Quantum Dots in Ocular Surface: A Systematic Review

The current advancements in quantum dot-based ocular surface applications identify critical gaps in existing research. A systematic search was conducted following PRISMA guidelines. Articles were retrieved from PubMed and Scopus using keywords including "quantum dots," "semiconductor nanocrystals," "ocular surface," "tear film," "cornea," "conjunctiva," "lacrimal glands," and "meibomian glands" with Boolean conjunctions. A total of 232 studies were initially selected based on titles and abstracts. After removing duplicates and screening, 21 studies were selected for review. A variety of QDs, including carbon, graphene, silicon, cadmium and gold-based, have been explored for bioimaging and therapeutic applications targeting the ocular surface. Carbon and silicon-based QDs are the most biocompatible. Surface functionalization of these QDs facilitates targeted imaging of tear film layers, conjunctiva, and cornea with stable fluorescence and minimal toxicity. QDs can also be antimicrobial, anti-inflammatory, and scavenge reactive oxygen species which might be used for the treatment of dry eye disease. Although cadmium-based QDs exhibit superior fluorescence, their cytotoxicity limits their clinical application. The optical properties of QDs are influenced by physicochemical properties such as particle size, surface charge, and surface functionalization. QDs represent a promising class of nanoscale materials for diagnostic and therapeutic applications on the ocular surface. While biocompatible variants of QDs, such as carbon and silicon QDs, show potential for clinical use, there is limited information on the standardized synthesis protocols, long-term cytotoxicity, systemic biodistribution, and clearance from ocular tissues. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.