Abstract：
Injectable hyaluronic acid (HA) hydrogels have been popularized in facial aesthetics as they provide a long-lasting effect, low risk of complications, allergenicity tests are not required before application and can be easily removed by the action of hyaluronidases. On the other hand, the development of these systems requires in-depth studies of chemical mechanisms involved in hydrogel formation. Ideal dermal fillers should temporarily fluidize during extrusion through the needle and quickly recover their original shape after application. Hydrogels with more elastic properties, for example, are difficult to inject while viscous materials are too liquid. A balance between both properties should be achieved. Each region of the face requires products with distinct rheological properties. High G\' dermal fillers are preferable for deeper wrinkles whereas the counterpart with lower values of G\' is more indicated in superficial wrinkles or lip augmentation. Factors such as molecular weight and concentration of HA, pH, type and concentration of the crosslinking agent, particle size, crosslinking reaction time and crosslinking agent/polysaccharide ratio should be modulated to achieve specific rheological properties. In this review, the effect of each variable is discussed in detail to guide the rational development of new dermal fillers.
摘要：
可注射透明质酸（HA）水凝胶已在面部美学中普及，因为它们提供了持久的效果，并发症风险低，在施用之前不需要变应原性测试,并且可以通过透明质酸酶的作用容易地去除。另一方面,这些系统的开发需要对水凝胶形成中涉及的化学机理进行深入研究。理想的真皮填充剂在通过针头挤出期间应暂时流化，并在施用后迅速恢复其原始形状。具有更多弹性特性的水凝胶，例如,很难注射，而粘性材料太液体。应该实现两种性质之间的平衡。面部的每个区域需要具有不同流变特性的产品。高G\'真皮填充物对于较深的皱纹是优选的，而具有较低G\'值的对应物更多地显示在浅表皱纹或嘴唇增大中。HA的分子量和浓度等因素，pH值,交联剂的类型和浓度，颗粒大小,应调节交联反应时间和交联剂/多糖比例以实现特定的流变性质。在这次审查中,详细讨论了各变量的影响，以指导合理开发新型真皮填充剂。
