Significance: Artificial skin (AS) is widely used in dermatology, pharmacology, and toxicology, and has great potential in transplant medicine, burn wound care, and chronic wound treatment. There is a great demand for high-quality AS product and a non-invasive detection method is highly desirable.Aim: To quantify the constructure parameters (i.e., thickness and surface roughness) of AS samples in the culture cycle and explore the growth regularities using optical coherent tomography (OCT).Approach: An adaptive interface detection algorithm is developed to recognize surface points in each A-scan, offering a rapid method to calculate parameters without constructing OCT B-scan pictures and further achieving realizing real-time quantification of AS thickness and surface roughness. Experiments on standard roughness plates and H&E-staining microscopy were performed as a verification.Results: As applied on the whole cycle of AS culture, our method's results show that during the air-liquid culture, the surface roughness of the skin first decreases and then exhibits an increase, which implies coincidence with the degree of keratinization under a microscope. And normal and typical abnormal samples can be differentiated by thickness and roughness parameters during the culture cycle. Conclusions:The adaptive interface detection algorithm is suitable for high-sensitivity, fast detection, and quantification of the interface with layered characteristic tissues, and can be used for non-destructive detection of the growth regularity of AS sample thickness and roughness during the culture cycle.

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Ultraviolet (UV) irradiation causes 90% of photodamage to skin and long-term exposure to UV irradiation is the largest threat to skin health. To study the mechanism of UV-induced photodamage and the repair of sunburnt skin, the key problem to solve is how to non-destructively and continuously evaluate UV-induced photodamage to skin. In this study, a method to quantitatively analyze the structural and tissue optical parameters of artificial skin (AS) using optical coherence tomography (OCT) was proposed as a way to non-destructively and continuously evaluate the effect of photodamage. AS surface roughness was achieved based on the characteristic peaks of the intensity signal of the OCT images, and this was the basis for quantifying AS cuticle thickness using Dijkstra’s algorithm. Local texture features within the AS were obtained through the gray-level co-occurrence matrix method. A modified depth-resolved algorithm was used to quantify the 3D scattering coefficient distribution within AS based on a single-scattering model. A multiparameter assessment of AS photodamage was carried out, and the results were compared with the MTT experiment results and H&E staining. The results of the UV photodamage experiments showed that the cuticle of the photodamaged model was thicker (56.5%) and had greater surface roughness (14.4%) compared with the normal cultured AS. The angular second moment was greater and the correlation was smaller, which was in agreement with the results of the H&E staining microscopy. The angular second moment and correlation showed a good linear relationship with the UV irradiation dose, illustrating the potential of OCT in measuring internal structural damage. The tissue scattering coefficient of AS correlated well with the MTT results, which can be used to quantify the damage to the bioactivity. The experimental results also demonstrate the anti-photodamage efficacy of the vitamin C factor. Quantitative analysis of structural and tissue optical parameters of AS by OCT enables the non-destructive and continuous detection of AS photodamage in multiple dimensions.

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Image formation based on computation and aberrated optical design provides a promising approach for volumetric imaging studies of biological dynamics at cellular and sub-cellular resolution. High-throughput optical imaging is playing an increasingly important role in biological imaging. The technique enables biological dynamics to be studied at a variety of different spatiotemporal scales. 1-3 One area that is poised to benefit from this capability is the study of collective or emergent behavior in embryonic development, tissue regeneration, and cancer. 4, 5 Existing modalities for high-speed volumetric imaging at cellular or sub-cellular resolution are typically based on the detection of fluorescence signals. Consequently, they are subject to photobleaching and phototoxicity constraints and, as a result of this, have limited scope in settings that preclude the use of exogenous contrast agents (e.g., many clinical settings). High-speed methods such as optical coherence tomography (OCT) could help to provide label-free imaging of biological dynamics, thereby filling this gap in biological imaging. Recent advances in ultrahigh-speed OCT have enabled the acquisition of volumetric datasets at video rates (i.e., one volume in 25ms). 6 However, combining this high-throughput acquisition with cellular-resolution optical coherence microscopy (OCM) presents significant challenges. The main factor limiting the volumetric acquisition rate of OCM is the rapid degradation of resolution and signal strength at increased distance from the point of optical focus. There are a number of hardware approaches to volumetric cellular-resolution OCM. These include the acquisition of multiple OCM datasets, each with a different focus depth, and subsequent synthesis of a single 'in-focus' volume. 7-9 The illumination and collection beam can also be engineered to provide an extended focal region. 10 Of these approaches, focus-scanning methods offer the highest