Combined photoultrasonic treatment of infected wounds

Abstract

A new combined photoultrasonic (CPUS) technology for the treatment of infected wounds is suggested. The CPUS principal operation is based on the topical application of a photosensitizer followed by light irradiation in combination with low frequency ultrasonic (US) treatment of wounds. In CPUS, two methods -photodynamic (PDT) and ultrasonic therapies supplement each other beneficially and in conjunction provide a significant effect of deep suppurative inflammatory wounds treatment. The main advantages of the new technology are the combined application of an antibiotic solution and photodynamic therapy to destroy antibiotic-resistant microorganisms, an effective mixing of a photosensitizer in the wound, the US enhancement of photosensitizer impregnation into the membranes of bacteria, the US clearing of wound surface from necrotic products, an increased effective light dose exposure in the whole volume of the deep wound when the light does not penetrate totally inside the wound, an additional bactericidal effect under the US impact, and the combined effect of CPUS activation of the immune system. The parameters of the developed CPUS therapy are as follows: the frequency of US oscillations is 26,5 kHz, the US tip elongation is 40±20 microns, an aluminum disulfonated phtalocyanine photosensitizer dissolved in a physiological solution, a photomatrix LEDs array with 660±10 nm used as a radiation source, light intensity from 0,5 to 10 mW/cm2, and the exposed surface is up to 1500 cm2. The experiments were carried out with 70 male chinchilla rabbits. The dynamics and character of wounds healing were studied by analyzing of clinical pathomorphological and histochemical data of the biopsy material and capillaroscopy of wounds edges. The experimental data on the animals model have demonstrated a high efficiency ofthe combined CPUS therapy.

Designing the Uniform Stochastic Photomatrix Therapeutic Systems

“…The photomatrix therapeutic system (PMTS), in its generalized form, is a net of light-emitting diode (LED) irradiation sources on a dimensional plane, and the LEDs themselves are located in the nodes of this grid, which in turn is fixed by the given spatial dimensions [1][2][3][4][5][6]. The issues of designing PMTS medical devices have already been described, making it possible to combine three principal aspects: illumination and optical characteristics of LEDs, their spatial and geometric arrangement on the surface of matrix substrate, and also the parameters of photobiological influence on the body in the context of the given biomedical requirements [7][8][9][10][11][12][13].…”

“…In general, over thirty different types of PMTS are presently available on the market or known as laboratory prototypes. The following operating modes of PMTS have been demonstrated [1][2][3][4][5][6][7][8][9][10][11][12][13]: constant, when all LEDs are on, but no modulation of irradiation is performed; blinking, where the LED sources are switched on at a specified frequency; blinking with pulse rate biosynchronization (based on pulse oximetry using a fingertip), in this case, the emission intensity of all LEDs is directly proportional to the volume of arterial blood supplying the vessels; looped modes of sequential single activation of each source or all LEDs lying on the same coordinate line; a variety of schematic modes such as 'treadmill' or specially designed modifiable 'patterns'; modes of sequential or predetermined changes in the wavelengths of the LED irradiation (in the case of tunable sources); various stochastic modes for turning on the LEDs that are controlled using a connected random number generator; and others.…”