Synthesis, structural, and optical properties of Mn2+ doped ZnS quantum dots for biosensor application

Abstract

Abstract Albumin as a globular protein plays a substantial role in the preserving plasma pressure and the nutritional balance and consequently the albumin level serves as an indicator of liver health and function. In this work a simple synthetic method of highly photoluminescent (PL) Mn x 2 + Zn 2 − x S (0\xa0≤\xa0x\xa0≤\xa00.1) doped quantum dots (QDs) were synthesized by the wet chemical method and capped with 3-mercaptopropionic acid (MPA). The prepared Mn doped ZnS QDs and the pristine ZnS QDs were characterized by fluorescent emission spectra, X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). The pristine ZnS QDs showed a relatively weak emission PL Gaussian peak at about 395\xa0nm while Mn doped ZnS QDs illustrated dual emission peaks at 425 and 570\xa0nm. HRTEM images appeared cubic nanocrystals for ZnS and Mn 0.04 2 + Zn 1.96 S QDs with average particle sizes of 13 and 16\xa0nm, respectively. The prepared Mn- doped ZnS QDs were applied as an optical sensor for determination of bovine serum albumin (BSA) in aqueous solutions. The QDs sensor exhibited a linear working range from 0.1 to 0.95\xa0μM of albumin with R2\xa0=\xa00.984. The limit of detection (LOD) of this system was found to be 1.56\xa0×\xa010−7\xa0M. This method is not only simple, sensitive and low cost, but also reliable for practical applications. Solution-processed ZnS QDs was used for the real time, label free optical detection of BSA.