Endovascular US enhanced vascular gene delivery and increased the efficiency of nonviral platforms to levels previously attained only by adenoviral strategies.
Large numbers of molecules can be delivered intracellularly using low-frequency ultrasound. Both uptake and viability correlate with acoustic energy, which is useful for design and control of ultrasound protocols.
This study provides a quantitative guide to designing ultrasound protocols useful for drug delivery. The acoustic measurements support the hypothesis that ultrasonic cavitation is the mechanism by which membranes are permeabilized. They also suggest that measurable acoustic signals can provide noninvasive, real-time feedback about membrane permeabilization and drug delivery.
It has been hypothesized that one role of the fish’s auditory system may be to detect and localize nearby fish by ‘‘imaging’’ ambient noise scattered by their swimbladders. This is analogous to the role of the visual system of most animals, where the relevant signal is ambient light scattered by objects rather than light emitted by luminous objects. A classical conditioning experiment has been performed which indicates that the fish auditory system is capable of functioning in this manner. The ambient noise was provided by a J-9 transducer driven by Gaussian noise. Scattering of ambient noise by the resonant swimbladder was simulated by applying a filtered version of the same Gaussian noise to a small spherical projector. The target strength and bandwidth of the scattered noise were controlled by the attenuation and passband of the filter. The fish was conditioned to respond to the presence of the signal from the spherical projector. Thresholds of simulated scattered noise as a function of range to the subject were measured for the species Carassius auratus (common goldfish). The fish’s ability to discriminate this signal is taken to be a measure of its ability to detect scattered ambient noise. [Work supported by ONR.]
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