Bioengineering / Biyomühendislik
Permanent URI for this collectionhttps://hdl.handle.net/11147/4529
Browse
7 results
Search Results
Conference Paper 3d Printing-Assisted Fabrication of Microfluidic Pneumatic Valves(IEEE, 2023) Keleş, Şeyda; Karakuzu, Betül; Tekin, Hüseyin CumhurPneumatic valves have a crucial place in the fluidic control in microfluidic systems. Pneumatic valves containing polydimethylsiloxane (PDMS) membrane structures are used in microfluidic systems such as cell separation, and cell manipulation due to their flexible structure, and ease of production. This study demonstrates the rapid and straightforward fabrication of pneumatic valve structures using PDMS membranes, achieved through the utilization of 3D-printed molds. As a result of our experiments, we observed valve closure in a fluidic channel with a height of 150 μm. This closure was achieved by utilizing 400 μm × 800 μm PDMS membrane with a thickness of 66 μm positioned between the fluidic and control channels, while applying 1.5 bar of pressure to the control channel. When the pressure is removed, the opening time of the valve is only 0.02 s, and this response time allows rapid valving function. The presented valve fabrication strategy would allow easy and low-cost production of sophisticated microfluidic chips. © 2023 IEEE.Article Citation - WoS: 15Citation - Scopus: 16Electromechanical Rt-Lamp Device for Portable Sars-Cov Detection(Elsevier, 2023) Tarım, Ergün Alperay; Öksüz, Cemre; Karakuzu, Betül; Appak, Özgür; Sayıner, Ayça Arzu; Tekin, Hüseyin CumhurRapid point-of-care tests for infectious diseases are essential, especially in pandemic conditions. We have developed a point-of-care electromechanical device to detect SARS-CoV-2 viral RNA using the reverse-transcription loop-mediated isothermal amplification (RT-LAMP) principle. The developed device can detect SARS-CoV-2 viral RNA down to 103 copies/mL and from a low amount of sample volumes (2 μL) in less than an hour of standalone operation without the need for professional labor and equipment. Integrated Peltier elements in the device keep the sample at a constant temperature, and an integrated camera allows automated monitoring of LAMP reaction in a stirring sample by using colorimetric analysis of unfocused sample images in the hue/saturation/value color space. This palm-fitting, portable and low-cost device does not require a fully focused sample image for analysis, and the operation could be stopped automatically through image analysis when the positive test results are obtained. Hence, viral infections can be detected with the portable device produced without the need for long, expensive, and labor-intensive tests and equipment, which can make the viral tests disseminated at the point-of-care.Article Citation - WoS: 10Citation - Scopus: 14An Electromechanical Lab-On Platform for Colorimetric Detection of Serum Creatinine(American Chemical Society, 2022) Karakuzu, Betül; Tarım, Ergün Alperay; Öksüz, Cemre; Tekin, Hüseyin CumhurChronic kidney disease (CKD) is a high-cost disease that affects approximately one in ten people globally, progresses rapidly, results in kidney failure or dialysis, and triggers other diseases. Although clinically used serum creatinine tests are used to evaluate kidney functions, these tests are not suitable for frequent and regular control at-home settings that obstruct the regular monitoring of kidney functions, improving CKD management with early intervention. This study introduced a new electromechanical lab-on-a-chip platform for point-of-care detection of serum creatinine levels using colorimetric enzyme-linked immunosorbent assay (ELISA). The platform was composed of a chip containing microreservoirs, a stirring bar coated with creatinine-specific antibodies, and a phone to detect color generated via ELISA protocols to evaluate creatinine levels. An electromechanical system was used to move the stirring bar to different microreservoirs and stir it inside them to capture and detect serum creatinine in the sample. The presented platform allowed automated analysis of creatinine in ~50 min down to ~1 and ~2 mg/dL in phosphate-buffered saline (PBS) and fetal bovine serum (FBS), respectively. Phone camera measurements in hue, saturation, value (HSV) space showed sensitive analysis compared to a benchtop spectrophotometer that could allow low-cost analysis at point-of-care.Article Citation - WoS: 37Citation - Scopus: 48Microfluidic-Based Virus Detection Methods for Respiratory Diseases(Springernature, 2021) Tarım, Ergün Alperay; Karakuzu, Betül; Öksüz, Cemre; Sarıgil, Öykü; Kızılkaya, Melike; Al-Ruweidi, Mahmoud Khatib A. A.; Yalçın, Hüseyin Çağatay; Özçivici, Engin; Tekin, Hüseyin CumhurWith the recent SARS-CoV-2 outbreak, the importance of rapid and direct detection of respiratory disease viruses has been well recognized. The detection of these viruses with novel technologies is vital in timely prevention and treatment strategies for epidemics and pandemics. Respiratory viruses can be detected from saliva, swab samples, nasal fluid, and blood, and collected samples can be analyzed by various techniques. Conventional methods for virus detection are based on techniques relying on cell culture, antigen-antibody interactions, and nucleic acids. However, these methods require trained personnel as well as expensive equipment. Microfluidic technologies, on the other hand, are one of the most accurate and specific methods to directly detect respiratory tract viruses. During viral infections, the production of detectable amounts of relevant antibodies takes a few days to weeks, hampering the aim of prevention. Alternatively, nucleic acid-based methods can directly detect the virus-specific RNA or DNA region, even before the immune response. There are numerous methods to detect respiratory viruses, but direct detection techniques have higher specificity and sensitivity than other techniques. This review aims to summarize the methods and technologies developed for microfluidic-based direct detection of viruses that cause respiratory infection using different detection techniques. Microfluidics enables the use of minimal sample volumes and thereby leading to a time, cost, and labor effective operation. Microfluidic-based detection technologies provide affordable, portable, rapid, and sensitive analysis of intact virus or virus genetic material, which is very important in pandemic and epidemic events to control outbreaks with an effective diagnosis.Article Citation - WoS: 11Citation - Scopus: 11Absorbance-Based Detection of Arsenic in a Microfluidic System With Push-And Pumping(Elsevier, 2021) Karakuzu, Betül; Gülmez, Yekta; Tekin, H. CumhurRapid and portable analysis of arsenic (As) contamination in drinking water is very important due to its adverse health effects on humans. Available commercial detection kits have shown low sensitivity and selectivity in analysis, and also they can generate harmful by-products. Microfluidic-based approaches allow portable analysis with gold nanoparticles (AuNPs) as labels. However, they need complex surface modification steps that complicate detection protocols. Due to the lack of precise sensing and affordable solution, we focused on developing a microfluidic platform that uses a push-and-pull pumping method for sensitive detection of As. In this detection principle, a sample is introduced in the microfluidic channel modified with -SH functional groups where As can bind. Then, AuNPs are given in the channel and AuNPs bind on free -SH functional groups which are not allocated with As. Absorbance measurements are conducted to detect AuNPs absorbed on the surfaces and the resulting absorbance value is inversely proportional with As concentration. The method enables detection of As down to 2.2 mu g/L concentration levels in drinking water, which is well-below the allowed maximum As concentration of 10 mu g/L in the drinking waters by the World Health Organization (WHO). The paper reveals that multiple push-and-pull pumping of fixed volume of sample and AuNPs with a syringe pump can improve the binding efficiency in the microfluidic channel. With this technique, low amounts of sample (1 mL) and short total assay time (25 min) are sufficient to detect As.Conference Object Electromechanical Lab-On Platform for Creatinine Analysis Using Automated Elisa Protocols(Chemical and Biological Microsystems Society, 2020) Karakuzu, Betül; Tarım, Ergün Alperay; Öksüz, Cemre; Tekin, Hüseyin CumhurWe present an electromechanical lab-on-a-chip (LOC) platform for the automated serum creatinine detection applying enzyme-linked immunosorbent assay (ELISA) principle. In the platform, antibody covered bar selectively captures the creatinine in the sample and the electromechanical system allows automatic movement between the designed reservoirs containing assay solutions. At the end of the protocol, the absorbance value of the appeared color is measured to determine creatinine concentration in the sample. Since this system allows measuring automatically creatinine levels with minimum time and cost, it can be utilized for point-of-care monitoring of chronic kidney diseases (CKD) for the future. © 2020 CBMS-0001Conference Object Citation - WoS: 3Citation - Scopus: 3Active Mixing Strategy With Electromechanical Platform for Lab-On Applications(Institute of Electrical and Electronics Engineers Inc., 2019) Karakuzu, Betül; Özçivici, Engin; Tekin, Hüseyin Cumhur; Tarım, E. AlperayThe main purpose of this study is to present a new active mixing strategy that can be used for lab-on-A-chip applications to shorten analysis time. An electromechanical platform composed of stepper and DC motors is designed and manufactured. This platform allows rapid mixing in microwells of a polydimethylsiloxane chip for analysis. Mixing in microwells is performed with a stirring bar spun automatically using the electromechanical platform. Mixing experiments performed at different spinning speeds and different time intervals on the platform. It was observed that mixing was achieved only in 300 ms inside 100 ?L microwell using 4300 revolutions per minute (rpm) spinning speeds. Hence, the proposed mixing strategy showed 200-fold faster mixing than pure diffusion-based mixing. © 2019 IEEE.