  Using low molecular weight chitosan nanoparticles (CNPs) prepared by an ionic
gelation method, we report the effect of low-intensity pulsed ultrasound (US)
on cell viability and nanoparticle uptake in cultured murine pre-osteoblasts.
Particle size and zeta potential are measured using Dynamic Light Scattering
(DLS), and cell viability is evaluated using the MTS assay. Results show that
30 min delivery of CNPs at 0.5 mg/mL is able to prevent loss of cell viability
due to either serum starvation or subsequent exposure to US (1 W/cm2 or 2
W/cm2, up to 1 min). Additionally, flow cytometry data suggest that there is a
close association between cellular membrane integrity and the presence of CNPs
when US at 2 W/cm2 is administered.
