Biology subjects

Tu, W.-c.

Publications and source records attributed to Tu, W.-c..

4 recordsLinked to original sources

bioRxiv2024

Open-Channel Droplet Microfluidic Platform for Passive Generation of Human Sperm Microdroplets

Sperm cryopreservation is important for many individuals across the globe. Recent studies show that vitrification is a valuable approach for maintaining sperm quality after freeze-thawing processes and requires sub-microliter to microliter volumes. A major challenge for the adoption of vitrification in fertility laboratories is the ability to pipette small volumes of sample. Here, we present an open droplet generator that leverages open-channel microfluidics to passively generate sub-microliter to microliter volumes of purified human sperm samples and preserves sperm kinematics. We conclude that our platform is compatible with human sperm, an important foundation for future implementation of vitrification in fertility laboratories. Table of contents artwork O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=108 SRC="FIGDIR/small/593416v3_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@1733ae0org.highwire.dtl.DTLVardef@1e638aorg.highwire.dtl.DTLVardef@119097forg.highwire.dtl.DTLVardef@be86f3_HPS_FORMAT_FIGEXP M_FIG C_FIG

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

Enhanced capillary pumping using open-channel capillary trees with integrated paper pads

The search for efficient capillary pumping has led to two main directions for investigation: first, assembly of capillary channels to provide high capillary pressures, and second, imbibition in absorbing fibers or paper pads. In the case of open microfluidics (i.e., channels where the top boundary of the fluid is in contact with air instead of a solid wall), the coupling between capillary channels and paper pads unites the two approaches and provides enhanced capillary pumping. In this work, we investigate the coupling of capillary trees-- networks of channels mimicking the branches of a tree--with paper pads placed at the extremities of the channels, mimicking the small capillary networks of leaves. It is shown that high velocities and flow rates (7 mm/s or 13.1 {micro}L/s) for more than 30 seconds using 50% (v/v) isopropyl alcohol, which has a 3-fold increase in viscosity in comparison to water; 6.5 mm/s or 12.1 {micro}L/s for more than 55 seconds with pentanol, which has an 3.75-fold increase in viscosity in comparison to water; >3.5 mm/s or 6.5 {micro}L/s for more than 150 seconds with nonanol, which has an 11-fold increase in viscosity in comparison to water) can be reached in the root channel, enabling higher sustained flow rates than that of capillary trees alone.

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↗