3D-Printed pHEMA Materials for Topographical and Biochemical Modulation of Dorsal Root Ganglion Cell Response

Abstract

Understanding and controlling the interactions occurring between cells and engineered materials are central challenges towards progress in the development of biomedical devices. In this work, we describe materials for direct ink writing (DIW), an extrusion-based type of 3D printing, that embed a custom synthetic protein (RGD-PDL) within the microfilaments of 3D-hydrogel scaffolds to modify these interactions and differentially direct tissue-level organization of complex cell populations in vitro. The RGD-PDL is synthesized by modifying poly-D-lysine (PDL) to varying extents with peptides containing the integrin-binding motif Arg-Gly-Asp (RGD). Compositional gradients of the RGD-PDL presented by both patterned and thin-film poly-(2-hydroxyethyl) methacrylate (pHEMA) substrates allow the patterning of cell-growth compliance in a grayscale form. The surface chemistry-dependent guidance of cell growth on the RGD-PDL-modified pHEMA materials is demonstrated using a model NIH-3T3 fibroblast cell line. The formation of a more complex cellular system — organotypic primary murine dorsal root ganglion (DRG) – in culture is also achieved on these scaffolds, where distinctive forms of cell growth and migration guidance are seen depending on their RGD-PDL content and topography. This experimental platform for the study of physicochemical factors on the formation and the reorganization of organotypic cultures offers useful capabilities for studies in tissue engineering, regenerative medicine, and diagnostics.

3D‐Printed Hydrogel Composites for Predictive Temporal (4D) Cellular Organizations and Patterned Biogenic Mineralization

“…The current work extends our earlier studies, utilizing the ink formulation nomenclature deeply studied therein, and here providing a new set of materials chemistries that can afford effective means through which to control and spatially modulate growth compliance in 3D printed scaffolds. [9a,11] The new materials, conjoined with printing‐based capacities for grayscale patterning, provide impactful ways to control the temporal evolution of supported 3D microcultures—and offer supporting materials chemistry for biologically compliant 4DP. In biological cultures, the earlier described pHH‐i ink behaves as a blank slate material in that cells do not attach to it without a prior activating protein treatment, but for which there is no adverse material attribute that inhibits immediately adjacent cellular attachment, motility, and spreading.…”

“…In biological cultures, the earlier described pHH‐i ink behaves as a blank slate material in that cells do not attach to it without a prior activating protein treatment, but for which there is no adverse material attribute that inhibits immediately adjacent cellular attachment, motility, and spreading. [9a] In addition to this printable ink material, we previously described two compositionally distinct, yet closely related, pHH‐i‐based material compositions (pHH‐2 and pHH‐4; Table , ID2 and ID3) that are amenable to thin‐film preparations via spin‐casting. [9a] The two film compositions, following treatment with the cellular attachment mediator, poly‐ʟ‐lysine (PLL; 30k–70k MW), function as oppositional binaries for 3T3 and E1 cellular attachment outcomes, with growth positive conditions found for these cells on treated pHH‐2 and growth negative ones on pHH‐4.…”

Real-time halo correction in phase contrast imaging

“…However, we choose to use quantitative phase imaging[22] (QPI), which enables objective measurements of the phase shift in a reproducible, system-independent manner. Recently, such systems have found fertile ground in studies of cellular morphology[23-31], plate reader style screening of whole cell populations[24, 32-35], and histopathology sections[36, 37].…”

Nylon as an in vitro scaffold for three‐dimensional study of neural cells

“…Physical cues have been shown to affect the orientation of axon extension in axon guidance studies . Therefore, provisions of a larger volume within 3D cultures can allow for increased axon growth and monitoring of axon development and regeneration – .…”

“…5,6 Physical cues have been shown to affect the orientation of axon extension in axon guidance studies. 7,8 Therefore, provisions of a larger volume within 3D cultures can allow for increased axon growth and monitoring of axon development and regeneration. [9][10][11] Neurons specifically are dissimilar to other classes of cell in that they extend their processes over remarkable distances, often into 100 mm range in vitro.…”