Lignin-Based CdS Dots as Multifunctional Platforms for Sensing and Wearable Photodynamic Coatings

Lignin, a natural biopolymer, is a sustainable and safe source to fabricate nanomaterials and coating agents for use in biomedical applications. We have therefore developed a simple, one-pot, and green strategy to prepare lignin-based cadmium sulfide quantum dots (L@CdS QDs) for use in sensing and photodynamic therapy applications. Initially, such lignin-based QDs were utilized in heavy metal sensing by screening a large range of metals. These QDs were highly selective toward sensing mercury and copper ions present in various water samples. The lignin-based QDs were also effective toward bacterial sensing. The promising reactive oxygen generation capability of such quantum dots prompted us to explore their potential in light-assisted antibacterial photodynamic activity (aPDT). Benefiting from the ease of synthesis and promising photodynamic properties, the QDs were next employed for the fabrication of wearable coatings. Interestingly, such lignin-based QD-derived coatings were highly effective in eradicating bacteria from personal protective equipment and biomedical devices (such as mask, gloves, scissors, etc.). This work paves a smart way to design natural biopolymer-based nanomaterials with the capability of disinfecting personal protective equipment and biomedical devices.