Spectroscopic observations on human pigmentation.

Area of Science:

• Dermatology
• Biophysics
• Spectroscopy

Background:

• Human skin contains multiple chromophores, including melanin and hemoglobin.
• Understanding the spectral signatures of these chromophores is crucial for various diagnostic applications.
• Melanin's spectral properties are key to studying skin conditions like vitiligo.

Purpose of the Study:

• To spectroscopically analyze skin melanin in vivo.
• To develop a method for detecting early signs of re-pigmentation in vitiligo.
• To establish spectral markers for quantifying melanin levels.

Main Methods:

• Utilized a bifurcated optical fiber probe for in vivo skin measurements.
• Connected the probe to a light source and spectrometer.
• Placed the common end of the probe directly onto the skin surface.

Main Results:

• Observed a characteristic absorbance spectrum for melanin in skin, with a peak at 335 nm.
• Absorbance values increased from 750 nm to 335 nm, then decreased.
• Demonstrated that steeper negative slopes between 620-720 nm correlate with higher melanin levels.

Conclusions:

• Successfully obtained differential spectra of melanin in vitiligo lesions using spectroscopy.
• The 335 nm absorption peak reliably indicates the presence of melanin.
• The method provides a quantitative measure of melanin, useful for monitoring skin repigmentation.