title: New insights into the HIFU-triggered release from polymeric micelles.
abstract: Continuous wave (CW), low frequency, high intensity focused ultrasound (HIFU) is a promising modality to trigger release of active compounds from polymeric micelles. The aim of the present study was to investigate whether high frequency CW as well as pulsed wave (PW) HIFU can induce the release of a hydrophobic agent from non-cross-linked (NCL) and core cross-linked (CCL) poly(ethylene glycol)-b-poly[N-(2-hydroxypropyl) methacrylamide-lactate] (mPEG-b-p(HPMAm-Lac(n))) micelles. It was shown that high frequency CW as well as PW HIFU was able to trigger the release (up to 85%) of a hydrophobic compound (i.e., nile red, NR) from NCL and CCL micelles. No changes in size distribution of the micelles after CW and PW HIFU exposure were observed and no degradation of polymer chain had occurred. We therefore hypothesize that the polymeric micelles are temporally destabilized upon HIFU exposure due to radiation force induced shear forces, leading to NR release on demand.
authors.affiliation: Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands. r.deckers-2@umcutrecht.nl
authors.forename: Roel
authors.initials: R
authors.lastname: Deckers
authors.forename: Agnes
authors.initials: A
authors.lastname: Paradissis
authors.forename: Chris
authors.initials: C
authors.lastname: Oerlemans
authors.forename: Marina
authors.initials: M
authors.lastname: Talelli
authors.forename: Gert
authors.initials: G
authors.lastname: Storm
authors.forename: Wim E
authors.initials: WE
authors.lastname: Hennink
authors.forename: J Frank W
authors.initials: JF
authors.lastname: Nijsen
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D007773:Lactates / Q000737:chemistry*; D008823:Micelles; D011092:Polyethylene Glycols / Q000737:chemistry*; D014465:Ultrasonics
chemical_list: D000178:Acrylamides; D007773:Lactates; D008823:Micelles; C509680:poly(N-(2-hydroxypropyl) methacrylamide lactate); D011092:Polyethylene Glycols