Shulian Wu

Quantitative analysis on collagen morphology in aging skin based on multiphoton microscopy

Multiphoton microscopy was employed for monitoring the structure changes of mouse dermis collagen in the intrinsic- or the extrinsic-age-related processes in vivo. The characteristics of textures in different aging skins were uncovered by fast Fourier transform in which the orientation index and bundle packing of collagen were quantitatively analyzed. Some significant differences in collagen-related changes are found in different aging skins, which can be good indicators for the statuses of aging skins. The results are valuable to the study of aging skin and also of interest to biomedical photonics.

Optical features for chronological aging and photoaging skin by optical coherence tomography

The characteristics of skins in different aging processes were obtained by optical coherence tomography (OCT) single scattering model, and their optical parameters were analyzed quantitatively. Significant differences were found in epidermis thickness and attenuation coefficients in chronological aging skins and photonaging skins. These parameters can be served as indicators of skin type as well as the progress of aging. These results are valuable to the study of aging skin, and they could further help to understand the mechanism of aging.

Monitoring photo-thermal response and collagen remodeling of mouse skin with multiphoton microscopy

Two-photon excitation fluorescence (TPEF) and second-harmonic generation (SHG) are detected through multiphoton microscopy (MPM). The major signals have the potential to monitor the process of tissue changes. TPEF and SHG are used to monitor the skin photo-thermal response to irradiation with intense pulsed light sources (\lambda is in the range of 560?1200 nm) and trace the process of skin remodeling in vivo at different time intervals. TPEF intensity is nearly unchanged at different time intervals after irradiation, whereas SHG intensity changes considerably. The results reveal the photo-thermal effect of nonablative light sources and the process of collagen remodeling at the sub-micron level.

Quantitative analysis on collagen of dermatofibrosarcoma protuberans skin by second harmonic generation microscopy.

Dermatofibrosarcoma protuberans (DFSP) is a skin cancer usually mistaken as other benign tumors. Abnormal DFSP resection results in tumor recurrence. Quantitative characterization of collagen alteration on the skin tumor is essential for developing a diagnostic technique. In this study, second harmonic generation (SHG) microscopy was performed to obtain images of the human DFSP skin and normal skin. Subsequently, structure and texture analysis methods were applied to determine the differences in skin texture characteristics between the two skin types, and the link between collagen alteration and tumor was established. Results suggest that combining SHG microscopy and texture analysis methods is a feasible and effective method to describe the characteristics of skin tumor like DFSP.

The analysis of aging skin based on multiphoton microscopy

Aging is a very important issue not only in dermatology, but also in cosmetic science. Cutaneous aging involves both chronological and photoaging aging process. The chronological aging is induced with the passage of time. And the photoaging skin is the extrinsic aging caused by sun exposure. The aim of this study is to use multiphoton microscopy (MPM) in vivo to assess intrinsic-age-related and photo-age-related difference. The changes of dermal collagen are measured in quantitively. The algorithm that we used automatically produced the transversal dermal map from MPM. Others, the texture of dermis are analyzed by Fourier transform and Gray Level Co-occurrence Matrix. And the object extraction in textured images is proposed based on the method in object edge extraction, and the aim of it is to detect the object hidden in the skin texture in difference aging skin. The result demonstrates that the approach is effective in detecting the object in epidermis and dermis textured image in different aging skin. It could help to further understand the aging mechanism.

Microscopic observation and mechanism discussion for the changes of mouse skin after interacted by intense pulse light

The technologies based on Differential Interference Contrast microscopy (DIC), Laser Scanning Confocal Microscopy (LSCM), Two Photon Emission Laser Scanning Microscopy (TPELSM) and Optical Coherent Tomography (OCT) were used to study the changes of mouse skin after irradiated by Intense Pulse Light (IPL). The experimental results were compared and analyzed by different microscopic observation tools. The relations of the epithelial or dermal interaction with IPL in different energy density were given, and the morphologic changes of mouse skin were observed before and after days irradiated respectively. The function of dermal collagen during the renovating of the tissue and the key factors were presented.

Skin Damage of Ablative Laser in Vivo Based on Multiphoton Microscopy

Recently, various lasers therapies have been employed in clinical practice. And the lasers which relied on their wide clinical applications in treating cutaneous diseases and performing cosmetic procedures have developed greatly. The effects in treatment of laser treatment depend on the immediate response of incident light irradiated in tissues and then the subsequent tissue regeneration and remodeling, especially ablative lasers. In this study, multiphoton microscopy with autofluorescence and second harmonic generation has developed to monitor the optic-thermal response of skin tissue irradiated by CO2 and the process of regeneration. The injury dimensions are also obtained in the experiment. Our findings show that the method has potential ability to monitor the process of tissue change and the remodeling in mouse dermis. The outcome indicates that the injury dimension and area increase with irradiated dose, and the injury threshold is 0.5W. And then the renovation time also increases with laser fluence.

Monitoring collagen remodeling on opto-thermal response of photoaged skin irradiated by Er:YAG laser with optical coherence tomography

The Optical Coherence Tomography technology was used to perform noninvasive cross-sectional imaging of internal structures in photoaged mouse skin irradiated by Er:YAG laser. The mice were irradiated chronically with a steady dose of ultraviolet irradiation. Various laser light doses were irradiated on the back skins of the photoaged mouse. An OCT was used to observe the process of the collagen remodeling in dermis. The relationship between optical characteristic parameter such as attenuation coefficient and light dose was discovered. The total attenuation coefficient increased when the light dose increased. Our findings showed that Er:YAG laser could be used for the symptoms of the photoaged skin with some degree of thermal damage in the dermis, and the OCT could image the progress of collagen remodeling in photoaged mouse dermis. The OCT may be a useful tool for the determination of optimal parameters for laser skin treatment.

Photorejuvenation observation based on two photon microscopy

With low risk of complications and little down-time, the non-ablative photo-rejuvenation is playing an increasing role in the therapy of the photo-damaged skin, but the appraisal standard is different. This paper mainly observed the effect of the mouse skin irradiated by intense pulse light source through two photo microscopy in sub-micrometer. The spectrum and morphological imaging between pre- and post-irradiated by Intense Pulse Light (IPL) were obtained from two photon microscopy respectively. The outcome showed that non-ablative IPL irradiated the aging mouse skin got the better effect, and then have gained the changes of spectrum intensity and corresponding photon numbers in a rectangular area, these probable achieve the mechanism of light irradiated skin. The intention of this was offer the theory basis in clinic.

Correlation between the skewness and the scattering coefficient of intralipid solution

We demonstrated that a simple image statistic, skewness, is able to distinguish the various concentration of Intralipid solution by using optical coherence tomography. The results showed that the skewness is increased with the concentration of Intralipid solution. According to Mie theory, the skewness is correlated with the scattering coefficient of Intralipid solution. And the correlation between skewness and scattering coefficient is explained that the skewness exploits the characteristic of asymmetry of probability density distribution of image intensity.