Versatile Bioconjugation Strategies of PEG-Modified Upconversion Nanoparticles for Bioanalytical Applications
| Authors | |
|---|---|
| Year of publication | 2020 |
| Type | Article in Periodical |
| Magazine / Source | Biomacromolecules |
| MU Faculty or unit | |
| Citation | |
| Web | https://pubs.acs.org/doi/10.1021/acs.biomac.0c00459 |
| Doi | http://dx.doi.org/10.1021/acs.biomac.0c00459 |
| Keywords | photon-upconversion nanoparticle; UCNP; bioconjugation; poly(ethylene glycol); click chemistry; upconversion-linked immunosorbent assay; ULISA; human serum albumin |
| Description | Lanthanide-doped upconversion nanoparticles (UCNPs) display highly beneficial photophysical features for background-free bioimaging and bioanalysis; however, they are instable in high ionic strength buffers, have no functional groups, and are nonspecifically interacting. Here, we have prepared NIR-excitable UCNPs that are long-term colloidally stable in buffered media and possess functional groups. Heterobifunctional poly(ethylene glycol) (PEG) linkers bearing neridronate and alkyne or maleimide were attached to UCNPs via a ligand exchange. Streptavidin (SA)-conjugates were prepared by click reaction of UCNP@PEG-alkyne and SA-azide. Antihuman serum albumin pAbF antibody was modified with azide groups and conjugated to UCNP@PEG-alkyne via click reaction; alternatively, the antibody, after mild reduction of its disulfide bonds, was conjugated to UCNP@PEG-maleimide. We employed these nanoconjugates as labels for an upconversion-linked immunosorbent assay. SA-based labels achieved the lowest LOD of 0.17 ng/mL for the target albumin, which was superior compared to a fluorescence immunoassay (LOD 0.59 ng/mL) or an enzyme-linked immunoassay (LOD 0.56 ng/mL). |
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