Photothermal Conversion for Antibacterial Application

Photothermal conversion is a very common phenomenon but it can be applied in many fields, such as solar-driven desalination, power generation, photothermal therapy and so on [1-4]. For our healthy, photothermal therapy for killing cancer or tumor cells is emphasized and the materials for photothermal therapy have attracted lots of attention in the past decades. However, photothermal materials are used more widely in other biological fields such as wasted water treatment by removing heavy cations or killing bacteria. The applications bring new paths to obtain fresh or healthy water and new chances for poor areas.

Antibacterial is considered an important issue for our healthy lives and abusing antibiotics results in various problems. Therefore, new strategies for antibacterial with low cost were expected to be employed on large scale and photothermal materials are the candidates for the new antibacterial strategies, such as drinking water treatment and the treatment of wound infections. Employing photothermal conversion for antibacterial to treat drinking water is viewed as a cheap way to obtain fresh water. Zhao et al. [5] prepared AgBP2-Ag2S quantum dots for antibacterial in a near-infrared II (NIR) window. They found that the antibacterial efficiency resulted from the photogenerated ·O2− and h+, but the photothermal effect enhanced the disinfection [5]. The study paves a new way for constructing photothermal agents for rapid disinfection which is expected to be used in antibacterial and water disinfection. MXenes are known as the important materials used in catalysis, and energy storage and meanwhile they also are widely used in antibacterial [2,6]. MXenes have high light absorption and fast thermal transport so that the heat generated from the photothermal conversion on MXenes can destroy the component of bacteria and consequently inhibits bacterial growth. Zhou and his coworkers constructed MXene composite hydrogel scaffolds via 3D printing and they found that the MXene composite inhibited the bacteria by destroying the membrane under the NIR irradiation [7]. The photothermal conversion for antibacterial also could be used by combining photothermal therapy for would treatment [8,9]. Xing et al. [9] used polyvinyl alcohol/carbonized polymer dots (PVA/CPDs) hydrogel to enhance the synergy of inherent cationic antibacterial action and NIR-assisted photothermal therapy [9]. Their results show that 2% PVA@CPDs could eradicate both S. aureus and E. coli quickly and effectively, which hints at the great chance of photothermal conversion for antibacterial.

Although the photothermal materials were designed and prepared with some special structure in different fields, their photothermal conversion efficiencies depend on the speed of photons transforming into heat. Therefore, it is a key point how to construct the special structures to promote the speed by transforming phonons into thermal, including regulating the electron structure of photothermal materials. In the recently employed photothermal materials, such as metal, carbon-based materials, semiconductors, polymers and their composites or heterostructure, their electron behaviors and chemical bonding would affect the photothermal capacity.

In summary, photothermal conversion for antibacterial applications is expected to bring new chances in wound infection treatment or drinking water treatment and how to accelerate the process of photothermal conversion should be emphasized to expand the applications.

1. Ji M, Xu M, Zhang W, Yang Z, Huang L, et al. (2016) Structurally well-defined Au@Cu2-xS Core–Shell nanocrystals for improved cancer treatment based on  enhanced photothermal efficiency. Adv Mater 28(16): 3094-3101.
2. Seidi F, Arabi Shamsabadi A, Dadashi Firouzjaei M, Elliott M,  Saeb MR,  et al. (2023) MXenes antibacterial properties and applications: a review and perspective. Small 19(14): e2206716.
3. Ji M, Liu H, Cheng M, Huang L, Yang G, et al. (2022) Plasmonic metal nanoparticle loading to enhance the photothermal conversion of carbon fibers. J Phys Chem C 126(5): 2454-2462.
4. Liu H, Huang G, Wang R, Huang L, Wang H, et al. (2022) Carbon nanotubes grown on the carbon fibers to enhance the photothermal conversion toward solar-driven applications. ACS Appl Mater Interface 14(28): 32404-32411.
5. Sun P, Li K,  Liu X,  Wang J,  Qiu X,  et al. (2023) Peptide-mediated aqueous synthesis of NIR-II emitting Ag₂S quantum dots for rapid photocatalytic bacteria disinfection. Angew Chem Int Ed 62(14): e202300085.
6. Hao S, Han H, Yang Z, Chen M, Jiang Y, et al. (2022) Recent advancements on photothermal conversion and antibacterial applications over MXenes-based materials. Nanomicro Lett 14(1): 178.
7. Nie R, Sun Y,  Lv H,  Lu M,  Huangfu H, et al. (2022) 3D printing of MXene composite hydrogel scaffolds for photothermal antibacterial activity and bone regeneration in infected bone defect models. Nanoscale 14(22): 8112-8129.
8. Chen L, Zhang D,  Cheng K,  Li W,  Yu Q, et al. (2022) Photothermal-responsive fiber dressing with enhanced antibacterial activity and cell manipulation towards promoting wound-healing. J Colloid Interface Sci 623: 21-33.
9. Lu H, Liu J, Yu M, Li P, Huang R, et al. (2022) Photothermal-enhanced antibacterial and antioxidant hydrogel dressings based on catechol-modified chitosan-derived carbonized polymer dots for effective treatment of wound infections. Biomater Sci 10(10): 2692-2705.