Behavior of Neural Cells Post Manufacturing and After Prolonged Encapsulation within Conductive Graphene‐Laden Alginate Microfibers

Abstract

While 3D cell cultures continue to grow in complexity and physiological relevance, more work must be done to reach the full potential of a real-time cell sensing system that is able to match the macro-and microenvironments of target tissues. 1D and 2D real-time sensors have been reliably created utilizing micro-and nano-electrodes, or planar electrodes, respectively. [1] This work furthers the cause by using biocompatible, graphene-laden microfibers as cellular constructs, which can be used in conjunction with 3D micro-electrode arrays for a highly complex real-time sensing system to analyze electrical cellto-cell communication that occurs within the brain. Additionally, this study works toward the important task of identifying genetic changes caused by manufacturing, and contrasting this against the effects of long-term encapsulation in four genes that are important to neural health, such as, tyrosine hydroxylase (TH), tubulin beta 3 class 3 (TUBB-3), interleukin 1 beta (IL-1β), and tumor necrosis factor alfa (TNF-α). Identifying the effects of manufacturing has been neglected in previous works, [2] and thus the current work provides a crucial understanding of the implications of using 3D cell cultures for tissue modeling.Hydrogels, with their high water content and the ease of diffusion across their borders, are ideal candidates for applications wherein the spatiotemporal properties of the cells must be controlled for long-term observation. [3] In particular, microfibers are well-suited for this purpose, as their higher surface-to-volume ratio expedites the diffusion of nutrients and waste across the cell border, while allowing for highly complex and specific scaffold geometries. [4,2,3b,3e,5] Cell-laden microfibers can be created in a number of different ways, including wetspinning/extrusion; [6] however, microfluidics provides unmatched control over the size, shape, and degredation rates of the resulting microfibers, while still allowing for all potential cell-safe gelation methods. [4,3h,7] In this way, a cell suspension might be mixed with a prepolymer solution before polymerization or gelation, thereby resulting in Engineering conductive 3D cell scaffoldings offer advantages toward the creation of physiologically relevant platforms with integrated real-time sensing capabilities. Dopaminergic neural cells are encapsulated into graphene-laden alginate microfibers using a microfluidic approach, which is unmatched for creating highly-tunable microfibers. Incorporating graphene increases the conductivity of the alginate microfibers by 148%, creating a similar conductivity to native brain tissue. The cell encapsulation procedure has an efficiency of 50%, and of those cells, ≈30% remain for the entire 6-day observation period. To understand how the microfluidic encapsulation affects cell genetics, tyrosine hydroxylase, tubulin beta 3 class 3, interleukin 1 beta, and tumor necrosis factor alfa are analyzed primarily with real-time reverse transcription-quantitative polymerase chain reaction and secondarily wi...

Efficiency enhancement of microparticles seeding density on the inner surface of polymer hollow microfibers using microfluidics

“…Lateral displacement of particles suspended in a fluid flowing through a microfluidic channel can be utilized in several applications such as cell sorting [1][2][3][4][5] , cell encapsulation [6][7][8][9][10][11][12][13][14] , sample preparation [15][16][17] , etc. The particle displacement in a microfluidic channel could be achieved by imposing active or utilizing passive forces depending on the type of associated particles and their corresponding applications.…”

Microfluidic Seeding of Cells on the Inner Surface of Alginate Hollow Microfibers

“…[16] Microfluidic fabrication of these microstructures has attracted researchers in the field of tissue engineering and organ-on-chips. [17][18][19][20][21][22] Microfluidic fabricated microfibers have made tremendous progress and can be used as scaffolds for different neural cells. [19] Microfluidic devices are powerful tools for diverse biomedical engineering applications and are second to none in creating continuous biocompatible hydrogel microfibers with tightly controlled cross-section dimensions and shapes.…”

Graphene Microelectrodes for Real-Time Impedance Spectroscopy of Neural Cells

“…16,17 There are numerous studies detailing neural attachment and the capability of graphene to mediate cell growth and proliferation. 18 Herein, it is desirable to create a layered microstructure through inkjet printing of the water-dispersed graphene to more effectively detect the induced damage in neural cells. The microfluidic deposition of graphene electrodes can provide texture cues that are favored by the cells.…”

“…They further demonstrated the stimulation of cardiomyocyte-like HL-1 cells and recorded the membrane potential using this interface. Among other carbon-based materials, graphene has received growing attention for biointerfacing within drug delivery, bioassays, biosensors, and biological tissue scaffolding for applications such as stem cell growth. , There are numerous studies detailing neural attachment and the capability of graphene to mediate cell growth and proliferation . Herein, it is desirable to create a layered microstructure through inkjet printing of the water-dispersed graphene to more effectively detect the induced damage in neural cells.…”