Biology subjects

Caira, T.

Publications and source records attributed to Caira, T..

3 recordsLinked to original sources

bioRxiv2026

From Fill to Freeze: Redesigning homeRNA to Enable Robust Sampling and Scalable Downstream Processing Workflows for Remote Blood Transcriptomics

In-person research can introduce barriers to participation, including proximity to a study site and scheduling constraints. Our lab developed the homeRNA platform to address these barriers, enabling remote blood collection and RNA stabilization for transcriptomic research. To increase the applicability of homeRNA for large-scale studies, a redesigned version was developed with modifications to 1) improve usability for both participants and downstream processing laboratories, 2) allow for high-throughput manufacturing, and 3) extend the shelf life of the stabilizer tube. In this work, we systematically tested this design against anticipated stresses that can occur throughout a remote study (e.g., high temperature exposure during shipment) to identify and characterize its limitations. We found that the homeRNA device can be prepared and stored at room temperature at least three months in advance of sampling with continued shelf life analysis underway. We also found that the homeRNA platform produces RNA of sufficient quality for downstream transcriptomic analysis under standard shipping durations (i.e., 2 days in transit) and ambient-to-high temperature conditions (i.e., 25-40 {degrees}C) and that RNA quality is unaffected by variable blood volumes collected by participants (mean RIN=7.8 in blood volumes 0.25-1 mL). Lastly, we also found that samples can be stored in typical cold storage temperatures and even up to standard room temperature for at least 4 weeks (mean RIN=8.1 after 4 weeks of storage at -80 to 20 {degrees}C). This work validates that the new homeRNA platform is robust to many of the expected stresses that samples can experience during remote studies.

bioengineering↗

bioRxiv2026

Modeling and validation of parallel co-flows layer widths in open-capillary trigger valve systems

Control of fluids is a hallmark of microfluidic systems and fundamental for the successful application of microfluidic devices. Trigger valves use geometric features to autonomously control the release of fluids in microfluidic devices. Our previous work has adapted geometries used in closed trigger valve systems to enable use in open systems, allowing for open microfluidic devices with up to three trigger valves. Here, we focus on the parallel co-flows produced by sequential release of trigger valves and present a model that predicts their layer widths as a function of the geometric characteristics of the different side channels of each trigger valve. We show layered co-flows with widths as low as 50 microns. Additionally, we expand the use of trigger valves in open microfluidic devices by incorporating 1) varied step heights, 2) devices with up to seven trigger valves, and 3) use of varied fluids and plastics. To validate the implementation and use of these trigger valves in open systems, we have developed a theoretical framework to compare predicted outcomes (i.e., fluid travel distance, velocity, and layering width) with our experimental values. This theoretical work offers applications in various fields, including hydrogel patterning for 3D cell culture, organ-on-a-chip models, at-home sample preparation, and autonomous microfluidic systems for biosensing.

bioengineering↗

bioRxiv2025

Detection of inertial effects in capillary flows in open and closed channels

The Lucas-Washburn-Rideal law is commonly applied to describe capillary flow dynamics in closed or open channels, microporous media, such as paper pads and fiber threads or even granulous soil. It assumes a viscous flow regime where capillary forces are counteracted by friction with the solid structure, a valid assumption given the small flow velocities and device dimensions. However, scenarios exist outside the viscous regime, where inertial effects become significant, meaning capillary and friction forces do not fully balance. One well-documented case is the transient inertial regime at the onset of capillary motion. With the advancement of capillary devices, other configurations also raise the possibility of inertia influencing flow behavior. This study introduces a criterion to identify inertial contributions in capillary-driven flows in spatially varying geometries within open or closed channels and demonstrates how the Bosanquet equation can account for inertial effects in rectangular open-channel configurations.

bioengineering↗