Porous hybrid structures based on P(DLLA‐co‐TMC) and collagen for tissue engineering of small‐diameter blood vessels

Abstract

Poly (D,L-lactide)-7co-(1,3-trimethylene carbonate) [P(DLLA-co-TMC)] (83 mol % DLLA) was used to produce matrices suitable for tissue engineering of small-diameter blood vessels. The copolymer was processed into tubular structures with a porosity of approximately 98% by melt spinning and fiber winding, thus obviating the need of organic solvents that may compromise subsequent cell culture. Unexpectedly, incubation in culture medium at 37 degrees C resulted in disconnection of the contact points between the polymer fibers. To improve the structural stability of these P(DLLA-co-TMC) scaffolds, a collagen microsponge was formed inside the pores of the synthetic matrix by dip coating and freeze drying. Hybrid structures with a porosity of 97% and an average pore size of 102 mum were obtained. Structural stability was preserved during incubation in culture medium at 37 degrees C. Smooth-muscle cells (SMCs) were seeded in these hybrid scaffolds and cultured under pulsatile flow conditions in a bioreactor (120 beats/min, 80-120 mmHg). After 7 days of culture in a dynamic environment viable SMCs were homogeneously distributed throughout the constructs, which were five times stronger and stiffer than noncultured scaffolds. Values for yield stress (2.8 +/- 0.6 MPa), stiffness (1.6 +/- 0.4 MPa), and yield strain (120% +/- 20%) were comparable to those of the human artery mesenterica.

3D printing of shape memory poly(d,l‐lactide‐co‐trimethylene carbonate) by direct ink writing for shape‐changing structures

“…Several studies have reported the fabrication of poly(DLLA‐ co ‐TMC) (abbreviated as PLMC) and the optimization of their thermal, physical, mechanical, and biodegradable properties by modulating the ratios of the monomers . In previous research, this copolymer with approximately 80 mol % of DLLA behaved well as biomaterial with high attachment and proliferation with human cells, displaying adequate material–cell interactions . However, the application of this biodegradable copolymer is far from fully exploited, as its intrinsic shape‐changing characteristics are rarely focused .…”

A hybrid small‐diameter tube fabricated from decellularized aortic intima‐media and electrospun fiber for artificial small‐diameter blood vessel

“…Potentially, such fibers can be produced by electrospinning, a powerful technique used to produce an array of biomaterials that mimic the pores, ridges, fibers, and other features in the natural extracellular matrix. [11][12][13][14][15][16] For example, electrospun segmented polyurethane is widely used in a variety of medical devices and experimental tissue engineering scaffolds to take advantage of an optimal combination of chemical and mechanical properties. [17][18][19][20] Indeed, segmented polyurethane also has potential as small-diameter blood vessels.…”

Dynamically vulcanized blends of polypropylene and ethylene octene copolymer: Influence of various coagents on thermal and rheological characteristics

“…Unfortunately, they show poor mechanical properties compared to synthetic degradable polymers and are most commonly used as coatings on biostable grafts. Several synthetic degradable polymers have been proposed, mainly aliphatic biodegradable polyesters like poly(lactic‐ co ‐glycolic acid) (PLGA),32, 33 poly(lactic acid) (PLA),34–37 but also polycarbonate derivatives38, 39 or polydioxanone,40 since they are already in use in some biomaterial and drug delivery applications. The main problem encountered with these synthetic biodegradable polymers is their rapid loss of mechanical properties, which is due to an accelerated in vivo biodegradation of the nanofibers as a direct consequence of their very high surface/ volume ratio.…”