Influence of Chitosan-Based Carbon Dots on Astaxanthin Production of Green Alga Tetraselmis sp.

CDs are carbon fluorescent nanomaterials that have gained significant attention in recent years owing to their unique properties. In this work, we utilized a simple solution to produce CDs with func-tionalized amino groups via a one-step carbonization from a chitosan precursor. This simultaneous approach does not use special reagent for either the formation step or the amino-functionalization step of CDs. The as-prepared amino-functionalized CDs that possesses expected characteristics, such as nano-size distribution, monodispersible, high blue light emission, high absolute quantum yield of 5.52%, and functionalized amino groups on the surface. Furthermore, this work demonstrated the low cytotoxicity and high biocompatibility of the CDs, through the improvements in the astaxanthin production of alga Tetraselmis sp. (more than doubled (up to 0.044 mg/L), relative to the control). Thus, as-prepared CDs have promising properties not only for applications in bioimaging, drug delivery or sensors, but also as promoter in algal biorefinery