Pub Date : 2025-09-02DOI: 10.1016/j.sbsr.2025.100877
Jacob Wekalao , Hussein A. Elsayed , Ahmed Mehaney , Haifa E. Alfassam , Mostafa R. Abukhadra , Wail Al Zoubi , Amuthakkannan Rajakannu , K. Vijayalakshmi
Male infertility affects approximately 15 % of reproductive-age couples globally, with male factors contributing to roughly 50 % of infertility cases, creating an urgent need for advanced, accessible diagnostic technologies for semen analysis. Current sperm assessment protocols rely predominantly on conventional light microscopy and Computer-Assisted Sperm Analysis (CASA) systems, which suffer from subjective interpretation, high costs, and limited accessibility in resource-constrained settings. This study presents a simple graphene-based Surface Plasmon Resonance (SPR) biosensor featuring a simple resonator architecture optimized for ultrasensitive sperm detection through label-free, real-time analysis. The electromagnetic analysis using COMSOL Multiphysics 6.3 demonstrates exceptional sensitivity ranging from 118 GHzRIU−1 to 5000 GHzRIU−1 across refractive indices of 1.33–1.3461 RIU, with a maximum figure of merit of 68.493 RIU−1 and detection limits as low as 0.028 RIU. Machine learning optimization using polynomial regression achieved prediction accuracies of 87–91 % (R2 values of 94–100 %) across critical operational parameters including graphene chemical potential (0.1–0.9 eV), geometric variations, and angular dependencies (0–80°), validating the sensor's robust performance for clinical sperm analysis applications.
{"title":"Label-free graphene-based surface plasmon resonance sensor for advanced male fertility evaluation with behavior prediction via polynomial regression","authors":"Jacob Wekalao , Hussein A. Elsayed , Ahmed Mehaney , Haifa E. Alfassam , Mostafa R. Abukhadra , Wail Al Zoubi , Amuthakkannan Rajakannu , K. Vijayalakshmi","doi":"10.1016/j.sbsr.2025.100877","DOIUrl":"10.1016/j.sbsr.2025.100877","url":null,"abstract":"<div><div>Male infertility affects approximately 15 % of reproductive-age couples globally, with male factors contributing to roughly 50 % of infertility cases, creating an urgent need for advanced, accessible diagnostic technologies for semen analysis. Current sperm assessment protocols rely predominantly on conventional light microscopy and Computer-Assisted Sperm Analysis (CASA) systems, which suffer from subjective interpretation, high costs, and limited accessibility in resource-constrained settings. This study presents a simple graphene-based Surface Plasmon Resonance (SPR) biosensor featuring a simple resonator architecture optimized for ultrasensitive sperm detection through label-free, real-time analysis. The electromagnetic analysis using COMSOL Multiphysics 6.3 demonstrates exceptional sensitivity ranging from 118 GHzRIU<sup>−1</sup> to 5000 GHzRIU<sup>−1</sup> across refractive indices of 1.33–1.3461 RIU, with a maximum figure of merit of 68.493 RIU<sup>−1</sup> and detection limits as low as 0.028 RIU. Machine learning optimization using polynomial regression achieved prediction accuracies of 87–91 % (R<sup>2</sup> values of 94–100 %) across critical operational parameters including graphene chemical potential (0.1–0.9 eV), geometric variations, and angular dependencies (0–80°), validating the sensor's robust performance for clinical sperm analysis applications.</div></div>","PeriodicalId":424,"journal":{"name":"Sensing and Bio-Sensing Research","volume":"50 ","pages":"Article 100877"},"PeriodicalIF":4.9,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145011094","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}
Pub Date : 2025-09-02DOI: 10.1016/j.sbsr.2025.100874
Md. Ismail Hossen , Saif Hannan , Heba G. Mohamed , Abdulwadoud A. Maash , Mohamad A. Alawad , Mohammad Tariqul Islam
This paper presents a staircase-shaped microwave metamaterial sensor designed for accurate oil detection in the S and C frequency bands. The sensor shows very high absorption, reaching 99.91 % at 3.6 GHz and 99.74 % at 5 GHz, and maintains stable performance even when the incident wave angle changes up to 180°. It is compact, with a unit cell size of only 0.144λ × 0.144λ, and has a high effective medium ratio (EMR) of 6.94. The sensor also demonstrates unique electromagnetic properties such as near-zero permittivity, permeability, and refractive index, along with single-negative behavior. An equivalent RLC circuit was developed in ADS software to verify its radio-frequency characteristics, and the results matched well with simulations. The sensor achieved a sensitivity of 2.59, a quality factor of 26.604, and a figure of merit of 43.19, proving its accuracy and reliability. Thanks to its low cost, high sensitivity, and wide usability, this sensor is a strong candidate for applications such as liquid detection, oil sensing, and microfluidic sensing.
{"title":"Square split enclosed by staircase-shaped metamaterial absorber for oil sensing applications","authors":"Md. Ismail Hossen , Saif Hannan , Heba G. Mohamed , Abdulwadoud A. Maash , Mohamad A. Alawad , Mohammad Tariqul Islam","doi":"10.1016/j.sbsr.2025.100874","DOIUrl":"10.1016/j.sbsr.2025.100874","url":null,"abstract":"<div><div>This paper presents a staircase-shaped microwave metamaterial sensor designed for accurate oil detection in the S and C frequency bands. The sensor shows very high absorption, reaching 99.91 % at 3.6 GHz and 99.74 % at 5 GHz, and maintains stable performance even when the incident wave angle changes up to 180°. It is compact, with a unit cell size of only 0.144λ × 0.144λ, and has a high effective medium ratio (EMR) of 6.94. The sensor also demonstrates unique electromagnetic properties such as near-zero permittivity, permeability, and refractive index, along with single-negative behavior. An equivalent RLC circuit was developed in ADS software to verify its radio-frequency characteristics, and the results matched well with simulations. The sensor achieved a sensitivity of 2.59, a quality factor of 26.604, and a figure of merit of 43.19, proving its accuracy and reliability. Thanks to its low cost, high sensitivity, and wide usability, this sensor is a strong candidate for applications such as liquid detection, oil sensing, and microfluidic sensing.</div></div>","PeriodicalId":424,"journal":{"name":"Sensing and Bio-Sensing Research","volume":"50 ","pages":"Article 100874"},"PeriodicalIF":4.9,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145047030","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}
Bacterial infections related to Listeria monocytogenes can lead to serious pathological conditions such as meningitis and meningoencephalitis in humans. Therefore, the detection of Listeria particles and byproducts is a very important issue in clinical settings. Nanostructures have been broadly utilized in different areas because of their unique physicochemical properties. Specifically, bimetallic nanostructures have been employed in the development of smart biosensor types. In the study, a simple and efficient platform utilizing bimetallic nanostructures was developed to create a diagnostic system for Listeria monocytogenes. The Au@Pt core-shell structure was synthesized and electrodeposited the glassy carbon electrode (GCE). A 24-mer thiolated single-strand probe, targeting the hly gene, was immobilized on the Au@Pt modified GCE to hybridize with the target sequence. Then, the electrochemical measurement with square wave voltammetry (SWV) technique was done to ensure the hybridization reaction. The biosensor's efficiency was validated using standard addition in real cerebrospinal fluid (CSF) samples, to assess biosensor specificity in the detection of bacterial genomics in biofluids. The obtained results indicate that the designed biosensor was able to detect the target genomic sequences. This platform was capable of detecting targets in 5 to 60 attomolar and was proved as a practical detection limit. It is suggested that the designed platform with high sensitivity and specificity for the detection of target gene sequences in biofluids.
{"title":"Bimetallic core-shell nano-architecture of Au@Pt as an effective electrochemical mediator for ultrasensitive detection of Listeria monocytogenes in cerebrospinal fluid","authors":"Leila Mehrannia , Morteza Milani , Balal Khalilzadeh , Abolfazl Barzegari , Solmaz Sadi , Mohammad Reza Rashidi","doi":"10.1016/j.sbsr.2025.100873","DOIUrl":"10.1016/j.sbsr.2025.100873","url":null,"abstract":"<div><div>Bacterial infections related to <em>Listeria monocytogenes</em> can lead to serious pathological conditions such as meningitis and meningoencephalitis in humans. Therefore, the detection of <em>Listeria</em> particles and byproducts is a very important issue in clinical settings. Nanostructures have been broadly utilized in different areas because of their unique physicochemical properties. Specifically, bimetallic nanostructures have been employed in the development of smart biosensor types. In the study, a simple and efficient platform utilizing bimetallic nanostructures was developed to create a diagnostic system for <em>Listeria monocytogenes</em>. The Au@Pt core-shell structure was synthesized and electrodeposited the glassy carbon electrode (GCE). A 24-mer thiolated single-strand probe, targeting the hly gene, was immobilized on the Au@Pt modified GCE to hybridize with the target sequence. Then, the electrochemical measurement with square wave voltammetry (SWV) technique was done to ensure the hybridization reaction. The biosensor's efficiency was validated using standard addition in real cerebrospinal fluid (CSF) samples, to assess biosensor specificity in the detection of bacterial genomics in biofluids. The obtained results indicate that the designed biosensor was able to detect the target genomic sequences. This platform was capable of detecting targets in 5 to 60 attomolar and was proved as a practical detection limit. It is suggested that the designed platform with high sensitivity and specificity for the detection of target gene sequences in biofluids.</div></div>","PeriodicalId":424,"journal":{"name":"Sensing and Bio-Sensing Research","volume":"50 ","pages":"Article 100873"},"PeriodicalIF":4.9,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144989834","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}
Pub Date : 2025-09-02DOI: 10.1016/j.sbsr.2025.100871
Abhilash Krishnamurthy , Kristina Žagar Soderžnik
Performance drift in electrochemical sensors remains a challenge in long-term and/or corrosive applications. We present a generalisable, in situ diagnostic framework based on electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), using screen-printed electrodes (SPE) and benzenediols (catechol, resorcinol and hydroquinone) in acidic media as a model system. Two sensor types, unmodified and Pt/C-modified SPEs, were tested across repeated CV cycles, with polarisation resistance (RP) and effective capacitance (Ceff) extracted from equivalent circuit models.
Unmodified SPEs showed progressive activation, while modified SPEs exhibited early improvement followed by degradation. To synthesise trends across RP, Ceff, and net charge transfer (Qₙ) obtained from CV data, principal component analysis (PCA) was applied. PCA revealed smooth, directional evolution for unmodified SPEs and disordered, non-monotonic drift in modified SPEs, reinforcing the EIS results.
This approach enables online, non-destructive tracking of electrochemical sensor health and offers a transferable framework for performance assurance, quality control, and lifecycle monitoring. It repositions EIS from static characterisation to an embedded, multivariate diagnostic tool.
{"title":"Multivariate diagnostics of electrochemical sensor drift by in situ impedance spectroscopy and voltammetry: A benzenediol-based framework","authors":"Abhilash Krishnamurthy , Kristina Žagar Soderžnik","doi":"10.1016/j.sbsr.2025.100871","DOIUrl":"10.1016/j.sbsr.2025.100871","url":null,"abstract":"<div><div>Performance drift in electrochemical sensors remains a challenge in long-term and/or corrosive applications. We present a generalisable<em>,</em> in situ diagnostic framework based on electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), using screen-printed electrodes (SPE) and benzenediols (catechol, resorcinol and hydroquinone) in acidic media as a model system. Two sensor types, unmodified and Pt/C-modified SPEs, were tested across repeated CV cycles, with polarisation resistance (<em>R</em><sub><em>P</em></sub>) and effective capacitance (<em>C</em><sub><em>eff</em></sub>) extracted from equivalent circuit models.</div><div>Unmodified SPEs showed progressive activation, while modified SPEs exhibited early improvement followed by degradation. To synthesise trends across <em>R</em><sub><em>P</em></sub>, <em>C</em><sub><em>eff</em></sub>, and net charge transfer (<em>Qₙ</em>) obtained from CV data, principal component analysis (PCA) was applied. PCA revealed smooth, directional evolution for unmodified SPEs and disordered, non-monotonic drift in modified SPEs, reinforcing the EIS results.</div><div>This approach enables online, non-destructive tracking of electrochemical sensor health and offers a transferable framework for performance assurance, quality control, and lifecycle monitoring. It repositions EIS from static characterisation to an embedded, multivariate diagnostic tool.</div></div>","PeriodicalId":424,"journal":{"name":"Sensing and Bio-Sensing Research","volume":"50 ","pages":"Article 100871"},"PeriodicalIF":4.9,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020480","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}
Pub Date : 2025-09-01DOI: 10.1016/j.sbsr.2025.100872
M.V. Arularasu , V. Vetrivelan , A. Muthukrishnaraj , Manikandan Ayyar , D.S. Vijayan , S. Sathiyamurthy , Prabhu Paramasivam , Sandeep Kumar , Gaurav Kumar
Humidity sensors play a crucial role in non-contact measurements, particularly in environmental monitoring and healthcare systems. Among various materials, semiconductor metal oxides have gained significant attention due to their favorable physicochemical and electrical properties, making them ideal candidates for humidity sensing applications. In this study, cerium oxide (CeO₂) nanoparticles (NPs) were synthesized via a green synthesis route using Morinda tinctoria leaf extract, inspired by biomimetic processes. Comprehensive characterization techniques-including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and UV–Vis spectroscopy-were employed to evaluate the structural, functional, morphological, elemental, and optical features of the synthesized NPs. XRD confirmed the formation of pure, crystalline CeO₂ in the cubic phase without any metallic Ce impurities. Microscopy revealed a porous morphology, contributing significantly to the enhanced humidity sensing performance. The sensor exhibited high sensitivity to relative humidity (RH) across the range of 5 %–98 % at room temperature, with a resistance variation of up to 2218 Ω—demonstrating a five-order magnitude response and excellent linearity. Moreover, the sensor showed rapid response and recovery times of 23 and 44 s, respectively, along with good long-term stability. These eco-friendly and cost-effective CeO₂-based humidity sensors are well-suited for agriculture and humidity monitoring applications. To further understand the sensing mechanism, density functional theory (DFT) calculations were performed. Topological analysis using electron localization function (ELF) maps elucidated the nature of bonding in CeO₂ and its interaction with water molecules.
{"title":"Humidity sensing application of CeO2 nanoparticles: mechanism interpretation with density functional theory","authors":"M.V. Arularasu , V. Vetrivelan , A. Muthukrishnaraj , Manikandan Ayyar , D.S. Vijayan , S. Sathiyamurthy , Prabhu Paramasivam , Sandeep Kumar , Gaurav Kumar","doi":"10.1016/j.sbsr.2025.100872","DOIUrl":"10.1016/j.sbsr.2025.100872","url":null,"abstract":"<div><div>Humidity sensors play a crucial role in non-contact measurements, particularly in environmental monitoring and healthcare systems. Among various materials, semiconductor metal oxides have gained significant attention due to their favorable physicochemical and electrical properties, making them ideal candidates for humidity sensing applications. In this study, cerium oxide (CeO₂) nanoparticles (NPs) were synthesized via a green synthesis route using <em>Morinda tinctoria</em> leaf extract, inspired by biomimetic processes. Comprehensive characterization techniques-including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and UV–Vis spectroscopy-were employed to evaluate the structural, functional, morphological, elemental, and optical features of the synthesized NPs. XRD confirmed the formation of pure, crystalline CeO₂ in the cubic phase without any metallic Ce impurities. Microscopy revealed a porous morphology, contributing significantly to the enhanced humidity sensing performance. The sensor exhibited high sensitivity to relative humidity (RH) across the range of 5 %–98 % at room temperature, with a resistance variation of up to 2218 Ω—demonstrating a five-order magnitude response and excellent linearity. Moreover, the sensor showed rapid response and recovery times of 23 and 44 s, respectively, along with good long-term stability. These eco-friendly and cost-effective CeO₂-based humidity sensors are well-suited for agriculture and humidity monitoring applications. To further understand the sensing mechanism, density functional theory (DFT) calculations were performed. Topological analysis using electron localization function (ELF) maps elucidated the nature of bonding in CeO₂ and its interaction with water molecules.</div></div>","PeriodicalId":424,"journal":{"name":"Sensing and Bio-Sensing Research","volume":"50 ","pages":"Article 100872"},"PeriodicalIF":4.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145027427","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}
Pub Date : 2025-09-01DOI: 10.1016/j.sbsr.2025.100876
McKenzie Bradley , Sydnee Barrett , Ty McKelvey, Jeremiah Carpenter, Delphine Dean
Melanin, the primary determinant of skin pigmentation, absorbs light at wavelengths that can have significant impact on the accuracy of pulse oximetry and other optical biosensing methods. This narrative review examines key factors influencing melanin-dependent pulse oximetry inaccuracies, including optical interference in transmission and reflectance modes. These inaccuracies further highlight the need for use of standardized skin tone metrics in device testing and design such as the Monk Skin Tone scale and Individual Typology Angle for performance stratification. There are several approaches in development that hope to address the errors in pulse oximetry measurements on melanin-rich skin. These include algorithmic and engineering approaches such as multi-wavelength sensing, regression-based correction, and machine learning models demonstrating significant reductions in melanin-induced error. Advances in pulse oximeter hardware and testing are also considered, including tissue-mimicking phantoms, optimized light sources, sensor design, and wearable innovations. Modeling tools, particularly Monte Carlo simulations, are also reviewed for their role in sensor design, spectral optimization, and algorithm training. Finally, evolving regulatory and equity frameworks are discussed, highlighting the January 2025 US FDA guidance on skin tone subgroup reporting. These findings underscore the need for skin-aware calibration and integrated modeling to ensure equitable pulse oximetry performance across diverse populations.
{"title":"Mitigating melanin-induced bias in pulse oximetry: Optical, algorithmic, engineering, hardware and modeling tools","authors":"McKenzie Bradley , Sydnee Barrett , Ty McKelvey, Jeremiah Carpenter, Delphine Dean","doi":"10.1016/j.sbsr.2025.100876","DOIUrl":"10.1016/j.sbsr.2025.100876","url":null,"abstract":"<div><div>Melanin, the primary determinant of skin pigmentation, absorbs light at wavelengths that can have significant impact on the accuracy of pulse oximetry and other optical biosensing methods. This narrative review examines key factors influencing melanin-dependent pulse oximetry inaccuracies, including optical interference in transmission and reflectance modes. These inaccuracies further highlight the need for use of standardized skin tone metrics in device testing and design such as the Monk Skin Tone scale and Individual Typology Angle for performance stratification. There are several approaches in development that hope to address the errors in pulse oximetry measurements on melanin-rich skin. These include algorithmic and engineering approaches such as multi-wavelength sensing, regression-based correction, and machine learning models demonstrating significant reductions in melanin-induced error. Advances in pulse oximeter hardware and testing are also considered, including tissue-mimicking phantoms, optimized light sources, sensor design, and wearable innovations. Modeling tools, particularly Monte Carlo simulations, are also reviewed for their role in sensor design, spectral optimization, and algorithm training. Finally, evolving regulatory and equity frameworks are discussed, highlighting the January 2025 US FDA guidance on skin tone subgroup reporting. These findings underscore the need for skin-aware calibration and integrated modeling to ensure equitable pulse oximetry performance across diverse populations.</div></div>","PeriodicalId":424,"journal":{"name":"Sensing and Bio-Sensing Research","volume":"50 ","pages":"Article 100876"},"PeriodicalIF":4.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155267","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}
Pub Date : 2025-08-01DOI: 10.1016/j.sbsr.2025.100865
Michael B. Nelappana , Catherine C. Applegate , Leopold J.B. Pinot , Elaine A. Nielsen , Karl Baumgartel , Goodluck Okoro , Leszek Kalinowski , Iwona T. Dobrucki , Lawrence W. Dobrucki
Alteration of blood perfusion leads to some of the most common cardiovascular pathologies. Current methods for measuring perfusion use fluorescent polystyrene microspheres (MS) that are systemically injected prior to processing to obtain the absolute number of MS trapped inside the tissue. The current standard method is cost-intensive and carries a high risk of MS loss, leading to underestimation of regional perfusion. This study aimed to develop an improved, cost-efficient protocol for measuring regional perfusion through the processing and direct imaging of fluorescent MS embedded ex vivo. Porcine and control samples treated with MS were chemically digested, filtered through either a polycarbonate (PCTE) or cellulose filter, and fluorescence was measured either through the standard fluorometric method or through the proposed direct imaging method. In the standard fluorometric method, interactions were found between the PCTE filter and porcine samples, leading to dampened signal and the subsequent underestimation of regional perfusion in practice. The proposed direct imaging method with cellulose filters showed improved sensitivity even within low MS levels (limit of detection improved significantly), amplification of sample fluorescence (11-13× when compared to PCTE filters), parity between porcine and control samples, and a reduction in cost providing a significant improvement over the industry standard for fluorescent MS perfusion measurement (28–51 % reduction compared to standard method). The proposed method also removed the need for 2-ethoxy ethyl acetate, a teratogen and plastic softener, and reduced complexity in the workflow.
{"title":"Development of a novel protocol for processing fluorescent microspheres used in quantifying tissue perfusion","authors":"Michael B. Nelappana , Catherine C. Applegate , Leopold J.B. Pinot , Elaine A. Nielsen , Karl Baumgartel , Goodluck Okoro , Leszek Kalinowski , Iwona T. Dobrucki , Lawrence W. Dobrucki","doi":"10.1016/j.sbsr.2025.100865","DOIUrl":"10.1016/j.sbsr.2025.100865","url":null,"abstract":"<div><div>Alteration of blood perfusion leads to some of the most common cardiovascular pathologies. Current methods for measuring perfusion use fluorescent polystyrene microspheres (MS) that are systemically injected prior to processing to obtain the absolute number of MS trapped inside the tissue. The current standard method is cost-intensive and carries a high risk of MS loss, leading to underestimation of regional perfusion. This study aimed to develop an improved, cost-efficient protocol for measuring regional perfusion through the processing and direct imaging of fluorescent MS embedded ex vivo. Porcine and control samples treated with MS were chemically digested, filtered through either a polycarbonate (PCTE) or cellulose filter, and fluorescence was measured either through the standard fluorometric method or through the proposed direct imaging method. In the standard fluorometric method, interactions were found between the PCTE filter and porcine samples, leading to dampened signal and the subsequent underestimation of regional perfusion in practice. The proposed direct imaging method with cellulose filters showed improved sensitivity even within low MS levels (limit of detection improved significantly), amplification of sample fluorescence (11-13× when compared to PCTE filters), parity between porcine and control samples, and a reduction in cost providing a significant improvement over the industry standard for fluorescent MS perfusion measurement (28–51 % reduction compared to standard method). The proposed method also removed the need for 2-ethoxy ethyl acetate, a teratogen and plastic softener, and reduced complexity in the workflow.</div></div>","PeriodicalId":424,"journal":{"name":"Sensing and Bio-Sensing Research","volume":"49 ","pages":"Article 100865"},"PeriodicalIF":4.9,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144907262","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}
Pub Date : 2025-08-01DOI: 10.1016/j.sbsr.2025.100866
Maria-Bianca Irimes , Alexandra Pusta , Daniel Coker , Paul Cristian Martian , Maria Suciu , Stanca-Lucia Pandrea , Mihaela Tertis , Cecilia Cristea , Radu Oprean
Cytokines are key signaling biomolecules involved in cell growth, immune regulation, inflammation, and cancer-related processes, being valuable biomarkers for diagnosing medical conditions, assessing prognosis, and monitoring treatment efficacy. This study aimed to develop a customized platform enabling the simultaneous electrochemical detection of Interleukin-6 (IL-6) and Tumor Necrosis Factor-α (TNF-α) in biological fluids.
The platform was fabricated using in-lab printed electrochemical cells. The working electrode was functionalized with Au and Pt nanoparticles to enhance detection sensitivity. The specificity towards the targets was achieved by immobilizing two distinct aptamers, each labeled with a different redox probe, allowing parallel signal readouts and implicitly the simultaneous detection of the two biomarkers. The aptasensor demonstrated simultaneous detection of IL-6 and TNF-α within a linear range of 5–5000 pg/mL, achieving a limit of detection of 1.6 pg/mL. The dual-target aptasensor was validated using real biological samples, including raw saliva and sweat, collected from patients and healthy individuals. Results obtained from the aptasensor were cross-verified with ELISA and validated through statistical analysis.
{"title":"Dual-target electrochemical aptasensor for the simultaneous detection of interleukin-6 and tumor necrosis factor-α in biological fluids","authors":"Maria-Bianca Irimes , Alexandra Pusta , Daniel Coker , Paul Cristian Martian , Maria Suciu , Stanca-Lucia Pandrea , Mihaela Tertis , Cecilia Cristea , Radu Oprean","doi":"10.1016/j.sbsr.2025.100866","DOIUrl":"10.1016/j.sbsr.2025.100866","url":null,"abstract":"<div><div>Cytokines are key signaling biomolecules involved in cell growth, immune regulation, inflammation, and cancer-related processes, being valuable biomarkers for diagnosing medical conditions, assessing prognosis, and monitoring treatment efficacy. This study aimed to develop a customized platform enabling the simultaneous electrochemical detection of Interleukin-6 (IL-6) and Tumor Necrosis Factor-α (TNF-α) in biological fluids.</div><div>The platform was fabricated using in-lab printed electrochemical cells. The working electrode was functionalized with Au and Pt nanoparticles to enhance detection sensitivity. The specificity towards the targets was achieved by immobilizing two distinct aptamers, each labeled with a different redox probe, allowing parallel signal readouts and implicitly the simultaneous detection of the two biomarkers. The aptasensor demonstrated simultaneous detection of IL-6 and TNF-α within a linear range of 5–5000 pg/mL, achieving a limit of detection of 1.6 pg/mL. The dual-target aptasensor was validated using real biological samples, including raw saliva and sweat, collected from patients and healthy individuals. Results obtained from the aptasensor were cross-verified with ELISA and validated through statistical analysis.</div></div>","PeriodicalId":424,"journal":{"name":"Sensing and Bio-Sensing Research","volume":"49 ","pages":"Article 100866"},"PeriodicalIF":4.9,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144865685","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}
This research presents a novel, cost-efficient and high-performance method for preconcentration and detection of lead ions [Pb(II)] using ultrasound-assisted dispersive liquid-liquid microextraction (USA-DLLME) combined with digital image colorimetry (DIC). The extraction phase included a natural deep eutectic solvent (NADES) made from choline chloride and thymol. The digital colorimetric analysis is based on the color transition of the Pb(II)[1-(2-pyridylazo)-2-naphthol (PAN)]2 complex, which changes from orange to wine red color in ethanol. The images of the NADES solution containing Pb(II) complex were captured using an Android smartphone and processed with the Color Grab application. Under the optimum conditions, a calibration curve for Pb(II) was constructed using the green channel intensity over the concentration range of 10 to 300 ng/mL, yielding a strong linear correlation (R2 = 0.9929). The detection limit and quantification limit were determined as 5.21 ng/mL and 17.38 ng/mL, respectively. The method demonstrated good precision with relative standard deviations (RSD) of 1.02 % within a single day and 1.25 % across multiple days. Finally, the current method was successfully applied to quantify the Pb(II) in mineral, tap and river water samples, achieving relative recoveries between 94.0 % and 102.5 %, confirming its reliability and suitability for analyzing real water samples.
{"title":"Ultrasound-assisted DLLME with natural deep eutectic solvent and smartphone-based colorimetry for Pb(II) detection in water","authors":"Nayyer Azhdari , Biuck Habibi , Zahra Ayazi , Elaheh Rahimpour","doi":"10.1016/j.sbsr.2025.100867","DOIUrl":"10.1016/j.sbsr.2025.100867","url":null,"abstract":"<div><div>This research presents a novel, cost-efficient and high-performance method for preconcentration and detection of lead ions [Pb(II)] using ultrasound-assisted dispersive liquid-liquid microextraction (USA-DLLME) combined with digital image colorimetry (DIC). The extraction phase included a natural deep eutectic solvent (NADES) made from choline chloride and thymol. The digital colorimetric analysis is based on the color transition of the Pb(II)[1-(2-pyridylazo)-2-naphthol (PAN)]<sub>2</sub> complex, which changes from orange to wine red color in ethanol. The images of the NADES solution containing Pb(II) complex were captured using an Android smartphone and processed with the Color Grab application. Under the optimum conditions, a calibration curve for Pb(II) was constructed using the green channel intensity over the concentration range of 10 to 300 ng/mL, yielding a strong linear correlation (R<sup>2</sup> = 0.9929). The detection limit and quantification limit were determined as 5.21 ng/mL and 17.38 ng/mL, respectively. The method demonstrated good precision with relative standard deviations (RSD) of 1.02 % within a single day and 1.25 % across multiple days. Finally, the current method was successfully applied to quantify the Pb(II) in mineral, tap and river water samples, achieving relative recoveries between 94.0 % and 102.5 %, confirming its reliability and suitability for analyzing real water samples.</div></div>","PeriodicalId":424,"journal":{"name":"Sensing and Bio-Sensing Research","volume":"49 ","pages":"Article 100867"},"PeriodicalIF":4.9,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144888782","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}
Pub Date : 2025-08-01DOI: 10.1016/j.sbsr.2025.100850
Yu Zhang , Hanneke M. van Santen , Ruben E.A. Musson , Panos Markopoulos , Yuan Lu
The human body maintains plasma sodium concentration within a narrow range of 135 to 145 mmol/L to ensure homeostasis. Being outside this range denotes hyponatremia (below 135 mmol/L) or hypernatremia (above 145 mmol/L), which can cause serious health problems. Current sodium monitoring is performed using point-of-care devices, which require blood sampling every time. It is cumbersome and uncomfortable for patients who require frequent sodium measurements daily. It would be ideal to continuously monitor plasma sodium concentration to reduce burden and detect abnormalities earlier. The sodium concentration in interstitial fluid is close to plasma sodium. Thus, this scoping review presents the current technological developments for continuous sodium monitoring (CSM) in plasma or interstitial fluid. The study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis extension for Scoping Reviews (PRISMA-ScR) checklist. 11 articles that presented technologies for the continuous monitoring of sodium concentrations in plasma or interstitial fluid with at least a technology readiness level of four were included for review. Seven of them presented microneedle(MN)-based solutions for CSM, and the remaining four were fluorescence(FS)-based. MN-based sodium sensors are all-solid-state sodium ion-selective electrodes designed as MN arrays or standalone MNs. FS-based CSM technologies inject sodium-sensitive fluorophores into the bloodstream or subcutaneously to reflect local sodium concentrations. Comparison of these two technological paths based on expected patient experience revealed that MN-based technologies appear more feasible for daily use and promising for further development due to their minimal invasiveness and compact wearability.
{"title":"Currently available technologies for continuous sodium monitoring in plasma or interstitial fluid: A scoping review","authors":"Yu Zhang , Hanneke M. van Santen , Ruben E.A. Musson , Panos Markopoulos , Yuan Lu","doi":"10.1016/j.sbsr.2025.100850","DOIUrl":"10.1016/j.sbsr.2025.100850","url":null,"abstract":"<div><div>The human body maintains plasma sodium concentration within a narrow range of 135 to 145 mmol/L to ensure homeostasis. Being outside this range denotes hyponatremia (below 135 mmol/L) or hypernatremia (above 145 mmol/L), which can cause serious health problems. Current sodium monitoring is performed using point-of-care devices, which require blood sampling every time. It is cumbersome and uncomfortable for patients who require frequent sodium measurements daily. It would be ideal to continuously monitor plasma sodium concentration to reduce burden and detect abnormalities earlier. The sodium concentration in interstitial fluid is close to plasma sodium. Thus, this scoping review presents the current technological developments for continuous sodium monitoring (CSM) in plasma or interstitial fluid. The study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis extension for Scoping Reviews (PRISMA-ScR) checklist. 11 articles that presented technologies for the continuous monitoring of sodium concentrations in plasma or interstitial fluid with at least a technology readiness level of four were included for review. Seven of them presented microneedle(MN)-based solutions for CSM, and the remaining four were fluorescence(FS)-based. MN-based sodium sensors are all-solid-state sodium ion-selective electrodes designed as MN arrays or standalone MNs. FS-based CSM technologies inject sodium-sensitive fluorophores into the bloodstream or subcutaneously to reflect local sodium concentrations. Comparison of these two technological paths based on expected patient experience revealed that MN-based technologies appear more feasible for daily use and promising for further development due to their minimal invasiveness and compact wearability.</div></div>","PeriodicalId":424,"journal":{"name":"Sensing and Bio-Sensing Research","volume":"49 ","pages":"Article 100850"},"PeriodicalIF":4.9,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739715","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}
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