Browsing by Author "Gómez-Pastora, Jenifer (TTU)"
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Item Advancements and Perspectives in Optical Biosensors(2024) Mostufa, Shahriar (TTU); Rezaei, Bahareh (TTU); Ciannella, Stefano (TTU); Yari, Parsa (TTU); Gómez-Pastora, Jenifer (TTU); He, Rui (TTU); Wu, Kai (TTU)Optical biosensors exhibit immense potential, offering extraordinary possibilities for biosensing due to their high sensitivity, reusability, and ultrafast sensing capabilities. This review provides a concise overview of optical biosensors, encompassing various platforms, operational mechanisms, and underlying physics, and it summarizes recent advancements in the field. Special attention is given to plasmonic biosensors and metasurface-based biosensors, emphasizing their significant performance in bioassays and, thus, their increasing attraction in biosensing research, positioning them as excellent candidates for lab-on-chip and point-of-care devices. For plasmonic biosensors, we emphasize surface plasmon resonance (SPR) and its subcategories, along with localized surface plasmon resonance (LSPR) devices and surface enhance Raman spectroscopy (SERS), highlighting their ability to perform diverse bioassays. Additionally, we discuss recently emerged metasurface-based biosensors. Toward the conclusion of this review, we address current challenges, opportunities, and prospects in optical biosensing. Considering the advancements and advantages presented by optical biosensors, it is foreseeable that they will become a robust and widespread platform for early disease diagnostics.Item Giant Magnetoresistance Based Biosensors for Cancer Screening and Detection(2023) Mostufa, Shahriar (TTU); Rezaei, Bahareh (TTU); Yari, Parsa (TTU); Xu, Kanglin (TTU); Gómez-Pastora, Jenifer (TTU); Sun, Jiajia; Shi, Zongqian; Wu, Kai (TTU)Early-stage screening of cancer is critical in preventing its development and therefore can improve the prognosis of the disease. One accurate and effective method of cancer screening is using high sensitivity biosensors to detect optically, chemically, or magnetically labeled cancer biomarkers. Among a wide range of biosensors, giant magnetoresistance (GMR) based devices offer high sensitivity, low background noise, robustness, and low cost. With state-of-the-art micro- and nanofabrication techniques, tens to hundreds of independently working GMR biosensors can be integrated into fingernail-sized chips for the simultaneous detection of multiple cancer biomarkers (i.e., multiplexed assay). Meanwhile, the miniaturization of GMR chips makes them able to be integrated into point-of-care (POC) devices. In this review, we first introduce three types of GMR biosensors in terms of their structures and physics, followed by a discussion on fabrication techniques for those sensors. In order to achieve target cancer biomarker detection, the GMR biosensor surface needs to be subjected to biological decoration. Thus, commonly used methods for surface functionalization are also reviewed. The robustness of GMR-based biosensors in cancer detection has been demonstrated by multiple research groups worldwide and we review some representative examples. At the end of this review, the challenges and future development prospects of GMR biosensor platforms are commented on. With all their benefits and opportunities, it can be foreseen that GMR biosensor platforms will transition from a promising candidate to a robust product for cancer screening in the near future.Item Measuring magnetic force field distributions in microfluidic devices: Experimental and numerical approaches(2023) Strayer, Jacob; Choe, Hyeon; Wu, Xian; Weigand, Mitchell; Gómez-Pastora, Jenifer (TTU); Zborowski, Maciej; Chalmers, Jeffrey J.Precisely and accurately determining the magnetic force and its spatial distribution in microfluidic devices is challenging. Typically, magnetic microfluidic devices are designed in a way to both maximize the force within the separation region and to minimize the necessity for knowing such details—such as designing magnetic geometries that create regions of nearly constant magnetic force or that dictate the behavior of the magnetic force to be highly predictable in a specified region. In this work, we present a method to determine the spatial distribution of the magnetic force field in a magnetic microfluidic device by particle tracking magnetophoresis. Polystyrene microparticles were suspended in a paramagnetic fluid, gadolinium, and this suspension was exposed to various magnetic field geometries. Polystyrene particle motion was tracked using a microscope and images processed using Fiji (ImageJ). From a sample with a large spatial distribution of particle tracks, the magnetic force field distribution was calculated. The force field distribution was fitted to nonlinear spatial distribution models. These experimental models are compared to and supported by 3D simulations of the magnetic force field in COMSOL.Item Nanomaterial-Based Biosensors for SARS-CoV-2 and Future Epidemics(2023) Yari, Parsa (TTU); Liang, Shuang; Chugh, Vinit Kumar; Razaei, Bahareh (TTU); Mostufa, Shahriar (TTU); Krishna, Venkatramana Divana; Saha, Renata; Cheeran, Maxim C. J. (TTU); Wang, Jian-Ping (TTU); Gómez-Pastora, Jenifer (TTU); Wu, Kai (TTU)The outbreak of the coronavirus disease 2019 (COVID-19) pandemic has put enormous pressure on global healthcare and economic systems. The cause of this pandemic, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a positive-sense single-stranded RNA (+ssRNA) virus belonging to the beta family of coronaviruses. This highly contagious virus mainly spread through droplet transmission and contact transmission. People who are infected can release droplets and aerosol particles that contain the SARS-CoV-2 virus in the air when they exhale, cough, or sneeze. The droplets or aerosol particles of different sizes (from visible to microscopic) will continue to spread in the air or land on subjects. Healthy people may catch the virus via inhalation of aerosol particles from the air, or through the contact with contaminated surfaces before touching their nose, eyes, or mouth. Besides the direct droplet and contact transmissions, other viral transmission routes are also reported, such as spatter (e.g., blood spatter, spatter during intubation, etc.), fecal-eye transmission, nasal-eye transmission, mouth-eye transmission (through contaminated hands or objects) and the transmission of eye secretions and tears. In addition to its strong transmission power, SARS-CoV-2 can cause acute respiratory distress syndrome (ARDS), septic shock, coagulation dysfunction, intestinal dysfunction, and other clinical symptoms post-infection. Many people infected with COVID-19 display light symptoms like the common cold and influenza, and in some cases they are asymptomatic. Nevertheless, these asymptomatic carriers can still transmit SARS-CoV- 2, making the prevention of COVID-19 infection a major challenge in the world. In view of this, implementing fast, low-cost, accurate, easy-to-access, and integrated diagnostic devices available at the point of care (POC) is paramount to contain not only COVID-19, but also to cope with future epidemics.