Synthetic nano-scale fibrous extracellular matrix

Abstract

Biodegradable polymers have been widely used as scaffolding materials to regenerate new tissues. To mimic natural extracellular matrix architecture, a novel highly porous structure, which is a three-dimensional interconnected fibrous network with a fiber diameter ranging from 50 to 500 nm, has been created from biodegradable aliphatic polyesters in this work. A porosity as high as 98.5% has been achieved. These nano-fibrous matrices were prepared from the polymer solutions by a procedure involving thermally induced gelation, solvent exchange, and freeze-drying. The effects of polymer concentration, thermal annealing, solvent exchange, and freezing temperature before freeze-drying on the nano-scale structures were studied. In general, at a high gelation temperature, a platelet-like structure was formed. At a low gelation temperature, the nano-fibrous structure was formed. Under the conditions for nano-fibrous matrix formation, the average fiber diameter (160-170 nm) did not change statistically with polymer concentration or gelation temperature. The porosity decreased with polymer concentration. The mechanical properties (Young's modulus and tensile strength) increased with polymer concentration. A surface-to-volume ratio of the nano-fibrous matrices was two to three orders of magnitude higher than those of fibrous nonwoven fabrics fabricated with the textile technology or foams fabricated with a particulate-leaching technique. This synthetic analogue of natural extracellular matrix combined the advantages of synthetic biodegradable polymers and the nano-scale architecture of extracellular matrix, and may provide a better environment for cell attachment and function.

Biomimetic materials for tissue engineering

“…A novel phase separation technique has been developed in our laboratory to fabricate nano fibrous matrices from synthetic biodegradable polymers [89,90]. For example, PLLA solutions are thermally induced following a series of processes to phase separate.…”

“…For example, PLLA solutions are thermally induced following a series of processes to phase separate. The solvent is directly sublimated or first exchanged with a different solvent and then sublimated to fabricate the desired nano-fibrous matrices (Figure 1) [89]. However, these matrices themselves have similar limitations to those of a collagen matrix, self-assembled PA gel, or electrospun mat, lacking of inter-connected macro-pores.…”

Poly(ε-caprolactone)/keratin-based composite nanofibers for biomedical applications

“…1 In the last few years, the electrospinning technique has been recognized as an efficient technology, compared to others such as self-assembly, 2 phase separation, 3 drawing, 4 and template-directed synthesis, 5 that allows creation of polymer nanofibers, in the form of nonwoven mats, and that can be scaled up from laboratory to industrial production. In biomedical engineering, electrospun nanofibers exhibit a lot of advantages, particularly to produce scaffolds whose physicochemical properties can closely resemble the naturally occurring properties of the extracellular matrix (ECM) components found in tissues.…”

Development of Biodegradable Polyphosphazene- Nanohydroxyapatite Composite Nanofibers Via Electrospinning

“…These synthetic, biocompatible matrices should degrade within the body at a rate similar to the rate of tissue regeneration resulting in non-toxic degradation products [3]. Biodegradable polymeric nanofibers, due to their extremely high surface area, high aspect ratio and structural similarity to the ECM are generating considerable interest as scaffolds for tissue engineering [4].Various processes are currently being investigated to fabricate fibers with diameters in the nanometer range such as template synthesis, self assembly, drawing, phase separation and electrospinning [5]. Among these, the process of electrospinning seems to be very promising due to the ease of fabrication, reproducibility, control over the process and comparatively lower cost [6].…”