Elina Genina1,2, Alexey N. Bashkatov1,2, Leonid E. Dolotov1, Ekaterina A. Kolesnikova1, Geordy S.Terentyuk1, Valery V. Tuchin1,2,
1 Saratov State University, Russia
2 Interdisciplinary Laboratory of Biophotonics, Tomsk State University, Tomsk, Russia
Fractional laser microablation (FLMA) is one of the relatively safe and effective methods of drug delivery into the skin at sufficiently large depth. Fractional devices create thermally induced microchannels of damage in the skin. The variation in laser radiation parameters allows for control the depth of the microchannels. In this study we are presenting the results of transcutaneous delivery of optical clearing agent (OCA).
The experiments were carried out with rat skin in vivo. Polyethylene glycol with molecular weight 300 Dalton (PEG-300) and refractive index 1.457 (at 930 nm) was used. FLMA of skin was provided by a system based on a pulsed Er:YAG laser (Palomar Medical Technologies Inc., Burlington, MA). The laser emission beam (2940 nm) was split into micro-beams using an array of micro-lenslets. Two laser modes with the following parameters were used: mode I with pulse energy 1.0 J and pulse duration 5 ms; and mode II with pulse energy 0.8 J and pulse duration 5 ms. In I mode 64 vertical micro-channels on the area 8x8 mm were created; and in II mode skin upper layer on the area 6x6 mm was ablated. Delivery of the OCA was monitored with optical coherence tomography (OCT) (~930 nm).
Optical probing depth during 60 min has increased from 180±10 μm for intact skin to 350±10 μm for skin after the complex action of FLMA (I mode) and OCA, and to 240±10 μm for skin after FLMA (II mode) and OCA. For skin after OCA alone the optical probing depth during the same period has increased only up to 205±10 μm. Results of the study have shown that the FLMA increases the probing depth in skin significantly.
Dr. Elina A Genina
Saratov State University, Associate Professor
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