Biology subjects

Olanrewaju, A.

Publications and source records attributed to Olanrewaju, A..

5 recordsLinked to original sources

bioRxiv2026

From Fabrication to Flow: Impact of Print Orientation on Surface Qualities and Capillary-Driven Flow in Laser SLA-based Open Microchannels

Stereolithography (SLA) 3D printing has become increasingly popular for fabricating microfluidic devices, with applications including hydrogel patterning and tissue modeling. In open-channel systems with surface tension-driven flow, 3D-printer-induced discrepancies in channel surface texture can significantly impact fluid flow and device performance. While previous work has focused on comparing different 3D printing methods for microchannel fabrication, the effect of device orientation during SLA printing on microchannel morphology and capillary-driven flow has not been systematically evaluated. Furthermore, there is minimal research elucidating the influence of channel surface texture on the flow of biologically relevant hydrogel precursors commonly used in organ-on-a-chip applications. Herein, we investigated the impact of print orientation on channel morphology, fluid wetting behavior, and fluid flow by comparing laser SLA-based parts where the length of the channel was tilted at 0{degrees}, 15{degrees}, 45{degrees}, or 90{degrees} during printing. We demonstrated that channel floor surface texture is greatly affected by print orientation: the highest axial surface roughness was measured in 15{degrees} printed channels, and the highest axial surface tortuosity-which describes the real length along the surface-was measured in 45{degrees} printed channels. Print angles of 15{degrees} and 45{degrees} also resulted in asymmetric roughness of the channel floor, which caused asymmetric wetting of glycerol solution. Surface tension-driven flow of glycerol solution, agarose precursor solution, and collagen precursor solution was affected by print orientation, in which the 45{degrees} printed flow devices had slowest flow for all test fluids. Root mean square roughness was not a reliable predictor of slower flow; instead, surface tortuosity should be considered. Potential alternatives to better theoretically model how print angle-induced surface texture affects open-channel flow are discussed as well. These findings provide a framework of fabrication considerations for laser SLA printing of open microchannels that can also be applied to other layer-by-layer, vat photopolymerization-based 3D printing technologies.

bioengineering↗

bioRxiv2024

Expanding the capillarics toolbox: 3D-printed microfluidic phaseguides and self-coalescence modules

Capillarics are microfluidic circuits that are assembled from individual fluidic elements, powered by surface tension forces encoded by microchannel geometry and surface chemistry, and enable instrument-free pre-programmed automation of multi-step liquid handling processes. 3D printing has recently transformed capillarics by enabling rapid and cost-effective prototyping, provided addition geometric degrees of freedom in multi-level fabrication, and facilitated new design paradigms with greater capabilities than traditional cleanroom fabrication. Despite widespread interest in 3D printing and development of custom high-resolution stereolithography printers for microfluidic applications, fluidic elements that require precise and tunable control over capillary pinning lines -- such as fluidic phaseguides and self-coalescence modules (SCMs) -- have so far only been manufactured with centralized and expensive cleanroom methods. Not only does this limit access to versatile capillaric features to only well-resourced settings, but it also slows innovation and widespread application of these fluid handling technologies. Here we expand the toolbox of 3D-printed capillarics to include phaseguides and SCMs, demonstrating their potential for precise instrument-free control over multi-step liquid handling and reagent rehydration. We employed benchtop stereolithography printers to prototype (up to 50X) scaled-up phaseguides and SCMs and integrated them into a capillaric circuit for inline reagent reconstitution, dynamic fluid control, and sequential drainage. We showcased scalable designs, customizable geometries, and robust self-coalescing flow for larger liquid volumes -- up to 50 L compared with 1.25 L in cleanroom-fabricated SCMs. This work represents a significant advance in democratizing access to microfluidics, with potential for broad applications in diagnostics, assay automation, and organ-on-chip systems.

bioengineering↗

bioRxiv2024

The dynamics of capillary flow in an open-channel system featuring trigger valves

Trigger valves are fundamental features in capillary-driven microfluidic systems that stop fluid at an abrupt geometric expansion and release fluid when there is flow in an orthogonal channel connected to the valve. The concept was originally demonstrated in closed-channel capillary circuits. We show here that trigger valves can be successfully implemented in open channels. We also show that a series of open-channel trigger valves can be placed alongside or opposite a main channel resulting in a layered capillary flow. We developed a closed form model for the dynamics of the flow at trigger valves based on the concept of average friction length and successfully validated the model against experiments. For the main channel, we discuss layered flow behavior in the light of the Taylor-Aris dispersion theory and in the channel turns by considering Dean theory of mixing. This work has potential applications in autonomous microfluidics systems for biosensing, at-home or point-of-care sample preparation devices, hydrogel patterning for 3D cell culture and organ-on-a-chip models.

bioengineering↗

bioRxiv2021

Improving Lab Culture Through Self-Assessment: A Case Study

PurposeMotivated by perceived dissatisfaction within our labs changed working environment brought about by the COVID-19 pandemic, we performed a self-assessment of our lab culture through anonymous surveys and live sessions. MethodsIn Survey 1, we asked each lab member to identify and rank up to 10 values that are important for a healthy lab environment. They were then asked to rate how well the lab embodied those values at two time points: before the COVID-19 pandemic while working onsite, and at the time of the survey while working remotely (10 months into the pandemic). In a series of live group sessions, we reviewed relevant literature and the survey results to finalize ten themes. We then reflected on each theme and proposed action items to address any deficiencies. Finally, we conducted Survey 2 after the self-assessment to judge the groups finalized themes, implemented changes, and overall satisfaction with the assessment process. ResultsThemes identified were attitude, accountability, teamwork/collaboration, communication, diversity/inclusion, emotional intelligence, integrity, training, well-being, and adaptability in crisis-management. All lab members liked the self-assessment process and felt their voices were heard. On average, there was a 12% increase in satisfaction across all themes from the start to end of the lab assessment. ConclusionWe successfully assessed the culture of our lab and subsequently improved lab member satisfaction. The success of this team project suggests that other scientific labs could benefit from similar interactive self-assessments.

scientific communication and education↗

bioRxiv2020

A traditional Chinese medicine, Respiratory Detox Shot (RDS), inhibits the infection of SARS-CoV, SARS-CoV-2, and the Influenza A virus in vitro

The ongoing global pandemic of coronavirus disease 2019 (COVID-19) has resulted in the infection of over 60 million people and has caused over 1.4 million deaths as of December 2020 in more than 220 countries and territories. Currently, there is no effective treatment for COVID-19 to reduce mortality. We investigated the potential anti-coronavirus activities from an oral liquid of traditional medicine, Respiratory Detox Shot (RDS), which contains mostly herbal ingredients traditionally used to manage lung diseases. Here we report that RDS inhibited the infection of target cells by SARS-CoV and SARS-CoV-2 pseudoviruses, and by infectious wild-type SARS-CoV-2. We further demonstrated that RDS inhibits viral early infection steps. In addition, we found that RDS can also block the infection of target cells by Influenza A virus. These results suggest that RDS may broadly inhibit the infection of respiratory viruses.

microbiology↗