Biology subjects

Aykar, S. S.

Publications and source records attributed to Aykar, S. S..

3 recordsLinked to original sources

bioRxiv2023

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

Lateral displacement of microparticles suspended in a viscoelastic fluid flowing through a microfluidic channel occurs due to an imbalance in the first (N1) and second (N2) normal stress differences. Here, we studied the lateral displacement of fluorescent microparticles suspended in a polyethylene glycol (PEG) solution in a two-phase flow with aqueous sodium alginate, flowing through a unique microfluidic device that manufactures microparticles seeded alginate-based hollow microfibers. Parameters such as concentration of the aqueous sodium alginate and flow rate ratios were optimized to enhance microparticle seeding density and minimize their loss to the collection bath. 4 % w/v aqueous sodium alginate was observed to confine the suspended microparticles within the hollow region of microfibers as compared to 2 % w/v. Moreover, the higher flow rate ratio of the core fluid, 250 L min-1 resulted in about 192 % increase in the microparticle seeding density as compared to its lower flow rate of 100 L min-1. The shear thinning index (m) was measured to be 0.91 for 2 % w/v and 0.75 for 4 % w/v sodium alginate solutions. These results help gain insights into understanding the microparticle displacement within a viscoelastic polymer solution flowing through a microfluidic channel and motivate further studies to investigate the cellular response with the optimized parameters.

bioengineering↗

bioRxiv2023

Human Brain Endothelial Cell Seeded on Inner Surface of Alginate Hollow Microfibers

Barrier functionality of the blood-brain barrier (BBB) is provided by the tight junctions formed by a monolayer of the human brain endothelial cells (HBECs) internally around the blood capillaries. To mimic such barrier functionality in vitro, replicating the hollow tubular structure of the BBB along with the HBECs monolayer on its inner surface is crucial. Here, we developed an invasive microfluidic technique to obtain the HBECs monolayer on the inner surface of alginate-based hollow microfibers. The HBECs were seeded on the inner surface of these microfibers using a custom-built microfluidic device. The seeded HBECs were monitored for 9 days after manufacturing and cultured to form a monolayer on the inner surface of the alginate hollow microfibers in the maintenance media. A higher cell seeding density of 217 cells/mm length of the hollow microfiber was obtained using our microfluidic technique. Moreover, high accuracy of around 96 % was obtained in seeding cells on the inner surface of alginate hollow microfibers. The microfluidic method illustrated in this study could be extrapolated to obtain a monolayer of different cell types on the inner surface of alginate hollow microfibers with cell-compatible ECM matrix proteins. Furthermore, it will enable us to mimic a range of microvascular systems in vitro by closely replicating the structural attributes of the native structure.

bioengineering↗

bioRxiv2022

Fabrication of Conductive Hollow Microfibers for Encapsulation of Astrocyte Cells

The manufacturing of 3D cell scaffoldings provides advantages for modeling diseases and injuries by physiologically relevant platforms. A triple-flow microfluidic device was developed to rapidly fabricate alginate/graphene hollow microfibers based on the gelation of alginate induced with CaCl2. This five-channel pattern actualized continuous mild fabrication of hollow fibers under an optimized flowing rate ratio of 300: 200: 100 L.min-1. The polymer solution was 2.5% alginate in 0.1% graphene, and a 30% polyethylene glycol solution was used as the sheath and core solutions. The morphology and physical properties of microstructures were investigated by scanning electron microscopy, electrochemical, and surface area analyzers. Subsequently, these conductive microfibers biocompatibility was studied by encapsulating mouse astrocyte cells within these scaffolds. The cells could successfully survive both the manufacturing process and prolonged encapsulation for up to 8 days. These unique 3D hollow scaffolds could significantly enhance the available surface area for nutrient transport to the cells. In addition, these conductive hollow scaffolds illustrated unique advantages such as 0.728 cm3.gr-1 porosity and twice more electrical conductivity in comparison to alginate scaffolds. The results confirm the potential of these scaffolds as a microenvironment that supports cell growth.

bioengineering↗