In this research, a facile “in-situ reduction” strategy was developed to construct silver clusters-loaded silica-based hybrid nanoparticles (Ag@SHNPs). Firstly, the formation of organosilica-micellar hybrid nanostructure was achieved by self-assembly of amphiphilic block copolymer PS₈₉-b-PAA₁₆ and hydrolysis, and polycondensation of (3-mercaptopropyl)trimethoxysilane (MPTMS) on the hydrophilic PAA segment. Then, the abundant thiol groups in the organosilica framework were used as reduction sites to in-situ convert the silver salt into silver clusters, and finally the Ag@SHNPs were obtained. Morphology, structure and composition of the hybrid nanoparticles were analyzed, and their cytotoxicity on different cell lines were explored, showing good biocompatibility. The surface enhanced Raman scattering (SERS) activity of the Ag@SHNPs substrate were detected by using 4-mercaptobenzoic acid (4-MBA) as the probe molecule. Under an excitation wavelength of 532 nm laser, 4-MBA-labeled Ag@SHNPs exhibited obvious Raman enhanced signal with an enhancement factor of about 10⁵. Therefore, the silica-based hybrid substrate material shows potential application prospects in SERS bioimaging and high-sensitivity detection.

Due to high stability and sensitivity, inorganic nanomaterials with enzyme-like activity have brilliant application prospects. Tuning the enzyme-like activity plays great significance for promoting the development of nanozymes. In this work, Pt-Au dendritic nanoparticles (Pt-Au DNPs) with good uniformity and stability were synthesized by a simple liquid phase reduction method, and used to colorimetrically detect ascorbic acid (AA) by using their oxidase-like activity to catalyze the oxidation of TMB (3,3′,5,5′-tetramethylbenzidine). The oxidase-like activity was found to be highly influenced by the composition and structure of Pt-Au dendritic nanoparticles, and the relationship between kinetic parameters and nanoparticle structure was investigated. Quantitative analysis of ascorbic acid in the 1-15 μmol/L range was performed with good linear relationship, and the detection limit was 78 nmol/L. At the same time, it’s found that continuous reaction would reduce the catalytic performance of Pt-Au DNPs, but still has the potential to be reused, which is not common. Data from this research not only suggests a method for synthesizing Pt-Au DNPs, but also shows its potential for AA analysis in biological samples.

Overhigh temperature can induce inflammation and heat radiation damage to normal tissues around the tumor. Therefore, the development of a magnetic material that can achieve high mortality of tumor cells at relatively low temperatures (e.g. 43 ℃) is critical for the clinical application of magnetocaloric therapy. This study focuses on the goal of low-temperature, safe, and effective magnetic thermotherapy. The liquid-solid phase transition material polylactic acid-glycolic acid (PLGA) approved by the FDA, is selected as raw material and superparamagnetic iron oxide nanoparticles prepared by a one-step mild reduction method are loaded to achieve magnetic resonance imaging and magnetic heating. Meanwhile, a small molecule inhibitor of heat shock protein HSP90, i.e, epigallocatechin gallate (EGCG), encapsulated in PLGA, could inhibit the body’s thermal protection function and achieve the purpose of killing tumor cells at lower temperatures. In vitro results indicated that the prepared superparamagnetic iron oxide nanoparticles not only have good T₂-weighted imaging performance, but also show excellent magnetothermal transformation performance. More details, when the obtained PLGA/Fe₃O₄/EGCG biocomposite was controlled to heated up to 43 ℃ for 40 min under an alternating magnetic field, around 70% of tumor cell could be killed, exhibiting promising potential for low-temperature magnetothermal treatment of tumor. Such novel injectable magnetic thermal phase transition material may provide new idea and material support for the treatment of osteosarcoma.