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Dextran-Functionalized Semiconductor Quantum Dot Bioconjugates for Bioanalysis and Imaging
journal contribution
posted on 2020-02-21, 19:06 authored by Kelly Rees, Michael V. Tran, Melissa Massey, Hyungki Kim, Katherine D. Krause, W. Russ AlgarThe 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 dextran-functionalized 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 polyhistidine-tagged 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.