K. Vijayakumar , S. Subha , N.K. Anushkannan , Kumaravel Kaliaperumal , U. Arun Kumar
{"title":"Multimetallic graphene-coated THz metasurface biosensor for high-sensitivity hCG detection in pregnancy testing: A simulation study","authors":"K. Vijayakumar , S. Subha , N.K. Anushkannan , Kumaravel Kaliaperumal , U. Arun Kumar","doi":"10.1016/j.sintl.2025.100351","DOIUrl":"10.1016/j.sintl.2025.100351","url":null,"abstract":"<div><div>Conventional pregnancy testing methods face significant limitations including low sensitivity, cross-reactivity issues, and requirement for sophisticated laboratory equipment, particularly in resource-limited settings. This research introduces an innovative terahertz (THz) biosensor using a graphene-metallic hybrid metasurface architecture to improve pregnancy detection by optical sensing of human chorionic gonadotropin (hCG) indicators. The sensor demonstrates remarkable performance with a maximum sensitivity of 1000 GHz/RIU achieved at the optimal resonant frequency of 0.309 THz within the 0.1–0.55 THz frequency band, corresponding to a refractive index of 1.343 RIU. The frequency-dependent sensitivity analysis reveals that the maximum sensitivity of 1000 GHz/RIU is achieved at 0.309 THz, where the electromagnetic field enhancement reaches its peak value. This optimal operating point corresponds to the fundamental resonance mode of the hybrid metasurface structure, where the coupling between the central graphene resonator and the surrounding metallic rings creates the strongest field localization. The sensitivity decreases progressively at frequencies away from this resonant peak, with values of 500 GHz/RIU at 0.310 THz and 200 GHz/RIU at 0.311 THz, demonstrating the critical importance of precise frequency tuning for optimal sensor performance. Comparative analysis shows competitive or superior performance against existing biosensor designs, offering significant potential for point-of-care pregnancy testing applications with enhanced sensitivity, real-time detection capability, and reduced sample preparation requirements.</div></div>","PeriodicalId":21733,"journal":{"name":"Sensors International","volume":"7 ","pages":"Article 100351"},"PeriodicalIF":0.0,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145044494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vaijayanthimala J , Vaishnavi K , Arun Kumar U , Dhivya R
{"title":"High-sensitivity terahertz metasensor for cervical cancer Diagnosis: Graphene modulation and XGBoost-Assisted optimization","authors":"Vaijayanthimala J , Vaishnavi K , Arun Kumar U , Dhivya R","doi":"10.1016/j.sintl.2025.100350","DOIUrl":"10.1016/j.sintl.2025.100350","url":null,"abstract":"<div><div>Cervical cancer remains a major cause of mortality, particularly in low-resource settings where traditional cytology-based screening faces challenges such as limited infrastructure and trained personnel. To address this, we present a terahertz (THz) graphene-enhanced metasurface biosensor enabling rapid, label-free detection of cervical cancer biomarkers without complex sample preparation or expensive labs. Using finite element method (FEM) simulations, we demonstrate that tuning graphene's chemical potential from 0.1 to 0.9 eV significantly modulates peak absorption from 0.223 to 1.316, providing a wide dynamic range for sensitive detection across varying sample concentrations. The sensor exhibits robust angular stability, with absorption increasing from 0.546 to 1.306 as the incident light angle shifts from 0° to 80°, ensuring reliable performance without precise optical alignment. Refractive index sensing experiments reveal frequency shifts of 50 GHz and consistently high absorption (55.16 %–56.54 %), achieving a sensitivity of 300 GHz per refractive index unit (RIU) and a figure of merit of 12 RIU<sup>−1</sup>. To enhance diagnostic accuracy, we integrated an XGBoost machine learning algorithm that analyzes the complex spectral data, achieving 86 % prediction accuracy with low error rates. This combination of advanced sensing and AI-assisted analysis offers a promising, cost-effective solution for cervical cancer screening in resource-limited environments.</div></div>","PeriodicalId":21733,"journal":{"name":"Sensors International","volume":"7 ","pages":"Article 100350"},"PeriodicalIF":0.0,"publicationDate":"2025-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144864714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A novel DHP-NH2 fluorescent dye for the determination of water content in organic solvents, rice, and aspirin: DFT calculations","authors":"Kittiporn Nakprasit , Panyakorn Taweechat , Pornthep Sompornpisut , Mongkol Sukwattanasinitt , Waroton Paisuwan , Anawat Ajavakom","doi":"10.1016/j.sintl.2025.100349","DOIUrl":"10.1016/j.sintl.2025.100349","url":null,"abstract":"<div><div>A novel aminodihydropyridine derivative (<strong>DHP-NH<sub>2</sub></strong>) was synthesized from hydrazine via a tandem cyclotrimerization of methyl propiolate. <strong>DHP-NH<sub>2</sub></strong> distinguishably exhibited either strong fluorescence in aprotic solvents or weak fluorescence in protic solvents. Its fluorescence quenching in THF and MeCN was quantitatively determined in the presence of water content, demonstrating the limit of detection (LOD) of 0.036 %wt and 0.014 %wt in THF and MeCN, respectively. The critical hydrogen-bonding interactions between water molecules and the amino group of <strong>DHP-NH<sub>2</sub></strong> were found to stabilize its excited state, supporting a quenching mechanism as confirmed by DFT/TDDFT calculations. To apply this <strong>DHP-NH<sub>2</sub></strong> probe for on-site analysis, smartphone-based photography together with the ImageJ program was employed for the moisture detection with the LOD of 0.28 %wt in MeCN. Moreover, the trace amount of moisture in organic solvents and solid samples (rice and aspirin) was successfully detected by using this developed method. In addition, we successfully immobilized the <strong>DHP</strong> derivative onto the cellulose paper to be used as a portable test strip for determining water content in MeCN by naked-eye detection.</div></div>","PeriodicalId":21733,"journal":{"name":"Sensors International","volume":"7 ","pages":"Article 100349"},"PeriodicalIF":0.0,"publicationDate":"2025-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144907781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qiming Yang , Baile Cui , Jing Jin , Lina Cheng , Xufeng Xue , Yining Yin , Wen Wang
{"title":"Review of surface acoustic wave-based gas sensors","authors":"Qiming Yang , Baile Cui , Jing Jin , Lina Cheng , Xufeng Xue , Yining Yin , Wen Wang","doi":"10.1016/j.sintl.2025.100348","DOIUrl":"10.1016/j.sintl.2025.100348","url":null,"abstract":"<div><div>Surface acoustic wave (SAW) gas-based sensors have attracted significant attention as an emerging sensing technology due to their unique micro/nano-scale acoustic sensing structures and multi-physical field coupling mechanisms, which feature high sensitivity, rapid response, wide detection range, and lightweight. This paper systematically reviews the SAW gas sensing effect and mechanisms, sensing device design and fabrication, signal acquisition and processing circuits. Potential applications in fields such as renewable energy, aerospace, defense, industrial control, and intelligent manufacturing are also discussed, followed by an outlook on future development trends.</div></div>","PeriodicalId":21733,"journal":{"name":"Sensors International","volume":"7 ","pages":"Article 100348"},"PeriodicalIF":0.0,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144713108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sameena Begum , P. Nagaraju , S. Sarika Yadav , M. Swathi
{"title":"Zinc oxide-nickel oxide-copper oxide mixed nanocomposite thin films for ammonia gas sensor applications","authors":"Sameena Begum , P. Nagaraju , S. Sarika Yadav , M. Swathi","doi":"10.1016/j.sintl.2025.100346","DOIUrl":"10.1016/j.sintl.2025.100346","url":null,"abstract":"<div><div>Mixed metal oxides are emerging materials in the gas-sensing industry because of their superior gas-sensing characteristics. ZnO-based ternary mixed-metal oxide nanocomposites were sprayed on glass substrates using the spray pyrolysis method with optimized deposition conditions by changing NiO and CuO molar concentrations. Microstructural, topographical, and chemical studies of synthesised thin films were conducted using XRD, Raman spectroscopy, TEM, FESEM, and XPS, respectively. The XRD studies showed that ZnO is hexagonal, NiO particles are cubic, and CuO has monoclinic structures. Using the Scherrer formula, the crystallite sizes of the nanocomposites were calculated and found to be in the range of 8 nm–10 nm. FESEM results indicate that the synthesised films show a uniform distribution of particles with a good porous nature. Raman spectroscopy and TEM results agree with the studies of XRD. XPS analysis also confirms the formation of ZnO-NiO-CuO composites. Using a static method, gas sensing studies were conducted towards different ammonia concentrations, starting from 5 ppm to 20 ppm, at room temperature. A ternary composite sprayed with a molar concentration of 50 wt% ZnO – 30 wt% NiO- 20 wt% CuO showed superior gas sensing properties compared to other samples with response and recovery times of 59 s and 66 s, respectively, towards 5 ppm of ammonia at room temperature due to uniformly distributed spherical nanoparticles with a highly porous and rough surface made it strong interparticle interactions, making it ideal for ammonia sensing applications.</div></div>","PeriodicalId":21733,"journal":{"name":"Sensors International","volume":"7 ","pages":"Article 100346"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144563302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Wearable sensors in Industry 4.0: Preventing work-related musculoskeletal disorders","authors":"Morteza Jalali Alenjareghi, Firdaous Sekkay, Camelia Dadouchi, Samira Keivanpour","doi":"10.1016/j.sintl.2025.100343","DOIUrl":"10.1016/j.sintl.2025.100343","url":null,"abstract":"<div><div>Work-related musculoskeletal disorders (WMSDs) are a global health and economic challenge, particularly in industrialized nations, accounting for up to 2 % of GDP losses due to disability and productivity reduction. Wearable sensors, driven by Industry 4.0 advancements, offer transformative potential for real-time ergonomic assessment and injury prevention. This systematic review analyzes 40 peer-reviewed studies (2013–2024) to evaluate the application of inertial measurement units (IMUs), electromyography (EMG) sensors, and pressure sensors in mitigating WMSD risks. Findings demonstrate that wearable technologies enhance workplace safety through real-time feedback, reducing ergonomic risks and improving productivity. Despite promising advancements, challenges such as scalability, user comfort, and data privacy persist. This review emphasizes the need for standardized protocols, ethical frameworks, and deeper integration with machine learning to optimize sensor accuracy and usability. Future research directions include advancing AI-driven predictive ergonomics, addressing privacy concerns, and improving sensor design for widespread industrial adoption. This study provides actionable insights to bridge the gap between academic research and practical deployment in diverse industrial settings.</div></div>","PeriodicalId":21733,"journal":{"name":"Sensors International","volume":"7 ","pages":"Article 100343"},"PeriodicalIF":0.0,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144563796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Dual electrochemical approaches for rapid gonorrhea DNA diagnosis","authors":"Abdulhadee Yakoh , Anaïs Charles , Panisak Boonamnaj , Sudkate Chaiyo , Sirirat Rengpipat","doi":"10.1016/j.sintl.2025.100345","DOIUrl":"10.1016/j.sintl.2025.100345","url":null,"abstract":"<div><div>Gonorrhea, caused by <em>Neisseria gonorrhoeae</em>, requires rapid diagnostics, especially with the post-pandemic surge in cases. Traditional PCR methods need specialized equipment and trained personnel, underscoring the need for alternative tools. Electrochemical biosensors offer a sensitive, portable solution but have limited reporting for gonorrhea detection. This study develops two electrochemical methods: label-free (signal-off) and labeling (signal-on). The label-free approach uses two DNA sequences and the [Fe(CN)<sub>6</sub>]<sup>3-</sup>/<sup>4-</sup> (potassium ferricyanide/ferrocyanide) redox indicator. The labeling method employs a molecularly amplified DNA sandwich assay with ferrocene-labeled helpers for signal amplification. The label-free method achieved a limit of detection (LOD) of 2.1 nM and a linear dynamic range (LDR) of 10–500 nM, while the labeling method showed an LOD of 4.8 pM and an LDR of 0.5–1000 nM. To enhance practicality, Near Field Communication (NFC)-enabled sensing was used during non-invasive urine sample testing, enabling real-time, wireless detection without sophisticated instruments. This confirmed the superior performance of the labeling method. Molecular dynamics simulations provided insights into structural dynamics, linking experimental data with computational models. This integrated approach highlights the importance of selecting methods based on sensitivity, cost, and ease of use, advancing gonorrhea DNA biosensing technologies.</div></div>","PeriodicalId":21733,"journal":{"name":"Sensors International","volume":"7 ","pages":"Article 100345"},"PeriodicalIF":0.0,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144563797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Munasir , Aditya Prapanca , Mohamad Fikri Aliansah , Frizky Audis Paramudhita , Nuhaa Faaizatunnisa , Muhammad Naufal Ariesta , Ahmad Taufiq
{"title":"Self-healing graphene-based composite hydrogels for motion Sensing: Source, fabrication, and applications in assistive technologies – A review","authors":"Munasir , Aditya Prapanca , Mohamad Fikri Aliansah , Frizky Audis Paramudhita , Nuhaa Faaizatunnisa , Muhammad Naufal Ariesta , Ahmad Taufiq","doi":"10.1016/j.sintl.2025.100338","DOIUrl":"10.1016/j.sintl.2025.100338","url":null,"abstract":"<div><div>Graphene-based self-healing hydrogels represent a significant advancement in motion sensing technologies, particularly for assistive applications aimed at improving the quality of life for individuals with disabilities. The use of renewable biomass as a feedstock for graphene production addresses environmental concerns related to traditional fossil fuel-derived methods, promoting sustainability. Unlike previous reviews that focus on general graphene or hydrogel sensors, this review specifically explores self-healing graphene-based hydrogels for wearable strain sensing in assistive technologies, with an emphasis on structure–property–performance relationships and design considerations. The review examines the conductive properties of graphene and compares production techniques, highlighting their influence on sensor performance. The role of hydrogel polymers as substrates is also discussed, with a focus on how their chemical composition and physical properties affect graphene integration and the self-healing capabilities of the composites. Fabrication and characterization methodologies are contrasted to assess their impact on material performance and sensor efficacy. Practical applications are evaluated based on sensitivity, response time, durability, and long-term stability. The review concludes with a discussion on ongoing challenges and future research directions, aiming to further advance the development of biomass-derived graphene-based motion sensing technologies.</div></div>","PeriodicalId":21733,"journal":{"name":"Sensors International","volume":"6 ","pages":"Article 100338"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143886592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hadiseh Masoumi, Amirsoheil Foroughi, Ahad Ghaemi, Hasan Farrokhzad
{"title":"Evaluation of the sensing and adsorption performance of the synthesized emeraldine salt polyaniline for CO2 elimination","authors":"Hadiseh Masoumi, Amirsoheil Foroughi, Ahad Ghaemi, Hasan Farrokhzad","doi":"10.1016/j.sintl.2025.100340","DOIUrl":"10.1016/j.sintl.2025.100340","url":null,"abstract":"<div><div>One of the paramount challenges confronting global communities is the precise measurement and effective mitigation of carbon dioxide (CO<sub>2</sub>) emissions, a primary contributor to global warming and its far-reaching impacts. This study focuses on the synthesis and characterization of polyaniline for CO<sub>2</sub> capture applications. Through experimentation conducted within a temperature range of 25–65 <span><math><mrow><mo>°C</mo></mrow></math></span> and a pressure range of 1–9 bar, the adsorption behavior of these polymers was comprehensively evaluated. Notably, polyaniline exhibited an impressive CO<sub>2</sub> adsorption capacity of 10.153 mmol/g under optimal conditions. Further analysis revealed the cyclic stability of these polymers, with polyaniline displaying a 96 % adsorption rate in the fifth cycle. Additionally, thin films of this polymer were synthesized to assess their sensing capabilities, with the thin polyaniline film exhibiting a 51.35 % response to pure CO<sub>2</sub>. Polyaniline demonstrated a linear response trend to varying CO<sub>2</sub> concentrations. Moreover, the optimal operating temperatures for the thin film sensors were determined to be 35 <span><math><mrow><mo>°C</mo></mrow></math></span>. The rapid response and recovery times for this sensor underscore their potential efficacy in real-world CO<sub>2</sub> sensing applications. In summary, the findings highlight the promising performance of polyaniline as a versatile material for CO<sub>2</sub> adsorption and sensing, offering significant implications for the development of sustainable solutions to address the pressing challenges of carbon emissions.</div></div>","PeriodicalId":21733,"journal":{"name":"Sensors International","volume":"6 ","pages":"Article 100340"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144230412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Olivia Sen , Poulami Poddar , Poulami Sarkar , Sanchita Das , Sreejan Manna
{"title":"Current advancements in microneedle technology for therapeutic and biomedical applications","authors":"Olivia Sen , Poulami Poddar , Poulami Sarkar , Sanchita Das , Sreejan Manna","doi":"10.1016/j.sintl.2024.100325","DOIUrl":"10.1016/j.sintl.2024.100325","url":null,"abstract":"<div><div>Microneedle technology has gained large interest as an innovative biomedical device to deliver molecules to the targeted site through the skin layers. Microneedle consists of microscale needle with a specific length about 0.1–1 mm. In comparison to conventional transdermal delivery approaches, the microneedle technique has several advantagesincluding minimal invasiveness, painlessand convenient administration, with higher patient compliance. Microneedles are categorized into several types such as solid microneedle, coated microneedle, hollow microneedle, dissolvable microneedle, hydrogel microneedle, swellable microneedle, and porous microneedle. Microneedles can be made of different materials, and may vary in size and forms. They may also vary in design depending on composition, manufacturing process and area of application. Silicon, stainless steel, polymers, coating materials, biodegradable materials, several crosslinking techniques and biosensing devices are used to fabricate microneedles. can be employed as a leading novel technology for drug administration, vaccinations, cosmetics, diagnostics, tissue engineering, cancer studies, and wound care. This review narrates the fabrication techniques of microneedles alongside its applications in drug delivery and biomedical field including sensory applications.</div></div>","PeriodicalId":21733,"journal":{"name":"Sensors International","volume":"6 ","pages":"Article 100325"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143099031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}