecules after proper functionalization.

Penetrative and Sustained Drug Delivery Using Injectable Hydrogel Nanocomposites for Postsurgical Brain Tumor Treatment

Postsurgical treatment of glioblastoma multiforme (GBM) by systemic chemotherapy and radiotherapy is often inefficient. Tumor cells infiltrating deeply into the brain parenchyma are significant obstacles to the eradication of GBM. Here, we present a potential solution to this challenge by introducing an injectable thermoresponsive hydrogel nanocomposite. As a liquid solution that contains drug-loaded micelles and water-dispersible ferrimagnetic iron oxide nanocubes (wFIONs), the hydrogel nanocomposite is injected into the resected tumor site after surgery. It promptly gelates at body temperature to serve as a soft, deep intracortical drug reservoir. The drug-loaded micelles target residual GBM cells and deliver drugs with a minimum premature release. Alternating magnetic fields accelerate diffusion through heat generation from wFIONs, enabling penetrative drug delivery. Significantly suppressed tumor growth and improved survival rates are demonstrated in an orthotopic mouse GBM model. Our system proves the potential of the hydrogel nanocomposite platform for postsurgical GBM treatment.

Stability improvement of polyaniline nanocomposite immunosensor for early detection of insulin receptor antibody as biomarker of type 2 diabetes.

Polyaniline nanocomposite with controllable properties was used to design and fabricate a novel electrochemical immunosensor for the early detection of type 2 diabetes. Insulin receptor antibody is a powerful predictor of type 2 diabetes development in individuals. A systematic study was carried out to investigate the effects of different polyaniline layers and the Nafion layer on the morphological, chemical, and electrochemical properties of nanocomposite immunosensor, especially the stability. The bioengineered Nafion-Au nanoparticles-polyaniline/gold electrode demonstrated outstanding electrocatalytic performance in the detection of insulin receptor antibodies with a high sensitivity (136.21 µA.ng-1.ml.cm-2) in a linear range from 0.001 to 200ng.ml-1 as well as a low detection limit of 1.827pg.ml-1, response time within 10min, remarkable selectivity, and significant stability of 80days. Therefore, the developed immunosensor is a suitable nanocomposite platform for insulin receptor antibody level determination in human plasma.

A stem-loop like aptasensor for sensitive detection of aflatoxin based on graphene oxide/AuNPs nanocomposite platform

Aflatoxin as the potent carcinogenic mycotoxin had been received great attention for detection in food industry and safety. Due to low quantity of aflatoxin in food samples, there is a need to develop a sensitive method toward its detection. In the present study, an aflatoxin B1 (AFB1) specific aptasensor with internal complementary sequence was developed for detection of AFB1. The FAM-functionalized aptamer was deposited on the surface of graphene oxide decorated with gold nanoparticles (GO/AuNPs) and following formation of heteroduplex stem-loop structure led to fluorescence quenching of FAM-labeled aptamer. After incubation of proposed aptasensor with AFB1, the aptamer-AFB1 complex resulted to denaturation in stem-loop structure of aptamer which caused restoration of single strand aptamer and recovery of fluorescence. The assay showed a convenient detection response in the range of 0.5-20 pg/mL with a very low detection limit (0.1 pg/mL) and it was highly selective for AFB1 over other mycotoxins.

A novel electrochemical sensor based on molecularly imprinted polymer nanocomposite platform for sensitive and ultra-selective determination of citalopram

• A novel sensing platform based on MIP/hNiNS/AMWCNT@GONRs composite was designed as the modifier for GCE. • For the first time the modified glassy carbon electrode (MIP/hNiNS/AMWCNT@ GONRs/GCE) was used to determine citalopram (CIT). • The sensor showed excellent selectivity and sensitivity towards determination of CIT. • The proposed sensor was applied successfully for determination of CIT in real samples. Citalopram (CIT) is an antidepressant of the selective serotonin reuptake inhibitor class widely used worldwide, so the development of analytical methods to determine it in real samples is essential for treatment purposes and drug development. This work presented an electrochemical-specific sensor for CIT based on the molecular imprinting technique. The sensor was fabricated by electropolymerizing molecularly imprinted polymer (MIP) film onto hollow nickel nanospheres (hNiNS)/activated multiwalled carbon nanotubes@graphene oxide nanoribbons (AMWCNTs@GONRs) composite modified glassy carbon electrode (GCE). The excellent synergistic effect of the combination of hNiNS and AMWCNTs@GONRs composite shows significantly enhanced electrocatalytic activity for CIT, which lead to high sensitivity of the sensor. The electropolymerized MIP provides specific imprinted sites, which can increase the selectivity for CIT. The preparation of the MIP/hNiNS/AMWCNT@GONRs/GCE was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and electrochemical methods, including cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electrochemical properties of the sensor were studied using differential pulse voltammetry (DPV) and CV. Main effective parameters on the performance of the imprinted electrodes such as electropolymerization cycles, pH buffer solution, incubation time and concentrations of template molecules were checked and optimized. The fabricated sensor displayed two linear dynamic ranges from 0.5 to 10 µM and 10 to 190 µM with a limit of detection (LOD, S/N = 3) of 0.042 µM. Examining the interfering effect of some structurally related compounds and some potential interferences existing in biological fluids on the analysis of citalopram showed that the designed MIP sensor could identify CIT selectively. Moreover, the constructed electrode exhibited good repeatability, reproducibility, stability and rapid response time for the electrochemical analysis of CIT. The presented sensor was successfully utilized for determining the CIT in real samples.

A highly sensitive nanobiosensor based on aptamer-conjugated graphene-decorated rhodium nanoparticles for detection of HER2-positive circulating tumor cells

AbstractAssessment of human epidermal growth factor receptor-2 (HER2) tumor marker status is an impressive factor in screening, diagnosing and monitoring breast cancer (BC). The electrochemical biosensor is a revolutionary method in cancer diagnosis, which is used in this research to detect HER2+circulating tumor cells. The electrochemical activity, size, shape, and morphology of the synthesized nanomaterials were analyzed. The hybrid nanocomposite established by the coupling of reduced graphene oxide nanosheets (rGONs) and rhodium nanoparticles (Rh-NPs) on the surface of graphite electrode resulted in improved surface area, electrochemical activity, and biocompatibility. The graphite electrode-based aptasensor (g-aptasensor) demonstrated exceptional performance against HER2-overexpressed SKBR3 cancer cells, with a linear dynamic range of 5.0 to 10.0 × 104 cells/mL, an analytical limit of detection (LOD) as low as 1.0 cell/mL, and a limit of quantification (LOQ) of 3.0 cells/mL. The G-rich DNA aptamers can fold into an intermolecular G-quadruplex, which specifically bind to the target molecule. Consequently, the advantages of this highly efficient nanocomposite platform include broad dynamic range, high specificity, selectivity, stability, reproducibility, and low cost. These characteristics indicate that the fabricated nanobiosensor has a high potential for use in detecting and monitoring HER2 level for the care of BC patients and clinical diagnosis.

Performance of graphene-zinc oxide nanocomposite coated-glassy carbon electrode in the sensitive determination of para-nitrophenol

Graphene: zinc oxide nanocomposite (GN:ZnO NC) platform was tried for the sensitive determination of para-nitrophenol (p-NP) through the electrochemical method. ZnO nanoparticles (NPs) were synthesized by the modified wet-chemical method where in potassium hydroxide and zinc nitrate were used as precursors and starch as a stabilizing agent. A green and facile approach was applied to synthesize GN:ZnO NC in which glucose was employed as a reductant to reduce graphene-oxide to graphene in the presence of ZnO NPs. The synthesized NC was characterized using scanning and high-resolution transmission electron microscopy, energy dispersive x-ray analysis, X-ray diffraction and Raman spectroscopic techniques to examine the crystal phase, crystallinity, morphology, chemical composition and phase structure. GN:ZnO NC layer deposited over the glassy carbon electrode (GCE) was initially probed for its electrochemical performance using the standard 1 mM K3[Fe(CN)6] model complex. GN:ZnO NC modified GCE was monitored based on p-NP concentration. An enhanced current response was observed in 0.1 M phosphate buffer of pH 6.8 for the determination of p-NP in a linear working range of 0.09 × 10–6 to 21.80 × 10–6 M with a lower detection limit of 8.8 × 10–9 M employing square wave adsorptive stripping voltammetric technique at a deposition-potential and deposition-time of − 1.0 V and 300 s, respectively. This electrochemical sensor displayed very high specificity for p-NP with no observed interference from some other possible interfering substances such as 2, 4-di-NP, ortho-NP, and meta-NP. The developed strategy was useful for sensitive detection of p-NP quantity in canals/rivers and ground H2O samples with good recoveries.