Light-driven structural detachment and controlled release in smart antibacterial multilayer platforms

Smart materials, especially light-responsive, have become a key research area due to their tunable properties. It is related to the ability to undergo physical or chemical changes in response to external stimuli such as heat, light, pH, electricity, and mechanical stress. Among them, photothermal responsive materials have attracted great interest. This study focuses on the development of a multilayer system (MS) consisting of benzophenone-modified polydimethylsiloxane (PDMS) ring and a thermo-responsive core made of poly(N-isopropylacrylamide-co-N-isopropylomethacrylamide) (P(NIPAAm-co-NIPMAAm)), gelatin, and gelatin methacrylate (GelMA). The system utilizes the thermal sensitivity of P(NIPAAm-co-NIPMAAm) and the photothermal effects of gold nanorods (AuNRs) mixed in a 5:1 ratio to achieve an on-demand controlled release mechanism within 6 min of NIR irradiation. The mechanical properties investigated in the compression test show significant improvement in MS, reaching 60 times greater value than the material without a PDMS ring. In addition, NIR irradiation for 15 min effectively activated the antimicrobial properties, eliminating 99.9% of E. Coli and 100% of S. Aureus, thus presenting pathogen eradication. This innovative platform provides a versatile methodology for developing next-generation smart materials, advanced delivery mechanisms, and multifunctional nanostructured composites. This work highlights the potential of photosensitive materials to revolutionize the field of soft robotics, optics and actuators, and on-demand systems by providing precise control over release dynamics and improved material properties.