New poly(ester urea) derived from l-leucine: Electrospun scaffolds loaded with antibacterial drugs and enzymes

Abstract

Electrospun scaffolds from an amino acid containing poly(ester urea) (PEU) were developed as promising materials in the biomedical field and specifically in tissue engineering applications. The selected poly(ester urea) was obtained with a high yield and molecular weight by reaction of phosgene with a bis(α-aminoacyl)-α,ω-dioldiester monomer. The polymer having L-leucine, 1,6-hexanediol and carbonic acid units had a semicrystalline character and relatively high glass transition and melting temperatures. Furthermore it was highly soluble in most organic solvents, an interesting feature that facilitated the electrospinning process and the effective incorporation of drugs with bactericidal activity (e.g. biguanide derivatives such as clorhexidine and polyhexamethylenebiguanide) and enzymes (e.g. α-chymotrypsin) that accelerated the degradation process. Continuous micro/nanofibers were obtained under a wide range of processing conditions, being diameters of electrospun fibers dependent on the drug and solvent used. Poly(ester urea) samples were degradable in media containing lipases and proteinases but the degradation rate was highly dependent on the surface area, being specifically greater for scaffolds with respect to films. The high hydrophobicity of new scaffolds had repercussions on enzymatic degradability since different weight loss rates were found depending on how samples were exposed to the medium (e.g. forced or non-forced immersion). New scaffolds were biocompatible, as demonstrated by adhesion and proliferation assays performed with fibroblast and epithelial cells.

The miscibility and spatial distribution of the components in electrospun polymer–protein mats

“…49 However, some proteins withstand both denaturation factors and retain their functionality aer electrospinning. These proteins include insulin, 50 chondroitinase, 9 lysozyme, 51,52 chymotrypsin, 53,54 and others.…”

Antimicrobial Activity of Poly(ester urea) Electrospun Fibers Loaded with Bacteriophages

“…The polymer is characterized by a melting temperature of 114 • C, a glass transition temperature of 47 • C, and a tensile strength at yield, elongation at break, and Young's modulus of 21 MPa, 114%, and 622 MPa, respectively. Previous works indicated that the polymer could be electrospun into micro/nanofibers loaded with antibacterial drugs [36]. Furthermore, hybrid electrospun scaffolds constituted of a mixture poly(3-thiophene methyl acetate) and a copolymer based on 1L6 showed promising conductive and biodegradable properties [37].…”

Incorporation of chloramphenicol and captopril into poly(GL)‐b‐poly(GL‐co‐TMC‐co‐CL)‐b‐poly(GL) monofilar surgical sutures

“…Probably, electrospinning technique constitute an ideal process to render materials for the study of antibacterial properties due to its versatility and the ability to load agents with different characteristics and stability . Different examples can be mentioned concerning the load, release, biocompatibility and bactericide effect of these common biocides in both new and commercial biodegradable polymers.…”