Development of 3D printed fibrillar collagen scaffold for tissue engineering

Abstract

Collagen is widely used in tissue engineering because it can be extracted in large quantities, and has excellent biocompatibility, good biodegradability, and weak antigenicity. In the present study, we isolated printable collagen from bovine Achilles tendon and examined the purity of the isolated collagen using sodium dodecyl sulfate polyacrylamide gel electrophoresis. The bands obtained corresponded to α, α and β chains with little contamination from other small proteins. Furthermore, rheological measurements of collagen dispersions (60 mg per ml of PBS) at pH 7 revealed values of viscosity of 35.62 ± 1.42 Pa s at shear rate of 10 s - 1 and a shear thinning behavior. Collagen gels and solutions can be used for building scaffolds by three-dimensional (3D) printing. After designing and fabricating a low-cost 3D printer we assayed the collagen printing and obtaining 3D printed scaffolds of collagen at pH 7. The porosity of the scaffold was 90.22% ± 0.88% and the swelling ratio was 1437% ± 146%. The microstructure of the scaffolds was studied using scanning electron microscopy, and a porous mesh of fibrillar collagen was observed. In addition, the 3D printed collagen scaffold was not cytotoxic with cell viability higher than 70% using Vero and NIH 3 T3 cells. In vitro evaluation using both cells lines demonstrated that the collagen scaffolds had the ability to support cell attachment and proliferation. Also a fibrillar collagen mesh was observed after two weeks of culture at 37 °C. Overall, these results are promising since they show the capability of the presented protocol to obtain printable fibrillar collagen at pH 7 and the potential of the printing technique for building low-cost biocompatible 3D plotted structures which maintained the fibrillar collagen structure after incubation in culture media without using additional strategies as crosslinking.

Microextrusion printing cell-laden networks of type I collagen with patterned fiber alignment and geometry

“…We show that collagen can be 3D printed while simultaneously controlling the spatial deposition, geometry, and alignment of the resulting fibrous network. Whereas several studies have 3D printed collagen inks [24][25][26][27][28] , we find that incorporating Matrigel into the ink allows us to print significantly lower concentrations of collagen (0.8 mg/ml). Our approach allows the collagen fiber geometry and orientation to be precisely analyzed throughout the volume of the printed construct.…”

Tissue mimetic hyaluronan bioink containing collagen fibers with controlled orientation modulating cell morphology and alignment

“…The shear thinning and viscosity behavior of high concentration neutralized Col (2-6% w/v) has been characterized by different groups [20,31]. In contrast, 3D printing of neutralized pure Col at low concentrations is challenging due to the lack of shear thinning and shape retention.…”

Electrobiofabrication: electrically based fabrication with biologically derived materials

“…As a major component of the ECM, collagen is integral to maintaining the structural integrity of the ECM, it provides sites for cell adhesion and spreading, and it continually undergoes re-modeling to refine cellular behavior and tissue function [267]. Collagen-based biomaterials have attracted great attention because they are intrinsically biocompatible, bioactive, biodegradable [268] and can be readily fabricated into a variety of forms, including 3D tissue engineering scaffolds using bottom-up approaches [269][270][271]. Often the motivation for fabricating with collagen is to recapitulate important features of tissue: the aligned and hierarchically organized structure ( figure 8(a)); and the molecular and mechanical cues that promote cell adhesion, ingrowth, proliferation and differentiation towards desired cell fates.…”