Au NPs Research Articles

Colorimetric and SERS dual-mode detection of GSH in human serum based on AuNPs@Cu-porphyrin MOF nanozyme

BackgroundRapid and accurate detection of glutathione content in human blood plays an important role in real-time tracking of related diseases. Currently, surface-enhanced Raman scattering/spectroscopy (SERS) combined with nanozyme material has been proven to have excellent properties in the detection applications compared to many other methods because of it combines the advantages of trace detection capability of SERS and efficient catalytic activity of nanozymes. However, there are still existing problems in real sample detection, and to achieve quantitative detection is still challenging. ResultsIn this study, gold nanoparticles (AuNPs) were synthesized in situ on the surface of two-dimensional Cu-porphyrin metal-organic framework (MOF) nanosheets to produce the AuNPs@Cu-porphyrin MOF nanozyme, which exhibited both oxidase-like activity and SERS detection ability. On one hand, the intrinsic oxidase-like activity of the nanozyme could be inhibited due to the chelation of glutathione (GSH) and Cu, which thus led to the visual color change of the solution. On the other hand, the abundant Raman “hot spots” at the nanogap generated by Au NPs and the internal standard (IS) signal provided by Cu-meso-tetra (4-carboxyphenyl) porphine (Cu-TCPP) MOF improved the sensitivity and quantitative accuracy of detection. Significance and noveltyA dual-mode signal output sensor based on the nanozyme was thus established, which could be used in the trace detection of GSH. Such a dual-mode sensor possesses excellent detection performance, with the advantage of both wide detection range from 1 to 300 μM in the colorimetric detection mode and high sensitivity with LOD of 5 nM in the SERS detection mode, and can be applied to GSH detection in actual serum samples with reliable results.

Immortalized nanodendritic cells decorated with immune-checkpoint inhibitors for personalized cancer immunotherapy

In our study, we have designated artificial nanoDCs (anDCs) by transferring the whole DC membrane onto the gold nanoparticles (Au NPs) to overcome the limitation of DC therapy. The anDCs were optimized by varying membrane-to-substrate ratio, exhibiting similar features with natural DC in having a T cell stimulation and tumor regression even after long-term stability of up to 30 days. This versatile anDCs platform allows engineering immune-boosting agents onto their surface on demand. We further functionalized one of the immune checkpoint inhibitors (ICI), αCTLA-4, on anDCs, leading to complete tumor clearance compared to DC membrane vesicles. Surprisingly, αCTLA-4 conjugated anDC (αCTLA-4-anDC) dramatically blocked the CTLA-4 pathway and resulted in increased frequency and effector cytokine functions in cytotoxic CD8+ T cells. Thus, our anDC system can effectively induce a tumor-specific T cell immune response by sustainable and potent T cell priming ability based on the high stability of anDCs, suggesting a great potential platform for next-generation personalized cancer immunotherapy.

Improved photocatalytic activities of TiO2/MoO3/Au nanocomposite prepared by hydrothermal method

The synthesis of TiO2/MoO3/Au nanocomposite has been carried out to study its photocatalysis activity. A hydrothermal technique was used to systematically incorporate titanium dioxide (TiO2), molybdenum trioxide (MoO3), and gold nanoparticles (Au NPs) to produce a synergistic nanostructured material. The analysis of prepared nanocomposite was performed using several characterization methods. UV-visible spectroscopy is used to examine the existence of materials and optical absorption. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were among the methods used to study the crystalline phases and surface morphologies. Methylene blue organic pollutants were used to evaluate the photocatalytic activity of the resulting TiO2/MoO3/Au nanocomposites under visible light irradiation. The TiO2/MoO3/Au composite showed significant photocatalytic performance among the three composites.

Self-assembled core-shell nanoparticles with embedded internal standards for SERS quantitative detection and identification of nicotine released from snus products.

Surface enhanced Raman spectroscopy (SERS) is a unique analytical technique with excellent performance in terms of sensitivity, non-destructive detection and resolution. However, due to the randomness and poor repeatability of hot spot distribution, SERS quantitative analysis is still challenging. Meanwhile, snus is a type of tobacco product that can release nicotine and other components in the mouth without burning, and the rapid detection technique based on SERS can reliably evaluate the amount of nicotine released from snus, which is of great significance for understanding its characteristics and regulating its components. Herein, the strategy was proposed to solve the feasibility of SERS quantitative detection based on self-assembled core-shell nanoparticles with embedded internal standards (EIS) due to EIS signal can effectively correct SERS signal fluctuations caused by different aggregation states and measurement conditions, thus allowing reliable quantitative SERS analysis of targets with different surface affinity. By means of process control, after the Au nanoparticles (Au NPs) were modified with 4-Mercaptobenzonitrile (4-MBN) as internal standard molecules, Ag shell with a certain thickness was grown on the surface of the AuNP@4-MBN, and then the Au@4-MBN@Ag NPs were used to regulate and control the assembly of liquid-liquid interface. The high-density nano-arrays assembled at the liquid-liquid interface ensure high reproducibility as SERS substrates, and which could be used for SERS detection of nicotine released from snus products. In addition, time-mapping research shows that this method can also be used to dynamically monitor the release of nicotine. Moreover, such destruction-free evaluation of the release of nicotine from snus products opens up new perspectives for further research about the impact of nicotinoids-related health programs.

A Co-Reactive Immunosensor Based on Ti3C2Tx MXene@TiO2-MoS2 Hybrids Promoting luminol@Au@Ni-Co NCs Electrochemiluminescence for CYFRA 21-1 Detection.

The construction of assays is capable of accurately detecting cytokeratin-19 (CYFRA 21-1), which is critical for the rapid diagnosis of nonsmall cell lung cancer. In this work, a novel electrochemiluminescence (ECL) immunosensor based on the co-reaction promotion of luminol@Au@Ni-Co nanocages (NCs) as ECL probe by Ti3C2Tx MXene@TiO2-MoS2 hybrids as co-reaction accelerator was proposed to detect CYFRA 21-1. Ni-Co NCs, as a derivative of Prussian blue analogs, can be loaded with large quantities of Au NPs, luminol, and CYFRA 21-1 secondary antibodies due to their high specific surface area. To further improve the sensitivity of the developed ECL immunosensor, Ti3C2Tx MXene@TiO2-MoS2 hybrids were prepared by in situ growth of TiO2 nanosheets on highly conductive Ti3C2Tx MXene, and MoS2 was homogeneously grown on Ti3C2Tx MXene@TiO2 surfaces by the hydrothermal method. Ti3C2Tx MXene@TiO2-MoS2 hybrids possess excellent catalytic performance on the electro-redox of H2O2 generating more O2·- and obtaining optimal ECL intensity of the luminol/H2O2 system. Under the appropriate experimental conditions, the quantitative detection range of CYFRA 21-1 was from 0.1 pg mL-1 to 100 ng mL-1, and the limit of detection (LOD) was 0.046 pg mL-1. The present sensor has a lower LOD with a wider linear range, which provides a new analytical assay for the early diagnosis of small-cell-type lung cancer labels.

Confinement-enhanced electrochemiluminescence by Ru(dcbpy)32+-functionalized γ-CD-MOF@COF-LZU1 porous hybrid material as micro-reactor for CYFRA 21-1 detection

The improvement of electrochemiluminescence (ECL) performance relies on the electron transfer efficiency between luminophore and coreactant. An ultrasensitive ECL micro-reactor with confinement-enhanced performance was prepared by using the covalent organic framework-LZU1-functionalized metal-organic framework (MOF@COF-LZU1) as a platform to assemble enormous N,N-dibutyl-2-hydroxyethylamine (DBAE) and tris(4,4′-dicarboxylic acid-2,2′-bipyridyl) ruthenium(II) [Ru(dcbpy)32+] into its pore channels. Compared to individual substances of γ-CD-MOF and COF-LZU1, the synergistic effects can conduce to the enhancement of the intensity, durability and sensitivity of the micro-reactor. Besides, COF-LZU1 can provide a mild environment to accommodate a certain amount of DBAE by concentrating them from the aqueous solution into its hydrophobic cavities and boost the oxidation efficiency of DBAE to generate more DBAE●+ and profited the survival of DBAE●, leading to an improved reaction efficiency with the Ru(dcbpy)32+ intermediate. Thanks to the confinement-enhanced strategy, engineered as high-functioning luminescent materials, Ru@γ-CD-MOF@COF-LZU1 micro-reactors decorated with Au NPs can facilitate electron transfer and capture primary antibodies (Ab1). Moreover, Au–Pd–Pt noble metal aerogels (NMAs) functionalized MoS2 NFs (Au–Pd–Pt NMAs@MoS2 NFs) were chosen as base material due to its large specific surface areas, high porosity, and excellent electrical conductivity. Based on above merits, the sensor demonstrated a sensitive response to CYFRA 21-1 detection in a linear concentration gradient from 10 fg/mL to 50 ng/mL with a detection limit of 0.0055 pg/mL (S/N = 3). The COF-LZU1 decorated ECL micro-reactors were constructed based on the signal amplification strategies to realize accurate CYFRA 21-1 detection.

Space-confined nanozyme with cascade reaction based on PCN-224 for synergistic bacterial infection treatment and NIR fluorescence imaging of wound bacterial infections

The rapid development of bacterial infections has become a significant global health challenge. The overuse or prolonged use of antibiotics is considered a major contributor to the development of bacterial resistance. Therefore, there is an urgent need to develop a new therapeutic approach to combat infectious diseases caused by bacteria. In this study, we demonstrate the effectiveness of a novel strategy for synergistic antibacterial therapy and fluorescence imaging of wound bacterial infections through the nano-confined construction of LL-37-HA-Au-Pt@PCN-224 nanozymes. The nanozyme is composed of Au NPs and Pt NPs confined to PCN-224 through in situ reduction, with its outer layer modified with HA and LL-37. The nanozyme catalyzes the conversion of low-concentration H2O2 into O2 and •OH, with the generated O2 further catalyzed into 1O2 by PCN-224. In vivo imaging experiments demonstrate that LL-37-HA-Au-Pt@PCN-224 labeled with near-infrared fluorescent dye MPA can effectively realize fluorescence imaging of wound bacterial infections and real-time monitoring of the wound healing process. In vitro and in vivo antibacterial experiments reveal that LL-37-HA-Au-Pt@PCN-224 enhances the healing efficiency of bacteria-infected wounds due to its synergistic antibacterial effect. The multifunctional nanozyme offers various synergistic antibacterial therapies, including antimicrobial peptides, peroxide nanozymes, hydrogen peroxide nanozymes, and photodynamic therapy. Moreover, it provides real-time wound imaging and monitoring of the wound healing process, while maintaining high biocompatibility. Overall, this study presents a promising perspective on the potential use of nanozymes as antibacterial agents against wound bacterial infections in the future.

FeNi-MIL-88B-based electrochemiluminescence immunosensor for ultra-sensitive detection of CD44 protein via dual-quenching strategy

BackgroundCluster of Differentiation 44 (CD44) is considered an important biomarker for various cancers, and achieving highly sensitive detection of CD44 is crucial, which plays a significant role in tumor invasion and metastasis, providing essential information for clinical tumor diagnosis. Commonly used methods for analysis include fluorescence spectroscopy (FL), photoelectrochemical analysis (PEC), electrochemical analysis (EC), and commercial ELISA kits. Although these methods offer high sensitivity, they can be relatively complex to perform experimentally. Electrochemiluminescence (ECL) has gained widespread research attention due to its high sensitivity, ease of operation, effective spatiotemporal control, and close to zero background signal. ResultsIn this work, a sandwich-type ECL immunosensor for detecting CD44 was constructed using luminol as a luminophore. In this sensing platform, bimetallic MOFs (Pd@FeNi-MIL-88B) loaded with palladium nanoparticles (Pd NPs) were used as a novel enzyme mimic, exhibiting excellent catalytic performance towards the electroreduction of H2O2. The hybrids provided a strong support platform for luminol and antibodies, significantly enhancing the initial ECL signal of luminol. Subsequently, core-shell Au@MnO2 nanocomposites were synthesised by gold nanoparticles (Au NPs) encapsulated in manganese dioxide (MnO2) thin layers, as labels. In the luminol/H2O2 system, Au@MnO2 exhibited strong light absorption in the broad UV–vis spectrum, similar to the black body effect, and the scavenging effect of Mn2+ on O2•−, which achieved the dual-quenching of ECL signal. Under the optimal experimental conditions, the immunosensor demonstrated a detection range of 0.1 pg mL−1 − 100 ng mL−1, with a detection limit of 0.069 pg mL−1. SignificanceBased on Pd@FeNi-MIL-88B nanoenzymes and Au@MnO2 nanocomposites, a dual-quenching sandwich-type ECL immunosensor for the detection of CD44 was constructed. The proposed immunosensor exhibited excellent reproducibility, stability, selectivity, and sensitivity, and provided a valuable analytical strategy and technical platform for the accurate detection of disease biomarkers, and opened up potential application prospects for early clinical treatment.

Green synthesis of silver and gold nanoparticles in Callistemon viminalis extracts and their antimicrobial activities.

In the current study, the bottlebrush [Callistemon viminalis (Sol. ex Gaertn.) G. Don] plant was selected for the green synthesis of silver (Ag) and gold (Au) nanoparticles and to evaluate its antibacterial and antifungal activities. Phytochemical screening of C. viminalis confirmed the presence of alkaloids, anthraquinones, saponins, tannins, betacyanins, phlobatanins, coumarins, terpenoids, steroids, glycosides, and proteins. To characterize the synthesized Ag and Au NPs, UV-Visible spectroscopy, FTIR spectroscopy for functional group identification, field emission scanning electron microscopy (FE-SEM) for particle size, and elemental analysis were performed using EDX. The UV-Visible absorption spectra of the green-synthesized Ag and Au nanoparticles were found to have a maximum absorption band at 420 nm for Ag NPs and 525 nm for Au NPs. FE-SEM analysis of the synthesized NPs revealed a circular shape with a size of 100 nm. Elemental analysis was performed for the synthesis of Ag and Au NPs, which confirmed the purity of the nanoparticles. The greenly synthesized Ag and Au NPs were also evaluated for their anti-bacterial and anti-fungal activities, which exhibited prominent inhibition activities against Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Candida albicans, C. krusei, Aspergillus sp., and Trichoderma species. The highest zone of inhibition 15.5±0.75 and 15±0.85mm was observed for Ag NPs against E. coli and P. aeruginosa. Similarly, Trichoderma sp. and Aspergillus sp. were inhibited by Ag NPs up to 13.5±0.95 and 13±0.70mm. This work will open doors for the development of new antimicrobial agents using green chemistry.

Sunlight-assisted green synthesis of gold nanocubes using horsetail leaf extract: A highly selective colorimetric sensor for Pb2+, photocatalytic and antimicrobial agent

This work aims to establish a novel approach for the selective synthesis of gold nanoparticles (Au NPs) with defined shape and size as well as excellent colloidal stability via a facile and environmentally friendly manner. The polar extract from the leaves of the plant E. diffusum (EDLE), also known as horsetail, was used to synthesize gold NPs (EDLE@Au NPs). Fourier-transform infrared (FTIR) and UV–visible spectroscopy, scanning electron microscopy-energy dispersive X-rays (SEM-EDX), PXRD, dynamic light scattering (DLS), and zeta potential (ZP) were used to characterize as-synthesized EDLE@Au NPs. The SEM imaging revealed the cubic shape of EDLE@Au NPs. Interestingly, EDLE@Au NPs interacted with different metal ions, and a shift in the LSPR band to a higher wavelength was observed only in the case of Pb2+ ions. This provided a basis for using the EDLE@Au NPs as a selective colorimetric sensor for Pb2+ ions. A linear range of 20–350 µM and a limit of detection of 4.4 µM for Pb2+ detection was achieved. To elucidate the sensing mechanism, DLS and zeta potential analyses were carried out after addition of Pb2+. A significant decrease in the zeta potential along with an increase in the particle size of the Au NPs was observed after the addition of Pb2+, suggesting the aggregation of the nanoparticles. Further, the results of the antimicrobial study showed that EDLE@Au NPs were active against both gram-positive and gram-negative bacteria. An exceptional photocatalytic activity with 96.5% degradation efficiency of EDLE@Au NPs was examined against methylene blue dye.

Piezo-photodynamic therapy of Au@PEG-ZnO nanostructures enabled with a battery-free wireless cancer therapeutic dot

Cancer remains a global health concern, necessitating advanced therapeutic strategies to address its fatal challenges. Conventional treatments, such as radiotherapy and chemotherapy, often lack tumor specificity and may induce systemic toxicity. Photodynamic therapy (PDT) and sonodynamic therapy (SDT) have emerged as promising alternatives, demonstrating high specificity and minimal side effects. In this study, we propose a novel piezo-photodynamic therapy (PPDT) enabled with battery-free wireless cancer therapeutic dot, in which the nanocomposites of gold nanoparticles (Au NPs), zinc oxide nanorods (ZnO NRs) and hydrophilic polyethylene glycol (PEG) can enhance reactive oxygen species (ROS) generation and effectively inhibit tumor growth. The therapeutic dot is implanted directly inside the tissue around the tumor and wirelessly controlled by ultrasound (US), allowing dual activation of electron-hole pairs from the nanocomposites via US and ultraviolet light (UV). The internally generated piezoelectric field minimizes electron-hole recombination, maximizing ROS induction within tumor cells. This PPDT approach surpasses the efficacy of conventional PDT and SDT, showcasing a synergistic therapeutic effect. The study further elucidates the detailed mechanism of Au@PEG-ZnO NRs catalysts, providing insights into their piezoelectric-photocatalytic action. The battery-free wireless control and minimally invasive implantation of the therapeutic dot with inorganic piezo-photocatalyst open new perspectives in cancer therapy.

Biosynthesis of gold nanoparticles mediated by Curcuma longa extract: Evaluation of its catalytic activity for the degradation of environmental pollutants and study of anti-lung adenocarcinoma effects

It is essential to recognize efficient heterogeneous catalysts for environmental remediation that can eliminate organic contaminants or transform them into beneficial byproducts. Herein, we have designed and developed a gold nanoparticle based green nanocomposite material templated over the Curcuma longa extract. The Au NPs/C. longa nanomaterial was thoroughly characterized by FT-IR and UV–Vis spectroscopy followed by FE-SEM, EDX, TEM and XRD analysis. Subsequently, towards the wastewater treatment, it demonstrated excellent potential in the reduction of water contaminant toxic organic dyes like methylene blue (MB), methyl orange (MO), and 4-nitrophenol (4-NP) following excellent kinetics, as monitored by UV–Vis spectrophotometer. The reaction followed a pseudo-first order kinetics. The robustness of the nanocatalyst was justified by reusability studies, and hot filtration test and the catalytic activity did not substantially decline over the course of seven cycles. Towards the assessment of biological activity of Au NPs/C. longa nanocomposite antioxidant capacity was evaluated first using the DPPH radical scavenging method. Further, the study was extended in the investigation of anti-lung cancer properties against a number of standard lung cancer cell lines, viz., NCI-H661, NCI-H1975, NCI-H1573, and NCI-H1563 following MTT colorimetric in vitro studies. Curcuma longa-modified Au NPs are thought to have potential biological activities because of their exceptional capacity to produce reactive oxygen species (ROS).

Local electric field enhancement in the vicinity of aggregates of Ag, Au, Rb containing nanoparticles in oxide glasses

Local electric field (LEF) distribution near Ag, Au, AgAu NPs synthesized by UV laser or temperature treatments, and near simulated Rb, AgRb, AuRb NPs in oxide glasses, was studied considering aggregates of 10–15 particles - necessary condition for description of optical extinction spectra. For efficient analysis of LEF spatial distributions under different sizes, components, agglomerations of NPs in these aggregates, approach was proposed that enables to obtain dependence of averaged LEF enhancement upon the distance from the nearest particles in aggregate. This approach reproduced enhancement of Er3+ luminescence intensity in zinc-tellurite glass after formation of Ag NPs and showed that average LEF enhancement per hypothetical Rare Earth ion (REI) is largest for aggregates of Ag, less for Rb, lowest for Au NPs. The optimal Ag NPs aggregate was estimated for best LEF enhancement per hypothetical REI. Simulated aggregates of Rb containing NPs demonstrated strong LEF, shifted in a wide range.

HAuCl4-mediated green synthesis of highly stable Au NPs from natural active polysaccharides: Synthetic mechanism and antioxidant property

Polysaccharide-functionalized gold nanoparticles (Polysaccharide-Au NPs) with high stability were successfully prepared by a straightforward method. Notably, the Au (III) ion acts as a strong Lewis acid to facilitate glycosidic bond breaking. Subsequently, the polysaccharide conformation was transformed to an open-chain form, exposing highly reduced aldehyde or ketone groups that reduce Au (III) to Au (0) crystal species, further growing into Au NPs. As-prepared Au NPs displayed excellent stability over a longer storage period (more than 70 days), a wide range of temperatures (25–60 °C), and pH range (3−11), varying concentrations (0–200 mM) and types of salt ions (Na+, K+, Ca2+, Mg2+), and glutathione solutions (5 mM). More interestingly, polysaccharide-Au NPs retained the antioxidant activity of polysaccharides and reduced oxidative damage at the cellular level through decreased reactive oxygen species (ROS) production. The intracellular levels of ROS pretreated with polysaccharide and polysaccharide-Au NPs were decreased 53.12–75.85 % compared to the H2O2 group, respectively. Therefore, the green synthesized Au NPs from natural active polysaccharides exhibit potential applications in biomedical fields.

Construction of Au-modified CN-based donor-acceptor system coupled with dual photothermal effects for efficient photoreduction of carbon dioxide

Conversion of CO2 into high value-added fuels through the photothermal effect is an effective approach for utilizing solar energy. In this study, we prepared the CN-based photocatalyst Py-CTN-Au with both donor-acceptor (D-A) system and dual photothermal effects using a simple two-step method involving calcination and photo-deposition. Real-time monitoring with a thermal imaging camera revealed that Py-CTN-Au0.5 achieved a maximum stable temperature of 180 °C, which was approximately 1.2 times higher than that of Py-CTN (155 °C) and 1.9 times higher than that of g-CN (95 °C) under the same reaction conditions. Under the optimized reaction conditions, Py-CTN-Au0.5 exhibited a CO release rate of 30.59 umol g−1 after 4 h of reaction, which was 7.3 times higher than that of pure g-CN (4.18 umol g−1). The D-A system not only facilitated the separation and transformation of charge carriers but also induced a photothermal effect to accelerate the photoreduction of CO2. Additionally, the cocatalyst Au nanoparticles (Au NPs) further enhanced the charge carrier dynamics and photothermal effect by increasing the built-in electric field intensity and localized surface plasmon resonance (LSPR) effect, respectively. The dual photothermal effects resulting from the non-radiative photon conversion of the D-A structure and the Au NPs LSPR effect, along with the enhanced charge carrier dynamics, catalyzed the efficient photoreduction of CO2. DFT simulations were used to confirm the effect of D-A system and Au NPs. In-situ FTIR results demonstrated that the synergistic photothermal effect promoted the formation of the key intermediate species COOH*, which is beneficial for the photocatalytic reduction of CO2. This study provides valuable insights into the multiple photothermal synergistic effects in photocatalytic reactions.

MDSC-targeting gold nanoparticles enhance PD-1 tumor immunotherapy by inhibiting NLRP3 inflammasomes

Myeloid-derived suppressor cells (MDSCs) play a crucial role in the immune escape mechanisms that limit the efficacy of immunotherapeutic strategies. In the tumor microenvironment, NLRP3 inflammasome-driven Interleukin-1β (IL-1β) production serves to dampen antitumor immune responses, promoting tumor growth, progression, and immunosuppression. In this study, we revealed that gold nanoparticles (Au NPs) with a size of 30 nm disrupted NLRP3 inflammasome, but not other inflammasomes, in bone marrow-derived macrophages through abrogating NLRP3-NEK7 interactions mediated by reactive oxygen species (ROS). Density functional theory (DFT) calculations provided insights into the mechanism underlying the exceptional ROS scavenging capabilities of Au NPs. Additionally, when coupled with H6, a small peptide targeting MDSCs, Au NPs demonstrated the capacity to effectively reduce IL-1β levels and diminish the MDSCs population in tumor microenvironment, leading to enhanced T cell activation and increased immunotherapeutic efficacy in mouse tumor models that are sensitive and resistant to PD-1 inhibition. Our findings unraveled a novel approach wherein peptide-modified Au NPs relieved the suppressive impact of the tumor microenvironment by inhibiting MDSCs-mediated IL-1β release, which is the first time reported the employing a nanostrategy at modulating MDSCs to reverse the immunosuppressive microenvironment and may hold promise as a potential therapeutic agent for cancer immunotherapy.

Thermophoretic Aggregation Imaging of Tumor-Derived Exosomes by CRISPR-Cas13a-Based Nanoprobes.

The inherent heterogeneity of tumor-derived exosomes holds great promise for enhancing the precision of cancer diagnostics. MicroRNAs (miRNAs) encapsulated in tumor-associated exosomes have emerged as valuable biomarkers for the early detection of cancers. Nevertheless, the flexible structure and inherent instability of RNA limit its application in biological diagnostics. The CRISPR-Cas13a system, distinguished by its target-responsive "collateral effect", represents a powerful tool for advancing cancer diagnostics. In this study, we harness the CRISPR-Cas13a system as an innovative signal amplification tool to image cancer-related exosomal miRNA in situ. Furthermore, we capitalize on the thermophoretic aggregation effect exhibited by gold nanoparticles (Au NPs) to consolidate the fluorescent signals generated by the CRISPR-Cas13a system. Subsequently, the developed nanoprobe is applied to detect lung cancer-related exosomal miRNA from human serum, enabling the aggregated visualization of low-abundance cancer exosomes in individuals with lung cancer compared with healthy individuals. This sensitive thermophoretic aggregation assay provides a diagnostic tool for lung cancer in the clinic.

Preparation and adjuvanticity against PCV2 of Viola philippica polysaccharide loaded in Chitosan-Gold nanoparticle

The present Porcine circovirus type 2 virus (PCV2) vaccine adjuvants suffer from numerous limitations, such as adverse effects, deficient cell-mediated immune responses, and inadequate antibody production. In this study, we explored the potential of a novel nanoparticle (CS-Au NPs) based on gold nanoparticles (Au NPs) and chitosan (CS) that modified Viola philippica polysaccharide (VPP) as efficient adjuvants for PCV2 vaccine. The characterization demonstrated that CS-Au-VPP NPs had a mean particle size of 507.42 nm and a zeta potential value of −21.93 mV. CS-Au-VPP NPs also exhibited good dispersion and a stable structure, which did not alter the polysaccharide properties. Additionally, the CS-Au-VPP NPs showed easy absorption and utilization by the organism. To investigate their immune-enhancing potential, mice were immunized with a mixture of CS-Au-VPP NPs and PCV2 vaccine. The evaluation of relevant immunological indicators, including specific IgG antibodies and their subclasses, cytokines, and T cell subpopulations, confirmed their immune-boosting effects. The in vivo experiments revealed that the medium-dose CS-Au-VPP NPs significantly elevated the levels of specific IgG antibodies and their subclasses, cytokines, and T cell subpopulations in PCV2-immunized mice. These findings suggest that CS-Au-VPP NPs can serve as a promising vaccine adjuvant due to their stable structure and immunoenhancement capabilities.

Influence of Oxide Coating Layers on the Stability of Gold Catalysts for Furfural Oxidative Esterification to Methyl Furoate

The use of gold nanoparticles (Au NPs) as catalysts has gained widespread attention in various reactions due to their high activity and selectivity under mild reaction conditions. However, one major challenge in utilizing these catalysts is their tendency to aggregate, leading to catalyst deactivation and hindering their amplification and industrial application. To overcome this issue, herein, we used a method by coating the surface of Au NPs with a thin layer of SiO2, which resulted in the formation of a superior catalyst denoted as Au@SiO2/ZA. Characterization studies revealed that the SiO2 layer is coated on the surface of Au NPs and effectively prevents the aggregation and growth of the gold particles during the reaction process, which makes the catalyst display excellent stability in furfural (FF) oxidative esterification to methyl furoate (MF). Moreover, the stabilization strategy is not limited to SiO2 alone. It can also be extended to other oxides such as ZrO2, CeO2, and TiO2. We believe this work will provide a good reference for the design and development of an efficient and stable gold catalyst for the oxidative esterification reaction.

Methanol Oxidation Reaction in Alkaline Media Using Gold Nanoparticles Recovered from Electronic Waste.

This study investigates the potential of using gold nanoparticles (Au NPs) synthesized from e-waste as electrocatalysts for the methanol oxidation reaction (MOR), with the aim of applying them as an anode in alkaline direct methanol fuel cells (ADMFCs). The research addresses the pressing environmental challenge of e-waste disposal and explores the recycling of e-waste to obtain valuable materials for sustainable applications. Vulcan-supported gold nanoparticles (Aue-w/C NPs) are synthesized from gold coatings recovered from Intel Pentium 4 processor pins, demonstrating the feasibility of e-waste as electrocatalyst precursors. Comprehensive characterization techniques such as UV-Vis spectroscopy, high-resolution transmission and transmission electron microscopy (HR-TEM, TEM), selected area electron diffraction (SAED), scanning electron microscopy (SEM), and X-ray diffraction (XRD) are employed to evaluate the structural properties of the electrocatalyst. Electrochemical evaluation in 0.5 M KOH electrolyte by cyclic voltammetry reveals that the synthesized Aue-w/C NPs exhibit electrocatalytic activity (25.5 mA·mg-1Au) comparable to their commercially synthesized counterparts (30.1 mA·mg-1Au). This study highlights the potential for sustainable approaches in the production of electrocatalysts by utilizing e-waste as a source of valuable catalyst materials. It represents a pioneering effort in harnessing e-waste as a sustainable resource, offering new avenues for sustainable energy technologies while addressing environmental concerns and technological challenges in the field of ADMFCs.