Synthesis of water-soluble and bio-taggable CdSe@ZnS quantum dots

Many synthesized semiconductor QDs materials are formed using trioctylphosphine oxide (TOPO) but it requires high temperature, is very expensive and is also hydrophobic. Our study deals with selective syntheses of CdSe and core-shell CdSe/ZnS quantum dots (QDs) in aqueous solution by a simple heating and refluxing method. It is more hydrophilic, needs less temperature, is economically viable and is eco-friendly. Bio-ligands, such as thioacetamide, itaconic acid and glutathione, were used as stabilizers for the biosynthesis of QDs. A simplified aqueous route was used to improve the quality of the colloidal nanocrystals. As a result, highly monodisperse, photoluminescent and biocompatible nanoparticles were obtained. The synthesized QDs were characterized by XRD, FTIR, confocal microscopy, ultraviolet (UV) absorption and photoluminescence (PL). The size of synthesized QDs was observed as 5.74 nm and the core-shell shape was confirmed by using XRD and confocal microscopy respectively. The QD nanoparticles showed antibacterial activity against pathogenic bacteria. The QDs could be applied for biological labelling, fluorescence bio-sensing and bio-imaging etc. Mystristic capped CdSe QDs with schematic diagram and formation mechanism of bio-taggable CdSe@ZnS QDs.