Applicability of Quantum Dots in Biomedical Science

Abstract

Quantum dots (QDs) are novel class of inorganic fluorophore with superior photophysical properties. Superior optical properties are a promising alternative to organic dyes for fluorescence biomedical applications. These nanoparticles have size-tunable emission, strong light absorbance, and very high levels of brightness and photostability. Highly luminescent QDs are prepared by coating the core with another material, resulting in core-shell quantum dots that are more stable in various chemical environments. These core-shell QDs are hydrophobic and only organic soluble as prepared. Hydrophobic QDs are insoluble in aqueous solution and cannot be directly employed in biomedical applications. They are necessarily made water soluble by surface modifying them with various bifunctional surface ligands or caps to promote aqueous solubility and enhancing biocompatibility. To make them useful for biomedical applications, QDs need to be conjugated to biological molecules without disturbing the biological function of these molecules. Most of the current studies were designed to ask questions concerning the physicochemical properties of novel QD products, not QD toxicity per se. The potential toxicity of the QDs is a cause for concern because they are made of heavy metals. The limitation of heavy metal-containing QDs stimulates extensive research interests in exploring alternative strategies for the design of fluorescent nanocrystals with high biocompatibility.

Omnidirectional and Highly Sensitive Microtubular Photodetectors Based on QD/2D Heterojunctions

“…The size of the QD is important in determining the photoabsorptivity of the device. , The particle size of the rhenium disulfide (ReS 2 ) QD was determined by high-resolution transmission electron microscopy (HRTEM) image. As shown in Figure a, the average diameter of the QD was estimated to be ∼8 nm.…”

Detection of Phytopathogens in Agricultural Crops Using Nanodiagnostic Techniques

“…Quantum dots are resistant to light bleached due to their 10-100 times higher molar attenuation value, distinguishable tunable fluorescence peak, and extended fluorescence lifetime [57]. The aforementioned features of quantum dots make them brighter than conventional fluorophores since they may be activated in a variety of colors from just one source without their emission impulses conflicting [58]. Due to these benefits, QDFRET-based nanosensors have become widely used in the farming and accompanying applications.…”

Recent Advancement on the Excitonic and Biexcitonic Properties of Low-Dimensional Semiconductors

“…Zero-dimensional semiconductor structures have captivated a notable interest owing to the fact that the motion is confined in all three directions, the size of a QDs being smaller than or comparable to the bulk exciton Bohr radius [109][110][111][112]. In this part of the chapter, some recent progresses in the topic which deals with the excitonic and biexcitonic effects for QDs applications case are emphasized, including computing and communication field, light-emitting devices, solar cells area, and biological domain [113,114].…”