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Poly­(vinylpyrrolidone) (PVP) was used as both a modifier and reductant to in situ deposit silver nanoparticles (denoted Ag NPs) on the surface of silica nanospheres (nanosilica or nano-SiO2), affording Ag-decorated nanosilica (denoted SiO2@Ag). The as-obtained SiO2@Ag composite can form silver nanoparticle-decorated silica nanosphere arrays (denoted SiO2@Ag arrays) via evaporation-induced self-assembly. The as-prepared SiO2@Ag composite and SiO2@Ag array were used as the SERS substrates to measure the Raman signals of the dilute solutions of rhodamine 6G (denoted R6G), an organic dye that is a potential pollutant to the environment. The findings indicate that the as-prepared SiO2@Ag composite and SiO2@Ag array as potential SERS substrates simultaneously exhibit a high degree of metal coverage and small size of Ag NPs as well as good stability and abundant “hot spots”, which contributes to their desired Raman enhancement capacities. For the detection of trace R6G, they provide a limit of detection of as low as 10–9–10–11 M as well as good reproducibility, showing promising potential for monitoring chemical and biological molecules.

Functional fabrics with antibacterial performance are more welcome nowadays. However, the fabrication of functional fabrics with durable, steady performance via a cost-effective way remains a challenge. Polypropylene (denoted as PP) nonwoven fabric was modified by polyvinyl alcohol (denoted as PVA), followed by the in-situ deposition of silver nanoparticles (denoted as Ag NPs) to afford PVA-modified and Ag NPs-loaded PP (denoted as Ag/PVA/PP) fabric. The encapsulation of PP fiber by PVA coating contributes to greatly enhancing the adhesion of the loaded Ag NPs to the PP fiber, and the Ag/PVA/PP nonwoven fabrics exhibit significantly improved mechanical properties as well as excellent antibacterial activity against Escherichia coli (coded as E. coli). Typically, the Ag/PVA/PP nonwoven fabric obtained at a silver ammonia concentration of 30 mM has the best mechanical properties and the antibacterial rate reaches 99.99% against E. coli. The fabric retains excellent antibacterial activity even after washing for 40 cycles, showing prospects in reuse. Moreover, the Ag/PVA/PP nonwoven fabric could find promising application in industry, thanks to its desired air-permeability and moisture-permeability. In addition, we developed a roll-to-roll production process and conducted preliminary exploration to verify the feasibility of this method.

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Surface engineering of human hair was successfully used as a self-supported electrochemical sensor to detect glucose in human serum. Polydopamine (PDA) was firstly grafted on hair by oxidative self-polymerization of dopamine and then the copper nanoparticles (CuNPs) were electrolessly deposited to achieve surface metallization of hair (hair@CuNPs). The hair@CuNPs composites with uniformly dispersed conductive layer in 8 µm thickness exhibited outstanding electrocatalytic activity towards glucose oxidation. Under optimal conditions, the amperometric response of glucose on hair@CuNPs composites as self-supported nonenzymatic glucose sensor covered two linear ranges of 0.002–5 mM and 5–35 mM, respectively, and the detection limit was 1.62 µM. The proposed method provides an easy and inexpensive way to fabricate hair@CuNPs biosensor for detecting glucose level in human serum samples, indicating that hair@CuNPs composites have promising practical applications in biological analysis.