Carbon Dots in Photodynamic Therapy: The Role of Dopant and Solvent on Optical and Photo-Responsive Properties.

Carbon dots (CDs) are novel carbon-based luminescent materials with wide-ranging applications in biosensing, bioimaging, drug transportation, optical devices, and beyond. Their advantageous attributes, including biocompatibility, biodegradability, antioxidant activity, photostability, small particle size (<10 nm), and strong light absorption and excitation across a broad range of wavelengths, making them promising candidates in the field of photodynamic therapy (PDT) as photosensitizers (PSs). Further enhancements in functionality are imperative to enhance the effectiveness of CDs in PDT applications, notwithstanding their inherent benefits. Recently, doping agents and solvents have been demonstrated to improve CDs' optical properties, solubility, cytotoxicity, and organelle targeting efficiency. These improvements result from modifications to the CDs' carbon skeleton matrices, functional groups on the surface state, and chemical structures. This review discusses the modification of CDs with heteroatom dopants, dye dopants, and solvents to improve their physicochemical and optical properties for PDT applications. The correlations between the surface chemistry, functional groups, the structure of the CDs, and their optical characteristics toward quantum yield, redshift feature, and reactive oxygen species (ROS) generation, have also been discussed. Finally, the progressive trends for the use of CDs in PDT applications are also addressed in this review.

"Light modulates transcriptomic dynamics upregulating astaxanthin accumulation in Haematococcus: A review".

Haematococcus pluvialis is a green alga that can accumulate high astaxanthin content, a commercially demanding market keto food. Due to its high predicted market value of about 3.4 billion USD in 2027, it is essential to increase its production. Therefore, it is crucial to understand the genetic mechanism and gene expressions profile during astaxanthin synthesis. The effect of poly- and mono-chromatic light of different wavelengths and different intensities have shown to influence the gene expression towards astaxanthin production. This includes transcriptomic gene analysis in H. pluvialis underneath different levels of illumination stress. This review has placed the most recent data on the effects of light on bioastaxanthin production in the context of previous studies, which were more focused on the biochemical and physiological sides. Doing so, it contributes to delineate new ways along the biotechnological process with the aim to increase bioastaxanthin production while decreasing production costs.