Biology subjects

Montazami, R.

Publications and source records attributed to Montazami, R..

4 recordsLinked to original sources

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↗

bioRxiv2021

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

Engineering conductive 3D cell scaffoldings offer unique advantages towards the creation of physiologically relevant platforms with integrated real-time sensing capabilities. Toward this goal, rat dopaminergic neural cells were encapsulated into graphene-laden alginate microfibers using a microfluidic fiber fabrication approach, which is unmatched for creating continuous, highly tunable microfibers. Incorporating graphene increases the conductivity of the alginate microfibers 148%, creating a similar conductivity to native brain tissue. Graphene leads to an increase in the cross-sectional sizes and porosities of the fibers, while reducing the roughness of the fiber surface. The cell encapsulation procedure has an efficiency rate of 50%, and of those cells, approximately 30% remain for the entire 6-day observation period. To understand how encapsulation effects cell genetics, the genes IL-1{beta}, TH, TNF-, and TUBB-3 are analyzed, both after manufacturing and after encapsulation for six days. The manufacturing process and combination with alginate leads to an upregulation of TH, and the introduction of graphene further increases its levels; however, the inverse trend is true of TUBB-3. Long-term encapsulation shows continued upregulation of TH and of TNF-, and six-day exposure to graphene leads to the upregulation of TUBB-3 and IL-1{beta}, which indicates increased inflammation.

bioengineering↗

bioRxiv2020

How do neuroglial cells respond to ultrasound induced cavitation?

Reactive astrocytes are known to play a vital role in the overall response of the brain during a traumatic brain injury (TBI). Modern studies have speculated the existence of cavitation in the skull during a TBI, which has alarming potential to cause detrimental damages. Previous studies have confirmed the upregulation of various harmful genes in neurodegenerative diseases. Studying the longitudinal presence of these harmful genes in response to cavitation allows for optimized understanding and treatment methods in cavitation exposure. We seek to characterize the longitudinal genetic expression levels that astrocytes exhibit after exposure to cavitation and further elucidate the startling presence of cranial cavitation. Astrocytic expression levels of various common genes that have been documented in TBI research are our target of interest, like, TNF, IL-1{beta}, and NOS1. Results summarize specific gene trends from 1-48 hours after cavitation. Our data concludes that maximum expression is not consistently exhibited immediately after cavitation exposure, and most genes have individualized genetic trends. IL-1{beta} shows a decreasing expression over 48 hours, and TNF shows upregulation until the 6 hour time point but then begins to decrease in expression. The upregulation of NOS1 has been documented in neurodegenerative diseases, like Alzheimers and Parkinsons disease. This study has shown a consistent upregulation in NOS1 expression from 0-48 hours. These results postulate a possible linkage between cavitation damage and neurodegenerative diseases. This analysis also provides novelty in optimizing treatments for astrocytic function post-TBI and legitimizing the concern of cranial cavitation existence. These results add motivation for future studies of cavitation elimination or minimization via advanced helmet and airbag engineering.

bioengineering↗