Biodegradable Polymer Scaffolds with Well-Defined Interconnected Spherical Pore Network

TLDR

Scaffolding is essential for tissue engineering. The study develops a novel method to produce 3‑D biodegradable polymer scaffolds with precisely controlled interconnected spherical pores. The method assembles heat‑bonded paraffin spheres, coats them with PLLA or PLGA, removes the paraffin, and tunes pore geometry and mechanical properties through fabrication parameters. Higher porosity and longer heat treatment reduce compressive modulus and enlarge pore openings, while smaller pore sizes lower modulus; PLLA foams show platelet skeletons and PLGA foams are homogeneous, illustrating the technique’s ability to tailor scaffold architecture and mechanics for tissue engineering.

Abstract

Scaffolding plays pivotal role in tissue engineering. In this work, a novel processing technique has been developed to create three-dimensional biodegradable polymer scaffolds with well-controlled interconnected spherical pores. Paraffin spheres were fabricated with a dispersion method, and were bonded together through a heat treatment to form a three-dimensional assembly in a mold. Biodegradable polymers such as PLLA and PLGA were dissolved in a solvent and cast onto the paraffin sphere assembly. After dissolving the paraffin, a porous polymer scaffold was formed. The fabrication parameters were studied in relation to the pore shape, interpore connectivity, pore wall morphology, and mechanical properties of the polymer scaffolds. The compressive modulus of the scaffolds decreased with increasing porosity. Longer heat treatment time of the paraffin spheres resulted in larger openings between the pores of the scaffolds. Foams of smaller pore size (100-200 μm) resulted in significantly lower compressive modulus than that of larger pore sizes (250-350 or 420-500 μm). The PLLA foams had a skeletal structure consisting of small platelets, whereas PLGA foams had homogeneous skeletal structure. The new processing technique can tailor the polymer scaffolds for a variety of potential tissue engineering applications because of the well-controlled architecture, interpore connectivity, and mechanical properties.