title: Simulation and modeling of laser-tissue interactions based on a liposome-dye system.
abstract: This work presents an overview of the use of liposomes for targeted delivery of photosensitizers to tumors for Photodynamic Therapy (PDT). It assesses the results of a quantitative model to explain the interaction of short-pulsed lasers (in the nanosecond and picosecond domains) with a liposome-dye complex in terms of a localized photo-induced thermal mechanism. Incorporation of an organic dye (sulforhodamine) within lipid vesicles has been investigated in conjunction with the effect of laser irradiation on the integrity of the liposome-dye complex. The variation of the absorption coefficient as a function of wavelength for dye-encapsulated liposomes before and after laser-induced release of dye was studied and modeled. The commercial software Mathematica was used to develop a Gaussian model for the energy absorption by the liposome-dye complex. Dye release from 3 microm - liposome encapsulating 25 mM aqueous solution of sulforhodamine dye was studied using 8 ns laser pulses at the second harmonic of the Nd:YAG laser (at 532 nm) and compared with dye release employing 25 ps - laser pulses. In addition, the temperature-dependence of the dye release has been included in the photo-thermal model.
authors.affiliation: University of the District of Columbia, Washington, DC, USA.
authors.forename: F E
authors.initials: FE
authors.lastname: Mensah
authors.forename: R
authors.initials: R
authors.lastname: Sridhar
authors.forename: P
authors.initials: P
authors.lastname: Misra
mesh_terms: D000818:Animals; D003198:Computer Simulation; D005456:Fluorescent Dyes / Q000737:chemistry / Q000378:metabolism; D007834:Lasers; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism; D008962:Models, Theoretical; D015394:Molecular Structure; D010778:Photochemotherapy / Q000295:instrumentation / Q000379:methods; D051381:Rats
chemical_list: D005456:Fluorescent Dyes; D008081:Liposomes