Lactate-triggered shape adaptive scaffold for advanced bone tissue regeneration: Injectable applications

​Grant funding 2022-2024
Ministry of Education and Sciences

The idea of this project is to create a composite injectable biomaterial for better bone grafting and regeneration through the study of dynamically changing scaffold architecture on bone regeneration in-vivo. We will take the advantage of enzymatic cascaded reactions to initiate the polymerization after injection, allowing the material to take the form of the defect, dynamically generating macroporous support through hydrogel formation.

Conventional strategies for bone fracture repair include autografts, allografts, and other bone grafts. However, due to the donor-site morbidity, the integration of any bone graft substitution may be limited. Therfore, creation of superior bone graft substitutes has been at the center of medical research for the past decade. Injectable biomaterials provide the most advanced solution in the treatment of minor defects in bone regenerative medicine. Injection allows reaching the most hindered locations in the body without opening soft tissues and conducting complex surgeries, minimizing the risks of infections, and improving the overall treatment experience for the patient, shortening the post-surgery rehabilitation period.

Expected results:
Lactate-triggered bone graft formulation that has structural integrity and geometrical fidelity up to 6 weeks in the culture; has tunable degradation kinetics and mechanical properties; can form a viable tissue in-vitro; can be directly injected into the defect site surgery-free; can improve bone regeneration and support neovascularization in-vivo

Achieved results:
Variable formulations of the precursor with gelatin were prepared to find the most promising formulations. Intermolecular crosslinking under the influence of lactate in gelatin media with suitable rheological properties has been studied. For this, a tandem of several enzymes LOx or GOx and Cat were used. The kinetics of cascade reactions in a gelatin medium was studied using an electrochemical method using a potentiostat. The catalytic activity of glucose oxidase (GOx) was tested by observing the reduction of H2O2 on a Prussian blue (PB) electrode in the buffer by an enzymatic reaction. Electrochemical study of the catalytic parameters of the cascade enzyme reaction showed that the use of 1 mg/ml GOx and 1 mg/ml Cat allows you to determine the activity of both enzymes in approximately 4% wt./about. gelatin under stirring conditions. Experimentally optimized 1 mg/mL Cat showed a twofold decrease in reduction currents during continuous chronoamperometry (decrease from 40 to 20 µA), which indicates the detectable catalytic activity of both enzymes at these concentrations.