Person:

Parker, Kevin

Organ chips can recapitulate organ-level (patho)physiology, yet pharmacokinetic and pharmacodynamic analyses require multi-organ systems linked by vascular perfusion. Here, we describe an ‘Interrogator’ employing liquid-handling robotics, custom software and an integrated mobile microscope for the automated culture, perfusion, medium addition, fluidic linking, sample collection and in situ microscopic imaging of up to 10 Organ Chips inside a standard tissue-culture incubator. The robotic interrogator maintained the viability and organ-specific functions of eight vascularized, two-channel organ chips (intestine, liver, kidney, heart, lung, skin, blood–brain barrier and brain) for 3 weeks in culture when intermittently fluidically coupled via a common blood substitute through their medium reservoirs and endothelium-lined vascular channels. We used the robotic interrogator and a physiological multi-compartmental reduced-order model of the experimental system to quantitatively predict the distribution of an inulin tracer perfused through the multi-organ Human-Body-on-Chips. The automated culture system allows for the imaging of cells in the organ chips, and for repeated sampling of both the vascular and interstitial compartments without compromising fluidic coupling.

Shape memory polymeric materials lack long-range molecular order enabling more controlled and efficient actuation mechanisms. Here, we develop a hierarchical structured keratin-based system that has long-range molecular order and shape memory properties in response to hydration. We explore the metastable reconfiguration of keratin secondary structure – alpha-helix-to-beta-sheet transition – as an actuation mechanism to design a high-strength shape memory material that is biocompatible and processable through fiber spinning and 3D printing. We extract keratin protofibrils from animal hair and subject them to shear stress to induce their self-organization into a nematic phase, which recapitulates the native hierarchical organization of the protein. This self-assembly process can be tuned to create materials with desired anisotropic structuring and responsiveness. Our combination of bottom-up assembly and top-down manufacturing allows for the scalable fabrication of strong and hierarchically structured shape memory fibers and 3D printed scaffolds with potential applications in bioengineering and smart textiles.

Food waste and food safety motivate the need for improved food packaging solutions. However, current films/coatings addressing these issues are often limited by inefficient release dynamics that require large quantities of active ingredients. Here, we developed antimicrobial pullulan fiber (APFs) based packaging that are biodegradable and capable of wrapping food substrates, increasing their longevity and food safety. APFs were spun using a high-throughput system termed focused rotary jet spinning (FRJS) with water as the only solvent, allowing the incorporation of nature-derived antimicrobial agents. Using avocados as a representative example, we demonstrate that APF-coated samples had their shelf life extended by inhibited proliferation of natural microflora, as well as reduced weight loss compared to uncoated control samples. This work offers a promising technique to produce scalable, low cost and environmentally friendly biodegradable antimicrobial packaging systems.

Helical alignments within the heart's musculature have been speculated to be important in achieving physiological pumping efficiencies. Testing this possibility is difficult, however, because it is challenging to reproduce the fine spatial features and complex structures of the heart's musculature using current techniques. Here we report focused rotary jet spinning (FRJS), an additive manufacturing approach that enables rapid fabrication of micro/nanofiber scaffolds with programmable alignments in three-dimensional geometries. Seeding these scaffolds with cardiomyocytes enabled the biofabrication of tissue-engineered ventricles, with helically aligned models displaying more uniform deformations, greater apical shortening, and increased ejection fractions compared with circumferential alignments. The ability of FRJS to control fiber arrangements in three dimensions offers a streamlined approach to fabricating tissues and organs, with this work demonstrating how helical architectures contribute to cardiac performance.