Antimicrobial protection of two controlled release silver nanoparticles on simulated silk cultural relic

Silver nanoparticles coated with organic-inorganic hybrid silica or inorganic silica have antimicrobial ability, and the coating can also effectively improve the dispersion and stability of the particles. The slow release of silver ions (Ag⁺) can improve the antimicrobial activity of silver nanoparticles. The synthesized nanoparticles are light yellow, which does not affect the look and feel of the silk cultural relics and meets the requirements of the principle of minimum interference.

Two kinds of silver-based nanoparticles were synthesized: silver core-shell nanoparticle (Ag@mSiO₂) and silver yolk-shell nanoparticle (Ag@YSiO₂). The morphology, surface properties and Ag⁺ release efficiency of two nanoparticles were characterized. The antimicrobial effects of two nanoparticles on Aspergillus niger (A. niger) and Penicillium citrinum (P. citrinum) were compared.

Both of Ag@mSiO₂ and Ag@YSiO₂ had uniform size and good stability. Two nanoparticles had pore structure and silver nanocore, which provided the basis for the dissolution and exchange of Ag⁺. Because more silver ions were released, Ag@mSiO₂ had higher antimicrobial activity than Ag@YSiO₂ for A. niger and P. citrinum. For various silk samples, Ag@mSiO₂ exhibited excellent antimicrobial properties. Meanwhile, there was little change in the color and tearing strength of Ag@mSiO₂ coated silk.