2.2.2 Characterization of THB@ANVs
THB@ANVs can be prepared by co-incubating THB nanoparticles (NPs) with
400 nm ANVs, followed by extruding the mixture through a 200 nm liposome
membrane. The obtained THB@ANVs were compared with THB NPs and 200 nm
ANVs without THB. As shown in Figure 1C, the characteristic absorption
band of THB at 464 nm can be observed in the UV/Vis absorption spectra
of THB@ANVs. The loaded THB NPs can be observed in the TEM morphology of
THB@ANVs (Figure 1A, right, marked with triangles).
Hydrodynamic particle size and
Zeta potentials tested by DLS and NTA at optimal conditions before and
after encapsulation were shown in Figure 1F~1H. The
hydration effect leads to a larger particle size measurement by DLS as
compared to NTA. The isolated ANVs and THB@ANVs mainly match the TEM
results, with diameters ranging from 30 to 300 nm. The particle sizes of
THB@ANVs prepared with different initial concentrations of THB NPs were
evaluated at a fixed ANVs concentrations of 100 μg/mL (Figure S7). An
optimal initial concentration of 50 μM THB NPs was chosen to obtained a
hydrodynamic diameter of 204.1 nm for THB@ANVs, which is close to that
of ANVs (230.6 nm). When the concentration of THB NPs is further
increased, they can also distribute onto the outer surface of the
membranes. This might result in electrostatic attraction between ANVs,
leading to an increase of hydrodynamic diameter. Calculated by the
standard curve (Figures S8), a final concentration of 35 nmol THB/100 μg
ANVs was obtained, corresponding to a loading capacity of approximately
19.6%. As shown in Figure 1J, the red fluorescence of THB has also been
utilized to co-localized with the membrane labeled with
3,3-dioctadecyloxacarbocyanine perchlorate (DiO), further confirming the
successful coupling of THB into ANVs.
2.3 In
vitro wound repair promoting experiment of ANVs and THB@ANVs