# Bio-heterojunction-engineered recombinant collagen hydrogel orchestrates multimodal sterilization and immunomodulation for MRSA-infected wound healing

## TL;DR

A new hydrogel uses light and chemical reactions to kill drug-resistant bacteria and speed up wound healing without antibiotics.

## Contribution

A bio-heterojunction-integrated hydrogel enables triple-modal antibacterial therapy with high efficacy and immunomodulation.

## Key findings

- The hydrogel achieves 99.95% MRSA eradication through photothermal, photodynamic, and POD-like mechanisms.
- It accelerates wound closure by 98% in vivo via macrophage polarization and angiogenesis.
- The Schottky junction enhances ROS production for synergistic bacterial killing.

## Abstract

Multidrug-resistant (MDR) bacterial infections, notably methicillin-resistant Staphylococcus aureus (MRSA), necessitate innovative antibiotic-free wound therapies. Here, a bio-heterojunction-integrated recombinant collagen hydrogel (CAP@MXene/CuTCPP) is designed that synergistically combines photothermal therapy (PTT), photodynamic therapy (PDT), and peroxidase-like (POD-like) activity for multimodal antibacterial action. The borate-bonded dynamically crosslinked hydrogel is composed of polyvinyl alcohol (PVA), 3-aminophenylboronic acid (APBA)-modified recombinant collagen (CF-1552), and MXene/CuTCPP bio-heterojunctions (bio-HJs). Under 808 nm near-infrared (NIR) irradiation, the MXene/CuTCPP bio-HJs exhibit a high photothermal conversion efficiency (44.51%), inducing localized hyperthermia to disrupt bacterial membranes. Importantly, the construction of a Schottky junction at the MXene/CuTCPP interface significantly accelerates photo-excited electron transfer, thereby catalytically amplifying the production of additional ROS (1O2, ·O2−, ·OH) for synergistic bacterial eradication. This triple antibacterial mechanism ensures a 99.95% MRSA eradication rate without inducing drug resistance, while effectively removing the biofilm. In vivo, the hydrogel accelerates wound closure (98% by day 11) not only by providing a biomimetic scaffold but also by regulating the polarization of macrophages from M1 to M2, and significantly promoting angiogenesis. This work presents a biocompatible and self-adaptable platform that overcomes the killing-healing trade-off through synergistic energy/charge transfer integration, offering insights for advanced immunomodulatory wound management.

A bio-heterojunction-integrated recombinant collagen hydrogel (CAP@MXene/CuTCPP) is designed for synergistic photothermal, photodynamic, and POD-like antibacterial therapy against MDR infections like MRSA. Featuring dynamic borate crosslinking and high photothermal efficiency (44.51%), it achieves 99.95% bacterial eradication, biofilm removal, and accelerated wound healing (98% closure by day 11) via ROS generation, macrophage polarization, and angiogenesis promotion. This platform advances antibiotic-free wound management.Image 1

•A bio-heterojunction-engineered recombinant collagen hydrogel was developed.•Schottky junction acts as an electron pump to amplify synergistic ROS yields.•Triple-modal therapy (PTT/PDT/POD) achieved a 99.95% MRSA eradication rate.•The hydrogel promotes the wound healing by immunoregulation and angiogenesis.

A bio-heterojunction-engineered recombinant collagen hydrogel was developed.

Schottky junction acts as an electron pump to amplify synergistic ROS yields.

Triple-modal therapy (PTT/PDT/POD) achieved a 99.95% MRSA eradication rate.

The hydrogel promotes the wound healing by immunoregulation and angiogenesis.