A “Test-to-Treat” Pad for Real-Time Visual Monitoring of Bacterial Infection and On-Site Performing Smart Therapy Strategies

Skin infections are major threats to human health, causing ∼500 incidences per 10 000 person-year. In patients with diabetes mellitus, particularly, skin infections are often accompanied by a slow healing process, amputation, and even death. Timely diagnosis of skin infection strains and on-site therapy are vital in human health and safety. Herein, a double-layered "test-to-treat" pad is developed for the visual monitoring and selective treatment of drug-sensitive (DS)/drug-resistant (DR) bacterial infections. The inner layer (using carrageenan hydrogel as a scaffold) is loaded with bacteria indicators and an acid-responsive drug (Fe-carbenicillin frameworks) for infection detection and DS bacteria inactivation. The outer layer is a mechanoluminescence material (ML, CaZnOS:Mn²⁺) and visible-light responsive photocatalyst (Pt@TiO₂) incorporated elastic polydimethylsiloxane (PDMS). On the basis of the colorimetric sensing result (yellow for DS-bacterial infection and red for DR-bacterial infection), a suitable antibacterial strategy is guided and then performed. Two available bactericidal routes provided by double pad layers reflect the advantage. The controllable and effective killing of DR bacteria is realized by in situ generated reactive oxygen species (ROSs) from the combination of Pt@TiO₂ and ML under mechanical force, avoiding physical light sources and alleviating off-target side effects of ROS in biomedical therapy. As a proof-of-concept, the "test-to-treat" pad is applied as a wearable wound dressing for sensing and selectively dealing with DS/DR bacterial infections in vitro and in vivo. This multifunctional design effectively reduces antibiotic abuse and accelerates wound healing, providing an innovative and promising Band-Aid strategy in point-of-care diagnosis and therapy.