Biosynthesized Quantum Dots as Improved Biocompatible Tools for Biomedical Applications

Abstract

: Quantum dots (QDs), whose diameters are often limited to 10 nm, have been of interest to researchers for their unique optical characteristics, which are attributed to quantum confinement. Following their early application in the electrical industry as light-emitting diode materials, semiconductor nanocrystals have continued to show great potential in clinical diagnosis and biomedical applications. The conventional physical and chemical pathways for QD syntheses typically require harsh conditions and hazardous reagents, and these products encounter non-hydrophilic problems due to organic capping ligands when they enter the physiological environment. The natural reducing abilities of living organisms, especially microbes, are then exploited to prepare QDs from available metal precursors. Low-cost and eco-friendly biosynthesis approaches have the potential for further biomedical applications which benefit from the good biocompatibility of protein-coated QDs. The surface biomass offers many binding sites for modifying substances or targeting ligands and so achieving multiple functions through simple and efficient operations. Biosynthetic QDs could function as bioimaging and biolabeling agents because of their luminescence properties similar to those of chemical QDs. In addition, extensive research has been carried out on the antibacterial activity, metal ion detection and bioremediation. As a result, this review details the advanced progress of biomedical applications of biosynthesized QDs and illustrates these principles as clearly as possible.

One-Step Synthesis of Water-Soluble Silver Sulfide Quantum Dots and Their Application to Bioimaging

“…Quantum dots have been attracting increasing attention recently. The general morphology of quantum dots is spherical or quasispherical with diameters less than 20 nm . Quantum dots with near-infrared (NIR) emission properties can be used to label different biomolecular drugs, to monitor various cellular processes, etc. , In this context, the widely studied near-infrared quantum dots, such as PbS, PbSe, PbTe, InP, and CdHgTe, contain highly toxic components, which limit their application in vivo.…”

Sunlight‐driven antibacterial activity of a novel zinc oxide quantum dot and its optimization using Box–Behnken design—A medicament for communicable disease protective wearables

“…21 In this case, natural leaf extracts and essential oils are being used as stabilizing, reducing, and capping agents in the production of QDs from metal precursors. 22 We were impressed by the systematic review on green synthesis of ZnO-NPs using A. indica, 23 A. vera, 14 and neem essential oil. 24 As a result, a thorough literature review was conducted for ZnO nanocomposites prepared from A. indica, A. vera, and neem essential oil.…”

“…Plant‐based methods are thus an appealing platform for the preparation of metal oxide NPs and QDs due to their cost‐effective approach, consistency, short production time, and performance 21 . In this case, natural leaf extracts and essential oils are being used as stabilizing, reducing, and capping agents in the production of QDs from metal precursors 22 …”

Carbon-Based Quantum Dots for Photovoltaic Devices: A Review

“…Recently, colloidal quantum dots (QDs) have gain huge attention of researchers due to their quantum confinement and excellent optical properties like tunable photoluminescence (PL), high photoluminescent quantum yield (PLQY), and shape emission. These excellent optical properties of colloidal quantum dots make them a promising material to be used for a variety of applications in energy technology, biomedicine, sensing, etc. − Among various colloidal QDs, the CQDs have recently gained popularity as a semiconductor nanomaterial capable of enhancing the performance of LSCs and solar cells. , CQDs are stable, nontoxic materials composed of commonly found elements (C, H, O, N) that are easily synthesized in bulk via facile hydrothermal or microwave synthesis pathways with a common feedstock. , GQDs, a specialized type of CQDs, have also been thoroughly investigated for their controllable functionalization and excellent conductivity. , Unlike typical CQDs, GQDs have little oxygen functionalization with large areas of sp 2 hybridized domains, resulting in more hydrophobic character and increased conductivity . For their tunable functionalization and biocompatibility, CQDs have been applied in other fields, including environmental remediation, bone regeneration, biosensing, catalysis, and oxygen evolution reaction .…”