A thermosensitive poly(organophosphazene) hydrogel for injectable tissue-engineering applications

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Polymer Chemistry

Background:

• Poly(organophosphazene) hydrogels exhibit thermoreversible sol-gel properties.
• These hydrogels can form strong gels at body temperature (10 wt% solutions).
• Their potential as injectable tissue-engineering matrices requires in vivo evaluation.

Purpose of the Study:

• To evaluate the efficacy of a poly(organophosphazene) hydrogel as an injectable tissue-engineering matrix in vivo.
• To determine optimal conditions for subcutaneous injection regarding cell number and collagen concentration.
• To assess the impact of collagen on cell proliferation within the hydrogel matrix.

Main Methods:

• A 10 wt% poly(organophosphazene) solution containing MC3T3-E1 cells and collagen was injected subcutaneously into nude mice.
• Various cell numbers and collagen concentrations (0.001-0.1 wt%) were tested.
• Cellular proliferation was monitored over 7 days.

Main Results:

• Cellular proliferation was dependent on collagen concentration and cell number.
• Optimal proliferation occurred at 0.01 wt% collagen and (2-10) x 10^5 cells.
• Significant enhancement of MC3T3-E1 cell proliferation was observed in the presence of collagen, unlike in the hydrogel alone.

Conclusions:

• Poly(organophosphazene) hydrogels are suitable injectable matrices for tissue engineering.
• Collagen incorporation is crucial for enhancing cell proliferation within the hydrogel.
• This composite material shows promise for in vivo applications in regenerative medicine.