Multimodal optical characterisation of collagen photodegradation by femtosecond infrared laser ablation

摘要: Collagen is a structural component of the human body, as connective tissue it can become altered result pathophysiological conditions. Although collagen degradation mechanism not fully understood, plays an important role in ageing, disease progression and applications therapeutic laser treatments. To understand alteration, our study photo-disruptive effects were induced I matrix by point-irradiation with femtosecond Ti-sapphire under controlled ablation settings. This was followed multi-modal imaging irradiated surrounding areas to analyse mechanism. Our methodology based on second harmonic generation (SHG), scanning electron microscope (SEM), autofluorescence (AF) average intensities fluorescence lifetime. allowed us quantitatively characterise degraded area into four distinct zones: (1) depolymerised zone focal spot indicated loss SHG signal, (2) enhanced crosslinking inner boundary cavity represented high ring, (3) reduced formed outer marked increased signal (4) native collagen. These identified zones good agreement expected photochemical changes shown using Raman spectroscopy. In addition, polarisation-resolved (p-SHG) revealed both degree fibre re-orientation change tensor ratios around irradiation spot. optical approach provide new for defining that be used clinical setting determine suitable thresholds applying safe treatments without affecting tissues. Furthermore this technique extended address challenges observed engineering minimally invasive diagnostic tool diseased non-diseased rich