3D biodegradable shape changing composite scaffold with programmable porous structures for bone engineering

Abstract

This study developed a biodegradable composite porous polyurethane scaffold based on polycaprolactone and polyethylene glycol by sequential in-situ foaming salt leaching and freeze-drying process with responsive shape changing performance. Biomineral hydroxyapatite (HA) was introduced into the polyurethane matrix as inorganic fillers. Infrared spectroscopy results proved a successful synthesis, scanning electron microscopy showed that the scaffold’s porosity decreased with the addition of HA while the average pore size increased. X-ray diffraction and differential scanning calorimetry showed that the addition of HA lowered the melting point of the scaffold, resulting in a transition temperature close to the human body temperature. From the bending experiments, it could be demonstrated that PUHA20 has excellent shape memory performance with shape fixity ratio >98.9% and shape recovery ratio >96.2%. Interestingly, the shape-changing capacity could be influenced by the porous structures with variation of HA content. The shape recovery speed was further accelerated when the material was immersed in phosphate buffered saline at 37 °C. Additionally, in vitro mineralization experiments showed that the scaffold incorporating HA had good osteoconductivity, and implantation assessment proved that scaffolds had good in vivo biocompatibility. This scaffold is a promising candidate for implantation of bone defects.

Synergistic utilization of cost-effective glycerophosphate and biologically active zein for innovative minimally invasive smart thermo-responsive hydrogels for potential hard tissue engineering applications

“…The hydrogel's sol phase at room temperature is highly injectable, offering significant advantages for minimally invasive procedures. As depicted in figure 2(b), the hydrogel smoothly passes through needles of various gauges (16,18, and 21 G), enabling precise delivery to targeted areas within the body. This property obviates the need for extensive incisions, thereby streamlining surgical interventions.…”

“…HA incorporation in a composite biomaterial as a reinforcement notably improved its mechanical properties [14][15][16][17]. Incorporating HA and calcium phosphate as inorganic fillers in polyurethane scaffolds enhances their shape memory performance, mechanical properties, and osteoconductivity [18,19]. CS HGs demonstrated good osteoblast adhesion and remarkable potential for tissue regeneration applications [20][21][22].…”

Application of Shape Memory and Self-Healable Polymers/Composites in the Biomedical Field: A Review

“…It is also necessary to determine the recovery time. For this purpose, the time taken by a sample with a temporary shape to return to its permanent shape under the given stimulus is measured. − For example, Kang et al fabricated a thermally induced biobased poly­(butanediol/isosorbide/sebacate/itaconate) (PBISI) SMP. It exhibited elastomeric behavior above its T m and was deformed into a temporary shape.…”

Overcoming the Dilemma of In Vivo Stable Adhesion and Sustained Degradation by the Molecular Design of Polyurethane Adhesives for Bone Fracture Repair

“…[38] Studies have shown that the introduction of HA can enhance the mechanical properties and osteocompatibility of PUA simultaneously. [39] In this study, the influences of HA content on the mechanical properties of adhesive materials have been investigated through compression tests (Figure 3e). As shown in Figure 3f,g and Figure S4b (Supporting Information), the compressive strength and compressive modulus increased with the increase of the HA contents, up to 6 wt% HA followed by a sudden decrease.…”