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Biology subjects

Akash, M. M. H.

Publications and source records attributed to Akash, M. M. H..

2 recordsLinked to original sources

Reduced-order modeling of solute transport within physiologically realistic solid tumor microenvironment

AO_SCPLOWBSTRACTC_SCPLOWSolid tumors are characterized by densely packed extracellular matrices and limited vascularization, creating significant resistance to both diffusive and convective transport. In this study, we developed an integration of numerical computations with a theoretical modeling framework that couples three phase viscous-laminar transient simulations of glycocalyx-patched tumor vessel resolving plasma, red blood cells (RBCs), and white blood cells (WBCs) and tracking their volume fractions to a calibrated reverse advection-diffusion (RAD) model for intratumoral plasma transport. The reduced-order tumor microenvironment model uses histology-informed extracellular matrix (ECM) tumor domain and packing fraction, together with explicit glycocalyx-patch electrohydrodynamics (EHD) at the tumor vessel wall. At the fenestra, EHD increases inlet plasma intensity relative to a non-EHD framework across all models (means: 0.576 non-EHD vs 0.722 EHD; gain 25.34%). Numerical simulations of plasma perfusion in both the tumor ECM domain and a microfluidic benchmark exhibit two-stage kinetics, with an initial advection-dominated regime. The RAD model reproduces this behavior and, after a simple temporal calibration to account for pore-scale hydrodynamic acceleration resolved by computational fluid dynamics (CFD), matches the observed propagation. By using fully resolved, EHD-inclusive multiphase CFD simulations to calibrate a reduced-order RAD model parameterized by measurable geometric features, we bridge the gap between classical Darcy-Starling tissue perfusion models and fully resolved CFD. The resulting framework provides a tractable, mechanism-grounded tool for quantifying plasma progression in dense solid tumors.

physiology↗

3D osteocyte networks under Pulsatile Unidirectional Fluid Flow Stimuli (PUFFS)

Although osteocytes are known to play a key role in skeletal mechano-adaptation, few in vitro models have investigated how pulsatile mechanical stimuli influence the properties of 3D osteocyte networks. Here we design and develop a microfluidic based in vitro model to study 3D osteocyte networks cultured under Pulsatile Unidirectional Fluid Flow Stimuli (PUFFS). Digital light projection stereolithography was used to design and fabricate a three-chambered PDMS microfluidic chip. Model osteocytes (murine MLO-Y4) were encapsulated in collagen matrix within the chip to form self-assembled three-dimensional (3D) cell networks. Daily stimulus in the form of PUFFS was then applied for upto 21 days. A combination of experiments, computational simulation and analytical modeling was used to characterize the mechanical environment experienced by embedded cells during PUFFS. Viability, morphology, cell-connectivity, expression of key proteins, and gene expression, and real-time calcium signaling within 3D osteocyte networks were characterized at select time-points and compared to static conditions. Results show that PUFFS stimulation at 0.33 and 1.66 Hz can initiate mechanotransduction via calcium signals that are propagated across the network of collagen encapsulated osteocytes via Cx43 junctions. Furthermore, osteocytes cultured in these devices maintain expression of several key osteocyte genes for up to 21d. Taken together, this model can potentially serve as a testbed to study how 3D osteocyte networks respond to dynamic mechanical stimulation relevant to skeletal tissues.

bioengineering↗