Dextran-Functionalized Semiconductor Quantum Dot Bioconjugates for Bioanalysis and Imaging

Abstract

The prerequisites for maximizing the advantageous optical properties of colloidal semiconductor quantum dots (QDs) in biological applications are effective surface functionalization and bioconjugation strategies. Functionalization with dextran has been highly successful with some nanoparticle materials, but has had very limited application with QDs. Here, we report the preparation, characterization, and proof-of-concept applications of dextranfunctionalized QDs. Multiple approaches to dextran ligands were evaluated, including performance with respect to colloidal stability across a range of pH, nonspecific binding with proteins and cells, and microinjection into cells and viability assays. Multiple bioconjugation strategies were demonstrated and applied, including covalent coupling to develop a simple pH sensor, binding of polyhistidinetagged peptides to the QD for energy transfer-based proteolytic activity assays, and binding with tetrameric antibody complexes (TACs) to enable a sandwich immunoassay and cell immunolabeling and imaging. Our results show that dextran ligands are highly promising for the functionalization of QDs, and that the design of the ligands is tailorable to help optimally meet the requirements of applications.

Functionalized Gold Nanoparticles: Synthesis, Properties and Biomedical Applications

“…Sandwich immunoassay and cellular immunolabeling and imaging are implemented. [69] However, due to the application of quantum dots in clinical medicine are prone to cytotoxic so nanoparticles as the most promising alternatives. [70] Behi et al utilized biomarkers such as sensitive polypeptide aptamer, designed a fast response selectivity of protein detection platform, the peptide gold point PACD carbon nanoprobe.…”

“…They bound the polyhistidine‐tagged peptides to quantum dots for energy‐transfer based proteolytic activity measurements, and to tetramer antibody complexes (TACs). Sandwich immunoassay and cellular immunolabeling and imaging are implemented [69] . However, due to the application of quantum dots in clinical medicine are prone to cytotoxic so nanoparticles as the most promising alternatives [70] .…”

Novel UV-activated biofunctionalization of up-converting nanocrystals for detection of proteins

“…1). Dextran is a polysaccharide composed of glucose, characterized by good solubility, biocompatibility, lack of toxicity and with many documented applications in medicine [44][45][46]. Its carboxymethylated derivative had been aminated that allowed subsequent coupling to PVP located on UCNPs by photoactivation of ANB-NOS.…”

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