Selection of precursor for natural product-derived carbon dots and their biomedical applications

Carbon dots (CDs), an emerging class of fluorescent carbon nanomaterials, have garnered considerable attention owing to their excellent optical properties and favorable biocompatibility. Among the diverse precursors for CDs synthesis, natural product-derived carbon dots (NCDs) have assumed a prominent role in promoting green and sustainable approaches because of their low cost and environmental compatibility, and research interest in these materials has expanded markedly in recent years. Whether produced from natural product monomers, plant extracts, traditional Chinese medicinal materials, or their associated waste products, NCDs often retain or confer intrinsic biological activities, thereby obviating the need for secondary drug-loading processes that are typical of conventional nanomaterials. Leveraging their remarkable photostability, low cytotoxicity, and excellent biocompatibility, NCDs demonstrate broad application potential in diverse fields such as in vivo and in vitro imaging, ion detection, drug delivery, and disease therapy. This review systematically summarizes strategies for selecting NCD precursors, delineates the characteristics and common features of NCDs derived from various precursor classes, and discusses the rationale and methodologies for precursor doping to enable precise modulation of CDs performance. The review aims to provide theoretical guidance for the rational design and optimization of precursors and synthesis conditions to meet defined performance criteria.