Reactive oxygen species (ROS) play an essential role in regulating various physiological functions of living organisms. The intrinsic biochemical properties of ROS, which underlie the mechanisms ne...

Reactive Oxygen Species (ROS)-Based Nanomedicine.

This article reviews acoustic microfiuidics: the use of acoustic fields, principally ultrasonics, for application in microfiuidics. Although acoustics is a classical field, its promising, and indeed perplexing, capabilities in powerfully manipulating both fluids and particles within those fluids on the microscale to nanoscale has revived interest in it. The bewildering state of the literature and ample jargon from decades of research is reorganized and presented in the context of models derived from first principles. This hopefully will make the area accessible for researchers with experience in materials science, fluid mechanics, or dynamics. The abundance of interesting phenomena arising from nonlinear interactions in ultrasound that easily appear at these small scales is considered, especially in surface acoustic wave devices that are simple to fabricate with planar lithography techniques common in microfluidics, along with the many applications in microfluidics and nanofluidics that appear through the literature.

/pdf/microscale-acoustofluidics-microfluidics-driven-via-5bet39j13p.pdf

Microscale acoustofluidics: Microfluidics driven via acoustics and ultrasonics

Polymeric micelles are demonstrating high potential as nanomedicines capable of controlling the distribution and function of loaded bioactive agents in the body, effectively overcoming biological barriers, and various formulations are engaged in intensive preclinical and clinical testing. This Review focuses on polymeric micelles assembled through multimolecular interactions between block copolymers and the loaded drugs, proteins, or nucleic acids as translationable nanomedicines. The aspects involved in the design of successful micellar carriers are described in detail on the basis of the type of polymer/payload interaction, as well as the interplay of micelles with the biological interface, emphasizing on the chemistry and engineering of the block copolymers. By shaping these features, polymeric micelles have been propitious for delivering a wide range of therapeutics through effective sensing of targets in the body and adjustment of their properties in response to particular stimuli, modulating the act...

Block Copolymer Micelles in Nanomedicine Applications.

https://www.saisei-mirai.or.jp/gan/pdf/2004-sonodynamic-therapy-ultrasound-review.pdf

Sonodynamic therapy--a review of the synergistic effects of drugs and ultrasound

High intensity focused ultrasound (HIFU) is gaining rapid clinical acceptance as a treatment modality enabling non-invasive tissue heating and ablation for numerous applications. HIFU treatments are usually carried out in a single session, often as a day case procedure, with the patient either fully conscious, lightly sedated or under light general anaesthesia. A major advantage of HIFU over other thermal ablation techniques is that there is no necessity for the transcutaneous insertion of probes into the target tissue. The high powered focused beams employed are generated from sources placed either outside the body (for treatment of tumours of the liver, kidney, breast, uterus, pancreas and bone) or in the rectum (for treatment of the prostate), and are designed to enable rapid heating of a target tissue volume, while leaving tissue in the ultrasound propagation path relatively unaffected. Given the wide-ranging applicability of HIFU, numerous extra-corporeal, transrectal and interstitial devices have been designed to optimise application-specific treatment delivery. Their principle of operation is described here, alongside an overview of the physical mechanisms governing HIFU propagation and HIFU-induced heating. Present methods of characterising HIFU fields and of quantifying HIFU exposure and its associated effects are also addressed.

https://www.tandfonline.com/doi/pdf/10.1080/02656730601186138

High intensity focused ultrasound: physical principles and devices.

By providing an ultrasonic irradiation apparatus for generating acoustic cavitation efficiently, it is intended to realize an ultrasonic therapeutic apparatus for generating the action of cavitation on a living body suitable for medical treatment of malignant tumors and medical treatment of thrombi and calculi, an ultrasonic diagnostic apparatus for generating cavitation for emphasizing an ultrasonic echo image such as a blood flow and utilizing the reflection capability of the cavitation, an ultrasonic chemical reaction accelerating apparatus, an ultrasonic cleaning apparatus or an ultrasonic sterilizing apparatus. Irradiation focus/code signals for defining irradiated acoustic fields of a fundamental wave and a second harmonic wave as well as focus positions/acoustic pressure distribution forms of the respective waves are applied from an irradiation unit main control circuit to drive phase generating circuits. Generated drive phases are applied to drive signal generating circuits, generated drive signals are applied to element drive circuits and a group of fundamental frequency elements and a group of second harmonic elements are driven. The drive phases are controlled such that the fundamental wave and second harmonic wave are superimposed on each other in a medium near a focal point, thus generating acoustic caviation locally and efficiently.

Ultrasonic irradiation apparatus and processing apparatus based thereon

In an ultrasound therapeutic system provided with an ultrasound transmitter having a focusing mechanism and a plurality of groups of ultrasound transmitters/receivers, each of which has a controllable directivity, each of the transmitters/receivers is constructed so as to be able to receive both echo of pulse-shaped ultrasound transmitted by itself and even order harmonic signals of the ultrasound transmitted by the transmitter, and a plurality of two-dimensional pulse echographical images constructed by ultrasound signals obtained by transmitting/receiving beams, while controlling the directivity of the beam emitted by each of the plurality of groups of ultrasound transmitters/receivers and a plurality of images indicating orientation and intensity, in which an even order harmonic wave signal due to the ultrasound transmitted by the transmitter is received by each of the plurality of groups of ultrasound transmitters/receivers, are displayed, superimposed on each other.

Ultrasound therapeutic system

In studying the feasibility of developing tissue-targeted contrast media that can be administered as liquids and vaporized by an external stimulus such as ultrasound, we have investigated the properties of emulsions of nanometer-size particles containing perfluoropentane and 2H,3H-perfluoropentane. We found that the ultrasound intensity required to induce echographically significant vaporization can be controlled by changing the ratio of 2H,3H-perfluoropentane to perfluoropentane and that the intensity threshold increases as this ratio increases. Significant azeotropic phenomena were not observed when the perfluorocarbon mixtures were heated, which indicates that mechanisms other than azotropy are involved in the threshold change. The vaporization of 2H,3H-perfluoropentane may have been due not only to ultrasound energy but also to the energy deposited by ultrasonically induced bubbles of perfluoropentane. Our results might lead to a phase-shift contrast agent with controllable ultrasound energy for phase shifting.

https://iopscience.iop.org/article/10.1143/JJAP.44.4548/pdf

Nanoparticles with Multiple Perfluorocarbons for Controllable Ultrasonically Induced Phase Shifting

An ultrasonic medical treating device suited for ultrasonic medical treatment of a prostate, capable of sighting a converging ultrasonic wave for the treatment precisely to a target portion, and preventing displacement from the target portion being irradiated effectively. An ultrasonic transducer (5) for generating a converging ultrasonic wave for treatment is arranged together with an imaging ultrasonic probe (6) in an applicator (4), and an ultrasonic transducer (2) for monitoring the sight of and the position displacement is provided in a catheter inserted in a ureter. Imaging means (7) drives the ultrasonic probe (6) to display an ultrasonic tomogram of the target portion and its vicinity on display means (10). The ultrasonic transducer (2) is driven pulsationally with the same frequency as that of the imaging ultrasonic wave at the timing at which the imaging ultrasonic wave, so that a point sound source image indicating the position of the transducer (2), as viewed from the applicator, is superimposed on the ultrasonic tomogram displayed on the display means (10). The position displacement of the applicator being irradiated with the converging ultrasonic wave can be monitored by monitoring the displacement from the position of the point sound source image at the end of the position adjustment of the applicator.

Ultrasonic medical treating device

An ultrasonic manipulation apparatus has a plurality of ultrasonic wave oscillators arranged in two dimensions to trap, fix or move particles to an optional position in the solution or perform cell fusion by using a gradient force obtained by superposing one over another the gradient force fields generated by ultrasonic waves produced by a plurality of ultrasonic wave oscillators. The ultrasonic wave oscillators, functioning independently of one another, can emit ultrasonic waves with optional intensities and phases, and by using an external force produced by superposed gradient force fields generated by ultrasonic waves, particles are handled easily.

Kenichi Kawabata

Papers

Ultrasonic irradiation apparatus and processing apparatus based thereon

Ultrasound therapeutic system

Nanoparticles with Multiple Perfluorocarbons for Controllable Ultrasonically Induced Phase Shifting

Ultrasonic medical treating device

Particle handling apparatus for handling particles in fluid by acoustic radiation pressure