Virtual biopsies and vibrational-mechanical analysis of skin rejuvenation: comparison of results obtained with micro-needling and topical treatments

Vibrational optical coherence tomography (VOCT) is a new non-invasive and non- destructive technique that can be used to image and measure the mechanical properties of skin. The technique uses infrared light and audible sound to image and measure the resonant frequency of tissue components. The stiffness (modulus) of each major tissue component is obtained from a calibration equation using values of the measured resonant frequency and tissue thickness. VOCT is used in this study to quantitatively compare the outcomes of cell proliferation and fibrous collagen deposition as a result of (1) a skin topical treatment (CE Ferulic) and (2) micro-needle roller application to human forehead skin. Both methods appear to quantitatively increase the ratio of cells to dermal collagen and the ratio of fibrotic collagen to dermal collagen with increasing time. Both chemical and mechanical treatments lead to cell proliferation and new collagen deposition using these skin rejuvenation procedures. While results obtained with micro-needle rolling are achieved more rapidly, collagen deposition with the topical is achieved painlessly. The new collagen that is deposited, using both methods, appears similar to that seen in wound healing and has a higher resonant frequency and modulus compared to normal dermal collagen. The results of this study suggest that VOCT can provide useful quantitative data to evaluate the efficacy of skin rejuvenation procedures. It is suggested that there is a need to develop techniques to regenerate normal dermal collagen as opposed to fibrotic collagen to reduce the stiffness of the new tissue formed.