Detection of tumor marker CA72-4 with an electrochemical immunosensor based on MnO2 nanosheets and HNM-AuPtPd nanocomposites.

To accurately detect tumor marker carbohydrate antigen 72-4 (CA72-4) of serum samples is of great significance for the early diagnosis of malignant tumors. In the present study, MnO2/hollow nanobox metal-organic framework (HNM)-AuPtPd nanocomposites were prepared via multi-step synthesis and superposition method and a series of characterizations were carried out. A highly sensitive immunosensor Ab/MnO2/HNM-AuPtPd/GCE based on the composite nanomaterial was further prepared and used to detect the tumor marker CA72-4. The constructed immunosensor achieved signal amplification by increasing the electrocatalytic activity to H2O2 by means of the synergistic effect of MnO2 ultra-thin nanosheets (MnO2 UNs) and HNM-AuPtPd. At the same time, the electrochemical properties of the immunosensor were analyzed using cyclic voltammetry, electrochemical impedance, amperometry (with the test voltage of -0.4 V), and differential pulse voltammetry. The experimental results showed that the MnO2/HNM-AuPtPd nanocomposites were successfully prepared, and the immunosensor Ab/MnO2/HNM-AuPtPd/GCE demonstrated an excellent electrochemical performance. The electrochemical immunosensor had the highest detection sensitivity under the optimal experimental conditions, such as incubation pH of 7.0, incubation time of 60 min, with the addition of 15 µL of H2O2, and in the concentration range 0.001-500 U/mL. It had a low detection limit of 1.78×10-5 U/mL (S/N = 3). Moreover, the serum sample recovery were in the range from 99.38 to 100.52%. This study provides a new method and experimental basis for the detection of tumor markers in clinical practice.

Nanocomposite microbeads made of recycled polylactic acid for the magnetic solid phase extraction of xenobiotics from human urine.

Nanocomposite microbeads (average diameter = 10-100 µm) were prepared by a microemulsion-solidification method and applied to the magnetic solid-phase extraction (m-SPE) of fourteen analytes, among pesticides, drugs, and hormones, from human urine samples. The microbeads, perfectly spherical in shape to maximize the surface contact with the analytes, were composed of magnetic nanoparticles dispersed in a polylactic acid (PLA) solid bulk, decorated with multi-walled carbon nanotubes (mPLA@MWCNTs). In particular, PLA was recovered from filters of smoked electronic cigarettes after an adequate cleaning protocol. A complete morphological characterization of the microbeads was performed via Fourier-transform infrared (FTIR) spectroscopy, UV-Vis spectroscopy, thermogravimetric and differential scanning calorimetry analysis (TGA and DSC), scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). The recovery study of the m-SPE procedure showed yields ≥ 64%, with the exception of 4-chloro-2-methylphenol (57%) at the lowest spike level (3 µg L-1). The method was validated according to the main FDA guidelines for the validation of bioanalytical methods. Using liquid chromatography-tandem mass spectrometry, precision and accuracy were below 11% and 15%, respectively, and detection limits of 0.1-1.8 µg L-1. Linearity was studied in the range of interest 1-15 µg L-1 with determination coefficients greater than 0.99. In light of the obtained results, the nanocomposite microbeads have proved to be a valid and sustainable alternative to traditional sorbents, offering good analytical standards and being synthetized from recycled plastic material. One of the main objectives of the current work is to provide an innovative and optimized procedure for the recycling of a plastic waste, to obtain a regular and reliable microstructure, whose application is here presented in the field of analytical chemistry. The simplicity and greenness of the method endows the procedure with a versatile applicability in different research and industrial fields.

Nanocomposites against Pseudomonas aeruginosa biofilms: Recent advances, challenges, and future prospects.

Pseudomonas aeruginosa is an opportunistic bacterial pathogen that causes life-threatening and persistent infections in immunocompromised patients. It is the culprit behind a variety of hospital-acquired infections owing to its multiple tolerance mechanisms against antibiotics and disinfectants. Biofilms are sessile microbial aggregates that are formed as a result of the cooperation and competition between microbial cells encased in a self-produced matrix comprised of extracellular polymeric constituents that trigger surface adhesion and microbial aggregation. Bacteria in biofilms exhibit unique features that are quite different from planktonic bacteria, such as high resistance to antibacterial agents and host immunity. Biofilms of P. aeruginosa are difficult to eradicate due to intrinsic, acquired, and adaptive resistance mechanisms. Consequently, innovative approaches to combat biofilms are the focus of the current research. Nanocomposites, composed of two or more different types of nanoparticles, have diverse therapeutic applications owing to their unique physicochemical properties. They are emerging multifunctional nanoformulations that combine the desired features of the different elements to obtain the highest functionality. This review assesses the recent advances of nanocomposites, including metal-, metal oxide-, polymer-, carbon-, hydrogel/cryogel-, and metal organic framework-based nanocomposites for the eradication of P. aeruginosa biofilms. The characteristics and virulence mechanisms of P. aeruginosa biofilms, as well as their devastating impact and economic burden are discussed. Future research addressing the potential use of nanocomposites as innovative anti-biofilm agents is emphasized. Utilization of nanocomposites safely and effectively should be further strengthened to confirm the safety aspects of their application.

Antibacterial and Anticandidal Activity of the Nanostructural Composite of a Spirothiazolidine-Derivative Assembled on Silver Nanoparticles.

Our aims in this work are the preparation of an ionic liquid based on heterocyclic compounds with Ag nanoparticles and the investigation of its application as an antibacterial and anticandidal agent. These goals were achieved through the fabrication of an ionic liquid based on Ag nanoparticles with 5-Amino-3-(4-fluorophenyl)-N-hexadecyl-7-(4-methylphenyl)-2-H spiro[cyclohexane1,2'-[1,3]thiazolo [4,5-b]pyridine]-6-carbonitrile (P16). The nanostructure of the prepared ionic liquid was characterized using techniques such as FTIR, 1HNMR, 13CNMR, UV, SEM, and TEM. The biological activity of the prepared compound (P16) and its nanocomposites with Ag nanoparticles was tested using five clinical bacteria (Pseudomonas aeruginosa 249; Escherichia coli 141; Enterobacter cloacae 235; Staphylococcus epidermidis BC 161, and methicillin-resistant S. aureus 217), and three Candida species (Candida utilis ATCC 9255; C. tropicalis ATCC 1362, and C. albicans ATCC 20402). The FTIR, 1HNMR, and 13CNMR results confirmed the chemical structure of the synthesized P16 compound. The nanostructure of the prepared ionic liquid was determined based on data obtained from the UV, SEM, and TEM tests. The antibacterial and anticandidal results showed that the biological activity of the compound (P16) was enhanced after the formation of nanocomposite structures with Ag nanoparticles. Moreover, the biological activity of the compound itself (P16) and that of its nanocomposite structure with Ag nanoparticles was higher than that of ampicillin and amphotericin B, which were used as control drugs in this work.

Synthesis of silver­bismuth oxide encapsulated hydrazone functionalized chitosan (AgBi2O3/FCS) nanocomposite for electrochemical sensing of glucose, H2O2 and Escherichia coli O157:H7.

In this work, silver­bismuth oxide encapsulated 1,3,5-triazine-bis(4-methylbenzenesulfonyl)-hydrazone functionalized chitosan (SBO/FCS) nanocomposite was synthesized by a simple hydrothermal method. The amine (-NH2) group was functionalized by the addition of cyanuric acid chloride followed by 4-methylbenzenesulfonol hydrazide. The SBO/FCS has been characterized by FT-IR, X-ray diffraction, XPS, HR-SEM, HR-TEM, AFM, and thermogravimetry (TGA). Under the optimum conditions, the SBO/FCS sensor showed brilliant electrochemical accomplishment for the sensing of glucose and H2O2 by a limit of detection (LOD) of 0.057 µM and 0.006 µM. It also showed linearity for glucose 0.008-4.848 mM and for H2O2 of 0.01-6.848 mM. Similarly, the sensor exhibited a low sensitivity to glucose (32 µA mM-1 cm-2) and a good sensitivity to H2O2 (295 µA mM-1 cm-2). In addition, that the prepared electrode could be used to sense the glucose and H2O2 levels in real samples such as blood serum and HeLa cell lines. The screen printed electrode (SPE) immunosensor could sense the E. coli O157:H7 concurrently and quantitatively with a linear range of 1.0 × 101-1.0 × 109 CFU mL-1 and a LOD of 4 CFU mL-1. Likewise, the immunosensor efficiently detect spiked E. coli O157:H7 in milk, chicken, and pork samples, with recoveries ranging from 89.70 to 104.72 %, demonstrating that the immunosensor was accurate and reliable.

Process-structure-property relationships of cellulose nanocrystals derived from Juncus effusus stems on Ò¡-carrageenan-based bio-nanocomposite films.

This study investigates the potential of Juncus plant fibers as a renewable source for producing cellulose nanocrystals (CNs) to reinforce polymers. Cellulose microfibers (CMFs) were extracted with a 0.43 ± 0.2 µm diameter and 69 % crystallinity through alkaline and bleaching treatments, then subjected to sulfuric acid hydrolysis, yielding four CN types (CN10, CN15, CN20 and CN30) with distinct physico-chemical properties and aspect ratios (47, 55, 57, and 60). The study assessed the influence of cellulose nanocrystals (CNs), incorporated at different weight percentages (3 %, 5 %, and 8 %), on thermal, transparency, and mechanical properties in k-carrageenan (CA) biocomposite films. The results indicate significant enhancements in these characteristics, highlighting good compatibility between CNs and CA matrix. Particularly noteworthy is the observed substantial improvement in tensile strength at an 8 wt% loading, with values of 23.43 ± 0.83 MPa for neat CA, 33.53 ± 0.83 MPa for CA-CN10, 36.67 ± 0.71 MPa for CA-CN15, 37.65 ± 0.56 MPa for CA-CN20, and 39.89 ± 0.77 MPa for CA-CN30 composites. Furthermore, the research explores the connection between the duration of hydrolysis and the properties of cellulose nanocrystals (CNs), unveiling their influence on the characteristics of nanocomposite films. Prolonged hydrolysis enhances CN crystallinity (CrI), aspect ratio, and surface charge content, consequently enhancing mechanical features like strength and flexibility in these films. These findings demonstrate the potential of Juncus plant fibers as a natural and eco-friendly resource for producing CNs that effectively reinforce polymers, making them an attractive option for diverse applications in the field.

Broad-spectrum nano-bactericide utilizing antimicrobial peptides and bimetallic Cu-Ag nanoparticles anchored onto multiwalled carbon nanotubes for sustained protection against persistent bacterial pathogens in crops.

Worldwide crop yields are threatened by persistent pathogenic bacteria that cause significant damage and jeopardize global food security. Chemical pesticides have shown limited effectiveness in protecting crops from severe yield loss. To address this obstacle, there is a growing need to develop environmentally friendly bactericides with broad-spectrum and sustained protection against persistent crop pathogens. Here, we present a method for preparing a nanocomposite that combines antimicrobial peptides (AMPs) and bimetallic Cu-Ag nanoparticles anchored onto multiwalled carbon nanotubes (MWCNTs). The nanocomposite exhibited dual antibacterial activity by disrupting bacterial cell membranes and splicing nucleic acids. By functionalizing MWCNTs with small AMPs (sAMPs), we achieved enhanced stability and penetration of the nanocomposite, and improved loading capacity of the Cu-Ag nanoparticles. The synthesized MWCNTs&CuNCs@AgNPs@P nanocomposites demonstrated broad-spectrum lethality against both Gram-positive and Gram-negative bacterial pathogens. Glasshouse pot trials confirmed the efficacy of the nanocomposites in protecting rice crops against bacterial leaf blight and tomato crops against bacterial wilt. These findings highlight the excellent antibacterial properties of the MWCNTs&CuNCs@AgNPs@P nanocomposite and its potential to replace chemical pesticides, offering significant advantages for agricultural applications.

Multifunctional Ti3C2Tx MXene-reinforced thermoplastic starch nanocomposites for sustainable packaging solutions.

Starch-derived films exhibit significant potential for packaging applications owing to their low cost, biodegradable characteristics, and natural abundance. Nonetheless, there is a demand to enhance their mechanical properties and moisture resistance to broaden their use. In this study, high performing sorbitol-plasticized starch/Ti3C2Tx MXene nanocomposites, reinforced with ultra-low filler contents, were fabricated for the first time in literature. The MXene nanoplatelets were well-dispersed within the starch matrix while there was a tendency for the fillers to align in-plane, as revealed by polarized Raman spectroscopy. The produced nanocomposite films demonstrate remarkable effectiveness in blocking UV light, offering an additional valuable attribute in food packaging. The Young's modulus and tensile strength of starch films containing 0.75 wt% MXene increased from 439.9 and 11.0 MPa to 764.3 and 20.8 MPa, respectively. The introduction of 1 wt% MXene nanoplatelets reduced the water vapour permeability of starch films from 2.78 × 10-7 to 1.80 × 10-7 g/m h Pa due to the creation of highly tortuous paths for water molecules. Micromechanical theories were also implemented to understand further the reinforcing mechanisms in the biobased nanocomposites. The produced starch nanocomposites not only capitalize on the biodegradable and renewable nature of starch but also harness the unique properties of nanomaterials, paving the way for sustainable and high-performance packaging solutions that align with both consumer and environmental demands.

Advances of Layered Double Hydroxide-Based Materials for Tumor Imaging and Therapy.

Layered double hydroxides (LDH) are a class of functional anionic clays that typically consist of orthorhombic arrays of metal hydroxides with anions sandwiched between the layers. Due to their unique properties, including high chemical stability, good biocompatibility, controlled drug loading, and enhanced drug bioavailability, LDHs have many potential applications in the medical field. Especially in the fields of bioimaging and tumor therapy. This paper reviews the research progress of LDHs and their nanocomposites in the field of tumor imaging and therapy. First, the structure and advantages of LDH are discussed. Then, several commonly used methods for the preparation of LDH are presented, including co-precipitation, hydrothermal and ion exchange methods. Subsequently, recent advances in layered hydroxides and their nanocomposites for cancer imaging and therapy are highlighted. Finally, based on current research, we summaries the prospects and challenges of layered hydroxides and nanocomposites for cancer diagnosis and therapy.

Green and facile fabrication of multifunctional cellulose nanocrystal and carvacrol together reinforced chitosan bio-nanocomposite coatings for fruit preservation.

The continuous development of sustainable food-active packaging materials and practices with high performance is a response to the increasing challenges posed by microbial food safety and environmental contamination. In this study, a multifunctional bio-nanocomposite composed primarily of chitosan, cellulose nanomaterials and carvacrol was proposed as a conformal coating for fruit preservation. The coating exhibits excellent antioxidant and antibacterial activities owing to the incorporation of the carvacrol. The inhibition rate of the coating on E. coli and S. aureus is enhanced by 57.13 % and 62.18 %, respectively. And its antioxidant activities is also improved by 77.45 %. In addition, the oxygen permeability (OP) and water vapor permeability (WVP) of this CS/CNC coating are significantly lowered by 67 % and 46 %, respectively, comparing with the CS coating. The coating exhibited excellent biosafety and cytocompatibility because of over 90 % of the HepG2 cells remained alive in each concentration of the coating after 24 h incubation. Additionally, the efficacy of the coating in prolonging the freshness and visual appeal of perishable fruits is substantiated by the experiment involving two fruit specimens. Furthermore, the coating's ease of production, ingestibility, washability, and utilization of cost-effective and easily accessible biomaterials, including renewable waste materials, indicate its potential as a viable economic substitute for commercially accessible fruit coatings.

Design and Development of Gold/reduced Graphene Oxide Nanocomposite loaded with Cyclophosphamide: Potential Application in Treatment of Breast Cancer.

OBJECTIVE: Cyclophosphamide (CP) is a widely used anti-cancer drug. It works by alkylation and is commonly used in cancer treatment. In this study, the goal was to create biodegradable drug delivery carriers with minimal side effects for breast cancer treatment by developing gold nanoparticles/reduced graphene oxide (Au-rGO) nanocomposites using a sustainable synthesis method and loading them with cyclophosphamide. METHODS: Cyclophosphamide-loaded gold/reduced graphene oxide nanocomposites (Au-rGOCP) were synthesized and evaluated using FT-IR, XRD, release pattern, and FE-SEM techniques. Furthermore, the anticancer effect against breast cancer cells was evaluated through MTT and Annexin V assays. CAT, SOD, and GPx biomarkers were used to assess the antioxidant effect of the free and nano-formulated cyclophosphamide. RESULTS: The characterization results showed the effective loading of cyclophosphamide in the nanocarriers. Additionally, Au-rGO had a higher drug loading capacity for cyclophosphamide during a 24-hour contact period (92.34%). The pH value affected the amount of cyclophosphamide released from the nanocarriers. Au-rGO/CP displayed significant in vitro anti-cancer activity against MCF-7 cancer cells relative to free CP and rGO/CP. According to Annexin V assay results, Au-rGO/CP induced a higher apoptosis rate in MCF-7 breast cancer cells than other forms. CONCLUSION: In conclusion, our findings demonstrate that the gold-decorated reduced graphene oxide nanocomposite enhances treatment efficacy and significantly increases apoptosis and cell death induction. As a result, CP-loaded Au-rGO-based compounds could be a promising treatment for breast cancer.

A comparative study on green synthesis and characterization of Mn doped ZnO nanocomposite for antibacterial and photocatalytic applications.

Biological and green synthesis of nanomaterial is a superior choice over chemical and physical methods due to nanoscale attributes implanted in a green chemistry matrix, have sparked a lot of interest for their potential uses in a variety of sectors. This research investigates the growing relevance of nanocomposites manufactured using ecologically friendly, green technologies. The transition to green synthesis correlates with the worldwide drive for environmentally sound procedures, limiting the use of traditional harsh synthetic techniques. Herein, manganese was decorated on ZnO NPs via reducing agent of Withania-extract and confirmed by UV-spectrophotometry with highest peak at 1:2 ratio precursors, and having lower bandgap energy (3.3 eV). XRD showed the sharp peaks and confirms the formation of nanoparticles, having particle size in range of 11-14 nm. SEM confirmed amorphous tetragonal structure while EDX spectroscopy showed the presence of Zn and Mn in all composition. Green synthesized Mn-decorated ZnO-NPs screened against bacterial strains and exhibited excellent antimicrobial activities against gram-negative and gram-positive bacteria. To check further, applicability of synthesized Mn-decorated Zn nanocomposites, their photocatalytic activity against toxic water pollutants (methylene blue (MB) dye) were also investigated and results showed that 53.8% degradation of MB was done successfully. Furthermore, the installation of green chemistry in synthesizing nanocomposites by using plant extract matrix optimizes antibacterial characteristics, antioxidant and biodegradability, helping to build sustainable green Mn decorated ZnO nanomaterial. This work, explains how biologically friendly Mn-doped ZnO nanocomposites can help reduce the environmental impact of traditional packaging materials. Based on these findings, it was determined that nanocomposites derived from biological resources should be produced on a wide scale to eradicate environmental and water contaminants through degradation.

Magnetic polyimide nanocomposite for analysis of parabens in cooking wine by magnetic solid-phase extraction coupled with gas chromatography - Mass spectrometry.

A magnetic polyimide (PI) nanocomposite has been synthesized by phase inversion of PI and simultaneous encapsulation of Fe3O4 nanoparticles. The Fe3O4/PI nanocomposite was characterized by a variety of characterization techniques, including infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption isotherms, and vibrating sample magnetometry. The results showed that the prepared nanocomposite had a homogeneous structure, adequate specific surface area (76.1 m2/g) and high saturation magnetization (42.9 emu/g). Using parabens as model analytes, the performance of the Fe3O4/PI nanocomposite as an adsorbent for magnetic solid-phase extraction (MSPE) was evaluated. The extracted parabens were desorbed and determined by gas chromatography-mass spectrometry (GC-MS). The parameters affecting the extraction and desorption efficiency of parabens were optimized. Under the optimal conditions, the developed MSPE/GC-MS method was successfully applied to the determination of parabens in cooking wine. The MSPE/GC-MS method exhibited broad linearity (0.2-100 µg/L), low detection limits (0.04-0.05 µg/L), and satisfactory extraction recoveries (79.2 %-113.3 %) with relative standard deviations (RSDs) ranging from 0.7 % to 10.4 %. For real cooking wine samples, the spiked recoveries ranged from 91.7 % to 118.7 % with RSDs of 1.0 %-11.2 %. The results demonstrated that the Fe3O4/PI nanocomposite was an effective adsorbent, and this work provides a novel reference for the easy preparation of magnetic adsorbent materials.

A NiFe PBA/AuNPs nanocomposite sensitive immunosensor for electrochemical detection of PSA.

In this paper, a label-free electrochemical immunosensor for sensitive detection of prostate antigen (PSA) was developed based on a NiFe PBA/AuNPs composite. The prostate antigen antibody was immobilized and the immunosensor was constructed by using a glassy carbon electrode modified with a nanocomposite consisting of nickel-iron Prussian blue analog (NiFe PBA) and gold nanoparticles (AuNPs). Due to the good biological affinity of AuNPs for biomolecules, as well as the porous nanostructure and regular shape of NiFe PBA, NiFe PBA/AuNPs nanocomposites significantly improve the electron transport rate, while achieving excellent performance for the sensor. Due to the interaction between the antibody and the antigen on the modified electrode, the current signal of the NiFe PBA itself is reduced due to the redox changes in Fe2+ and Fe3+, which can be determined by differential pulse voltammetry (DPV). Therefore, the monitoring of prostate antigen detection is realized. Under optimal experimental conditions, the immunosensor exhibited excellent detection performance with a dynamic response range from 0.5 pg mL-1 to 1000 pg mL-1 for the PSA concentration and a detection limit of 0.23 pg mL-1 (S/N = 3). In addition, the PSA aptasensor has good selectivity, high stability, and satisfactory reproducibility and has broad potential in clinical research and diagnostic applications.

Enhanced mitigation of acidic and basic dyes by ZnO based nano-photocatalysis: current applications and future perspectives.

Dye wastewater possess immense toxicity with carcinogenic properties and they persist in environment owing to their stability and resistance to chemical and photochemical changes. The bio degradability of dye-contaminated wastewater is low due to its complex molecular structure. Nano-photocatalysts based on zinc oxide are reported as one of the effective metal oxides for dye remediation due to their photostability, enhanced UV and visible absorption capabilities in an affordable manner. An electron-hole pair forms when electrons in the valence band of ZnO nano-photocatalyst transfer into the conduction band by absorbing UV light. The review article presents a detailed review on ZnO applications for treating acidic and basic dyes along with the dye degradation performance based on operating conditions and photocatalytic kinetic models. Several acidic and basic dyes have been shown to degrade efficiently using ZnO and its nanocomposites. Higher removal percentages for crystal violet was reported at pH 12 by ZnO/Graphene oxide catalyst under 400 nm UV light, whereas acidic dye Rhodamine B at a pH of 5.8 was degraded to 100% by pristine ZnO. The mechanism of action of ZnO nanocatalysts in degrading the dye contamination are reported and the research gaps to make these agents in environmental remediation on real time operations are discussed.

Electrochemical Sensors Based on Self-Assembling Peptide/Carbon Nanotube Nanocomposites for Sensitive Detection of Bisphenol A.

In this study, a cationic amphiphilic self-assembling peptide (SAP) Z23 was designed, and a simple bisphenol a (BPA) sensor, based on SAP Z23/multiwalled carbon nanotubes (Z23/MWCNTs) composite, was successfully fabricated on the surface of a glassy carbon electrode (GCE). The composite material was formed by π-π stacking interaction between the aromatic group on the hydrophobic side of Z23 and the side-wall of MWCNTs, with the charged hydrophilic group of Z23 exposed. During the electrocatalytic process of BPA, a synergistic effect was observed between Z23 and MWCNTs. The current response of the sensor based on composite material was 3.24 times that of the MWCNTs-modified electrode, which was much higher than that of the peptide-based electrode. Differential pulse voltammetry (DPV) was used to optimize the experimental conditions affecting the analytical performance of the modified electrode. Under optimal conditions, the linear range of the sensor was from 10 nM to 100 µM by amperometric measurement with sensitivity and limit of detection (LOD) at 6.569 µAµM-1cm-2 and 1.28 nM (S/N = 3), respectively. Consequently, the sensor has excellent electrochemical performance and is easy to fabricate, making it a good prospect in the field of electrochemical detection in the future.

A novel electrochemical strategy to detect hydrogen peroxide by utilizing peroxidase-mimicking activity of cerium oxide/graphene oxide nanocomposites.

We herein describe a novel electrochemical strategy to detect hydrogen peroxide (H2O2) by utilizing the peroxidase-mimicking activity of cerium oxide nanoparticles (CeO2 NP) and reduced graphene oxide (rGO). Particularly, CeO2 NP/rGO nanocomposites were deposited on the commercial electrode by a very convenient and direct electrochemical reduction of graphene oxide. Due to the peroxidase-mimicking activity of CeO2 NP and the outstanding electrochemical properties of reduced graphene oxide, the reduction current of H2O2 was greatly enhanced. Based on this strategy, we reliably determined H2O2 down to 1.67 µM with excellent specificity and further validated its practical capabilities by robustly detecting H2O2 present in heterogeneous human serum samples. We believe that this work could serve as a new facile platform for H2O2 detection.

Near-infrared light triggered upconversion nanocomposites with multifunction of enhanced antimicrobial photodynamic therapy and gas therapy for inflammation regulation.

Antibacterial photodynamic therapy (aPDT) is highly effective in killing bacteria, while the problem of hypoxia and limited light penetration in deep tissue has not been properly solved. In addition, few aPDT works take into account the regulation of inflammation, which is an important regulatory process after antimicrobial therapy and the final purpose of treatment. In this work, to address the above isssues, we have designed a multi-functional composite UCNPs-Ce6-Mn(CO)5Br@Silane (referred to as UCM@Si), which consists of several key components: Up-conversion nanoparticles (UCNPs: NaErF4:Tm3+@NaYF4:Yb3+), Chlorin e6 (Ce6) and Manganese pentacarbonyl bromide (Mn(CO)5Br). When exposed to near-infrared (NIR) light (980 nm), the UCNPs can emit strong red light at 655 nm which further trigger the aPDT of Ce6. The generated reactive oxygen (ROS) subsequently break the metal carbonyl bond of Mn(CO)5Br, leading to the production of carbon monoxide (CO) molecules as well as manganese ions (Mn2+), which further decomposes hydrogen peroxide (H2O2) in the microenvironment to oxygen (O2). Therefore, this simple nanocomposite not only provides substantial self-oxygen replenishment for enhanced aPDT, but also facilitates effective inflammation regulation via CO across a wide range of deep infections. This approach leverages the unique properties of these materials to combat bacterial infections by simultaneously killing bacteria, regulating inflammation, and enhancing the oxygen levels in the affected microenvironment. This O2 and CO gas based aPDT treatment system offers a promising approach to comprehensively address microbial-induced infectious diseases, particularly deep infections, holding the potential clinical applications.

One pot fabrication of diamino naphthalene -AuNPs decorated graphene nanoplatform for the MRSA detection in the biological sample.

Early monitoring of MRSA can effectively mitigate the disease risk by using Penicillin-binding protein 2a (PbP2a) biomarker. Diamino naphthalene-AuNPs decorated graphene (AuNPsGO-DN) nanocomposite was synthesized for a rapid and sensitive immunosensor detecting PbP2a. The synthesized AuNPsGO-DN nanocomposites were characterized by field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (SEM-EDX), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, and X-ray diffraction spectroscopy (XRD). Electrochemical characterization done with cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrical impedance spectroscopy (EIS) techniques. Anti-PbP2a monoclonal antibodies immobilized at AuNPsGO-DN/GCE via covalent bonding. AuNPs enhanced the electrode surface area and the antibodies' loading. Mercaptopropionic acid (MPA) was a linker between the AuNPs and antibodies, orientated the antibodies as opposite to the PbP2a antigen, and improved the sensitivity and specificity. The antiPbP2a/MPA/AuNPsGO-DN/GCE electrode displayed sensitive and selective detection towards the PbP2a antigen in phosphate buffer saline (PBS pH 7.4). The broad linear range from 0.01 to 8000 pg/mL was obtained with LOD of 0.154 pg/mL and 0.0239 pg/mL, respectively. A label-free, simple, and sensitive immunosensor was developed with a 98-106 % recovery rate in spiked biological samples. It shows the potential applicability of the developed immunoelectrode.

Ultrasensitive, Label-Free Voltammetric Detection of Dibutyl Phthalate Based on Poly-l-lysine/poly(3,4-ethylenedioxythiophene)-porous Graphene Nanocomposite and Molecularly Imprinted Polymers.

Development of an efficient technique for accurate and sensitive dibutyl phthalate (DBP) determination is crucial for food safety and environment protection. An ultrasensitive molecularly imprinted polymers (MIP) voltammetric sensor was herein engineered for the specific determination of DBP using poly-l-lysine/poly(3,4-ethylenedioxythiophene)/porous graphene nanocomposite (PLL/PEDOT-PG) and poly(o-phenylenediamine)-imprinted film as a label-free and sensing platform. Fabrication of PEDOT-PG nanocomposites was achieved through a simple liquid-liquid interfacial polymerization. Subsequently, poly-l-lysine (PLL) functionalization was employed to enhance the dispersibility and stability of the prepared PEDOT-PG, as well as promote its adhesion on the sensor surface. In the presence of DBP, the imprinted poly(o-phenylenediamine) film was formed on the surface of PLL/PEDOT-PG. Investigation of the physical properties and electrochemical behavior of the MIP/PLL/PEDOT-PG indicates that the incorporation of PG into PEDOT, with PLL uniformly wrapping its surface, significantly enhanced conductivity, carrier mobility, stability, and provided a larger surface area for specific recognition sites. Under optimal experimental conditions, the electrochemical response exhibited a linear relationship with a logarithm of DBP concentration within the range of 1 fM to 5 µM, with the detection limit as low as 0.88 fM. The method demonstrated exceptional stability and repeatability and has been successfully applied to quantify DBP in plastic packaging materials.