Page 26 - 00. Complete Version - Progress Report IPEN 2014-2016

26 Lasers Technology | Progress Report

properties. In addition to colorization, highly sive form and shows a pattern of possible met-
light-absorbing structures were produced on astatic profile.
metal surfaces, with an absorption rate above
95% for the visible and near infrared regions. 5-aminolevulinic acid (ALA) and its methylat-
Also(,) in metals are being developed micro- ed ester (MAL) are the most common topical
metric textures (are being developed in metals) agents used in photodynamic therapy (PDT) as
with the purpose of improving the tribological precursors of the photosensitizer protoporphy-
properties of their surfaces. These textures can rin IX (PpIX). The induction of newly PpIX de-
reduce the friction and wear of surfaces used pends on incubation time of each photosen-
in numerous engineering processes. sitizer in the tissue and the presence of high
intralesional porphyrin levels is an important
The glass processing with ultra-short femto- parameter for the PDT effectiveness. We used
second pulses has been developed and is be- laser-induced fluorescence (LIF) spectroscopy
ing used mainly for the production of compo- to evaluate the optimum time to light exposure
nents for microfluidic circuits. Micro channels, of PDT mediated by ALA (20% w/w) and MAL
micro reactors, valves and micro pumps are (10% w/w) to treat malignant lesions precur-
some of the regularly produced components. sors of cutaneous squamous cell carcinoma in-
With them, several complete microfluidic cir- duced in mice. The therapeutic effects obtained
cuits were produced, including the injection by optimized ALA- and MAL-PDT were assessed
and control systems. The main circuits already 10 and 20 days after treatments. Higher PpIX
in operation are being used for ELISA assay levels were evidenced in the lesions photosen-
(Enzyme Linked Immuno Sorbent Assay), for sitized by ALA than MAL and according to LIF
the growth of luminescent nanocrystals and measurements the PDT irradiation was per-
for the control of size and shape of metallic formed, respectively, at 300 and 330 minutes
nanoparticles. after ALA and MAL incubation. Histopatholog-
ical analysis evidenced necrosis and epithelial
Laser Health Applications has developed to atrophy after 10 days of PDT using both pro-
a new field known as Biophotonics as an ex- drugs, as well as reepitelization and collagen
citing interdisciplinary research field which deposition at 20 days. Thus, despite the distinct
studies the interaction of photons with bio- concentration of ALA and MAL used in the for-
logical structures, imaging and sensing cells
and tissue. The interaction of light with mat-
ter results in reflection, absorption, scatter-
ing or transmission of the beam which can
tell us information about the molecule or tis-
sue structure. Since 1992(,) Biophotonics and
lasers research at IPEN is providing to the so-
ciety (with) a wide range of applications from
fundamental medical research to diagnosis,
therapy and surgery.

Nonmelanoma skin cancers represent 95% of Figure 8: (a) Illustration of fluorescence from skin tu-
cutaneous neoplasms. Among them, squa- mor treated by PDT mediated by ALA and MAL and his-
tological results. (b) Discrimination of healthy and
mous cell carcinoma (SCC) is the more aggres- skin tumor by multivariate statistical analysis.

Instituto de Pesquisas Energéticas e Nucleares