Elisseeff J, Anseth K, Sims D, McIntosh W, Randolph M, Langer R
Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology and Massachusetts Institute of Technology Department of Chemical Engineering, Cambridge, MA 02139, USA.
Proc Natl Acad Sci U S A. 1999 Mar 16;96(6):3104-7. doi: 10.1073/pnas.96.6.3104.
Photopolymerizations are widely used in medicine to create polymer networks for use in applications such as bone restorations and coatings for artificial implants. These photopolymerizations occur by directly exposing materials to light in "open" environments such as the oral cavity or during invasive procedures such as surgery. We hypothesized that light, which penetrates tissue including skin, could cause a photopolymerization indirectly. Liquid materials then could be injected s.c. and solidified by exposing the exterior surface of the skin to light. To test this hypothesis, the penetration of UVA and visible light through skin was studied. Modeling predicted the feasibility of transdermal polymerization with only 2 min of light exposure required to photopolymerize an implant underneath human skin. To establish the validity of these modeling studies, transdermal photopolymerization first was applied to tissue engineering by using "injectable" cartilage as a model system. Polymer/chondrocyte constructs were injected s.c. and transdermally photopolymerized. Implants harvested at 2, 4, and 7 weeks demonstrated collagen and proteoglycan production and histology with tissue structure comparable to native neocartilage. To further examine this phenomenon and test the applicability of transdermal photopolymerization for drug release devices, albumin, a model protein, was released for 1 week from photopolymerized hydrogels. With further study, transdermal photpolymerization potentially could be used to create a variety of new, minimally invasive surgical procedures in applications ranging from plastic and orthopedic surgery to tissue engineering and drug delivery.
光聚合反应在医学领域被广泛应用，用于制造聚合物网络，以用于诸如骨修复和人工植入物涂层等应用。这些光聚合反应是通过在“开放”环境（如口腔）或在诸如手术等侵入性操作过程中直接将材料暴露于光线下而发生的。我们推测，穿透包括皮肤在内的组织的光可能会间接引发光聚合反应。然后可以将液体材料皮下注射，并通过将皮肤外表面暴露于光线下使其固化。为了验证这一假设，研究了紫外线A和可见光透过皮肤的穿透情况。模型预测了经皮聚合的可行性，只需2分钟的光照就能使人体皮肤下的植入物发生光聚合反应。为了确定这些模型研究的有效性，首先将经皮光聚合应用于组织工程，以“可注射”软骨作为模型系统。将聚合物/软骨细胞构建体皮下注射并进行经皮光聚合。在2周、4周和7周时收获的植入物显示出胶原蛋白和蛋白聚糖的产生，并且组织学检查显示其组织结构与天然新软骨相当。为了进一步研究这一现象并测试经皮光聚合在药物释放装置中的适用性，从光聚合水凝胶中释放模型蛋白白蛋白1周。随着进一步的研究，经皮光聚合有可能用于创造各种新的微创手术，其应用范围从整形外科和矫形外科到组织工程和药物递送。
