Laser surface treatment of polymeric biomaterials for enhanced cell response

生物技术具有改善人们生活质量的潜力，尽管公众对此表示担忧，但它是解决许多未得到满足的临床需求的关键。生物技术可能是继信息技术之后的下一件大事。如今，英国生物技术市场价值45亿英镑。对未来5年市场增长的估计在10%到15%之间。许多人认为，这种增长是由越来越多地使用廉价和易于制造的高分子生物材料推动的。许多不同类型的高分子生物材料在医学上被用作植入物。它们的应用范围从面部假体到气管管，从肾脏和肝脏部件到心脏部件，从假牙到髋关节和膝关节。这种广泛的应用是因为它们可以很容易地制成多种形式：纤维；纺织品;薄膜和固体。聚合材料也可能与天然组织成分非常相似，这允许与其他物质直接结合。虽然高分子科学是一个快速发展的研究领域，但在生物和植入技术中遇到的最棘手的问题之一仍然是高分子生物材料的性能取决于其体积和表面特性。通常情况下，这些都是相互对照的，因为表面性能的适用性受到损害，有利于体积性能。使这种权衡更加复杂的是，在某些应用和某些情况下，高分子生物材料的表面特性根本不适合支持所需的生物活性水平。通常，由于缺乏与骨的直接结合，聚合生物材料植入装置在临床上经常失败；也就是说，生物整合（骨整合）不足。这意味着，除非聚合生物材料的表面可以改变为仿生（产生可以模仿自然生物表面的表面），并提供必要的生物活性水平，而不会对表面的性能产生有害影响，否则要么必须找到一种更昂贵的解决方案，要么必须搁置植入的想法——通常更昂贵的解决方案的成本太高，植入的想法被搁置。诺贝尔生物医药公司（Nobel Biocare Inc.，临床应用的“传声筒”）的研发经理Matts Andersson博士表示：要提高生物材料的性能，不能再通过从表面到整体的工作来实现；现在是时候把注意力集中在身体表面，开始指定向细胞发出信号的材料。如果没有一种有效的方法来改变高分子生物材料的表面特性，高分子生物材料在植入技术中的未来应用很可能会像今天一样。目前在生物技术领域工作的科学家可以选择的改变高分子生物材料的表面特性以增加生物相容性的方法非常有限。这就限制了生物技术市场的扩展范围，因为缺乏处理聚合生物材料表面的有效手段，限制了材料可应用的领域数量。为了提高生物相容性，现有的技术通常只改变表面特征的一个方面，比如粗糙度。另一方面，激光同时改变许多方面-其中一个方面是润湿性。润湿性在促进细胞粘附和生长中起着重要作用。先前对金属和陶瓷进行的研究表明，润湿性和生物相容性之间存在关系（表面具有增强的性能和更活跃）。该项目将重点研究和开发技术，利用红外和紫外激光改变选定的高分子生物材料的表面化学和形貌，以产生更具生物相容性的表面（具有增强的表面性能）

Biotechnology has the potential to improve people's quality of life and, despite public concerns, it holds the key to a number of unmet clinical needs. Biotechnology may be the next big thing after information technology. The UK biotechnology market is today worth 4.5 billion. Estimates of future growth in the market over the next five years range from 10 to 15%. Many see this growth being driven by the increased use of inexpensive and easy to manufacture polymeric biomaterials. Many different types of polymeric biomaterials are used in medicine as implants. Their applications range from facial prostheses to tracheal tubes, from kidney and liver parts to heart components, and from dentures to hip and knee joints. This wide variety of applications is because they can be easily fabricated into many forms: fibres; textiles; films and solids. Polymeric materials may also bear a close resemblance to natural tissue components, which allows for direct bonding with other substances.Although polymer science is a rapidly developing area of research, it remains that one of the most intractable problems encountered in bio and implant technology is that the performance of a polymeric biomaterial depends on the bulk and surface properties. More often than not these are in contrast to one another as the suitability of the surface properties is compromised in favour of the bulk properties. Compounding this trade-off is the fact that for certain applications and in certain instances the surface properties of the polymeric biomaterial are simply not suited to support sufficiently the level of bioactivity required. Typically, a polymeric biomaterial implant device will often fail clinically due to a lack of direct bonding with bone; that is, insufficient biointegration (osseointegration). This means that unless the surface of the polymeric biomaterial can be altered to become biomimetic (producing a surface that can mimic a natural biological surface) and provide the necessary level of bioactivity required without having a deleterious effect on the surface's performance, then either a generally more expensive solution has to be found or the implant idea will have to shelved - often the cost of the more expensive solution is too prohibitive and the implant idea is shelved. According to Dr. Matts Andersson, R&D Manager for Nobel Biocare Inc. (a 'sounding board' for clinical applications): No more can be done to improve a biomaterial's performance by working from the surface into the bulk; it is now time to concentrate on the surface to body to start to specify materials that signal to cells. Without an effective means of altering the surface properties of polymeric biomaterials the future uses of polymeric biomaterials in implant technology will likely remain as they are today.The options currently available to scientists working in the biotechnology field for altering the surface characteristics of polymeric biomaterials for increased biocompatibility are very limited. This places a limit on the extent to which the biotechnology market can expand because the lack of an effective means to treat the surface of polymeric biomaterials places a ceiling on the number of areas into which the materials can be applied. To improve biocompatibility, existing techniques typically only change one aspect of the surface characteristics, such as roughness. Lasers on the other hand change many aspects simultaneously - one such aspect is wettability. Wettability plays a significant role in promoting cell adhesion and growth. Previous work conducted with metals and ceramics revealed that there was a relationship between wettability and biocompatibility (the surface had enhanced properties and was more active). This project will focus on investigating and developing techniques to alter the surface chemistry and topography of selected polymeric biomaterials using IR and UV lasers to generate a more biocompatible surface (possessing enhanced surface propert