Investigating on the Effective Wound Healing Therapy Utilizing Laser Optical System Xuan-Hieu Le, Ngọc-Bao-Tran Nguyen, Minh-Vy Huynh, Thi-Phuong-Trinh Vo, and Thi-Thu-Hien Pham Abstract Recent advances in wound healing treatment and man- agement using Low- level Laser Therapy (LLLT) has been emphasized in many types of research for wound healing stimulation. Many studies have indicated the effects of this method; and thus, there is a concern that which wavelength and dosages would take more benefits, in term of wound closure and collagen synthesis. This research is conducted to re-emphasize and improve the ef ficiency of this therapy in chronic wounds and standard rat model to study and analyze the best conditions and protocol for these kinds of wound healing treatment. By utilizing red laser beams from an optical system to treat excisions on mice’s dorsal regions, we aim to determine the irradiation parameters (i.e., wavelength, light inten- sity, time irradiation) that provide the optimal conditions to promote the healing process. Two round excision wounds are created on the back of each mouse: one for a control group and one for treated group. The treated group wound were irradiated with the red (635 nm wavelength), following these intensities: 2; 3; 5 J/cm 2 . After every one week, the wound skins were taken and stained for results comparison. The experimental results showed that the wound closures were significantly different between treated and control group. At day 5th, 10th the follow-up tests indicated that the laser group had smaller wound areas compared to control group (non-diabetes and untreated). The improvement of impairment (>20%) and the faster time to wound closure indicated that this phototherapy could be used to heal chronic wounds in diabetic subjects. The healing progress analysis shows that the positive result and promising application of this therapy in future aid of wound control and healing. Keywords Wound healing  Diabetes  Chronic wounds  Healing process  LLLT 1 Introduction There are many methods used in treating the wound. For example, electrical stimulation, electromagnetic stimulation, ultrasound, and ultraviolet light have been used extensively in wound healing [1]. Among these methods—there is a therapy receiving much attention, and expected to be long-standing and promising research in the application of healing and wound healing as light therapy—Low-Level Light Therapy (LLLT). Laser means “amplification of light by stimulating emission,” was invented in 1960 [1]. Since their inception in 1960, lasers have been used for many applications in dif- ferent fields. In 1980, Endre Master discovered that there is a positive effect on the wound of the rats by using 694 nm wavelength [2]. Also more and more research has been done on the development and application of lasers in the medical field, especially wound healing. These studies have more or less demonstrated the positive effect of lasers on wound healing [3, 4]. There are two types of light commonly used in this field, including blue light and red light. Blue light has been shown to have antibacterial effects, and red light has been considered capable of shortening wound healing and cell proliferation [5, 6]. In fact, blue light and red light have been introduced to the direct treatment of acne inflammatory disease in humans and have resulted in significant results, which demonstrate that the effect of blue light and red light is effective and reliable [7]. However, the exact biological mechanisms of low-intensity light in tissues are still not explained. The application of light, especially laser, in wound healing and stimulation has been proposed and discussed long time ago. The first report on this field is the work of X.-H. Le  N.-B.-T. Nguyen  M.-V. Huynh T.-P.-T. Vo  T.-T.-H. Pham (&) Biomedical Engineering Department, International University— VNU HCMC, Ho Chi Minh City, Vietnam e-mail: ptthien@hcmiu.edu.vn © Springer Nature Singapore Pte Ltd. 2020 V. Van Toi et al. (eds.), 7th International Conference on the Development of Biomedical Engineering in Vietnam (BME7), IFMBE Proceedings 69, https://doi.org/10.1007/978-981-13-5859-3_70 395