Browsing by Author "Rezaei, Bahareh (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 Flexible Magnetic Field Nanosensors for Wearable Electronics: A Review(2023) Mostufa, Shahriar (TTU); Yari, Parsa (TTU); Rezaei, Bahareh (TTU); Xu, Kanglin (TTU); Wu, Kai (TTU)Flexible magnetic field nanosensors hold immense potential for wearable electronics, offering a range of advantages such as comfort, real-time health monitoring, motion sensing, durability, and seamless integration with other sensors. They are expected to revolutionize wearable technologies and drive innovation in various domains, enhancing the overall user experience. In this review, we provide an overview of recent advances in flexible magnetic field nanosensors, including flexible Hall sensors, flexible magnetoresistive (MR) sensors such as giant magnetoresistance (GMR), magnetic tunnel junction (MTJ), and anisotropic magnetoresistance (AMR) sensors, flexible fluxgate sensors, and flexible giant magnetoimpedance (GMI) sensors. We discuss different fabrication methods and real-life applications for each type of sensor as well as the technical challenges faced by these sensors. The use of these flexible nanosensors opens more possibilities for human–computer interaction and presents exciting opportunities for wearable technology in diverse fields. The robustness of these sensors along with the trend to reduce energy consumption will continue to be important research areas. Future trends in flexible magnetic field nanosensors include energy harvesting from the body, miniaturization and lower power consumption, improved durability and reliability, and reduced cost. These advancements have the potential to drive the widespread adoption of flexible magnetic field nanosensors in wearable devices, enabling innovative applications and enhancing the overall user experience.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 Magnetic Particle Spectroscopy for Point-of-Care: A Review on Recent Advances(2023) Yari, Parsa (TTU); Rezaei, Bahareh (TTU); Dey, Clifton (TTU); Chugh, Vinit Kumar; Veerla, Naga Venkata Ravi Kumar (TTU); Wang, Jian Ping; Wu, Kai (TTU)Since its first report in 2006, magnetic particle spectroscopy (MPS)-based biosensors have flourished over the past decade. Currently, MPS are used for a wide range of applications, such as disease diagnosis, foodborne pathogen detection, etc. In this work, different MPS platforms, such as dual-frequency and mono-frequency driving field designs, were reviewed. MPS combined with multi-functional magnetic nanoparticles (MNPs) have been extensively reported as a versatile platform for the detection of a long list of biomarkers. The surface-functionalized MNPs serve as nanoprobes that specifically bind and label target analytes from liquid samples. Herein, an analysis of the theories and mechanisms that underlie different MPS platforms, which enable the implementation of bioassays based on either volume or surface, was carried out. Furthermore, this review draws attention to some significant MPS platform applications in the biomedical and biological fields. In recent years, different kinds of MPS point-of-care (POC) devices have been reported independently by several groups in the world. Due to the high detection sensitivity, simple assay procedures and low cost per run, the MPS POC devices are expected to become more widespread in the future. In addition, the growth of telemedicine and remote monitoring has created a greater demand for POC devices, as patients are able to receive health assessments and obtain results from the comfort of their own homes. At the end of this review, we comment on the opportunities and challenges for POC devices as well as MPS devices regarding the intensely growing demand for rapid, affordable, high-sensitivity and user-friendly devices.Item Metamaterial as perfect absorber for high sensitivity refractive index based biosensing applications at infrared frequencies(2023) Mostufa, Shahriar (TTU); Yari, Parsa (TTU); Rezaei, Bahareh (TTU); Xu, Kanglin (TTU); Sun, Jiajia; Shi, Zongqian; Wu, Kai (TTU)In this paper, we introduce a novel design of a metamaterial unit cell absorber, which is based on a metal/insulator/metal sandwich structure. The design is subjected to comprehensive finite element method computational analysis to ensure accurate and reliable results. The proposed metamaterial sandwich structure demonstrates exceptional absorption performance, achieving a nearly perfect absorption rate of 99.996% at the resonance infrared frequency of 39.8 THz. To provide a detailed theoretical explanation of nearly perfect absorption, we employ the effective medium theory, impedance matching, and field distribution analysis. Additionally, we have optimized the structural parameters of the sensor to maximize its absorption peak. This includes optimizing the thickness of the gold (Au) layer (from 0.03 to 0.28 μm), the distance between the L shape corners (from 0.60 to 0.90 μm), and the thickness of SiC dielectric spacer (from 0.20 to 0.45 μm). Furthermore, we showcase the remarkable sensitivity of the proposed metamaterial unit cell in detecting subtle changes in the refractive index through the implementation of a sensing medium setup in our model. Remarkably, we achieve a frequency shift sensitivity of 3.74 THz/RIU, along with a quality factor of 10.33, for a wide range of refractive indices (1.0–2.0). Moreover, for cancer detection, we attain a sensitivity of 3.5 THz/RIU. These findings highlight the exceptional performance of our approach in accurately detecting changes in refractive index, making it a promising candidate for various sensing applications. The novelty of our work lies in the design of a metamaterial unit cell structure. This configuration exhibits several noteworthy features, including wide incident angle ($\theta $) coverage up to 60°, polarization insensitivity, exceptional frequency shift sensitivity, high absorption peaks across a wide range of refractive indices, and the ability to distinguish cancer cells from healthy ones.Item Static and dynamic magnetization models of magnetic nanoparticles: an appraisal(2023) Yari, Parsa (TTU); Chugh, Vinit Kumar; Saha, Renata; Tonini, Denis; Rezaei, Bahareh (TTU); Mostufa, Shahriar (TTU); Xu, Kanglin (TTU); Wang, Jian-Ping; Wu, Kai (TTU)Nowadays, magnetic nanoparticles (MNPs) have been extensively used in biomedical fields such as labels for magnetic biosensors, contrast agents in magnetic imaging, carriers for drug/gene delivery, and heating sources for hyperthermia, among others. They are also utilized in various industries, including data and energy storage and heterogeneous catalysis. Each application exploits one or more physicochemical properties of MNPs, including magnetic moments, magnetophoretic forces, nonlinear dynamic magnetic responses, magnetic hysteresis loops, and others. It is generally accepted that the static and dynamic magnetizations of MNPs can vary due to factors such as material composition, crystal structure, defects, size, shape of the MNP, as well as external conditions like the applied magnetic fields, temperature, carrier fluid, and inter-particle interactions (i.e., MNP concentrations). A subtle change in any of these factors leads to different magnetization responses. In order to optimize the MNP design and external conditions for the best performance in different applications, researchers have been striving to model the macroscopic properties of individual MNPs and MNP ensembles. In this review, we summarize several popular mathematical models that have been used to describe, explain, and predict the static and dynamic magnetization responses of MNPs. These models encompass both individual MNPs and MNP ensembles and include the Stoner-Wohlfarth model, Langevin model, zero/non-zero field Brownian and Néel relaxation models, Debye model, empirical Brownian and Néel relaxation models under AC fields, the Landau–Lifshitz–Gilbert (LLG) equation, and the stochastic Langevin equation for coupled Brownian and Néel relaxations, as well as the Fokker–Planck equations for coupled/decoupled Brownian and Néel relaxations. In addition, we provide our peers with the advantages, disadvantages, as well as suitable conditions for each model introduced in this review. The shrinking size of magnetic materials brings about a significant surface spin canting effect, resulting in higher anisotropy and lower magnetization in MNPs compared to bulk materials. Accurate prediction of static and dynamic magnetizations in MNPs Requires both precise data on their magnetic properties and an accurate mathematical model. Hence, we introduced the spin canting effect and models to estimate anisotropy and saturation magnetization in MNPs.