Facile Cholesterol Loading with a New Probe ezFlux Allows for Streamlined Cholesterol Efflux Assays

Here, we report a
nanoparticle-based probe that affords facile
cell labeling with cholesterol in cholesterol efflux (CE) assays.
This probe, called ezFlux, was optimized through a screening of multiple
nanoformulations engineered with a Förster resonance energy
transfer (FRET) reporter. The physicochemical- and bio-similarity
of ezFlux to standard semi-synthetic acetylated low-density lipoprotein
(acLDL) was confirmed by testing uptake in macrophages, the intracellular
route of degradation, and performance in CE assays. A single-step
fast self-assembly fabrication makes ezFlux an attractive alternative
to acLDL. We also show that CE testing using ezFlux is significantly
cheaper than that performed using commercial kits or acLDL. Additionally,
we analyze clinical trials that measure CE and show that ezFlux has
a place in many research and clinical laboratories worldwide that
use CE to assess cellular and lipoprotein function.