Identification of Synergistic Flow Characteristics in Microscale Rayleigh-Benard Convection to Enrich Biochemical Processes
Year: 2023
Type: dissertation
Abstract: Complex flow arising from microscale Rayleigh-Bénard convection can develop favorable physical conditions that can promote biochemical processes. The inherent complexity within small length scales in microchannels, however, remains undetermined requiring complex visualization setups or advanced simulation techniques to gain an in-depth understanding of these systems. Thus, the interplay between the flows and the corresponding biochemical processes that can be achieved in these systems remains unexplored. \nHydrothermal vents across the universe have gained tremendous interest as potential hotspots for prebiotic biochemical processes owing to the inherently rich biochemical environments and favorable physical conditions. Previous studies have shown the formation of protocell-like vesicles using infinite fatty acid precursors in regions mimicking thin cracks (d ≤ 200 µm) in the hydrothermal vents resulting in extreme thermal gradients (100-1000 °C/mm) [1, 2]. However, these pore sizes do not constitute the predominant volume fraction within hydrothermal vents and the fatty acid precursors studied do not constitute representative cell membrane components. Recent studies have shown that thermally actuated chaotic flows that exhibit complex and seemingly disruptive flow behaviors, although counterintuitive, are capable of accelerated transport and enhanced enrichment within these microenvironments [3]. Therefore, first, we aim to answer an unresolved question in the Origin of Life (OoL) theory by identifying inherent flow characteristics of convective systems, a dominant flow mechanism within hydrothermal vent pore systems, which can drive the assembly of protocell-like vesicles. Using a combination of experiments and simulations, we rationally evaluate and quantify optimally favorable 3-D chaotic flow fields with synergistic mechanisms of localized trapping and chaotic mixing that drive the assembly of micron-sized phosphatidylcholine vesicles, a primary cell membrane component. \nSubsequently, we aim to apply our comprehension of three-dimensional convective flows within microchannel systems to enhance our insights into these setups in the context of DNA replication through the polymerase chain reaction (PCR). Recent experimental investigations conducted in our laboratory have revealed a significant breakthrough: the potential to establish a microscale Rayleigh-Bénard convective polymerase chain reaction (PCR) system capable of achieving 100% repeatability. Additionally, these experiments have shed light on the correlation between varying repeatability levels and the GC content variation, highlighting an optimal value at 55% GC—notably higher than conventional suggestions. Therefore, using computational fluid dynamic simulations, we attempt to synchronize the PCR biochemistry with the computationally identified flow field characteristics to identify optimal conditions that achieve 100% repeatability. We also aim to understand the flow characteristics and thermal profiles of this optimal condition in-depth to identify a range of design states where the convective thermocycling functions optimally.
Author: Ravisankar, Vijay
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7047715917