A bioprintable form of chitosan hydrogel for bone tissue engineering

Abstract

Bioprinting can be defined as 3D patterning of living cells and other biologics by filling and assembling them using a computer-aided layer-by-layer deposition approach to fabricate living tissue and organ analogs for tissue engineering. The presence of cells within the ink to use a 'bio-ink' presents the potential to print 3D structures that can be implanted or printed into damaged/diseased bone tissue to promote highly controlled cell-based regeneration and remineralization of bone. In this study, it was shown for the first time that chitosan solution and its composite with nanostructured bone-like hydroxyapatite (HA) can be mixed with cells and printed successfully. MC3T3-E1 pre-osteoblast cell laden chitosan and chitosan-HA hydrogels, which were printed with the use of an extruder-based bioprinter, were characterized by comparing these hydrogels to alginate and alginate-HA hydrogels. Rheological analysis showed that all groups had viscoelastic properties. It was also shown that under simulated physiological conditions, chitosan and chitosan-HA hydrogels were stable. Also, the viscosity values of the bio-solutions were in an applicable range to be used in 3D bio-printers. Cell viability and proliferation analyses documented that after printing with bio-solutions, cells continued to be viable in all groups. It was observed that cells printed within chitosan-HA composite hydrogel had peak expression levels for early and late stages osteogenic markers. It was concluded that cells within chitosan and chitosan-HA hydrogels had mineralized and differentiated osteogenically after 21 days of culture. It was also discovered that chitosan is superior to alginate, which is the most widely used solution preferred in bioprinting systems, in terms of cell proliferation and differentiation. Thus, applicability and printability of chitosan as a bio-printing solution were clearly demonstrated. Furthermore, it was proven that the presence of bone-like nanostructured HA in alginate and chitosan hydrogels improved cell viability, proliferation and osteogenic differentiation.

Synthesis and characterization of osteoinductive visible light‐activated adhesive composites with antimicrobial properties

“…Previous groups have demonstrated the ability of growth factors such as BMP‐2 to induce osteogenic differentiation of MC3T3‐M1 cells in vitro (Ogasawara et al, ). Alternatively, other groups have explored the encapsulation of MC3T3‐M1 cells into polymeric hydrogels with embedded bioactive cues such as nanostructured bone‐like HA (Demirtas, Irmak, & Gumusderelioglu, ), inorganic polyphosphate chains (Wu et al, ), and different types of BGs (Marelli et al, ; Zeng, Han, Li, & Chang, ). Here, we hypothesized that the incorporation of BG‐5/5 into GelMA hydrogels could yield a highly cytocompatible matrix with intrinsic osteogenic activity.…”

Incorporation of Conductive Materials into Hydrogels for Tissue Engineering Applications

“…Biological evaluation also showed a spread of PC12 cells on the conductive hydrogel, which was confirmed by the strong neurite outgrowth of cells on the conductive hydrogel induced during the differentiation process after growth factor treatment. A polyurethane hybrid composite was devised using PSS doped PEDOT and liquid crystal GO, a polyether-based liner polyurethane and the conductive hydrogel obtained high biocompatibility, conductivity, and flexibility [172]. The synthesized polyurethane hybrid composite conductive hydrogel showed 10-times higher conductivity, 1.6-times higher tensile modulus, and 1.56-times the yield strength than a control group.…”

3D printing of hydrogel composite systems: Recent advances in technology for tissue engineering

“…Various sizes of HAp particles from nano to micro scale were dispersed in hydrogels and printed as bone substitute scaffolds. Demirtas et al printed chitosan-HA hydrogels using a 3D plotting method and compared them with alginate-HAp hydrogels [104] . With the addition of about 180 nm HAp particles, elastic modulus of alginateHAp hydrogels and chitosan-HAp hydrogels increased approximately 3-and-5 fold compare to pure alginate and chitosan hydrogels.…”