Advances in terahertz technology for cancer detection applications

A predictive model for MGMT promoter methylation status in glioblastoma based on terahertz spectral data

O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation is a crucial biomarker in glioblastoma (GBM) that influences response to temozolomide. Traditional detection methods, such as gene sequencing, are time-consuming and limited to postoperative analysis. This study explores the use of terahertz time-domain spectroscopy (THz-TDS) combined with machine learning to predict MGMT methylation status intraoperatively. By analyzing 180 GBM tissue samples, a Random Forest model was developed, achieving an AUC of 0.862. The findings suggest that THz spectroscopy offers a rapid, intraoperative alternative to traditional MGMT methylation detection methods, potentially enhancing surgical decision-making and personalized treatment strategies in GBM.

Terahertz wave induces the structural and functional changes in voltage-gated calcium channel Cav1.1: A molecular dynamics study

Terahertz waves, owing to the special feature of inducing resonance with numerous biomolecules, thus affecting biological activities, have become a novel and promising biological technology. Recently, the effect of terahertz waves on neuroscience via ion channel proteins on the cell membrane has received more attention. A cell membrane model with the voltage-gated calcium channel Cav1.1 embedded was constructed. The vibrational spectra of TIP3P molecules and carboxyl and carbonyl groups in the selectivity filter region (13.4, 48.7, and 53.2 THz) were calculated. The change in ion channel pore radius distribution and secondary structures of Cav1.1 triggered by external terahertz electromagnetic fields are measured. The umbrella sampling method is carried out to assess the functional changes of Cav1.1 via potential of mean force profiles of Ca2+ permeation. The results showed that Cav1.1 has highly frequency specificity, emphasizing the importance of terahertz resonance with biomolecules in terahertz-related neuroscience research.

Breaking barriers in cancer diagnosis: unveiling the 4Ms of biosensors

Cancer, an insidious affliction, continues to exact a heavy toll on humanity, necessitating early detection and nuanced comprehension of its intricacies for effective treatment. Recent strides in micro and nanoscale electronic chip fabrication have revolutionized biosensor technology, offering promising avenues for biomedical and telemedicine applications. Micro Electromechanical System (MEMS)-based integrated circuits (ICs) represent a paradigm shift in detecting chemical and biomolecular interactions pertinent to cancer diagnosis, supplanting conventional methodologies. Despite the wealth of research on biosensors, a cohesive framework integrating Material, Mechanism, Modeling, and Measurement (4M) dimensions is often lacking. This review aims to synthesize these dimensions, exploring recent breakthroughs in biosensor design and development. Categorized based on electromechanical integration, material selection, and fabrication processes, these biosensors bridge crucial knowledge gaps within the research community. A comparative analysis of sensing methods in point-of-care (PoC) technology provides insights into their practicality and efficacy. Moreover, we critically evaluate biosensor limitations, pivotal in addressing challenges hindering their global commercialization.

Terahertz scanning near-field optical microscopy for biomedical detection: Recent advances, challenges, and future perspectives

Terahertz (THz) radiation is widely recognized as a non-destructive, label-free, and highly- sensitive tool for biomedical detections. Nevertheless, its application in precision biomedical fields faces challenges due to poor spatial resolution caused by intrinsically long wavelength characteristics. THz scanning near-field optical microscopy (THz-SNOM), which surpasses the Rayleigh criterion, offers micrometer and nanometer-scale spatial resolution, making it possible to perform precise bioinspection with THz imaging. THz-SNOM is attracting considerable attention for its potential in advanced biomedical research and diagnosis. Currently, its family typically includes four members based on distinct principles, which are suitable for different biological applications. This review provides an overview of the principles of these THz-SNOM modalities, outlines their various applications, identifies the obstacles hindering their performance, and envisions their future development.

Wearable and Flexible Sensor Devices: Recent Advances in Designs, Fabrication Methods, and Applications

The development of wearable sensor devices brings significant benefits to patients by offering real-time healthcare via wireless body area networks (WBANs). These wearable devices have gained significant traction due to advantageous features, including their lightweight nature, comfortable feel, stretchability, flexibility, low power consumption, and cost-effectiveness. Wearable devices play a pivotal role in healthcare, defence, sports, health monitoring, disease detection, and subject tracking. However, the irregular nature of the human body poses a significant challenge in the design of such wearable systems. This manuscript provides a comprehensive review of recent advancements in wearable and flexible smart sensor devices that can support the next generation of such sensor devices. Further, the development of direct ink writing (DIW) and direct writing (DW) methods has revolutionised new high-resolution integrated smart structures, enabling the design of next-generation soft, flexible, and stretchable wearable sensor devices. Recognising the importance of keeping academia and industry informed about cutting-edge technology and time-efficient fabrication tools, this manuscript also provides a thorough overview of the latest progress in various fabrication methods for wearable sensor devices utilised in WBAN and their evaluation using body phantoms. An overview of emerging challenges and future research directions is also discussed in the conclusion.

Advances in the Identification Methods of Food-Medicine Homologous Herbal Materials

As a key component of both traditional medicine and modern healthcare, Food-Medicine Homologous Herbal Materials have attracted considerable attention in recent years. However, issues related to the quality and authenticity of medicinal materials on the market often arise, not only compromising their efficacy but also presenting potential risks to consumer health. Therefore, the establishment of accurate and efficient identification methods is crucial for ensuring the safety and quality of Food-Medicine Homologous Herbal Materials. This paper provides a systematic review of the research progress on the identification methods for Food-Medicine Homologous Herbal Materials, starting with traditional methods such as morphological and microscopic identification, and focusing on the applications of modern techniques, including biomimetic recognition, chromatography, mass spectrometry, chromatography-mass spectrometry coupling, hyperspectral imaging, near-infrared spectroscopy, terahertz spectroscopy, and DNA barcoding. Moreover, it provides a comprehensive analysis of the fundamental principles, advantages, and limitations of these methods. Finally, the paper outlines the current challenges faced by identification methods and suggests future directions for improvement, aiming to offer a comprehensive technical perspective on identifying Food-Medicine Homologous Herbal Materials and foster further development in this field.

Towards autonomous robotic THz-based in vivo skin sensing: the PicoBot

Terahertz (THz) light has the unique properties of being very sensitive to water, non-ionizing, and having sub-millimeter depth resolution, making it suitable for medical imaging. Skin conditions including eczema, psoriasis and skin cancer affect a high percentage of the population and we have been developing a THz probe to help with their diagnosis, treatment and management. Our in vivo studies have been using a handheld THz probe, but this has been prone to positional errors through sensorimotor perturbations and tremors, giving spatially imprecise measurements and significant variations in contact pressure. As the operator tires through extended device use, these errors are further exacerbated. A robotic system is therefore needed to tune the critical parameters and achieve accurate and repeatable measurements of skin. This paper proposes an autonomous robotic THz acquisition system, the PicoBot, designed for non-invasive diagnosis of healthy and diseased skin conditions, based on hydration levels in the skin. The PicoBot can 3D scan and segment out the region of interest on the skin's surface, precisely position (± 0.5/1 mm/degrees) the probe normal to the surface, and apply a desired amount of force (± 0.1N) to maintain firm contact for the required 60 s during THz data acquisition. The robotic automation improves the stability of the acquired THz signals, reducing the standard deviation of amplitude fluctuations by over a factor of four at 1 THz compared to hand-held mode. We show THz results for skin measurements of volunteers with healthy and dry skin conditions on various parts of the body such as the volar forearm, forehead, cheeks, and hands. The tests conducted validate the preclinical feasibility of the concept along with the robustness and advantages of using the PicoBot, compared to a manual measurement setup.

Making liquid crystals twitch under metamaterial-enhanced terahertz illumination: toward strong optical nonlinearity

We provide the first direct experimental evidence for the reorientation of liquid crystals by polarized radiation from a conventional, low power, oscillator-based terahertz time-domain spectrometer. Using a terahertz pump - optical probe setup, we observed that the reorientation occurs locally through the resonant amplification of the terahertz field in a specially designed planar metamaterial, adjacent to the liquid crystal layer, and increases with increasing incident terahertz intensity. Our work thus demonstrates that it is possible to induce strong optical nonlinearity in liquid crystals in the terahertz part of the spectrum, paving the way toward the development of new all-optical active terahertz devices as well as electric field sensors for localized resonant systems.

Novel Octa-Structure Metamaterial Architecture for High Q-Factor and High Sensitivity in THz Impedance Spectroscopy

Terahertz (THz) electric inductive-capacitive (ELC) resonant metamaterials (MMs) are well established tools that can be used to detect the presence of dielectric material (e.g., nanoparticles, bioparticles, etc.) spread on their surfaces within the gap of the capacitive plates of a nanoantenna array. In THz spectroscopy, the amount of the red shift in the resonance frequency (ΔF) plays an important role in the detection of nanoparticles and their concentration. We introduce a new LC resonant MM architecture in the ELC category that maximizes dielectric sensitivity. The newly proposed architecture has an octahedral structure with uniform capacitive gaps at each forty-five-degree interval, making the structure super-symmetric and polarization independent. The inductor core is condensed into a central solid circle connecting all the eight lobes of the octahedron, thereby completing the LC circuit. This ELC resonator has very large active areas (capacitor-gaps), with hotspots at the periphery of each unit cell. The MM structure is repeated in a clustered fashion, so that the peripheral hotspots are also utilized in dielectric sensing. This results in enhancing the quality factor of MM resonance, as well as in increasing ΔF. The research comprises a combination of rigorous system-level simulations along with THz impedance spectroscopy laboratory experiments. We achieved a highly sensitive MM sensor with sensitivity reaching 1600 GHz/RIU. This sensor is fully CMOS compatible and has promising potential applications in high-sensitivity bio-sensing, characterization of nanoparticles, and ultra-low-concentration dielectrics detection, as well as in sensing differential changes in the composition of substances deposited on the metasurface.

Statistical Analysis of Gastric Cancer Cells Response to Broadband Terahertz Radiation with and without Contrast Nanoparticles

The paper describes the statistical analysis of the response of gastric cancer cells and normal cells to broadband terahertz radiation up to 4 THz, both with and without the use of nanostructured contrast agents. The THz spectroscopy analysis was comparatively performed under the ATR procedure and transmission measurement procedure. The statistical analysis was conducted towards multiple pairwise comparisons, including a support medium (without cells) versus a support medium with nanoparticles, normal cells versus normal cells with nanoparticles, and, respectively, tumor cells versus tumor cells with nanoparticles. When generally comparing the ATR procedure and transmission measurement procedure for a broader frequency domain, the differentiation between normal and tumor cells in the presence of contrast agents is superior when using the ATR procedure. THz contrast enhancement by using contrast agents derived from MRI-related contrast agents leads to only limited benefits and only for narrow THz frequency ranges, a disadvantage for THz medical imaging.

Terahertz Spectra of Mannitol and Erythritol: A Joint Experimental and Computational Study

Sugar substitutes, which generally refer to a class of food additives, mostly have vibration frequencies within the terahertz (THz) band. Therefore, THz technology can be used to analyze their molecular properties. To understand the characteristics of sugar substitutes, this study selected mannitol and erythritol as representatives. Firstly, PXRD and Raman techniques were used to determine the crystal structure and purity of mannitol and erythritol. Then, the THz time-domain spectroscopy (THz-TDS) system was employed to measure the spectral properties of the two sugar substitutes. Additionally, density functional theory (DFT) was utilized to simulate the crystal configurations of mannitol and erythritol. The experimental results showed good agreement with the simulation results. Finally, microfluidic chip technology was used to measure the THz spectroscopic properties of the two sugar substitutes in solution. A comparison was made between their solid state and aqueous solution state, revealing a strong correlation between the THz spectra of the two sugar substitutes in both states. Additionally, it was found that the THz spectrum of a substance in solution is related to its concentration. This study provides a reference for the analysis of sugar substitutes.

Consumer electronics based smart technologies for enhanced terahertz healthcare having an integration of split learning with medical imaging

The proposed work contains three major contribution, such as smart data collection, optimized training algorithm and integrating Bayesian approach with split learning to make privacy of the patent data. By integrating consumer electronics device such as wearable devices, and the Internet of Things (IoT) taking THz image, perform EM algorithm as training, used newly proposed slit learning method the technology promises enhanced imaging depth and improved tissue contrast, thereby enabling early and accurate disease detection the breast cancer disease. In our hybrid algorithm, the breast cancer model achieves an accuracy of 97.5 percent over 100 epochs, surpassing the less accurate old models which required a higher number of epochs, such as 165.

Biomarkers in Cancer Detection, Diagnosis, and Prognosis

Biomarkers are vital in healthcare as they provide valuable insights into disease diagnosis, prognosis, treatment response, and personalized medicine. They serve as objective indicators, enabling early detection and intervention, leading to improved patient outcomes and reduced costs. Biomarkers also guide treatment decisions by predicting disease outcomes and facilitating individualized treatment plans. They play a role in monitoring disease progression, adjusting treatments, and detecting early signs of recurrence. Furthermore, biomarkers enhance drug development and clinical trials by identifying suitable patients and accelerating the approval process. In this review paper, we described a variety of biomarkers applicable for cancer detection and diagnosis, such as imaging-based diagnosis (CT, SPECT, MRI, and PET), blood-based biomarkers (proteins, genes, mRNA, and peptides), cell imaging-based diagnosis (needle biopsy and CTC), tissue imaging-based diagnosis (IHC), and genetic-based biomarkers (RNAseq, scRNAseq, and spatial transcriptomics).

Terahertz Detectors Using Microelectromechanical System Resonators

The doubly clamped microelectromechanical system (MEMS) beam resonators exhibit extremely high sensitivity to tiny changes in the resonance frequency owing to their high quality (Q-) factors, even at room temperature. Such a sensitive frequency-shift scheme is very attractive for fast and highly sensitive terahertz (THz) detection. The MEMS resonator absorbs THz radiation and induces a temperature rise, leading to a shift in its resonance frequency. This frequency shift is proportional to the amount of THz radiation absorbed by the resonator and can be detected and quantified, thereby allowing the THz radiation to be measured. In this review, we present an overview of the THz bolometer based on the doubly clamped MEMS beam resonators in the aspects of working principle, readout, detection speed, sensitivity, and attempts at improving the performance. This allows one to have a comprehensive view of such a novel THz detector.

Recent Progress in Micro- and Nanotechnology-Enabled Sensors for Biomedical and Environmental Challenges

Micro- and nanotechnology-enabled sensors have made remarkable advancements in the fields of biomedicine and the environment, enabling the sensitive and selective detection and quantification of diverse analytes. In biomedicine, these sensors have facilitated disease diagnosis, drug discovery, and point-of-care devices. In environmental monitoring, they have played a crucial role in assessing air, water, and soil quality, as well as ensured food safety. Despite notable progress, numerous challenges persist. This review article addresses recent developments in micro- and nanotechnology-enabled sensors for biomedical and environmental challenges, focusing on enhancing basic sensing techniques through micro/nanotechnology. Additionally, it explores the applications of these sensors in addressing current challenges in both biomedical and environmental domains. The article concludes by emphasizing the need for further research to expand the detection capabilities of sensors/devices, enhance sensitivity and selectivity, integrate wireless communication and energy-harvesting technologies, and optimize sample preparation, material selection, and automated components for sensor design, fabrication, and characterization.

Evaluating Hyperbolic Dispersion Materials for Cancer Detection

Current biosensors have limited application in clinical diagnostics as they lack the high order of specificity needed to detect low molecular analytes, especially in complex fluids (such as blood, urine, and saliva). In contrast, they are resistant to the suppression of non-specific binding. Hyperbolic metamaterials (HMMs) offer highly sought- after label-free detection and quantification techniques to circumvent sensitivity issues as low as 105 M concentration in angular sensitivity. This review discusses design strategies in detail and compares nuances in conventional plasmonic techniques to create susceptible miniaturized point-of-care devices. A substantial portion of the review is devoted to developing low optical loss reconfigurable HMM devices for active cancer bioassay platforms. A future perspective of HMM-based biosensors for cancer biomarker detection is provided.

Terahertz Meets AI: The State of the Art

Terahertz (THz) is a promising technology for future wireless communication networks, particularly for 6G and beyond. The ultra-wide THz band, ranging from 0.1 to 10 THz, can potentially address the limited capacity and scarcity of spectrum in current wireless systems such as 4G-LTE and 5G. Furthermore, it is expected to support advanced wireless applications requiring high data transmission and quality services, i.e., terabit-per-second backhaul systems, ultra-high-definition streaming, virtual/augmented reality, and high-bandwidth wireless communications. In recent years, artificial intelligence (AI) has been used mainly for resource management, spectrum allocation, modulation and bandwidth classification, interference mitigation, beamforming, and medium access control layer protocols to improve THz performance. This survey paper examines the use of AI in state-of-the-art THz communications, discussing the challenges, potentials, and shortcomings. Additionally, this survey discusses the available platforms, including commercial, testbeds, and publicly available simulators for THz communications. Finally, this survey provides future strategies for improving the existing THz simulators and using AI methods, including deep learning, federated learning, and reinforcement learning, to improve THz communications.