Date of Graduation


Document Type


Degree Name

Master of Science in Biomedical Engineering (MSBME)

Degree Level



Biomedical Engineering


Kyle P. Quinn

Committee Member

Timothy J. Muldoon

Second Committee Member

Jeffrey C. Wolchok


skin metabolism, Ischemic skin flap, phasor analysis, skin necrosis


Necrotic skin flaps are difficult to predict and treat due to the lack of quantitative biomarkers. Label-free multiphoton microscopy is well suited for non-invasively monitoring skin metabolism through NAD(P)H and other intrinsic fluorophores, and offers immediate future directions for assessing necrosis in the clinic. The objective of this study was to assess whether phasor FLIM could be used to evaluate skin flap status and treatment efficacy in ex vivo skin sections. Phasor maps revealed differences in growth factor treatment and region, but changes in skin flap autofluorescence at 755nm excitation and 460nm emission were not just related to NAD(P)H. A very short lifetime component accumulated in the necrotic distal region of the skin flap, and we partitioned phasor space to detect necrosis, which revealed a sensitivity to IL-10/VEGF and IL-10/HGF gene transfer therapy.