Enhanced Luminescence of a Quantum Dot Complex Following Interaction with Protein for Applications in Cellular Imaging, Sensing, and White-Light Generation

Abstract

Herein, we report the sustainable, cost-effective, and greener surface modification strategy of a quantum dot complex (QDC)—comprised of zinc chalcogenide quantum dot (Qdot; for example, undoped ZnS and Mn2+-doped ZnS) and surface zinc quinolate (ZnQ2) complexes—following interaction with bovine serum albumin (BSA) protein. The interaction of BSA with QDC led to an enhancement in their luminescence properties (such as the quantum yield and emission lifetime), solubility, and stability (in water), compared to their bare form. The enhanced luminescence properties of BSA coupled with QDC—also termed herein as the BSA–QDC nanocomposite—are due to the BSA-induced structural rigidity of the ZnQ2 complex (being present on the surface of zinc chalcogenide Qdot). The highly green luminescent nontoxic BSA–QDC nanocomposite—consisting of undoped ZnS and the ZnQ2 complex—showed better imaging capability of HeLa cells in comparison to only QDC and sensing ability of an enzyme (trypsin) with a detection limit of 0.06 μ...