Quantum Dots in Biosensing, Bioimaging, and Drug Delivery

Abstract

AbstractSemiconductor quantum dots have been a matter of significant research interest owing to their potential biomedical applications, especially in drug delivery, biosensing, and, bioimaging. Practical biomedical applications of quantum dots require high fluorescence quantum yield, good aqueous solubility, narrow size distribution, and crystallinity of as-synthesized nano-sized particles. Several types of nanocarriers have been investigated for drug delivery. Out of different nanocarriers, semiconductor quantum dots have been favored due to their distinctive size-dependent optical, electrical, and, other physico-chemical characteristics. QDs have been explored for a wide variety of biomedical applications, e.g., detection of disease, drug delivery, biosensing, bioimaging, different type of therapeutic applications, including cancer therapeutics, tissue engineering, etc. QDs have excellent surface functionalization properties as well as biocompatibility. Encapsulation of QD core with different metal, metal oxides, polymers, or biomolecules facilitates core–shell structure, which, in turn, improves the efficacy of QDs for biomedical applications. The main advantage of using QDs as a nanocarrier for delivery of different types of drugs is its high surface to volume ratio, biocompatibility, and its cell-membrane permeability, which allows multiple sites for attachment of drug molecules. Moreover, surface functionalization of QDs enables loading of drug molecules to the QD surface through covalent as well as non-covalent bonding. On the other hand, bright photoluminescence ranging up to NIR region, excellent photostability, compressed light scattering, low tissue absorption, and unique size-tunable optical and electrical properties enable quantum dots for a wide range of biosensing as well as bioimaging applications. Furthermore, QDs provide a suitable platform for engineering of multifunctional nanodevices with capabilities of exploiting multiple imaging modalities or merging imaging and therapeutic functionalities within a single nanoparticle. Altogether, QDs have been a potential candidate for next-generation clinical and diagnostics research. In this book chapter, we aim to cover applications of different types of quantum dots in drug delivery, biosensing, and bioimaging.KeywordsQuantum dotsBiosensingBioimagingDrug delivery