Transition metal chalcogenide quantum dots (QDs), especially
MoS2 QDs, are an emerging class of novel optical probes
for versatile
bioanalytical applications owing to their distinct physicochemical
properties. However, the reasonable use of these QDs for biological
imaging has been largely restricted due to the challenge of controllable
surface functionalization. In this work, we report a new strategy
to engineer the surface of MoS2 QDs by taking advantage
of cyclodextrin (CD)-based host–guest chemistry. The prepared
β-CD-modified QDs (β-CD-MoS2 QDs) exhibit enhanced
fluorescence properties, excellent biocompatibility, and good stability,
making them promising as novel optical probes for bioimaging. Cellular
imaging experiments revealed that these β-CD-MoS2 QDs can enter living cells through multiple internalization pathways,
which differs significantly from pristine QDs. Particularly, we observed
that the intracellular accumulation of MoS2 QDs in lipid
droplets was enhanced owing to the specific binding of β-CD
to cholesterol, which was then harnessed for monitoring the lipid
metabolism in living cells via fluorescence imaging. Furthermore,
we also demonstrated the potential use of β-CD-MoS2 QDs for targeted cell imaging and microplate-based cell recognition,
which can be easily achieved via bioconjugation with functional motifs
(e.g., folate acid) through host–guest chemistry. Altogether,
these results illustrate the great potential of engineering the surface
of MoS2 QDs and other analogous materials via CD-based
host–guest chemistry for advancing their cell imaging applications.