Design and Fabrication of an Automatable, 3D Printed Perfusion Device for Tissue Infusion and Perfusion Engineering.

Tissue decellularization for generating extracellular matrices has become a staple of regenerative medicine in the recent decades, extending from the research setting to clinical usage. Although methods and protocols for tissue decellularization are abundant throughout the literature, they can be time intensive and typically require specific overhead in terms of equipment. To reduce these barriers to entry, a functional and reproducible prototype of a tissue infusion/perfusion device (TIPD) has been designed and fabricated using three-dimensional printed parts in conjunction with commercially available components. This TIPD forms a system composed of two peristaltic pumps, two 3-way valves, and a chamber in which tissue is contained, and is controlled by user-customizable software. To increase repeatability among decellularization protocols, an automation function has been integrated into the software, which is able to specify fluid flow rates and define specific valve locations enabling selection of solutions to be introduced into a scaffold over the course of a decellularization process. The prototype has been tested for proof of concept through infusion and perfusion decellularization of skeletal muscle and intact kidneys, respectively, and has shown successful removal of cellular content while maintaining an intact ultrastructure. In an effort to increase the reproducibility of experimental designs and to promote an open source hardware initiative in the field of tissue engineering, a novel device was conceptualized and prototyped with printable part files made available for its fabrication in tandem with instructions for assembly. Impact Statement Repeatable methods for decellularization are essential for achieving consistent substrates between batches, laboratories, and facilities. To meet this end, an automatable tissue infusion/perfusion device composed of three-dimensional printed parts and commercially available components has been prototyped and tested. Materials and instructions for its assembly have been made available in an effort to reduce variability among equipment as well as to provide a platform on which to iterate open-source hardware in tissue engineering.

Adipose derived delivery vehicle for encapsulated adipogenic factors.

Hydrogels derived from adipose tissue extracellular matrix (AdECM) have shown potential in the ability to generate new adipose tissue in vivo. To further enhance adipogenesis, a composite adipose derived delivery system (CADDS) containing single- and double-walled dexamethasone encapsulated microspheres (SW and DW Dex MS) has been developed. Previously, our laboratory has published the use of Dex MS as an additive to enhance adipogenesis and angiogenesis in adipose tissue grafts. In the current work, AdECM and CADDS are extensively characterized, in addition to conducting in vitro cell culture analysis. Study results indicate the AdECM used for the CADDS has minimal cellular and lipid content allowing for gelation of its collagen structure under physiological conditions. Adipose-derived stem cell (ASC) culture studies confirmed biocompatibility with the CADDS, and adipogenesis was increased in experimental groups containing the hydrogel scaffold. In vitro studies of AdECM hydrogel containing microspheres demonstrated a controlled release of dexamethasone from SW and DW formulations. The delivery of Dex MS via an injectable hydrogel scaffold combines two biologically responsive components to develop a minimally, invasive, off-the-shelf biomaterial for adipose tissue engineering. STATEMENT OF SIGNIFICANCE: Scientists and doctors have yet to develop an off-the-shelf product for patients with soft tissue defects. Recently, the use of adipose derived extracellular matrix (adECM) to generate new adipose tissue in vivo has shown great promise but individually, adECM still has limitations in terms of volume and consistency. The current work introduces a novel composite off-the-shelf construct comprised of an adECM-based hydrogel and dexamethasone encapsulated microspheres (Dex MS). The hydrogel construct serves not only as an injectable protein-rich scaffold but also a delivery system for the Dex MS for non-invasive application to the defect site. The methods and results presented are a progressive step forward in the field of adipose tissue engineering.