Chitosan-stabilized silver nanoclusters with luminescent, photothermal and antibacterial properties

[Display omitted] •New hybrid AgNCs have been synthetized by in situ photochemical efficient process.•Chitosan acts as reducing/protective agent during the auto-assembly of metal cores.•The chitosan macromolecular shell preserves the properties from both components.•The new silver hybrid nanomaterials have multifunctional behavior. The aim of this paper is to achieve in situ photochemical synthesis of silver nanoclusters (AgNCs) stabilized by the multiple-amine groups of chitosan (Ch@AgNCs) with luminescent and photothermal properties. Ch@AgNCs were obtained by applying a fast and simple methodology previously described by our group. Direct functionalization of AgNCs with chitosan template provided new nanohybrids directly in water solution, both in the presence or absence of oxygen. The formation of hybrid AgNCs could be monitored by the rapid increase of the absorption and emission maximum band with light irradiation time. New Ch@AgNCs not only present photoluminescent properties but also photothermal properties when irradiated with near infrared light (NIR), transducing efficiently NIR into heat and increasing the temperature of the medium up to 23 °C. The chitosan polymeric shell associated to AgNCs works as a protective support stabilizing the metal cores, facilitating the storage of nanohybrids and preserving luminescent, photothermal and bactericide properties.