# Microbial-Responsive Wound Dressings Based on Biopolymer Degradation Strategy for Detecting Bacterial Infections

## TL;DR

This paper introduces a wound dressing that detects bacterial infections by degrading in response to enzymes from pathogens like Pseudomonas aeruginosa and Staphylococcus aureus.

## Contribution

The study presents a novel biopolymer-based strategy for detecting bacterial proteolytic activity without requiring pathogen-specific recognition elements.

## Key findings

- Gelatin films with 25% PEO degraded 4-fold faster in the presence of Pseudomonas aeruginosa compared to cross-linked gelatin.
- The dressing showed 80% degradation within 12–24 h with Pseudomonas aeruginosa and 35% with drug-resistant Staphylococcus aureus.
- Real-time acoustic measurements and imaging confirmed the correlation between enzymatic activity and structural changes in the films.

## Abstract

Chronic wounds remain a major clinical challenge due
to their strong
association with antibiotic-resistant microbial biofilms. These nonhealing
wounds demand advanced therapeutic strategies that go beyond passive
protection to actively monitor and respond to changes in the wound
environment. To address this, we propose an activity-based sensing
strategy that detects bacterial proteolytic activity using composition-tunable
biopolymer films that degrade in response to pathogen-secreted enzymes.
Gelatin films cross-linked with (3-glycidyloxypropyl)­trimethoxysilane
(GPTMS) and blended with poly­(ethylene oxide) (PEO) were engineered
to undergo selective peptide-bond cleavage by proteolytic activity.
The incorporation of PEO enhanced water uptake and accelerated enzymatic
degradation, with the optimal composition (25% PEO) exhibiting 4-fold
faster mass loss compared to cross-linked gelatin, reaching ∼80%
degradation within 12–24 h in the presence of the bacterial
pathogen Pseudomonas aeruginosa and
∼35% within 24–48 h with drug resistant Staphylococcus aureus. Real-time acoustic measurements
revealed distinct degradation kinetics and viscoelastic signatures
at nanoscale that correlated with P. aeruginosa protease activity, while Fourier-transform infrared spectroscopy
and scanning electron microscopy confirmed structural and morphological
changes following enzymatic exposure. Together, these findings establish
a label-free, enzyme-responsive sensing platform that transduces bacterial
activity, including biofilm-associated proteolysis, into quantitative
physical signals. These findings establish composition-tunable enzyme-responsive
biopolymer degradation as a viable broad-spectrum platform responding
to total proteolytic activity. As no pathogen-specific recognition
elements are required, this platform offers excellent potential to
detect challenging polymicrobial infections.