Nicholas A. Franks

Bio: Nicholas A. Franks is an academic researcher from Brigham Young University. The author has contributed to research in topics: Extracellular matrix & Organoid. The author has an hindex of 1, co-authored 4 publications receiving 18 citations.

Biocompatible PEGDA Resin for 3D Printing.

Abstract: We report a non-cytotoxic resin compatible with and designed for use in custom high-resolution 3D printers that follow the design approach described in Gong et al., Lab Chip 17, 2899 (2017). The non-cytotoxic resin is based on a poly(ethylene glycol) diacrylate (PEGDA) monomer with avobenzone as the UV absorber instead of 2-nitrophenyl phenyl sulfide (NPS). Both NPS-PEGDA and avobenzone-PEGDA (A-PEGDA) resins were evaluated for cytotoxicity and cell adhesion. We show that NPS-PEGDA can be made effectively non-cytotoxic with a post-print 12-hour ethanol wash, and that A-PEGDA, as-printed, is effectively non-cytotoxic. 3D prints made with either resin do not support strong cell adhesion in their as-printed state; however, cell adhesion increases dramatically with a short plasma treatment. Using A-PEGDA, we demonstrate spheroid formation in ultra-low adhesion 3D printed wells, and cell migration from spheroids on plasma-treated adherent surfaces. Given that A-PEGDA can be 3D printed with high resolution, it has significant promise for a wide variety of cell-based applications using 3D printed microfluidic structures.

The ECM: To Scaffold, or Not to Scaffold, That Is the Question

Abstract: The extracellular matrix (ECM) has pleiotropic effects, ranging from cell adhesion to cell survival. In tissue engineering, the use of ECM and ECM-like scaffolds has separated the field into two distinct areas—scaffold-based and scaffold-free. Scaffold-free techniques are used in creating reproducible cell aggregates which have massive potential for high-throughput, reproducible drug screening and disease modeling. Though, the lack of ECM prevents certain cells from surviving and proliferating. Thus, tissue engineers use scaffolds to mimic the native ECM and produce organotypic models which show more reliability in disease modeling. However, scaffold-based techniques come at a trade-off of reproducibility and throughput. To bridge the tissue engineering dichotomy, we posit that finding novel ways to incorporate the ECM in scaffold-free cultures can synergize these two disparate techniques.

Vascular lung triculture organoid via soluble extracellular matrix suspension

Abstract: Scaffold-free tissue engineering is desired in creating consistently sized and shaped cell aggregates but has been limited to spheroid-like structure and function, thus restricting its use in accurate disease modeling. Here, we show formation of a viable lung organoid from epithelial, endothelial, and fibroblast stable cell lines in suspension culture supplemented with soluble concentrations of extracellular matrix proteins (ECM). We demonstrate the importance of soluble ECM in organotypic patterning with the emergence of air space-like gas exchange units, formation of branching, perfusable vasculature, and increased 3D growth. Our results show a dependent relationship between enhanced fibronectin fibril assembly and the incorporation of ECM in the organoid. Endothelial branching was found to depend on both soluble ECM and fibroblast. We successfully applied this technology in modeling lung fibrosis via bleomycin induction and test a potential antifibrotic drug in vitro while maintaining fundamental cell-cell interactions in lung tissue. Our human fluorescent lung organoid (hFLO) model accurately represents features of pulmonary fibrosis which were ameliorated by fasudil treatment. We demonstrate a 3D culture method with potential of creating organoids from mature cells, thus opening avenues for disease modeling and regenerative medicine, enhancing understanding of lung cell biology in health and lung disease.

An Improved Scalable Hydrogel Dish for Spheroid Culture.

Abstract: Research in fields studying cellular response to surface tension and mechanical forces necessitate cell culture tools with tunability of substrate stiffness. We created a scalable hydrogel dish design to facilitate scaffold-free formation of multiple spheroids in a single dish. Our novel design features inner and outer walls, allowing efficient media changes and downstream experiments. The design is easily scalable, accommodating varying numbers of microwells per plate. We report that non-adherent hydrogel stiffness affects spheroid morphology and compaction. We found that spheroid morphology and viability in our hydrogel dishes were comparable to commercially available Aggrewell™800 plates, with improved tunability of surface stiffness and imaging area. Device function was demonstrated with a migration assay using two investigational inhibitors against EMT. We successfully maintained primary-derived spheroids from murine and porcine lungs in the hydrogel dish. These features increase the ability to produce highly consistent cell aggregates for biological research.

Natural Hydrogel-Based Bio-Inks for 3D Bioprinting in Tissue Engineering: A Review

Abstract: Three-dimensional (3D) printing is well acknowledged to constitute an important technology in tissue engineering, largely due to the increasing global demand for organ replacement and tissue regeneration. In 3D bioprinting, which is a step ahead of 3D biomaterial printing, the ink employed is impregnated with cells, without compromising ink printability. This allows for immediate scaffold cellularization and generation of complex structures. The use of cell-laden inks or bio-inks provides the opportunity for enhanced cell differentiation for organ fabrication and regeneration. Recognizing the importance of such bio-inks, the current study comprehensively explores the state of the art of the utilization of bio-inks based on natural polymers (biopolymers), such as cellulose, agarose, alginate, decellularized matrix, in 3D bioprinting. Discussions regarding progress in bioprinting, techniques and approaches employed in the bioprinting of natural polymers, and limitations and prospects concerning future trends in human-scale tissue and organ fabrication are also presented.

Spatially and optically tailored 3D printing for highly miniaturized and integrated microfluidics.

Abstract: Traditional 3D printing based on Digital Light Processing Stereolithography (DLP-SL) is unnecessarily limiting as applied to microfluidic device fabrication, especially for high-resolution features. This limitation is due primarily to inherent tradeoffs between layer thickness, exposure time, material strength, and optical penetration that can be impossible to satisfy for microfluidic features. We introduce a generalized 3D printing process that significantly expands the accessible spatially distributed optical dose parameter space to enable the fabrication of much higher resolution 3D components without increasing the resolution of the 3D printer. Here we demonstrate component miniaturization in conjunction with a high degree of integration, including 15 μm × 15 μm valves and a 2.2 mm × 1.1 mm 10-stage 2-fold serial diluter. These results illustrate our approach’s promise to enable highly functional and compact microfluidic devices for a wide variety of biomolecular applications. The ever-growing need for highly functional, compact, and integrated microfluidic devices often incurs lengthy and expensive manufacturing processes. Here, authors introduce a generalized 3D printing process that enables fast parallel fabrication of miniaturized, high resolution 3D components.

Current and emerging trends in polymeric 3D printed microfluidic devices

Abstract: During the last two decades, 3D printing technology has emerged as a valid alternative for producing microfluidic devices. 3D printing introduces new strategies to obtain high precision microfluidic parts without complex tooling and equipment, making the production of microfluidic devices cheaper, faster, and easier than conventional fabrication methods such as soft lithography. Among the main 3D techniques used for this purpose, fused filament manufacturing (FFF), inkjet 3D printing (i3Dp) and vat polymerization (VP) are of the greatest interest since they are well-established techniques in the field and are cost-affordable both in equipment and material. However, there are still some barriers in terms of technology and materials to overtake for definitively establishing 3D printing as a truly microfluidic production method. For example, the level of resolution and precision of 3D printed microfluidic parts still does not reach the level of conventional fabrication techniques, and, from a materialistic point of view, few materials present the desired characteristics (e.g., biocompatibility, optical transparency, and mechanical properties) for target areas such as medicine, analytical chemistry, and pharmaceuticals. This review intends to evaluate and analyze the current state of polymeric 3D printing techniques and materials to manufacture microfluidic chips. The article will show and discuss the latest innovations, materials, and applications of such 3D printed microstructures. The focus of this review is to provide an overview of recent and future developments in 3D printing and materials in the branch of microfluidics fabrications, showing that the selection of the right materials together with the design freedom afforded by 3D printing will be the cornerstone for microfluidic development.