Extracellular Matrix-Modified Fiber Scaffolds as a Proadipogenic Mesenchymal Stromal Cell Delivery Platform

Melt electrowriting (MEW) is an additive manufacturing technology that produces readily handleable fibrous scaffolds with controlled geometry to support cell infiltration. Although MEW scaffolds have excellent potential for cell delivery in regenerative medicine applications, studies to date have primarily focused on polymers such as poly(ε-caprolactone) (PCL) that lack bioactive cues to affect cell function. To address this aspect, MEW scaffolds with extracellular matrix (ECM) coatings were developed as a proadipogenic platform for human mesenchymal stromal cells (hMSCs). More specifically, highly flexible PCL scaffolds fabricated through MEW were coated with a complex ECM suspension prepared from human decellularized adipose tissue (DAT), purified fibronectin, or laminin to determine the effects of two key bioactive proteins present within adipose-derived ECM. In vitro studies exploring the response of human bone marrow-derived mesenchymal stromal cells cultured under adipogenic differentiation conditions indicated a high level of differentiation on all substrates studied, including unmodified PCL scaffolds and two-dimensional controls. To more fully assess the intrinsic proadipogenic capacity of the composite biomaterials, a modified culture regime was established that involved a short-term adipogenic induction in differentiation medium, followed by continued culture in maintenance medium supplemented with insulin for up to 3 weeks. Under these conditions, adipogenic differentiation was enhanced on all fiber scaffolds as compared to the tissue culture controls. Notably, the highest adipogenic response was consistently observed on the PCL + DAT scaffolds, based on the analysis of multiple markers including adipogenic gene [lipoprotein lipase, fatty acid binding protein 4 (FABP4), adiponectin, perilipin 1] and protein (FABP4, leptin) expression and intracellular triglyceride accumulation. Taken together, the PCL scaffolds incorporating DAT provide an adipoinductive microenvironment for the hMSCs, with particular applicability of this cell-instructive delivery platform for applications in plastic and reconstructive surgery.