Poster P3 - 3D-printed polymeric microchambers as a Materiobiology Platform for Studying the biological response of Stem Cells

Friday, October 25, 2024

3:30 PM - 4:30 PM EST

Location: Exhibit Hall E, F & G

Presenting Author(s)

Jenise Jones-Coleman

Lab Assistant
Alabama State University
Montgomery, Alabama, United States

Co-Author(s)

Amrita Natarajan, PhD

Postdoctoral Fellow
Alabama State University
MONTGOMERY, Alabama, United States
DD

Derrick Dean

Professor of Biomedical Engineering
Alabama State University, United States

Primary Investigator(s)

VINEETH VIIJAYAN, PhD

Assistant Professor of Biomedical Engineering
Alabama State University, United States

Introduction: Materiobiology is the systematic study of the interaction of biomaterials with cells which can provide valuable information on designing biomaterials for different applications. Different biomaterial properties such as surface coatings, nano-micro topography, and mechanical strength influence the cell response. Stem cells have a unique potential to differentiate into different lineages upon interaction with biomaterials. However, the process of interaction of stem cells with biomaterials is complex and needs a systematic platform to unravel the interactions reliably. Surface properties of biomaterials such as biomimetics surface coating and nano/microlevel topography are reported to be the most important factors controlling the stem cells' fate. Among the different surface coatings, polydopamine is a sea mussel-inspired surface coating found to enhance the response of stem cells on biomaterials. However, the coating of PDA on hydrophobic materials like polymers takes long time (24h) to deposit a uniform surface coating.

In the present study, we aim to design a polymeric microchamber platform that combines polydopamine coatings and microtopography (groove structure) to be used as a materiobiology platform to study the stem cell response. We anticipate that this materiobiology platform based on a combination of 3D printing and plasma surface modification can be used to reliably study the materiobiology response of stem cells.

Materials and

Methods: CreatorMax flashforge printer was used for the 3D printing. Specifically, we generated two distinct surface patterns, the honeycomb and triangle patterns, with infill densities ranging from 40% to 70% and base layer thicknesses from 2 to 5 layers. The 3D microchambers were plasma treated using a PlasmaFlo PDC-FMG on high initially for 10 minutes in atmospheric air plasma condition followed by PDA coating (2mg/ml). Our samples (honeycomb and triangle patterned microchambers) were thus grouped as templates alone/control (no coating), templates underwent plasma treatment only, templates underwent PDA coating only or a combination of polydopamine (PDA) coating and plasma treatment to enhance surface properties. To evaluate the surface characteristics and grooving at the base of microchambers, we utilized a Moticam 2.0 MP USB camera stereoscopic microscope. For invitro cell studies, the microchambers were subsequently loaded with Bone marrow derived Mesenchymal Stem Cells (BM-MSCs) (cell suspension containing 3.25x 105 cells/ 100 µl) of passage 3 after initial conditioning with cell culture medium (DMEM-HG +10% FBS+1% ABAM) for 3hrs. The cells were further cultured for 72hrs at 37o C, 5% CO2 in a humidified chamber. To study the cytoskeletal organization, confocal microscopy was used to capture detailed 3D images of cell seeded templates. The actin filaments were visualized by using Alexa fluor 488 Phalloidin stain.

Results, Conclusions, and Discussions: We developed a strategy for engineering a materiobiology platform for reliably studying the response of Mesenchymal stem cells within 3D-printed polymeric microchambers. As surface coatings and topography influence the response of stem cell behavior. We have attempted to modulate PDA coating and microtopography (groove structures) on the microchambers. The microtopography was modulated by 3D printing the microchambers with different infill densities (50, 60, 70%) and base layer thickness (3 and 4). Meanwhile, the PDA coating was modulated by using the low-temperature air plasma treatment on PLA microchambers before the dopamine polymerization. It was expected that the plasma surface treatment will increase the surface energy of the microchambers which can improve the coating efficiency of PDA on hydrophobic PLA microchambers. The Stereo microscopy imaging analysis revealed that honeycomb and triangle shaped microchambers within a single platform are consistent among each infill density. Moreover, distinct repeated ridges and grooves are observed on the base layer of each chamber fabricated at different infill densities and varying base layers, which may influence the microtopography/grooving on the surface of the microchambers (Figure 1). Plasma surface modification was found to improve the uniformity of the PDA coating on the microchambers as evident from the stereo light microscopy imaging (Figure 2). As a preliminary attempt to study the stem cell response, we compared the attachment of Mesenchymal Stem Cells (MSCs) on the surface of the PDA coated and non-coated honeycomb microchamber. The confocal microscopic images of actin staining at 72h highlighted significantly higher attachment of MSCs and well-organized cytoskeletal structures for the PDA-coated microchambers in comparison with the non-coated microchambers. This indicated the positive impact of the architecture and PDA coating on the stem cell attachment. More detailed and in-depth studies are needed to better elucidate the response of the stem cells under different conditions in the microchambers. We aim to conduct more systematic testing such as comparing the different thickness groove structure microchambers with and without PDA coating.

Acknowledgements (Optional): Authors thank the National Science Foundation RUI Grant # 2330023