PROPOSTA DE CARACTERIZAÇÃO FOTOACÚSTICA DO NÍVEL DE OLEOSIDADE DA PELE

Abstract

The present paper has aimed to propose a direct experimental
method based in the photoacoustic analysis to evaluate comparatively the
skin oiliness level. Photoacoustic technique is a method employed in the
characterization of different materials, offering, in many cases, meaningful
advantages over traditional techniques, allowing the analysis of intact
biological tissues and highly light-scattering samples, as the human skin.
In the research, two cosmetics were used, an oil and a body talcum powder,
both clinically tested and commercially available. The study was performed
through measurements in nineteen volunteers, being nine of them with dry
skin and ten of them with oily skin. Four series of measurements were carried
out after previous hygienization of the samples (cleaning in the forearm region
to be measured with cotton soaked in 70% alcohol): 1) the first one, in the
forearm skin after asepsis protocol; 2) measurement in the same forearm
skin as the previous item, after application of body talcum powder; 3)
measurement in the opposite forearm after asepsis protocol; and 4)
measurement in the same forearm skin as 3), after application of body oil.
Measurement results in clean forearm did not show statistically significant
differences between dry and oily skin, possibly due to the asepsis protocol
employed. On the other side, for both skin types, the photoacoustic technique
was able to show differences in human skin after application of different
products (oil or talcum powder), showing significant elevation of the
photoacoustic signal amplitude after talcum powder application and significant
reduction after oil application.