Self-assembly of quantum dots/denatured BSA-oligonucleotides bioconjugate and its application on aptameric gold nanoparticles-based biosensor for the determination of rHuEPO-α

In this paper, denatured bovine serum albumin (dBSA) has been developed as a useful scaffold for appending multiple oligonucleotides (ODNs), and the resulted novel dBSA-ODNs covalent hybrid can be self-assembled to the surface of CdTe quantum dots (QDs) via complexation with unoccupied coordination metal sites on QDs' surface. The formed QDs/dBSA-ODNs bioconjugate could keep a long-term stability in aqueous solution while maintaining its fluorescence quantum yield and spectral properties. Furthermore, the QDs/dBSA-ODNs also can be readily hybridized with an anti-rHuEPO-α aptamers linked AuNPs (Apt-AuNPs) to form a fluorescent resonance energy transfer-based nano-biosensing system for highly sensitive and selective detection of rHuEPO-α protein lowered to 53.6 pM in a rapid, simple manner.

► Denatured bovine serum albumin (dBSA)-ODNs covalent ligand was synthesized and characterized. ► A simple, direct, and reproducible method for fabricating CdTe QDs and single stranded oligonucleotides (ODNs) conjugation is proposed. ► Conjugation ligand exhibits high affinity toward CdTe QDs and can be readily self-assembly on CdTe QDs surface. ► We devised a simple fluorescence turn-on sensing strategy for rHuEPO-α based on proposed QDs/dBSA-cODNs conjugate, AuNPs and aptamer. ► This sensing system containing QDs/dBSA-ODNs and Apt-AuNPs provides a highly sensitive and selective detection of rHuEPO-α protein.