Effects of acoustic streaming from moderate-intensity pulsed ultrasound for enhancing biofilm mitigation effectiveness of drug-loaded liposomes.
Because biofilms have resistance to antibiotics, their control using minimum amounts of chemicals and energy becomes a critical issue particularly for resource-constrained long-term space and deep-sea explorations. This preliminary study investigates how ultrasound promoting penetration of antibiotic-loaded liposomes into alginate-based bacterial biofilms, resulting in enhanced bacterial (Ralstonia insidiosa) killing. Nano-sized liposomes are used as a delivery vehicle for the antibiotic gentamicin. Alginate-based synthetic biofilms, which are widely acknowledged as biofilm phantoms, filled with liposome solution are formed at the bottoms of six-well Petri dishes and exposed to ultrasound (frequency = 2.25 MHz, 10% duty cycle, and spatially and temporally averaged intensity ISAPA = 4.4 W/cm(2)). Gentamicin is released from liposomes after they are lysed using detergent solution (0.05% sodium dodecyl sulfate, 1.0% Triton X-100) and incubated for 20 min. The alginate biofilm is dissolved and diluted, counting of colony-forming units shows about 80% of the bacteria are killed. It has also been shown the liposome-capture density by the alginate film increases linearly with the ultrasound intensity up to ISAPA = 6.2 W/cm(2) reaching approximately threefold that without ultrasound. Measurement by using particle-image velocimetry has demonstrated the acoustic streaming with modification by thermal convection controls the enhancement of the liposome capture rate.
Department of Physics, University of Vermont, Burlington, Vermont 05405, USA.
Dong
D
Ma
School of Engineering, University of Vermont, Burlington, Vermont 05405, USA.
Adam M
AM
Green
Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405, USA.
Graham G
GG
Willsey
School of Engineering, University of Vermont, Burlington, Vermont 05405, USA.
Jeffrey S
JS
Marshall
Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405, USA.
Matthew J
MJ
Wargo
Department of Physics, University of Vermont, Burlington, Vermont 05405, USA.
Junru
J
Wu
D000464:Alginates; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D058491:Bacterial Load; D018441:Biofilms; D004203:Disinfection / Q000379:methods*; D004337:Drug Carriers; D016650:Fluorescein-5-isothiocyanate / Q000032:analysis; D005839:Gentamicins / Q000008:administration & dosage*; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D006358:Hot Temperature; D020100:Hydrogels; D017078:Laser-Doppler Flowmetry; D008081:Liposomes; D043367:Ralstonia / Q000187:drug effects; D000069453:Ultrasonic Waves; D018508:Water Purification / Q000379:methods*
D000464:Alginates; D000900:Anti-Bacterial Agents; D004337:Drug Carriers; D005839:Gentamicins; D006603:Hexuronic Acids; D020100:Hydrogels; D008081:Liposomes; D020723:Glucuronic Acid; D016650:Fluorescein-5-isothiocyanate