Open AccessMelanin concentration maps by label-free super-resolution photo-thermal imaging on melanoma biopsies
Author(s) -
Margaux Bouzin,
Mario Marini,
Giuseppe Chirico,
Francesca Granucci,
Francesca Mingozzi,
Roberto Colombo,
Laura D Alfonso,
Laura Sironi,
Maddalena Collini
Publication year - 2022
Publication title -
biomedical optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.362
H-Index - 86
ISSN - 2156-7085
DOI - 10.1364/boe.445945
Subject(s) - melanin , melanoma , h&e stain , eosin , pathology , histopathology , materials science , biopsy , microscopy , in vivo , staining , biomedical engineering , chemistry , medicine , biology , cancer research , biochemistry , microbiology and biotechnology
Surgical excision followed by histopathological examination is the gold standard for melanoma screening. However, the color-based inspection of hematoxylin-and-eosin-stained biopsies does not provide a space-resolved quantification of the melanin content in melanocytic lesions. We propose a non-destructive photo-thermal imaging method capable of characterizing the microscopic distribution and absolute concentration of melanin pigments in excised melanoma biopsies. By exploiting the photo-thermal effect primed by melanin absorption of visible laser light we obtain label-free super-resolution far-infrared thermal images of tissue sections where melanin is spatially mapped at sub-diffraction 40-μm resolution. Based on the finite-element simulation of the full 3D heat transfer model, we are able to convert temperature maps into quantitative images of the melanin molar concentration on B16 murine melanoma biopsies, with 4·10 -4 M concentration sensitivity. Being readily applicable to human melanoma biopsies in combination with hematoxylin-and-eosin staining, the proposed approach could complement traditional histopathology in the characterization of pigmented lesions ex-vivo.