Matrix Assisted Pulsed Laser Evaporation of Poly (D, L) Lactic Acid Films
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AA5.8.1
Matrix Assisted Pulsed Laser Evaporation of Poly (D, L) Lactic Acid Films Timothy M. Patz1, Anand Doraiswamy1, and Roger Narayan1 Nicola Menegazzo2, Christine Kranz2, and Boris Mizaikoff2 Rohit Modi3 and Douglas B. Chrisey3 1
Bioengineering Program and School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, USA 2 School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA 3 US Naval Research Laboratory, Washington, DC, USA ABSTRACT We have deposited poly (D, L lactic acid) (PDLLA) thin films using matrix assisted pulsed laser evaporation (MAPLE). FTIR spectroscopy revealed that the PDLLA had similar absorption bands to the dropcast material. X-ray photoelectron spectroscopy has shown that peaks corresponding to C-H, C-O and C=O represented 38.4, 30.1 and 31.4% of the C1s spectrum, respectively. XPS O1s analysis revealed that the O=C and O-C components make up 52 and 48 % of the O1s content. Atomic force microscopy revealed that MAPLE deposition provides smooth, continuous thin biomaterial films. These matrix assisted pulsed laser evaporation-deposited biomaterial thin films may serve to improve the implant/tissue interface. INTRODUCTION The implantation of synthetic materials is characterized by several vascular and cellular processes, including fibroblast proliferation, collagen synthesis, and blood vessel proliferation [1-2]. These events lead to the formation of an avascular connective tissue capsule that surrounds the implant. The connective tissue capsule consists of several different cellular layers, including an inner layer of macrophages, a concentric layer of fibrous tissue and fibroblasts (30–100 µm), and an outer vascularized tissue layer. This dense fibrous tissue retards the transport of low-molecular weight molecules (e.g., glucose) due to steric hindrance and increased diffusion path tortuosity. Steroidal antiinflammatory agents may serve to counter inflammation through release of vasoactive and chemoattractive factors, changes in the circulatory kinetics of leukocytes, alterations in the function of inflammatory cells, and modification of soluble mediators [3-5]. These anti-inflammatory actions must be provided during acute (24-48 hours) and chronic (1-2 weeks) phases of the inflammatory response in order to prevent encapsulation and ensure normal tissue growth. Long-term systemic use of steroids is not desirable. Individuals on systemic steroid therapy are more susceptible to viral, bacterial, and fungal infections. In addition, many side effects, including posterior subcapsular cataracts, glaucoma, and peptic ulcers, may result from systemic use of corticosteroids. Local, continuous, controlled release of steroids may serve to reduce systemic side effects and improve prevention inflammation at the implant/tissue interface. Matrix assisted pulsed laser evaporation (MAPLE) may be a useful technique for depositing biodegradable
AA5.8.2
polymer/anti-inflammatory agent multilayer coatings for preventing inflammation at the impla
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