Bioinspired Design of Novel Microscaffolds for Fibroblast Guidance toward In Vitro Tissue Building

Porous microscaffolds (mu-scaffs) play a crucial role in modular tissue engineering as they control cell functions and guide hierarchical tissue formation toward building new functional tissue analogues. In the present study, we developed a new route to prepare porous polycaprolactone (PCL) mu-scaffs with a bioinspired trabecular structure that supported in vitro adhesion, growth, and biosynthesis of human dermal fibroblasts (HDFs). The method involved the use of poly(ethylene oxide) (PEO) as a biocompatible porogen and a fluidic emulsion/porogen leaching/particle coagulation process to obtain spherical mu-scaffs with controllable diameter and full pore interconnectivity. To achieve this objective, we investigated the effect of PEO concentration and the temperature of the coagulation bath on the mu-scaff architecture, while we modulated the mu-scaff diameter distribution by varying the PCL-PEO amount in the starting solution and changing the flow rate of the continuous phase (Q(CP)). mu-Scaff morphology, pore architecture, and diameter distribution were assessed using scanning electron microscopy (SEM) analysis, microcomputed tomography (microCT), and Image analysis. We reported that the selection of 60 wt % PEO concentration, together with a 4 degrees C coagulation bath temperature and ultrasound postprocessing, allowed for the design and fabrication of mu-scaff with porosity up to 80% and fully interconnected pores on both the mu-scaff surface and the core. Furthermore, mu-scaff diameter distributions were finely tuned in the 100-600 mu m range with the coefficient of variation lower than 5% by selecting the PCL-PEO concentration in the 1-10% w/v range and Q(CP) of either 8 or 18 mL/min. Finally, we investigated the capability of the HDF-seeded PCL mu-scaff to form hybrid (biological/synthetic) tissue in vitro. Cell culture tests demonstrated that PCL mu-scaff enabled HDF adhesion, proliferation, colonization, and collagen biosynthesis within inter- and intraparticle spaces and guided the formation of a large (centimeter-sized) viable tissue construct.

Automated summary

Porous microscaffolds play a crucial role in tissue engineering by controlling cell functions and guiding tissue formation. The study developed a new method to prepare porous PCL microscaffolds with a bioinspired structure, supporting the growth and biosynthesis of human dermal fibroblasts. By adjusting PEO concentration, coagulation bath temperature, and starting solution composition, the microscaffolds showed controllable diameter and interconnected pores, enabling the formation of hybrid tissue constructs in vitro.