Enhanced antibacterial activity of silver-decorated sandwich-like mesoporous silica/reduced graphene oxide nanosheets through photothermal effect.

Drug resistance of bacteria has become a global health problem, as it makes conventional antibiotics less efficient. It is urgently needed to explore novel antibacterial materials and develop effective treatment strategies to overcome the drug resistance of antibiotics. Herein, we successfully synthesized silver decorated sandwich-like mesoporous silica/reduced graphene oxide nanosheets (rGO/MSN/Ag) as a novel antibacterial material through facile method. The rGO and Ag nanoparticles can be reduced in the reaction system without adding any other reductants. In addition, the rGO/MSN/Ag showed higher photothermal conversion capacity due to the modification of silver nanoparticles and exhibited excellent antibacterial activities against Pseudomonas putida, Escherichia coli and Rhodococcus at relatively low dosages, which was confirmed by the minimum inhibitory concentration (MIC) test. Meanwhile, the E. coli with a high concentration was selected for exposure using an 808 nm laser, and the antibacterial effect was obviously enhanced by the near-infrared irradiation induced photothermal effect. Moreover, the hepatocyte LO2 were used for the cytotoxicity evaluation, and the rGO/MSN/Ag showed low toxicity and were without detectable cytotoxicity at the antimicrobial dose. As the prepared rGO/MSN/Ag nanosheets have the advantages of low-cost and high antibacterial activity, they might be of promising and useful antibacterial agents for different applications.

One-Pot Synthesis of Fe3O4@PS@P(AEMH-FITC) Magnetic Fluorescent Nanocomposites for Bimodal Imaging.

Magnetic fluorescent nanocomposites have attracted much attention because of their merging magnetic and fluorescent properties for biomedical application. However, the procedure of synthesis of magnetic fluorescent nanocomposites is always complicated. In addition, the properties of fluorescent component could be easily influenced by magnetic component, retaining both of the magnetic and fluorescent properties into one single nanoparticle considered to be a significant challenge. Herein, we report one-pot method to synthesize multifunctional magnetic fluorescent Fe3O4@PS@P(AEMH-FITC) nanocomposites for bimodal imaging. The asprepared Fe3O4@PS@P(AEMH-FITC) nanocomposites with well-define spherical core/shell structure were stable properties. Moreover, the Fe3O4@PS@P(AEMH-FITC) nanocomposites displayed efficient fluorescent and magnetic properties, respectively. Meanwhile, the magnetic resonance imaging (MRI) and HePG2 cancer cell fluorescent images experiment results suggested that Fe3O4@PS@P(AEMH-FITC) nanocomposites could be used as MRI contrast agents and Fluorescence Imaging (FLI) agents for bioimaging application. Our investigation paves a facile avenue for synthesized magnetic fluorescent nanostructures with well biocompatibility for potential bioimaging application in MRI and FLI.

Optimal Design of the Austenitic Stainless-Steel Composition Based on Machine Learning and Genetic Algorithm.

As the fourth paradigm of materials research and development, the materials genome paradigm can significantly improve the efficiency of research and development for austenitic stainless steel. In this study, by collecting experimental data of austenitic stainless steel, the chemical composition of austenitic stainless steel is optimized by machine learning and a genetic algorithm, so that the production cost is reduced, and the research and development of new steel grades is accelerated without reducing the mechanical properties. Specifically, four machine learning prediction models were established for different mechanical properties, with the gradient boosting regression (gbr) algorithm demonstrating superior prediction accuracy compared to other commonly used machine learning algorithms. Bayesian optimization was then employed to optimize the hyperparameters in the gbr algorithm, resulting in the identification of the optimal combination of hyperparameters. The mechanical properties prediction model established at this stage had good prediction accuracy on the test set (yield strength: R2 = 0.88, MAE = 4.89 MPa; ultimate tensile strength: R2 = 0.99, MAE = 2.65 MPa; elongation: R2 = 0.84, MAE = 1.42%; reduction in area: R2 = 0.88, MAE = 1.39%). Moreover, feature importance and Shapley Additive Explanation (SHAP) values were utilized to analyze the interpretability of the performance prediction models and to assess how the features influence the overall performance. Finally, the NSGA-III algorithm was used to simultaneously maximize the mechanical property prediction models within the search space, thereby obtaining the corresponding non-dominated solution set of chemical composition and achieving the optimization of austenitic stainless-steel compositions.

Prediction of the Fatigue Strength of Steel Based on Interpretable Machine Learning.

Most failures in steel materials are due to fatigue damage, so it is of great significance to analyze the key features of fatigue strength (FS) in order to improve fatigue performance. This study collected data on the fatigue strength of steel materials and established a predictive model for FS based on machine learning (ML). Three feature-construction strategies were proposed based on the dataset, and compared on four typical ML algorithms. The combination of Strategy Ⅲ (composition, heat-treatment, and atomic features) and the GBT algorithm showed the best performance. Subsequently, input features were selected step by step using methods such as the analysis of variance (ANOVA), embedded method, recursive method, and exhaustive method. The key features affecting FS were found to be TT, mE, APID, and Mo. Based on these key features and Bayesian optimization, an ML model was established, which showed a good performance. Finally, Shapley additive explanations (SHAP) and symbolic regression (SR) are introduced to improve the interpretability of the prediction model. It had been discovered through SHAP analysis that TT and Mo had the most significant impact on FS. Specifically, it was observed that 160 < TT < 500 and Mo > 0.15 was beneficial for increasing the value of FS. SR was used to establish a significant mathematical relationship between these key features and FS.

Polydopamine-doped virus-like mesoporous silica coated reduced graphene oxide nanosheets for chemo-photothermal synergetic therapy.

Multifunctional nanocarriers have been widely accepted and utilized for biomedical applications, because of their structural regularity, convenient post-modification and controllable structure and morphology. Herein, we reported polydopamine-doped virus-like mesoporous silica coated reduced graphene oxide nanosheets (rGO@PVMSNs) nanocomposites by a facile oil-water biphase stratification method. The synthesized rGO@PVMSNs nanocomposites performed excellent biocompatibility and photothermal performance. They could be employed as photoacoustic imaging contrast in vivo. Furthermore, the rGO@PVMSNs nanocarriers were used for loading the antitumor drug doxorubicin (DOX), the rGO@PVMSNs@DOX nanocomposites were also demonstrated to be with high inhibition of HepG2 cancer cells, especially with the help of near-infrared irradiation, which were more efficient than single chemotherapy or photothermal therapy. The rGO@PVMSNs@DOX nanocomposites of this work could be used as photoacoustic imaging and chemo-photothermal synergetic therapy agents, which show a new perspective for clinical tumor diagnosis and therapy.

Three dimensional Pt island-on-Au architectures coupled with graphite carbon nitride nanosheets for effective photo-accelerated methanol electro-oxidation.

Two dimensional (2D) visible-light-activated graphite carbon nitride (CN) nanosheets were used to deposit the traditional electrocatalyst of Pt and Au through a facile one-pot hydrothermal approach. By adjusting different amount of Pt and Au, 3D Pt island-on-Au architectures were formed on the surface of CN nanosheets (Pt-Au/CN). The obtained Pt-Au/CN composite was used for electrocatalytic methanol oxidation reaction (MOR). Comparing with Pt/CN modified electrode, Pt-Au/CN exhibited 13.8 times enhancement on the electrocatalytic activity of MOR. Interestingly, when Pt-Au/CN composite was illuminated with visible light, the current density and stability were continuously enhanced by evaluating of cyclic voltammetry (CV), chronopoenttiometric (CP), chronoamperometry (CA), and electrochemical impedance spectra (EIS). The bimetallic electronic effects of Pt and Au; 3D Pt islands-on-Au architectures; 2D support nanosheet of CN, and the synergistic effect of photo- and electro-catalytic processes resulted in the improved electrocatalytic activity and stability. The present investigations provide a promising future to construct highly efficient electrocatalyst by combining bimetal on semiconductor support and with the assistance of visible light irradiation.

A review of graphene-based nanomaterials for removal of antibiotics from aqueous environments.

Antibiotics as emerging pharmaceutical pollutants have seriously not only threatened human life and animal health security, but also caused environmental pollution. It has drawn enormous attention and research interests in the study of antibiotics removal from aqueous environments. Graphene, an interesting one-atom-thick, 2D single-layer carbon sheet with sp2 hybridized carbon atoms, has become an important agent for removal of antibiotic, owing to its unique physiochemical properties. Recently, a variety of graphene-based nanomaterials (GNMs) are reported to efficiently remove antibiotics from aqueous solutions by different technologies. In this review, we summarize different structure and properties of GNMs for the removal of antibiotics by adsorption. Meanwhile, advanced oxidation processes (AOPs), such as photocatalysis, Fenton process, ozonation, sulfate radical and combined AOPs by the aid of GNMs are summarized. Finally, the opportunities and challenges on the future scope of GNMs for removal of antibiotics from aqueous environments are proposed.

Polydopamine doped reduced graphene oxide/mesoporous silica nanosheets for chemo-photothermal and enhanced photothermal therapy.

The nanoplatform of synergistic chemo-photothermal therapy has superior advantages on antitumor. It is urgently needed to explore novel nanocarrier for improving photothermal performance in drug delivery process. Herein, we synthesized polydopamine doped mesoporous silica-coated reduced graphene oxide (rGO/MSN/PDA) by simply adding dopamine hydrochloride into the oil-water biphasic reaction system as a multifunctional drug carrier for anticancer treatment, which combines chemotherapy and photothermal therapy. The rGO/MSN/PDA showed nearly twice the photothermal conversion efficiency of mesoporous silica-coated graphene oxide (GO/MSN) due to the reduction of GO and doping with PDA. In addition, the rGO/MSN/PDA showed pH-response DOX release abilities, which means higher release of DOX in tumor cells. The cell experiments in vitro proved that rGO/MSN/PDA with better biocompatibility compare to GO/MSN might offer a promising tool for improving the therapeutic effects of hepatocellular carcinoma cells through synergistic chemo-photothermal therapy.

Fabrication of Red Blood Cell-Based Multimodal Theranostic Probes for Second Near-Infrared Window Fluorescence Imaging-Guided Tumor Surgery and Photodynamic Therapy.

The therapeutic efficacy of fluorescence image-guided tumor surgery and photodynamic therapy (PDT) is impaired by the penetration depth limitation, low signal-to-noise ratio of traditional first near-infrared window (NIR I) fluorescence and the hypoxic tumor microenvironment. Here, a "red blood cell-based multimodal probe" was proposed to achieve enhanced tumor targeting and retention of fluorescent probes after an intravenous injection, so that second near-infrared window (NIR II) fluorescence bioimaging-guided complete tumor resection and high-efficiency photodynamic therapy could then be realized. Methods: The hexanoic acid ester-modified rose bengal (RB-HA), RGD (Arginine-Glycine-Aspartic) peptide and avidin were covalently coupled onto amine-modified upconversion nanoparticles (UCNPs) via EDC/NHS reaction (UCNPs@RB@RGD@avidin). Afterwards, the complex of ICG with bovine serum albumin (BSA) was loaded into RBCs through hypotonic dialysis (RBC@ICG). Then, the membrane proteins of RBC@ICG were biotinylated by biotin-modified phospholipids (RBC@ICG@biotin). Finally, the RBCp (Red Blood Cell based probe) was obtained by crosslinking UCNPs@RB@RGD@avidin to RBC@ICG@biotin through the interaction of avidin and biotin. The obtained multimodal RBCp was extensively characterized, both in vitro and in vivo, including analysis of chemical, physical and fluorescent features, O2 delivery ability, tumor accumulation, NIR II fluorescence bioimaging ability, photodynamic therapeutic efficiency, and biosafety. Results: The RBCp experienced efficient tumor targeting and long tumor retention for almost 4 h after intravenous injection, and the superior signal-to-noise ratio at the optimal time window can be used for guiding precise tumor resection under an 808-nm laser irradiation to facilitate lymph popliteal metastasis surgical delineation. Meanwhile, the RBCp can provide laser-responsive O2 release to enhance the PDT efficiency of popliteal lymph node metastasis under NIR II fluorescence bioimaging guidance. These excellent performances obviously lead to remarkably enhanced synergistic therapeutic effects of tumor surgery and metastatic inhibition. Conclusion: The proposed strategy will develop a new platform to increase surgical resection completeness and improve PDT efficiency, resulting in the successful and complete inhibition of tumor and metastasis, which could offer a promising approach for the clinical translation of malignant tumor treatment.

Folic acid-conjugated gold nanorod@polypyrrole@Fe3O4 nanocomposites for targeted MR/CT/PA multimodal imaging and chemo-photothermal therapy.

Integrating multimodal bioimaging and different therapies into one nanoplatform is a promising strategy for biomedical applications, but remains a great challenge. Herein, we have synthesized a biocompatible folic acid (FA) functionalized gold nanorod@polypyrrole@Fe3O4 (GNR@PPy@Fe3O4-FA) nanocomposite through a facile method. The conjugated FA has endowed the nanocomposite with the ability to recognize targeted cancer cells. Importantly, the nanocomposite has been successfully utilized for magnetic resonance (MR), computed tomography (CT) and photoacoustic (PA) multimodal imaging. Moreover, the GNR@PPy@Fe3O4-DOX nanocomposite shows pH-responsive chemotherapy and enables the integration of photothermal therapy and chemotherapy to achieve superior antitumor efficacy. The GNR@PPy@Fe3O4-DOX nanocomposites have a drug release of 23.64%, and the photothermal efficiency of the GNR@PPy@Fe3O4 nanocomposites reaches 51.46%. Cell viability decreases to 15.83% and 16.47% because of the combination of chemo-photothermal therapy effects. Moreover, the GNR@PPy@Fe3O4-DOX-FA nanocomposite could target cancer cells via folic acid and under a magnetic field. The in vivo multimodal imaging and chemo-photothermal therapy effects showed that the GNR@PPy@Fe3O4-DOX-FA nanocomposites are a good contrast and theranostic agent. Thus, this multifunctional nanocomposite could be a promising theranostic platform for cancer diagnosis and therapy.

One-pot synthesis of biodegradable polydopamine-doped mesoporous silica nanocomposites (PMSNs) as pH-sensitive targeting drug nanocarriers for synergistic chemo-photothermal therapy.

Nanomaterials have been widely used as drug carriers in the biomedical field. However, most of them have limited application because of their poor biocompatibility, targeting, and degradability. Therefore, exploring and developing novel drug nanocarriers to overcome these problems has widely attracted attention. In this study, polydopamine-doped mesoporous silica nanocomposites (PMSNs) were controllably synthesized by a one-pot oil-water biphase stratification approach. PMSNs showed good biodegradability in degradation experiments and also proved to have superior biocompatibility toward hepatocellular carcinoma cells (HepG2) compared with mesoporous silica nanoparticles (MSNs). And PMSNs loaded doxorubicin (DOX) (PMSNs@DOX) exhibited a pH-responsive release effect. Meanwhile, compared with PMSNs@DOX, folic acid-modified PMSNs@DOX (PMSNs@DOX@FA) displayed a targeted uptake and higher inhibition of HepG2 cells. Additionally, PMSNs@DOX@FA had excellent ability to kill tumor cells under synergistic chemo-photothermal therapy. Moreover, this synthetic strategy is promising for the fabrication of unique nanocomposites with various functional cores with PMSNs shells for diverse applications.

Cancer cell membrane-coated magnetic nanoparticles for MR/NIR fluorescence dual-modal imaging and photodynamic therapy.

Theranostic nanoprobes integrated with dual-modal imaging and therapeutic functions, such as photodynamic therapy (PDT), have exhibited significant potency in cancer treatments due to their high imaging accuracy and non-invasive advantages for cancer elimination. However, biocompatibility and highly efficient accumulation of these nanoprobes in tumor are still unsatisfactory for clinical application. In this study, a photosensitizer -loaded magnetic nanobead with surface further coated with a layer of cancer cell membrane (SSAP-Ce6@CCM) was designed to improve the biocompatibility and cellular uptake and ultimately achieve enhanced MR/NIR fluorescence imaging and PDT efficacy. Compared with similar nanobeads without CCM coating, SSAP-Ce6@CCM showed significantly enhanced cellular uptake, as evidenced by Prussian blue staining, confocal laser scanning microscopy (CLSM) and flow cytometric analysis. Consequently, SSAP-Ce6@CCM displayed a more distinct MR/NIR imaging ability and more obvious photo-cytotoxicity towards cancer cells under 670 nm laser irradiation. Furthermore, the enhanced PDT effect benefited from the surface coating of cancer cell membrane was demonstrated in SMMC-7721 tumor-bearing mice through tumor growth observation and tumor tissue pathological examination. Therefore, this CCM-disguised nanobead that integrated the abilities of MR/NIR fluorescence dual-modal imaging and photodynamic therapy might be a promising theranostic platform for tumor treatment.

Ultrasound extraction optimization, structural features, and antioxidant activity of polysaccharides from Tricholoma matsutake.

An ultrasonic-assisted technique was employed to extract crude polysaccharide from Tricholoma matsutake fruiting bodies. Single-factor tests and orthogonal experimental design (L9(33)) were used to obtain the optimal extraction conditions. Results showed that the optimal parameters were as follows: ultrasonic temperature, 40 °C; ultrasonic time, 50 min; water to raw material ratio, 25 ml/g; ultrasonic frequency, 45 kHz; and ultrasonic power, 100 W. Three novel T. matsutake polysaccharide (TMP) fractions (TMP30, TMP60, and TMP80) were isolated and purified from TMP by stepwise alcohol precipitation. Their preliminary structural features were determined by high-performance anion-exchange chromatography with pulsed-amperometric detection (HPAEC-PAD) and Fourier transform infrared spectrophotometer (FT-IR) analyses. Furthermore, their in vitro antioxidant activity was investigated in terms of a reducing power assay and the scavenging rates of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radicals. The order of the various fractions based on their antioxidant activity was TMP80>TMP>TMP60>TMP30. These findings suggested that novel polysaccharide fractions from T. matsutake, especially TMP80, could be promising active macromolecules for biomedical use.

Microenvironment-Driven Bioelimination of Magnetoplasmonic Nanoassemblies and Their Multimodal Imaging-Guided Tumor Photothermal Therapy.

Biocompatibility and bioelimination are basic requirements for systematically administered nanomaterials for biomedical purposes. Gold-based plasmonic nanomaterials have shown potential applications in photothermal cancer therapy. However, their inability to biodegrade has impeded practical biomedical application. In this study, a kind of bioeliminable magnetoplasmonic nanoassembly (MPNA), assembled from an Fe3O4 nanocluster and gold nanoshell, was elaborately designed for computed tomography, photoacoustic tomography, and magnetic resonance trimodal imaging-guided tumor photothermal therapy. A single dose of photothermal therapy under near-infrared light induced a complete tumor regression in mice. Importantly, MPNAs could respond to the local microenvironment with acidic pH and enzymes where they accumulated including tumors, liver, spleen, etc., collapse into small molecules and discrete nanoparticles, and finally be cleared from the body. With the bioelimination ability from the body, a high dose of 400 mg kg(-1) MPNAs had good biocompatibility. The MPNAs for cancer theranostics pave a way toward biodegradable bio-nanomaterials for biomedical applications.

Multifunctional Fe3O4@P(St/MAA)@chitosan@Au core/shell nanoparticles for dual imaging and photothermal therapy.

Merging different components into a single nanoparticle can exhibit profound impact on various biomedical applications including diagnostics, imaging, and therapy. However, retaining the unique properties of each component after integration has proven to be a significant challenge. Our previous research demonstrated that gold nanoshells on polystyrene spheres have potential in photohermal therapy. Here, we report a facile and green strategy to synthesize a multifunctional nanocomposite with Fe3O4 core coated gold nanoshells as dual imaging probes and photothermal agents. The as-prepared nanoparticles exhibit well-defined structure and excellent physical properties such as magnetic and plasmonic activities. Therefore, they were applied as contrast agents in magnetic resonance imaging (MRI) and dark field imaging (DFI). Besides, we demonstrated their potential application in photothermal therapy. Moreover, the obtained multifunctional nanoparticles have shown excellent biocompatibility for their low cytotoxicity and hemolyticity.