title: Control of protein adsorption on functionalized electrospun fibers.
abstract: Electrospun fibers that are protein resistant and functionalized with bioactive signals were produced by solution electrospinning amphiphilic block copolymers. Poly (ethylene glycol)-block-poly(D,L-lactide) (PEG-b-PDLLA) was synthesized in two steps, with a PEG segment of 10 kDa, while the PDLLA block ranged from 20 to 60 kDa. Depending on the PEG and PDLLA segment ratio, as well as solvent selection, the hydrophilicity and protein adsorption could be altered on the electrospun mesh. Furthermore, an alpha-acetal PEG-b-PDLLA was synthesized that allowed the conjugation of active molecules, resulting in surface functionalization of the electrospun fiber. Electrospun material with varying morphologies and diameter were electrospun from 10, 20, and 30 wt.% solutions. Sessile drop measurements showed a reduction in the contact angle from 120 degrees for pure poly(D,L-lactide) with increasing PEG/PDLLA ratio. All electrospun block PEG-b-PDLLA fibers had hydrophilic properties, with contact angles below 45 degrees . The fibers were collected onto six-arm star-poly(ethylene glycol) (star-PEG) coated silicon wafers and incubated with fluorescently labeled proteins. All PEG-b-PDLLA fibers showed no detectable adsorption of bovine serum albumin (BSA) independent of their composition while a dependence between hydrophobic block length was observed for streptavidin adsorption. Fibers of block copolymers with PDLLA blocks smaller than 39 kDa showed no adsorption of BSA or streptavidin, indicating good non-fouling properties. Fibers were surface functionalized with N(epsilon)-(+)-biotinyl-L-lysine (biocytin) or RGD peptide by attaching the molecule to the PEG block during synthesis. Protein adsorption measurements, and the controlled interaction of biocytin with fluorescently labeled streptavidin, showed that the electrospun fibers were both resistant to protein adsorption and are functionalized. Fibroblast adhesion was contrasting between the unfunctionalized and RGD-coupled electrospun fabrics, confirming that the surface of the fibers was functionalized. The PEG-b-PDLLA surface functionalized electrospun fibers are promising substrates for controlling cell-material interactions, particularly for tissue-engineering applications.
authors.affiliation: DWI e.V. and Institute of Technical and Macromolecular Chemistry, RWTH Aachen, Pauwelsstr. 8, D-52056 Aachen, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Grafahrend
authors.forename: Julia Lleixa
authors.initials: JL
authors.lastname: Calvet
authors.forename: Kristina
authors.initials: K
authors.lastname: Klinkhammer
authors.forename: Jochen
authors.initials: J
authors.lastname: Salber
authors.forename: Paul D
authors.initials: PD
authors.lastname: Dalton
authors.forename: Martin
authors.initials: M
authors.lastname: Möller
authors.forename: Doris
authors.initials: D
authors.lastname: Klee
mesh_terms: D000327:Adsorption; D008970:Molecular Weight; D011091:Polyesters / Q000737:chemistry / Q000378:metabolism*; D011092:Polyethylene Glycols / Q000737:chemistry / Q000378:metabolism*; D011108:Polymers / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism*
chemical_list: D011091:Polyesters; D011108:Polymers; D011506:Proteins; C507889:polylactide-polyethylene glycol-polylactide; D011092:Polyethylene Glycols