Hyaluronic acid Hyaluronic acid is a kind of hyaluronic acid (HA), also known as uronic acid. Natural hyaluronic acid is a kind of macromolecular polysaccharide, which is a linear macromolecular polysaccharide with glucuronic acid -N- glucosamine acetate as disaccharide molecular unit. Its average molecular weight is between 6,543.8+10,000 and 6,543.8+10,000 daltons, and it exists in intercellular spaces. Originally used only for moisturizing, it has now been included in the ranks of wrinkle removal and plastic surgery. This plastic surgery technique is to inject hyaluronic acid, which is non-animal stable and cultured by bacterial fermentation, into wrinkles and depressions of dermis or parts that want to be full, to remove wrinkles and modify the face, which can immediately remove wrinkles and change appearance. Hyaluronic acid, which originally exists in the dermal tissue of human skin in the form of colloid, is responsible for storing water, increasing skin volume and making skin look full, plump and elastic. However, hyaluronic acid will disappear with age, making the skin lose its water storage capacity, gradually becoming dull, aging and forming fine wrinkles. Thanks to the progress of biotechnology, hyaluronic acid can be extracted from connective tissues of vertebrates, such as cockscomb, eyeball, umbilical cord and cartilage. In the past, hyaluronic acid was mostly extracted from animals, but now it is artificially synthesized, which avoids problems such as allergies and infections. Hyaluronic acid is mainly used in the field of medical beauty, and now it has greatly replaced collagen. Placenta and Botox. According to statistics, in 2004, the global hyaluronic acid application market was about $3 billion, with cosmeceuticals, skin care products, additives and therapeutic products accounting for half of the market. Europe, America and Japan are the largest markets for the production and use of hyaluronic acid products, with an estimated annual growth rate of 15%. There are two main methods to produce hyaluronic acid: tissue extraction and microbial fermentation. At present, only five international manufacturers in the world have the technology of producing medical-grade hyaluronic acid by microbial fermentation. In the second half of 2004, the demand for hyaluronic acid in Europe, America and Japan surged, leading to the shortage of raw materials and rising prices. Domestic parties predict that the supply of hyaluronic acid will be in short supply until after 2006. Hyaluronicacid: hyaluronic acid (HA for short) or uronic acid, a linear macromolecular polysaccharide composed of disaccharide units (glucuronic acid -N- ethylglucosamine) in Taiwan Province Province, is a naturally occurring substance in tissues. Widely distributed in connective tissue, mucous tissue, eyeball lens and some bacteria in nature, it plays an important role in the dermis of human skin, and plays an important role in the overall maintenance of tissue structure and the transportation between cells. In A.D. 1934, Meyer, a professor of ophthalmology at Columbia University, isolated hyaluronic acid from bovine vitreous for the first time and analyzed its structure. Because it is uronic acid extracted from vitreous body (vitreous body, Greek), it is named hyaluronic acid. The structure of hyaluronic acid is mainly composed of disaccharide, N- acetylglucosamine (N-D- glucosamine) and D- glucuronic acid (D-), and the average molecular weight is between 105- 107 Dalton. Hyaluronic acid can be said to be a skin moisturizing factor, which can absorb 500- 1000 times the volume, and can only carry 30 times the water compared with collagen molecules. It can be said that it is the most moisturizing substance in today's literature. Hyaluronic acid not only has the characteristics of volume expansion after moisturizing, but also has the characteristics of biological stability, non-transferability, impermeability and so on, and is a good choice for tissue fillers. Hyaluronic acid metabolizes rapidly in nature, so it must be made into polymer if it wants to be used as a filler between tissues. The bonding between molecules not only provides biological durability, but also strengthens the viscosity and water insolubility of hyaluronic acid. Types of Hyaluronic Acid The production technology and technology of Hyaluronic acid determine the difference in quality, so the products produced from the correct source must have therapeutic effect in use. Generally speaking, there are three extraction methods: 1. Animal tissue: The main raw materials are Celosia cristata and bovine vitreous. Defat that raw materials with acetone or ethanol, dehydrate, soaking in distilled water, filter, treating with sodium chloride aqueous solution and chloroform solution, adding trypsin, keeping the temperature to obtain mixed solution, and finally treating with ion exchanger and purifying to obtain refined hyaluronic acid. The extraction rate of this method is very low, only about 1%, and the separation process is complicated, which makes hyaluronic acid expensive, reaching 5000 US dollars/kg, which limits its large-scale use in cosmetics. 2. Microbial fermentation: fermentation broth with glucose as carbon source. Fermented in the culture medium for 48 hours, filtered to remove mycelium and impurities, and then obtained high-purity products through simple operations such as alcohol precipitation. Hyaluronic acid produced by fermentation has the advantage that the molecular weight can be set according to the product design. The key of fermentation method lies in the selection of strains. At present, streptococcus, Lactococcus and so on are mostly used. 3. Chemical synthesis: natural enzyme polymerization; Firstly, the polysaccharide polymer was used to synthesize "hyaluronic acid oxocyclopentene derivatives", and then hydrolase was added to make the complex of derivatives and enzymes. Finally, the enzyme was removed from the reaction solution at 90 degrees Celsius, and hyaluronic acid was synthesized. The synthetic method can greatly reduce the manufacturing cost of hyaluronic acid, but the structure is not pure. It is also a product of hyaluronic acid, which has obvious influence on the effect because of the different sources of raw materials and manufacturing processes. The concentration of the product can not be used as a reference for product selection, but the purity, molecular weight and 3D structure will directly affect the water absorption effect of hyaluronic acid. Generally, the larger the molecular weight, the more complete the network structure and the best water absorption effect. Skin care products and cosmetics are very popular in the market, but hyaluronic acid made by many manufacturers is cheap, but it is not necessarily effective. Even the oral hyaluronic acid promoted by some people will be decomposed into small unit molecules of sugars and amino acids after being absorbed by the stomach, and it can only be produced by self-synthesis in skin and connective tissue, and the effect will definitely be discounted. Application of hyaluronic acid At present, hyaluronic acid is mainly used in ophthalmic surgery, that is, high molecular weight hyaluronic acid solution is injected into the eye as a viscoelastic fluid to maintain the normal shape and function of the eye. In addition, it is also widely used in the treatment of degenerative arthritis and arthroscopic surgery. In recent years, the application of hyaluronic acid in anti-adhesion and drug release after operation has been gradually developed. After the operation, a large amount of tissue fluid will ooze from the surface of the originally separated tissue, causing abnormal adhesion of the tissue. Mentina Mentina Taiwan Province Province is prone to pain and intestinal obstruction after abdominal surgery. However, if there is intestinal adhesion in patients undergoing gynecological surgery, it will lead to pelvic pain and even infertility. Hyaluronic acid has also become the hottest topic in skin moisturizing, anti-aging and plastic surgery. Hyaluronic acid skin care efficacy Hyaluronic acid originally exists in the skin, which can help the skin absorb moisture from the body and skin surface, and also enhance the skin's long-term water retention ability. When hyaluronic acid absorbs water, elastic fibers and collagen are in a moist environment, so the skin is elastic. However, hyaluronic acid in the skin began to lose after the age of 25, leaving only 65% in infancy at the age of 30 and only 25% at the age of 60. The moisture of the skin will also lose its elasticity and luster with the loss of hyaluronic acid, and wrinkles will appear after a long time. To keep the skin moist and young, we must pay attention to the functions of blocking water loss, sun protection, hydrophilicity and moisture absorption. Hyaluronic acid has the benefits of the latter two. Hyaluronic acid must have enough water to use, so for dry skin, it is necessary to moisturize the skin first and add a blocking agent for water loss to have a good effect. The application of hyaluronic acid in plastic surgery is characterized by its insolubility, low metabolic rate, high water absorption, high water retention, and difficulty in tissue metastasis. Recently, the hot development is the application of hyaluronic acid in soft tissue augmentation. Hyaluronic acid, a tissue filler for injection, can often get good results when it is used to correct dermal scars left by trauma or acne. The combination of Botox and hyaluronic acid can be used to treat wrinkles around eyes and eyebrows. In addition, hyaluronic acid also plays a certain role in shaping the obvious lip and nose lines or lip and nose chin. However, before deciding the treatment policy, professional consultation must be conducted by qualified plastic or cosmetic surgeons. Some cases are not suitable for injection of hyaluronic acid, such as wrinkles caused by some skin lesions, irregular skin surface is too shallow, and the skin is too loose. Other more suitable treatment methods should be used. Generally speaking, the effect of hyaluronic acid injected into the body is about 6-9 months, but this is related to the different injection sites and personal physique. For example, when used for lip plastic surgery, it can last shorter than other facial parts. Hylan Gel (Hylan B, Hylaform) and Ial Syste are hyaluronic acid products available in the market at present.