Antimicrobial Light-Activated Polypropylene Modified with Chitosan: Characterization and Reusability.

Area of Science:

• Materials Science
• Biotechnology
• Polymer Chemistry

Background:

• Chitosan is a natural polycationic compound with inherent antimicrobial properties.
• Developing stable, reusable, and light-activated antimicrobial materials is crucial for various applications.
• Reactive blending offers a method for creating robust composite materials.

Purpose of the Study:

• To prepare a robust, stable, and reusable light-activated antimicrobial plastic using reactive blending.
• To evaluate the antimicrobial efficacy of the prepared plastic against Escherichia coli K12 under UV-A light exposure.
• To investigate the durability and mechanism of the antimicrobial action over multiple cycles.

Main Methods:

• Reactive blending of polypropylene, maleic anhydride-grafted vinyl ether, and chitosan.
• Antimicrobial challenge testing against Escherichia coli K12 with simultaneous UV-A light exposure.
• Repetitive testing over 10 cycles to assess reusability and durability.
• Surface chemistry analysis using Infrared spectroscopy.
• Mechanism investigation via fluorometric evaluation for reactive oxygen species (ROS) generation.
• Microscopic techniques (SEM) to assess bacterial morphology and material fouling.

Main Results:

• A stable, light-activated antimicrobial plastic (PP-MVE-CHI) was successfully prepared.
• The plastic demonstrated significant antimicrobial efficacy, achieving a 94.0 ± 3.3% reduction in Escherichia coli K12 population over 10 cycles.
• Antimicrobial activity was sustained across multiple reuse cycles, indicating robustness.
• Reactive oxygen species (ROS) generation was identified as the primary mechanism of antimicrobial action.
• Microscopic analysis revealed damage to bacterial cell morphology and no material fouling.
• Infrared spectroscopy confirmed minimal changes to surface chemistry after 10 cycles.

Conclusions:

• The developed light-activated antimicrobial plastic is a reusable and effective material for microbial control.
• The material's efficacy is attributed to ROS generation under UV-A light, leading to bacterial cell damage.
• Its stability and sustained performance over multiple cycles highlight its potential for practical antimicrobial applications.