Biomaterials 24 (2003) 4977–4985 Control of degradation rate and hydrophilicity in electrospun non-woven poly(d, l-lactide) nanofiber scaffolds for biomedical applications Kwangsok Kim a,b , Meiki Yu a , Xinhua Zong a , Jonathan Chiu c , Dufei Fang b , Young-Soo Seo d , Benjamin S. Hsiao a,c, *, Benjamin Chu a,c,d, *, Michael Hadjiargyrou c a Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400, USA b Stonybrook Technology & Applied Research, Inc., P.O. Box 1336, Stony Brook, NY 11790, USA c Department of Biomedical Engineering, State University of New York at Stony Brook, Stony Brook, NY 11794-8181, USA d Department of Materials Science and Engineering, State University of New York at Stony Brook, Stony Brook, NY 11794-2275, USA Received 2 October 2002; accepted 30 May 2003 Abstract Typical properties of poly(d,l-lactide) (PLA)-based scaffolds (films and foams), such as long degradation time, mechanical stiffness and hydrophobicity, are sometimes not suitable for biomedical applications. These properties can be substantially altered by electrospinning of PLA blends with miscible poly(lactide-co-glycolide) (PLGA) random copolymers, poly(lactide-b-ethylene glycol-b-lactide) (PLA-b-PEG-b-PLA) triblock copolymers, and a lactide (used as a hydrolytic catalyst). Electrospun scaffolds based on the multi-component PLA blends, comprised of randomly interconnected webs of sub-micron sized fibers, have a bulk density of 0.3–0.4 g/cm 3 . In this study, the concentration effects of PLA-b-PEG-b-PLA triblock copolymer and lactide on the cell proliferation and the hydrophilicity of electrospun scaffolds were investigated. Based on in vitro degradation study, we found that the electrospun scaffold having PLA (40 wt%), PLGA (LA/GA=50/50, 25 wt%), PLA-b-PEG-b-PLA (20 wt%), and lactide (15 wt%) underwent a rapid weight loss of B65% in 7 weeks. The hydrophobicity of this membrane, as determined by contact angle measurements in a cell buffer solution, decreased by B50% from 105  (of an electrospun PLA scaffold) to 50  . The selection of suitable chemical compositions in conjunction with the non-invasive electrospinning process is useful in the production of a new kind of biodegradable scaffolds suitable for different biomedical applications such as cell storage and delivery as well as prevention of post- surgical adhesion because of their porosity, mechanical flexibility and tunable biodegradability. r 2003 Elsevier Ltd. All rights reserved. Keywords: Electrospinning; Poly(lactide); Nanofiber; Degradation; Hydrophobicity; Cell scaffolds 1. Introduction Poly(lactide) (PLA) has been widely used in various biomedical applications [1–3] due to its biodegradabi- lity, biocompatibility, good mechanical properties and ability to be dissolved in common solvents for proces- sing. However, the processing of this material by conventional means (such as film casting and foaming) often imposes several limitations in the optimization of their final properties. (1) PLA possesses a slow biodegradation rate even in the non-crystalline form of poly(d,l-lactide) (PDLLA) (abbreviated as PLA from here on) as well as in enantiomeric semicrystalline forms of poly(d-lactide) (PDLA) and poly(l-lactide) (PLLA). Thus the degradation rate of the PLA-based materials may be too long for certain biomedical applications. (2) The PLA cast films are not suitable for cell scaffolding because they are not porous and cannot facilitate the transport of nutrients and oxygen to the cells. In addition, the cast films can be mechanically too brittle to be handled. (3) In the foam format, even though its morphology and porosity are suitable for tissue engi- neering [4], the hydrophobic nature of PLA can become a serious problem in a predominantly hydrophilic ARTICLE IN PRESS *Corresponding authors. Department of Chemistry, State Univer- sity of New York at Stony Brook, Stony Brook, NY 11794-3400, USA. Tel.: +1-631-632-7793 (B.S. Hsiao); +1-631-632-7928 (B. Chu); fax: +1-631-632-6518. E-mail addresses: bhsiao@notes.cc.sunysb.edu (B.S. Hsiao), bchu@notes.cc.sunysb.edu (B. Chu). 0142-9612/03/$ - see front matter r 2003 Elsevier Ltd. All rights reserved. doi:10.1016/S0142-9612(03)00407-1