# Functionalization Strategies and Fabrication of Solvent-Cast PLLA for Bioresorbable Stents  
[PERSON]  
1 Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Engineering, Technical University of Catalonia (UPC), EBEE, Av. [PERSON], 10-14, 08019 Barcelona, Spain; [EMAIL_ADDRESS](R.S. ); [EMAIL_ADDRESS](Y.R. ); [EMAIL_ADDRESS](C.C. ); [EMAIL_ADDRESS](C.C.) [PERSON]  
1 Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Engineering, Technical University of Catalonia (UPC), EBEE, Av. [PERSON], 10-14, 08019 Barcelona, Spain; [EMAIL_ADDRESS](R.S. ); [EMAIL_ADDRESS](Y.R. ); [EMAIL_ADDRESS](C.C. ); [EMAIL_ADDRESS](C.C.) [PERSON]  
1 Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Engineering, Technical University of Catalonia (UPC), EBEE, Av. [PERSON], 10-14, 08019 Barcelona, Spain; [EMAIL_ADDRESS](R.S. ); [EMAIL_ADDRESS](Y.R. ); [EMAIL_ADDRESS](C.C. ); [EMAIL_ADDRESS](C.C.) [PERSON]  
[PERSON]  
1 Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Engineering, Technical University of Catalonia (UPC), EBEE, Av. [PERSON], 10-14, 08019 Barcelona, Spain; [EMAIL_ADDRESS](R.S. ); [EMAIL_ADDRESS](Y.R. ); [EMAIL_ADDRESS](C.C. ); [EMAIL_ADDRESS](C.C.) [PERSON]  
5 Research Centre for Biomedical Engineering (CREB), UPC, 08019 Barcelona, Spain 5  
Ideally, poly(L-lactic acid) (PLLA) stents should maintain the artery widely open during the first months following implantation, are expected to degrade in a controlled manner and, finally, heal the vessel and restore the physiological function of the artery [6]. However, current PLLA BRS fail to reduce ISR and LST [7; 8; 9]. A strategy to reduce this complication could be to design new BRS surfaces that enhance re-endothelialization [10]. Surface modifications onto biomaterials are a common approach to control the biological response and can be classified into three main categories. First, topographical modifications that obtain specific nano- or micro-patterned surfaces can accelerate ECs migration [10; 11]. Second, physico-chemical modifications that generate suitable functional groups [12; 13] and/or modulate surface energy [14; 15] have demonstrated to modify ECs adhesion and spreading. Third, surface biofunctionalization by immobilizing specific biomolecules derived from extracellular matrix (ECM) proteins that have selectivity for ECs, could facilitate a cascade of biological events and eventually regenerate the damaged area with a functional endothelium [16; 17; 18]. A strong covalent bonding between the implant and the biomolecules is desired to obtain a stable biofunctionalization [19]. The most common chemical routes to obtain covalent bonding are the generation of functional groups at the surface, generally carboxyl (-COOH) or hydroxyl (-OH) groups, which react with a specific part of the biomolecule. Consequently, modifications that increase surface implant functional groups are of double interest since they can increase biocompatibility and enhance biofunctionalization. In that sense, surface treatments such as cold plasma treatment [20; 21; 22], ultraviolet irradiation [12], sodium hydroxide (NaOH) etching [23; 24], or ozone irradiation [13] have shown to ameliorate surface functionalization. Moreover, enzymatic treatments have been proposed and successfully used for the surface modification of natural and synthetic polymers [18; 25]. For polyesters, such as PLLA, the hydrolysis of the ester bond by applying cutinase enzymes generates new hydroxyl and carboxyl groups on the surface, which have been used to direct drug loading [26] or to bind serum albumin in order to increase biocompatibility [18]. Different activation treatments work differently on PLLA surfaces.