Biodegradable Polymer Scaffolds with Well-Defined Interconnected Spherical Pore Network

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 microm) resulted in significantly lower compressive modulus than that of larger pore sizes (250-350 or 420-500 microm). 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.

Microporous bacterial cellulose as a potential scaffold for bone regeneration

“…Briefly, a 5% w/v polyvinyl alcohol (Sigma-Aldrich, St. Louis, MO) solution was heated to 90°C in a 2 l beaker and agitated with an impeller (1000-1200 rpm). Paraffin wax (Joel Svenssons Vaxfabrik, Ljungby, Sweden), that was melted at 90°C in a water bath, was sprayed into the PVA-solution with a syringe as described by Ma and Choi [17] The solution was then cooled by the addition of cold tap water to solidify the wax particles. The particles were collected, thoroughly rinsed with deionized water, and sieved to obtain a size range of 300-500 lm.…”

Biomimetic materials for tissue engineering

“…After the solvent removal, the sugar fiber assembly is dissolved away using water to achieve nanofibrous scaffolds with predesigned helicoidal tubular pore network (Figure 2 A&B). Similarly, we have combined a technique to generate inter-connected spherical pore network [92] with the nano-fiber techniques to fabricate nano-fibrous scaffolds with interconnected spherical macro pores (Figure 2 C&D) [93,94].…”

Hydroxyapatite coating on porous zirconia

“…The decrease of compressive strength due to increasing pore size was also found in porous polymers and porous metals. For example, Ma et al [9] noticed the increase of compressive modulus of porous poly (L-lactic acid) (PLLA) foam (94.5% porosity) with the decreases of pore size (from ~450 μm to ~300 μm). On the other hand, for porous magnesium foam (45% porosity), when pore size varied from 100 μm to 400 μm, the compressive strength changed from 16 MPa to 10 MPa [10].…”