Evaluation of Mechanical Properties of Porous Chitosan/Gelatin/Polycaprolactone Bone Scaffold Prepared by Microwave Foaming Method

Abstract

Bone tissue may suffer from bone injury and bone defects due to accidents or diseases. Since the demand for autologous bone and allograft tissue far exceeds the supply, bone scaffolds have taken the lead. The use of bone scaffolds is one of the measures to help heal or regenerate bone tissue. Therefore, a new bone scaffold was proposed in this study, which has a simpler preparation process and stronger performance. This study proposes bone scaffolds with an attempt to use polymers that are synthesized separately with three types of minerals as the filler using the microwave foaming method as follows. A 0.1 wt% of montmorillonite (MMT), zinc oxide (ZnO), or titanium dioxide (TiO2) is added to chitosan (CS)/gelatin mixtures, respectively, after which sodium bicarbonate is added as a foaming agent, thereby forming porous gels. The polymer synthesized from three minerals was used as filler. The following microwave foaming method was adopted: 0.1 wt% MMT, ZnO, or TiO2 was added to the CS/gelatin mixture, and then sodium bicarbonate was added as a foaming agent to form a porous gel. Next, porous gels and polycaprolactone were combined in a self-made mold in order to form bone scaffolds. A stereo microscope is used to observe the morphology of bone scaffolds, after which the pore size analysis, pore connectivity, swell property, porosity, and compressive strength are tested, examining the effects of the mineral type on bone scaffolds. The test results indicate that with MMT being the filler and sodium bicarbonate being the foaming agent, the resulting bone scaffolds yield a porous structure with a pore size between 120 μm and 370 μm. Besides, the incorporation of polycaprolactone also provides samples of 1MCG-P, 2MCG-P, and 5MCG-P with a certain compressive strength of 150–170 MPa. To sum up, the test results substantiate that a combination of the microwave foaming method and MMT generates a porous structure for bone scaffolds (1MCG-P, 2MCG-P, and 5MCG-P), involving a porosity of 38%, an inter-connected porous structure, and the compressive strength that exceeds 150 MPa.

3D-printed porous zinc scaffold combined with bioactive serum exosomes promotes bone defect repair in rabbit radius

“…The scaffold exhibits interconnected internal pores with a large pore size of approximately 500 micrometers and a porosity of 60–70%. This multi-level and porous structure, resembling natural cancellous bone, facilitates the infiltration, proliferation, and osteogenic differentiation of BMSCs, as well as enhances the inward growth of bone tissue to improve the integration of bone in the body [ 16 , 28 ]. Concurrently, zinc ions, as an essential trace element, play a crucial role in improving the cellular immune environment, accelerating bone regeneration, and inhibiting biofilm formation [ 29 ].…”

“…For instance, electrospinning technology can mimic the extracellular matrix structure to promote cell proliferation, but the mechanical performance of the scaffold is very low [ 14 , 15 ]. In contrast, freeze-drying and sintering techniques can produce scaffolds with good mechanical properties and porous structures, but the structure is not controllable [ 16 ]. To address the above issues, we propose the effective preparation of structurally controllable scaffolds using laser melting rapid prototyping technology [ 4 ].…”