Biology subjects

Thongpang, S.

Publications and source records attributed to Thongpang, S..

10 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

Characterization of pre-analytical blood collection and stabilization parameters to maintain endogenous protein levels for remote blood sampling technology

Blood biomarkers are central to monitoring disease progression and evaluating treatment responses, yet traditional venipuncture captures a single physiological snapshot in time and becomes burdensome with repeated sampling. Remote blood self-sampling offers a path toward longitudinal, decentralized monitoring, but maintaining protein integrity from draw to analysis remains a critical challenge. Here, we optimized pre-analytical blood collection and stabilization parameters to maintain protein levels at the time of collection for use with remote sampling technology. First, we optimized blood collection time with Tasso remote self-sampling devices to minimize interference from clotting, finding that a 2.5 min collection time best reduces clot formation while collecting enough blood. Next, we found that Protein Plus, a commercial protein stabilizer, limited hemolysis (a metric for stabilizer efficacy) in venous blood for up to 5 days at 25{degrees}C-35{degrees}C and for 1 day at 40{degrees}C. In addition, we optimized the stabilizer volume and acceptable blood volume range for self-sampling as the stabilizer efficacy is impacted by the stabilizer to blood ratio and collection volume can vary with remote self-sampling devices. Finally, we incubated stabilized blood samples collected via Tasso device at 25{degrees}C-35{degrees}C for 72 h, mimicking a 2-day shipping period. Using a panel of 21 inflammatory proteins, we found that Protein Plus limited intracellular protein release for various proteins (e.g., VEGF-A, CCL11, and IL-8), inhibited protein degradation for CCL2, and enabled minimal hemolysis. These results support Protein Plus as a viable stabilization strategy for remote blood collection technology targeting longitudinal inflammatory protein monitoring.

biochemistry↗

bioRxiv2025

To the homeRNAmax: Developing an Improved Blood Self-Collection and Stabilization Platform for Remote Transcriptomic Studies

Shifting human subjects research from research sites to participants homes removes barriers to participation, including transportation and scheduling difficulties. Previously, we developed homeRNA, a kit for immediate stabilization of RNA in self-collected blood using a custom-engineered tube containing RNA stabilizer fluid. The stabilized RNA is extracted and used for downstream gene expression analysis. Here, we introduce homeRNAmax, which improves our original design by interfacing with a commercially available blood collection tube (BD Microtainer), allowing homeRNAmax to be used with any blood collection method that uses this tube and doubling the possible sample volume that can be collected and stabilized compared to the original homeRNA. Through a pilot study (n=19 participants), we show that homeRNAmax (with the Tasso+ blood collection device) produces RNA samples of sufficient quality (mean RIN=7.8) and yield (mean yield=1.93 g) for downstream analysis and can reach participants across the United States, who generally (n=17/19) found the homeRNAmax kit easy to use. A key aspect of the homeRNA and homeRNAmax platforms is a fluidic feature that prevents the RNA stabilizer from spilling, however our previous work had not yet fully characterized the mechanism of this feature. Here, we developed a theoretical model of the spill-resistant feature. In brief, fluid in the tube is suspended due to a balance of pressures; an increase in air volume within the tube reduces the air pressure above the fluid, creating a small vacuum, and preventing fluid leakage. Overall, we show that homeRNAmax is a user-friendly, effective tool for remote blood RNA stabilization.

bioengineering↗

bioRxiv2025

CandyCollect Open to Closed (O2C) Microfluidic System for Rapid and User-Centric Detection of Group A Streptococcus

We created CandyCollect, a lollipop-inspired, child-friendly saliva sampling device that provides enhanced comfort compared to common throat and mouth swabs. The device has an open microchannel and a functionalized surface that effectively captures and stores the saliva and pathogens. We recently demonstrated the ability to combine the CandyCollect with rapid antigen detection tests (RADTs) for fast and accessible detection of group A streptococcus (GAS). However, the current procedure necessitates manual steps to elute and transfer captured antigens from the lollipop to RADTs, which relies on the user to follow complex instructions, increasing the likelihood of error. In this work, we developed the CandyCollect Open to Closed (O2C) microfluidic system to automate antigen elution and streamline detection with RADTs. The O2C system securely seals the open microchannels of the CandyCollect device to create a continuous closed channel for seamless delivery of elution reagents to release antigens at the press of a button for subsequent lateral flow detection. Our system leverages and combines the unique benefits of both open channel and closed channel microfluidics into one platform, further enhancing the potential of both methods. We performed experiments with GAS bacteria spiked into saliva and compared the manual and O2C elution methods. Both the manual and O2C methods showed clear test lines on the RADT strips at clinically relevant GAS concentrations (between 5 x105 and 109 CFU/mL). The O2C provided comparable or better results than the manual procedure in a more convenient form factor. The O2C platform has the potential to enable user-friendly screening for respiratory pathogens by minimally trained users in decentralized settings.

bioengineering↗

bioRxiv2024

CandyCollect: An Open-Microfluidic Device for the Direct Capture and Enumeration of Salivary-Extracellular Vesicles

Extracellular vesicles (EVs) are promising biomarkers for disease detection using a liquid biopsy approach, in which they are enriched and analyzed directly from biofluids. However, implementing EV biomarker technologies in the clinic remains limited by the need for practical and patient-centric biofluid collection methods that are compatible with downstream EV processing and analysis. While saliva offers a non-invasive source of EVs, its complexity and heterogeneity--cells, debris, and other non-EV proteins--can present hurdles when using traditional analytical platforms. Here, we present the CandyCollect, a lollipop-inspired sampling device with open microfluidic channels, as a patient-friendly approach for rapid salivary EV capture. CandyCollect simplifies sample preparation by effectively pre-concentrating EVs in oxygen-plasma treated open microfluidic channels. In this proof-of-principle study, we show that following a 3-5 minute-oral sampling period, EVs collected by the CandyCollect can be released with high purity within minutes and subsequently quantified and analyzed for cargo content. We observed consistent EV capture across repeated collections within individuals and expected variability across healthy participants. Additionally, single and pooled collections of EVs from a healthy participant resulted in a concordant protein profile. Overall, the CandyCollect is a new platform for rapid, non-invasive salivary EV collection and analysis for clinical diagnostics.

bioengineering↗

bioRxiv2023

On the dynamic contact angle of capillary-driven microflows in open channels

The true value of the contact angle between a liquid and a solid is a thorny problem in capillary microfluidics. The Lucas-Washburn-Rideal (LWR) law assumes a constant contact angle during fluid penetration. However, recent experimental studies have shown lower liquid velocities than predicted by the LWR equation, which are attributed to a velocity-dependent dynamic contact angle that is larger than its static value. Inspection of fluid penetration in closed channels has confirmed that a dynamic angle is needed in the LWR equation. In this work, the dynamic contact angle in an open channel configuration is investigated using experimental data obtained with a range of liquids, aqueous and organic, and a PMMA substrate. We demonstrate that a dynamic contact angle must be used to explain the early stages of fluid penetration, i.e., at the start of the viscous regime, when flow velocities are sufficiently high. Moreover, the open channel configuration, with its free surface, enhances the effect of the dynamic contact angle, making its inclusion even more important. We found that for the liquids in our study, the molecular-kinetic theory (MKT) is the most accurate in predicting the effect of the dynamic contact angle on liquid penetration in open channels.

bioengineering↗

bioRxiv2023

At-home oral bacteria collection using a lollipop-based microfluidic device

Respiratory infections are common in children, and there is a need for user-friendly collection methods. Here, we performed the first human subjects study using the CandyCollect device, a lollipop inspired saliva collection device.1 We showed the CandyCollect device can be used to collect salivary bacteria from healthy adults using Streptococcus mutans and Staphylococcus aureus as proof-of-concept commensal bacteria. We enrolled healthy adults in a nationwide (USA) remote study in which participants were sent study packages containing CandyCollect devices and traditional commercially available oral swabs and spit tubes. Participants sampled themselves at home, completed usability and user preference surveys, and mailed the samples back to our laboratory for analysis by qPCR. Our results showed that for participants in which a given bacterium (S. mutans or S. aureus) was detected in one or both of the commercially available methods (oral swab and/or spit tubes), CandyCollect devices had a 100% concordance with the positive result (n=14 participants). Furthermore, the CandyCollect device was ranked the highest preference sampling method among the three sampling methods by 26 participants surveyed (combining survey results across two enrollment groups). We also showed that the CandyCollect device has a shelf life of up to 1 year at room temperature, a storage period that is convenient for clinics or patients to keep the CandyCollect device and use it any time. Taken together, we have demonstrated that the CandyCollect is a user-friendly saliva collection tool that has the potential to be incorporated into diagnostic assays in clinic visits and telemedicine. For Table of Contents Only O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=126 SRC="FIGDIR/small/524039v6_ufig1.gif" ALT="Figure 1"> View larger version (37K): org.highwire.dtl.DTLVardef@1356b32org.highwire.dtl.DTLVardef@10c737org.highwire.dtl.DTLVardef@1872455org.highwire.dtl.DTLVardef@1625069_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2022

At-home blood collection and stabilization in high temperature climates using homeRNA

Expanding whole blood sample collection for transcriptome analysis beyond traditional phlebotomy clinics will open new frontiers for remote immune research and telemedicine. Determining the stability of RNA in blood samples exposed to high ambient temperatures (>30{degrees}C) is necessary for deploying home-sampling in settings with elevated temperatures (e.g., studying physiological response to natural disasters that occur in warm locations or in the summer). Recently, we have developed homeRNA, a technology that allows for self-blood sampling and RNA stabilization remotely. homeRNA consists of a lancet-based blood collection device, the Tasso-SST which collects up to 0.5 mL of blood from the upper arm, and a custom-built stabilization transfer tube containing RNAlater. In this study, we investigated the robustness of our homeRNA kit in high temperature settings via two small pilot studies in Doha, Qatar (no. participants = 8), and the Western and South Central USA during the summer of 2021, which included a heatwave of unusually high temperatures in some locations (no. participants = 11). Samples collected from participants in Doha were subjected to rapid external temperature fluctuations from being moved to and from air-conditioned areas and extreme heat environments (up to 41{degrees}C external temperature during brief temperature spikes). In the USA pilot study, regions varied in outdoor temperature highs (between 25{degrees}C and 43.4{degrees}C). All samples that returned a RNA integrity number (RIN) value from the Doha, Qatar group had a RIN [≥]7.0, a typical integrity threshold for downstream transcriptomics analysis. RIN values for the Western and South Central USA samples (n=12 samples) ranged from 6.9-8.7 with 9 out of 12 samples reporting RINs [≥]7.0. Overall, our pilot data suggest that homeRNA can be used in some regions that experience elevated temperatures, opening up new geographical frontiers in disseminated transcriptome analysis for applications critical to telemedicine, global health, and expanded clinical research. Further studies, including our ongoing work in Qatar, USA, and Thailand, will continue to test the robustness of homeRNA.

bioengineering↗

bioRxiv2021

CandyCollect: At-home saliva sampling for respiratory pathogen capture

Streptococcus pyogenes is a major human-specific bacterial pathogen and a common cause of a wide range of symptoms from mild infection such as pharyngitis (commonly called strep throat) to life-threatening invasive infection and post-infectious sequelae. Traditional methods for diagnosis include collecting a sample using a pharyngeal swab, which can cause discomfort and even discourage adults and children from seeking proper testing and treatment in the clinic. Saliva samples are an alternative to pharyngeal swabs. To improve the testing experience for strep throat, we developed a novel lollipop-inspired sampling platform (called CandyCollect) to capture bacteria in saliva. The device can be used in clinics or in the home and shipped back to a lab for analysis, integrating with telemedicine. CandyCollect is designed to capture bacteria on an oxygen plasma treated polystyrene surface embedded with flavoring substances to enhance the experience for children and inform the required time to complete the sampling process. In addition, the open channel structure prevents the tongue from scraping and removing the captured bacteria. Flavoring substances did not affect bacterial capture and the device has a shelf life of at least 2 months (with experiments ongoing to extend the shelf life). We performed a usability study with 17 participants who provided feedback on the device design and the dissolving time of the candy. This technology and advanced processing techniques, including polymerase chain reaction (PCR), will enable user-friendly and effective diagnosis of streptococcal pharyngitis.

bioengineering↗

bioRxiv2019

μECoG Recordings Through a Thinned Skull

The studies described in this paper for the first time characterize the acute and chronic performance of optically transparent thin-film {micro}ECoG grids implanted on a thinned skull as both an electrophysiological complement to existing thinned skull preparation for optical recordings/manipulations, and a less invasive alternative to epidural or subdurally placed {micro}ECoG arrays. In a longitudinal chronic study, {micro}ECoG grids placed on top of a thinned skull maintain impedances comparable to epidurally placed {micro}ECoG grids that are stable for periods of at least one month. Optogenetic activation of cortex is also reliably demonstrated through the optically transparent ECoG grids acutely placed on the thinned skull. Finally, spatially distinct electrophysiological recordings were evident on {micro}ECoG electrodes placed on a thinned skull separated by 500-750{micro}m, as assessed by stimulation evoked responses using optogenetic activation of cortex as well as invasive and epidermal stimulation of the sciatic and median nerve at chronic time points. Neural signals were collected through a thinned skull in multiple species, demonstrating potential utility in neuroscience research applications such as in vivo imaging, optogenetics, calcium imaging, and neurovascular coupling.

neuroscience↗