# Effect of AgNPs on PLA-Based Biocomposites with Polysaccharides: Biodegradability, Antibacterial Activity and Features

## TL;DR

This paper explores biocomposites made from PLA, silver nanoparticles, and polysaccharides, showing they are biodegradable, have antibacterial properties, and maintain mechanical strength.

## Contribution

The study introduces a new method for creating biodegradable and antibacterial biocomposites using PLA, AgNPs, and polysaccharides.

## Key findings

- Adding polysaccharides to PLA biocomposites reduced mechanical strength but increased biodegradability.
- AgNPs provided antibacterial properties but did not prevent fungal growth on the biocomposites.
- Chitosan increased the destruction of biocomposites by fungi over time.

## Abstract

According to existing ecological problems, one of the promising developments is the creation of polyfunctional materials, which can be biodegradable, along with possessing antibacterial activity. The present research proposes biocomposites based on PLA with silver nanoparticles (AgNPs) and natural polysaccharides obtained in a twin-screw extruder. Introduction of polysaccharides to PLA-based biocomposites with/without AgNPs led to significant decrease in the elastic modulus and tensile strength, while the elongation at break remained almost unchanged. Thanks to the presence of natural polysaccharides, there was intensified biodegradation in soil despite the AgNP availability. The maximal mass loss was 29% for the PLA–PEG1000–starch + AgNPs (80:10:10 + 0.5 wt%) biocomposite. Analyses of the systems before and after soil exposure were carried out using DSC and FTIR spectroscopy methods. According to a thermal analysis, it was found that PLA crystalline regions degrade during exposure to soil. The same feature was detected during the spectral analysis. The intensity of the characteristic absorption bands of PLA decreased. Furthermore, it was found that the dark areas on the surface of the materials are of a polysaccharide nature and may be signs of biofouling of the materials by microbial flora. The tests on fungus resistance showed that biocidal additives such as AgNPs in PLA-based biocomposites with polysaccharides did not inhibit the development of mycelial fungi–biodestructors. And the increased amount of chitosan in the films contributed to their more active destruction by the end of the observation period. It was demonstrated that such biocomposites can inhibit bacterial growth.