Laser Modification of Surface Crystallinity of Biodegradable Polymers

生物可降解聚合物表面结晶度的激光改性

• 批准号: 1030536
• 负责人: Y Lawrence Yao
• 金额: $ 30万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1030536&HistoricalAwards=false
• 关键词: Laser; Modification; Surface; Crystallinity; Biodegradable

This grant provides funding for investigating laser modifying the surface crystallinity of biodegradable polymers. Thermal processes, including rapid melting at the surface and subsequent high quench rates, in pulsed laser irradiation in conjunction with slow crystallization kinetics of the polymers produce a surface layer with reduced crystallinity. Since hydrolytic degradation rates are a strong function of polymer crystallinity, the process can be utilized to alter degradation profiles of such polymers. The project will focus on poly (a-hydroxy acid) polymers, especially poly (L-lactide) (PLLA), as they are USFDA approved, are crystalline if solvent cast, and have desirable mechanical properties. Depth profiling of crystallinity and degradation testing will be conducted to relate changes along the depth with mass loss measurements. Effects of laser processing parameters on chemical and molecular weight changes will be investigated. Primary characterizations include Differential Scanning Calorimetry (DSC), Wide Angle X-ray Diffractometer, and Fourier Transform Infrared spectroscopy in Attenuated Total Reflectance (FTIR-ATR). Numerical models will incorporate heat transfer with microstructure evolution to predict degradation, weight loss and erosion rate.If successful, the technology could impact a wide range of applications such as fixation devices, sutures, tissue engineering, drug delivery, pesticide dissemination, and packaging. In particular, drug delivery systems based on bulk eroding polymers can benefit from the ability of designing a desirable degradation profile and thus a controlled drug releasing profile. In conjunction with optimum device shape and size design, the technology can potentially help tailor drug release rates in delivery devices to enable desired therapeutic effects. Significantly advanced understanding of laser processing of homopolymer PLLA, will provide insight into laser interactions with other semicrystalline biodegradable copolymers.

该赠款为研究激光改性可生物降解聚合物的表面结晶度提供资金。 脉冲激光照射中的热过程，包括表面的快速熔化和随后的高淬火速率，与聚合物的缓慢结晶动力学相结合，产生结晶度降低的表面层。由于水解降解速率是聚合物结晶度的重要函数，因此该过程可用于改变此类聚合物的降解曲线。该项目将重点关注聚（α-羟基酸）聚合物，尤其是聚（L-丙交酯）（PLLA），因为它们已获得美国食品和药物管理局（FDA）批准，如果采用溶剂浇铸，则为结晶态，并且具有理想的机械性能。 将进行结晶度的深度分析和降解测试，以将沿深度的变化与质量损失测量联系起来。 将研究激光加工参数对化学和分子量变化的影响。 主要表征包括差示扫描量热法 (DSC)、广角 X 射线衍射仪和衰减全反射傅里叶变换红外光谱 (FTIR-ATR)。数值模型将传热与微观结构演化相结合，以预测降解、重量损失和侵蚀率。如果成功，该技术可能会影响广泛的应用，例如固定装置、缝合线、组织工程、药物输送、农药传播和包装。 特别地，基于本体侵蚀聚合物的药物递送系统可以受益于设计期望的降解曲线并因此控制药物释放曲线的能力。 结合最佳的设备形状和尺寸设计，该技术可以帮助调整输送设备中的药物释放速率，以实现所需的治疗效果。 对均聚物 PLLA 激光加工的深入了解，将有助于深入了解激光与其他半结晶可生物降解共聚物的相互作用。