title: Heat enhances gas delivery and acoustic attenuation in CO(2) filled microbubbles.
abstract: Thermo-responsive chitosan microbubbles were developed as new therapeutic device for vehiculating gases to tissues concomitantly to hyperthermic treatments. Aiming at applications to non-invasive temperature monitoring, microbubbles were characterized for acoustic attenuation properties in the 1-15 MHz range both by direct methods and by B-mode Ultrasound imaging up to 43 degrees C, which is the temperature used in clinical hyperthermia. The chitosan microbubbles showed a mean diameter of 1 microm at room temperature, which slightly decreases after heating, enhancing gas delivery. Acoustic attenuation monotonically increases with temperature, being the extent of such variation larger than that observed in tissues. Both the physico-chemical and the acoustic profiles showed reversible variations of microbubbles approaching 43 degrees C, which might be of interest for applications in hyperthermic therapies.
authors.affiliation: Department of Neuroscience, University of Torino, Italy. pgiustetto@gmail.com
authors.forename: Pierangela
authors.initials: P
authors.lastname: Giustetto
authors.forename: Agnese
authors.initials: A
authors.lastname: Bisazza
authors.forename: Angelo
authors.initials: A
authors.lastname: Biagioni
authors.forename: Adriano
authors.initials: A
authors.lastname: Alippi
authors.forename: Andrea
authors.initials: A
authors.lastname: Bettucci
authors.forename: Roberta
authors.initials: R
authors.lastname: Cavalli
authors.forename: Caterina
authors.initials: C
authors.lastname: Guiot
mesh_terms: D001672:Biocompatible Materials; D002245:Carbon Dioxide / Q000737:chemistry*; D048271:Chitosan; D003287:Contrast Media / Q000737:chemistry*; D006358:Hot Temperature; D045423:Microbubbles; D014464:Ultrasonic Therapy / Q000379:methods; D014465:Ultrasonics
chemical_list: D001672:Biocompatible Materials; D003287:Contrast Media; D002245:Carbon Dioxide; D048271:Chitosan