Gold nanoparticles gated mesoporous carbon with optimal particle size for photothermal-enhanced thermochemotherapy

Amino acid-mediated amorphous copper sulphide with enhanced photothermal conversion efficiency for antibacterial application

Pathogenic bacteria in daily life, such as Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), often seriously affect human life and health. The extensive use of antibiotics has led to the emergence of drug-resistant bacteria, so it is urgent to develop efficient and non-drug-resistant sterilization methods. Here, we use small-molecule cysteine (Cys) as an auxiliary agent to synthesize spherical porous amorphous CuS-Cysteine (CuS-C) nanoparticles, which have good dispersion in aqueous solutions, and explore the reaction mechanism of Cys-induced CuS synthesis. The synthesized composite nanomaterials have strong near-infrared light absorption ability and efficient photothermal conversion ability and can effectively ablate pathogenic bacteria under the irradiation of an 808 nm laser. In addition, antibacterial experiments showed that CuS-C composites had no bactericidal effect without near-infrared light, but they had a good photothermal bactericidal effect on S. aureus and E. coli under radiation conditions. Considering the simple synthesis process, strong photothermal conversion ability, low cost, and suitability for large-scale production, CuS-C nanocomposites, as a promising antibacterial material, will provide a feasible scheme for the treatment of drug-resistant pathogens.

Emerging SERS biosensors for the analysis of cells and extracellular vesicles

Cells and their derived extracellular vesicles (EVs) or exosomes contain unique molecular signatures that could be used as biomarkers for the detection of severe diseases such as cancer, as well as monitoring the treatment response. Revealing these molecular signatures requires developing non-invasive ultrasensitive tools to enable single molecule/cell-level detection using a small volume of sample with low signal-to-noise ratio background and multiplex capability. Surface-enhanced Raman scattering (SERS) can address the current limitations in studying cells and EVs through two main mechanisms: plasmon-enhanced electric field (the so-called electromagnetic mechanism (EM)), and chemical mechanism (CM). In this review, we first highlight these two SERS mechanisms and then discuss the nanomaterials that have been used to develop SERS biosensors based on each of the aforementioned mechanisms as well as the combination of these two mechanisms in order to take advantage of the synergic effect between electromagnetic enhancement and chemical enhancement. Then, we review the recent advances in designing label-aided and label-free SERS biosensors in both colloidal and planar systems to investigate the surface biomarkers on cancer cells and their derived EVs. Finally, we discuss perspectives of emerging SERS biosensors in future biomedical applications. We believe this review article will thus appeal to researchers in the field of nanobiotechnology including material sciences, biosensors, and biomedical fields.

Van-mediated self-aggregating photothermal agents combined with multifunctional magnetic nickel oxide nanoparticles for precise elimination of bacterial infections

Building a novel and efficient photothermal antibacterial nanoplatform is a promising strategy for precise bacterial elimination. Herein, a nanocomposite NiO NPs@AuNPs@Van (NAV) for selective MRSA removal was constructed by electrostatic self-assembly of highly photothermal magnetic NiO NPs and vancomycin (Van)-modified gold nanoparticles (AuNPs). In the presence of MRSA and under NIR irradiation, Van-mediated AuNPs can self-aggregate on MRSA surface, generating photothermal effect in situ and killing 99.6% MRSA in conjunction with magnetic NiO NPs. Additionally, the photothermal efficiency can be improved by magnetic enrichment due to the excellent magnetism of NAV, thereby enhancing the bactericidal effect at a lower experimental dose. In vitro antibacterial experiments and full-thickness skin wound healing test demonstrated that this combination therapy could effectively accelerate wound healing in MRSA-infected mice, increase collagen coverage, reduce IL-6 and TNF-α content, and upregulate VEGF expression. Biological safety experiments confirmed that NAV has good biocompatibility in vivo and in vitro. Overall, this work reveals a new type of nanocomposite with enhanced photothermal antibacterial activity as a potential nano-antibacterial agent for treating bacteria-infected wounds.

Biomimetic smart mesoporous carbon nanozyme as a dual-GSH depletion agent and O2 generator for enhanced photodynamic therapy

Photodynamic therapy (PDT) has been thriving in the theranostics of cancer in recent years. However, due to a series of problems such as high concentration of GSH and insufficient O₂ partial pressure in the tumor micro-environment, it is difficult to achieve the desired therapeutic effects with single PDT. Mesoporous carbon (MC-COOH) has been widely used in photothermal therapy (PTT) due to its high photothermal conversion efficiency and drug loading. In addition, we have discovered that MC-COOH owned high-efficiency glutathione oxidase-like activity for intracellular lasting GSH consumption. Hence, a smart mesoporous carbon nanozyme (CCM) was designed as a dual-GSH depletion agent and O₂ generator combined with PTT to overcome the dilemma of PDT. MnO₂-doped carbon nanozyme (MC-Mn) was developed as the photothermal vehicles for the efficient loading of photosensitizer (Ce6). Subsequently, 4T1 membrane-coated nanozyme (Ce6/CCM) was constructed to achieve homologous targeting capability. The carbon nanozyme owned the sustained dual-GSH depletion function through MC-COOH and MnO₂, which greatly destroyed the antioxidant system of the tumor. Meanwhile, MnO₂ could produce affluent O₂ in the presence of H₂O₂, thereby alleviating the hypoxic state of tumor tissues and further promoting the generation of ROS. In addition, the novel carbon nanozyme was designed as photoacoustic imaging (PAI) agent and magnetic resonance imaging (MRI) contrast for real-time imaging during tumor therapy. In summary, this work showed that the biomimetic carbon nanozyme could be used as dual-GSH depletion agent and O₂ generator for dual-mode imaging-guided PTT-PDT. STATEMENT OF SIGNIFICANCE: - MC-COOH with highly efficient GSH-OXD activity was first discovered and applied in PDT. - MnO₂ acted as an O₂ generator and GSH depletion agent to enhance PDT. - The tumor-targeting ability of the nanozyme was improved by cell membrane camouflage. - CCM nanozyme possesses both PAI and MRI dual-mode imaging modalities to guide PDT/PTT.

Green and facile synthesis of gold/perlite nanocomposite using Allium Fistulosum L. for photothermal application

Photothermal therapy (PTT) procedure is anticipated as a new generation of cancer therapy techniques. With this in mind, in this work, an effective drug-free approach was developed to kill MCF7 breast cancer cells using PTT. A novel biocompatible nanocomposite as a PTT transducer was prepared from the in situ phytosynthesis of gold nanoparticles (Au NPs) in the presence of perlite as a platform and extract of Allium Fistulosum L. as a stabilizing and reducing agent (Au/perlite NC). The common characterization techniques such as Fourier transform infrared (FT-IR), zeta potential, dynamic light scattering (DLS), X-ray diffraction (XRD), ultraviolet-visible (UV-vis), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) were used to approve the synthesis of Au/perlite NC. The potential of the synthesized NCs on ROS generating and antioxidant activity was assessed by DPPH. In the following, the PTT efficacy of the Au/perlite NC on the destruction of MCF-7 breast cancer cells was assessed in vitro via the cell cycle, cell viability, and DAPI staining assays. The DPPH assay results showed that Au/perlite NC had a radicals scavenging capacity of about 41.47 % in 30 min. Cellular uptake results indicated a significant cell uptake after 1.5 h exposure with Au/perlite NC. Interestingly, cell death was increased dramatically by increasing irradiation time from 6 to 10 min. Cell viability assay revealed that the maximum number of cell death is around 50 % which was observed in the presence of Au/perlite NC by irradiation time of 10 min. Cell cycle results showed that the maximum amount of apoptotic cells (85 %) was observed in Au/perlite NC treatment group received laser irradiation for 10 min. The outcomes demonstrated that the Au/perlite NC can be used as a new drug-free and efficient agent for PTT of breast cancer cells without any concern cytotoxicity.