3.1.3 Applications of biomedical polymers in skin ...
Polymer material is one of the three major materials in today's society，and it is an indispensable material basis for human production and life.With the birth of polymer science and technology，the almost simultaneous development of biomedical polymers and their products have been widely recognized and clinically applied.Polymer materials and their products can be seen in every step of medical work.In recent years，the application of polymer materials in the field of skin，including the diagnosis and treatment of skin diseases，skin beauty，wearable skin devices and electronic skin，and skin repair and regeneration，etc.，has achieved remarkable results and more complete cognition through scientific research and clinical practice.
Skin disease is a general term for a variety of diseases that occur in the skin and skin appendages.There are many types of skin diseases and currently more than 2000 skin diseases with different clinical characteristics can be named.They can be affected by all ages from birth to death，and any part of the body can be affected.From a medical point of view，there are almost no individuals who are not troubled by skin diseases in a person's life.Therefore，skin disease is the most common disease.At the same time，the lesions that occur in the internal organs often present on the skin.In addition，skin diseases caused by infectious factors（e.g.，leprosy，scabies，skin bacteria，fungal diseases）are usually contagious，which not only affects physical health，but also leads to social discrimination and psychological problems，etc.The common skin diseases are infectious diseases and allergic dermatitis，but with the degenerative changes of aging，senile skin diseases and skin cancer are also important skin diseases.With people's pursuit of a healthy and beautiful life，the diagnosis and treatment of skin diseases have attracted more and more attention.The diagnosis and differential diagnosis of skin diseases include physical examination，laboratory examination，etc.At the same time，in order to clarify the tissue structure of the organism and clarify the various physiological functions of the organism，bioimaging technology has been widely used in the research and clinical diagnosis of skin diseases.For this content，please refer to chapter 5“Imaging in Dermatology”.
Traditional treatments of skin diseases mostly employ external use medicines，which have some disadvantages such as low drug utilization，and multidrug resistance.Recent studies have shown that the usage of polymer nanoparticles（NPs）as drug carriers can achieve targeted delivery and slow down the purpose of controlled-release drug delivery，which has gradually developed into an effective way to treat skin diseases.For details，please refer to chapter 6“Polymer Nano-Drug Carriers and Their Applications in Skin Diseases Treatments”.Melanoma is a tumor produced by melanocytes of the skin and other organs.It has early metastasis，high malignancy，and high mortality，and is a very important content in the treatment of skin diseases.For detailed introduction，please refer to chapter 7“Applications of Biomedical Polymers in Immunotherapy of Melanoma”.Compared with traditional drug delivery methods，new drug delivery technologies（e.g.，transdermal drug delivery）refer to new technologies that administer drugs on the surface of the skin to allow drugs to pass through the skin into the body circulation at a controlled rate or procedure to achieve local or systemic treatment.Transdermal drug delivery technology has significant advantages in the treatment of skin diseases，including not being interfered by factors such as strong acidity in the digestive tract，food，and transit time.It can avoid the liver first-pass effect，and can overcome the adverse reactions resulted from the high blood concentration caused by the rapid drug absorption.The drug delivery speed can be controlled continuously，and the drug delivery can be personalized and flexible.For the latest research progress and clinical application of transdermal drug delivery，please refer to chapter 8“Transdermal Drug Delivery”.
The biomedical polymers in skin cosmetology can be classified into three types according to the duration of the filling material：short-acting（6-12 months），semi-permanent（18-30 months）and permanent（over 5 years）.The important basic materials for skin filling are collagen，poly（lactic acid）and hyaluronic acid，as shown in Table 3-3.Regarding the biomedical polymer materials in skin cosmetology，please refer to chapter 9“Applications of Biomedical Polymers in Cosmetic Dermatology”for details.(https://www.daowen.com)
Table 3-3 Introduction to biomedical polymers in skin beauty
In addition，wearable electronic skin is a detection technology that can measure human health physiological indicators，such as heart rate，pulse，blood pressure，body temperature，and muscle vibration.Its advantages lie in the timely sensing and feedback of changes in human health data，and even the early prevention and diagnosis of diseases.For this part of the content，please refer to chapter 10“Wearable Electronic Skin Devices”.Organisms have great ability to repair and restore tissue damage and defects，including the repair of different levels of skin tissue structure，and the reconstruction of its tissue and body function.For skin damage，epidermal damage can usually be regenerated.It is usually difficult to completely repair it once the damage reaches the dermis and subcutaneous tissue.Biomedical polymer materials for skin repair and regeneration include traditional wound dressings and artificial skins that have recently been developed.The characteristic of wound dressings is the pursuit of fast and good wound repair，while artificial skin is mainly dedicated to the complete restoration of the structure and function of the skin（e.g.，skin regeneration）.The structure and function of natural skin are very complicated.Therefore，based on the knowledge of skin structure and function，research and thorough understanding of the mechanism of skin wound repair and healing are important for the design and construction of new facial fillers，wound dressings and artificial skin significance.For the physiological process of skin wound healing，complications and treatment of skin wound repair，and biomedical polymer materials for skin repair and regeneration，please refer to chapter 11“Applications of Biomedical Polymers in Skin Wound Repair”.