title: Controlling Spatial Heat and Light Distribution by Using Photothermal Enhancing Auto-Regulated Liposomes (PEARLs).
abstract: Photothermal therapy (PTT) is enhanced by the use of nanoparticles with a large optical absorption at the treatment wavelength. However, this comes at the cost of higher light attenuation that results in reduced depth of heating as well as larger thermal gradients, leading to potential over- and under-treatment in the target tissue. These limitations can be overcome by using photothermal enhancing auto-regulating liposomes (PEARLs), based on thermochromic J-aggregate forming dye-lipid conjugates that reversibly alter their absorption above a predefined lipid phase-transition temperature. Under irradiation by near-infrared light, deeper layers of the target tissue revert to the intrinsic optical absorption, halting the temperature rise and enabling greater light penetration and heat generation at depth. This effect is demonstrated in both nanoparticle solutions and in gel phantoms containing the nanoparticles.
authors.affiliation: Princess Margaret Cancer Centre and TECHNA Institute, University Health Network, Toronto, ON, M5G 1L7, Canada.
authors.forename: Kenneth K
authors.initials: KK
authors.lastname: Ng
authors.affiliation: Princess Margaret Cancer Centre and TECHNA Institute, University Health Network, Toronto, ON, M5G 1L7, Canada.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Weersink
authors.affiliation: Princess Margaret Cancer Centre and TECHNA Institute, University Health Network, Toronto, ON, M5G 1L7, Canada.
authors.forename: Liang
authors.initials: L
authors.lastname: Lim
authors.affiliation: Princess Margaret Cancer Centre and TECHNA Institute, University Health Network, Toronto, ON, M5G 1L7, Canada.|Department of Medical Biophysics, University of Toronto, Ontario, M5G 1L7, Canada.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Wilson
authors.affiliation: Princess Margaret Cancer Centre and TECHNA Institute, University Health Network, Toronto, ON, M5G 1L7, Canada. gang.zheng@uhnres.utoronto.ca.|Department of Medical Biophysics, University of Toronto, Ontario, M5G 1L7, Canada. gang.zheng@uhnres.utoronto.ca.
authors.forename: Gang
authors.initials: G
authors.lastname: Zheng
mesh_terms: D006358:Hot Temperature; D008027:Light; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism*; D053758:Nanoparticles / Q000737:chemistry; D055668:Photochemical Processes; D010789:Phototherapy; D012996:Solutions
chemical_list: D008081:Liposomes; D012996:Solutions
keywords: J-aggregates; feedback mechanisms; nanoparticles; phase transitions; photothermal therapy