title: Enhancing laser thermal-therapy using ultrasound-microbubbles and gold nanorods of in vitro cells.
abstract: Gold nanorods (GNRs) are being exploited for their absorption properties to improve thermal therapy. However, a key challenge is delivering sufficient concentration of GNRs to induce a therapeutic effect. In this study, ultrasound and microbubbles (USMBs) were used to enhance intracellular uptake of GNRs. AML-5 cells in suspension (0.6 mL) were exposed to ultrasound (1.3 and 1.7 MPa peak negative pressure) and definity microbubbles (1.7% v/v) for 1 min at varying GNR concentrations (0-2.5×10(11) per mL). Following ultrasound-microbubble treatment, cells were centrifuged twice and treated with an 810 nm laser at an average fluence rate of 3.6 W/cm(2) for 5 min. In addition, cells were incubated with GNRs for 12 h prior to laser treatment. Following the treatment, cell viability (V(PI)) was assessed using propidium iodide (PI) and flow cytometry. Cell viability decreased by ∼4-folds with the combined treatment of USMB+GNR+Laser (V(PI)=17%) compared to cells incubated with GNR+Laser (V(PI)=68%). This effect depended on ultrasound pressure and GNR concentration. Higher cell death was achieved at higher GNR concentration and 1.3 MPa peak negative pressure. Cell viability decreased from 92% to 29% with increasing GNR concentration from 1×10(11) to 1.5×10(11) GNR/mL. In addition, higher temperatures were observed using a thermal camera with the combined treatment (USMB+GNR+Laser) of 59±1°C compared to 54±0.9°C for cells incubated with GNRs. The combined treatment of ultrasound-microbubble and gold nanorod laser induced thermal-therapy improved treatment response of in vitro cells.
authors.affiliation: Ryerson University, Department of Physics, Toronto, Ontario, Canada.
authors.forename: Christine
authors.initials: C
authors.lastname: Tarapacki
authors.forename: Carl
authors.initials: C
authors.lastname: Kumaradas
authors.forename: Raffi
authors.initials: R
authors.lastname: Karshafian
mesh_terms: D045744:Cell Line, Tumor; D003131:Combined Modality Therapy; D005434:Flow Cytometry; D006046:Gold / Q000737:chemistry*; D006801:Humans; D006979:Hyperthermia, Induced / Q000379:methods*; D053685:Laser Therapy / Q000379:methods*; D015470:Leukemia, Myeloid, Acute / Q000601:surgery*; D045423:Microbubbles; D046529:Microscopy, Electron, Transmission; D043942:Nanotubes / Q000737:chemistry*; D013535:Suspensions; D014465:Ultrasonics
chemical_list: D013535:Suspensions; D006046:Gold