Fiber Biosensor Research Articles

Multiple covalent modification enables nylon fiber biosensor with robust scrub-resistant and signal-capture ability for multiscenario health monitoring and security warning

Nylon fibers have great potentials in smart textiles due to excellent wear resistance, resilience, and chemical stability, whereas poor combination between fibers and conductive materials causes discontinuous signal capture. In this work, nylon fibers/di-aldehyde cellulose nanocrystals/polypyrrole (NFACP) biosensors with robust scrub-resistant and signal-capture ability were fabricated by interfacial multiple covalent reactions. The best NFACP0.2 biosensor exhibited high conductivity (354 S/m), robust mechanical strength and stretching-releasing dynamic durability. Especially, its textile sensors still possessed high sensitivity and excellent sensing performance after repeated washing and friction. Moreover, NFACP0.2 biosensor was designed into various multifunctional health monitoring and security warning systems for “stress reducing exercise” enthusiasts, high-altitude activities, and deep-sea exploration, demonstating great potentials of conductive nylon fiber biosensor in flexible electronics.

Optical Fiber Biosensors Based on Surface Plasmon Resonance Effect: A Review

Optical Fiber Biosensors Based on Surface Plasmon Resonance Effect: A Review

A highly sensitive photonic crystal fibre biosensor for early malaria detection via RBC variation monitoring

Abstract Every year, more than one million individuals die from malaria, an infection spread by mosquitoes infected by haemoparasites with only one cell of the Plasmodium class. In this work, a photonic crystal fibre (PCF)-based refractive index (RI) biosensor for the early detection of malaria in individuals, using red blood cell (RBC) variation monitoring, is presented. The proposed PCF includes three layers of hexagonal lattices of elliptical air holes and also contains a small vertical elliptical channel in which the RBC samples are placed. Because of the RI difference between samples from both healthy and malaria-infected human RBCs, the peak wavelength of infected RBC samples differs from that of normal RBC samples. From calculation, the achieved wavelength sensitivities of the biosensor are 3571.42 nm/RIU, 3157.89 nm/RIU, and 3103.44 nm/RIU in the x-polarized direction and 2857.14 nm/RIU, 2631.57 nm/RIU, and 2758.6 nm/RIU in the y-polarized direction in different phases—ring, trophozoite, and schizont respectively—with a highest possible detection limit of 0.029. Because of the small detection limit and high sensitivity, the proposed PCF biosensor has enhanced sensing abilities that make it suitable for primary diagnosis of malaria. With its high sensitivity and low detection limit, this PCF biosensor has improved sensing capabilities that make it appropriate for malaria diagnosis at the outset.

Single hollow-core microstructure fiber biosensor for pancreatic cancer diagnosis in terahertz regime

Abstract Pancreatic cancer is a kind of malignant tumor that is difficult to detect in its early stages, developing rapidly and with a 5-year survival rate of only 5% to 10%. Therefore early diagnosis and discovery of pancreatic cancer are very important for the successful treatment of the disease. Here, we report a single hollow-core microstructural fiber (SHC-MSF) biosensor based on a ZEONEX substrate, which has been optimized for the early detection of pancreatic cancer biomarkers. The proposed SHC-MSF biosensor adopts a single-aperture structure to increase the contact range with assay analytes to improve the detection sensitivity. Its biosensing performance was numerically analyzed using a finite element method with a perfect matching layer. Numerical results demonstrated that the proposed MSF-biosensor presented ultra-high sensitivity (bilirubin: 105.55%, glucose: 105.34%, creatinine: 105.67%) and negligible confinement loss (bilirubin: 5.52×10-14 cm-1, glucose: 1.65×10-14 cm-1, creatinine: 5.57×10-14 cm-1) in the range of 0.3~2.0 THz. Moreover, the SHC-MSF biosensor could selectively detect and distinguish cancer markers of different concentrations in the blood to achieve a more accurate diagnosis of pancreatic cancer. Finally, fabrication tolerance analysis of the proposed MSF-biosensor is provided to ensure the feasibility of rapid preparation.

Chitosan-coated iron(III) oxide nanoparticles and tungsten disulfide quantum dots-immobilized Fiber-based WaveFlex Biosensor for Staphylococcus Aureus bacterial detection in real food samples

The research proposes and investigates an extraordinarily sensitive, label-free WaveFlex biosensor utilizing optical fiber technology for the detection of Staphylococcus aureus (S. aureus), a common foodborne bacterium. The WaveFlex biosensor (plasmon Wave based Flexible optical fiber Biosensor) is based on a novel flexible tapered single-mode fiber structure, utilizing gold nanoparticles (AuNPs) to trigger the phenomenon of localized surface plasmon resonance (LSPR). Additionally, the sensitivity is further enhanced using chitosan-coated iron(III) oxide nanoparticles (Fe3O4–CS NPs) and tungsten disulfide quantum dots (WS2-QDs). The optical fiber surface is functionalized with antibodies to achieve specific detection of S. aureus. For S. aureus concentrations at 1 × 108 CFU/mL (colony-forming units per milliliter), the sensor's maximum sensitivity of 2.74 nm/lg (CFU/mL), and a detection limit (LOD) of 6.67 CFU/mL. This ultra-sensitive biosensor holds great potential for widespread applications in various fields, including disease detection, medical diagnostics, and food safety inspection.

Floral-core terahertz photonic crystal fiber bio-sensor: An exclusive approach to recognizing milk from various animal species

In this article, an advanced-level type of Photonic Crystal Fiber (PCF) sensor, having a flower shape core with a unique hexagonal cladding, is proposed. Performance for detecting is evaluated in various animal's milk, such as camel, cow, and buffalo milk, with the suggested PCF sensor. The maximum Relative Sensitivities (RS) of the PCF sensor are 88.2 %, 88.5 %, and 88.8 % for detecting camel milk, cow milk, and buffalo milk, respectively. Moreover, it has a negligible Confinement Loss (CL) of 2.04018402 × 10−14 dB/m and Total Loss (TL) of 2.1520000 × 10−01 dB/m and Effective Material Loss (EML) of 0.21520 cm−1. Since Milk is as great source of nutrients such as Calcium, Vitamin D, Vitamin B12, Phosphorus and Protein. The nutrient composition of different animals' milks and their respective quantities are determined by set values at the beginning and differ among the types of milk. As all of them hold the same tone, it becomes challenging to identify them. Our suggested PCF sensor comes with its remarkable detection capacity to identify them. Therefore, the use of suggested PCF sensor will be helpful for both the industry and consumers. For the industry, it aids in ensuring the quality and composition of animal milk. For consumers, it means they can trust that the milk they purchase has been accurately tested and verified for its nutrient content and safety. With the implementation of the PCF sensor, the industry can better ensure the quality and authenticity of animal milk, reducing the risk of fraud and helping consumers make more informed choices about the milk they consume. This contributes to better assurance of proper nutrient intake.

Unpacking the packaged optical fiber bio-sensors: understanding the obstacle for biomedical application.

A biosensor is a promising alternative tool for the detection of clinically relevant analytes. Optical fiber as a transducer element in biosensors offers low cost, biocompatibility, and lack of electromagnetic interference. Moreover, due to the miniature size of optical fibers, they have the potential to be used in microfluidic chips and in vivo applications. The number of optical fiber biosensors are extensively growing: they have been developed to detect different analytes ranging from small molecules to whole cells. Yet the widespread applications of optical fiber biosensor have been hindered; one of the reasons is the lack of suitable packaging for their real-life application. In order to translate optical fiber biosensors into clinical practice, a proper embedding of biosensors into medical devices or portable chips is often required. A proper packaging approach is frequently as challenging as the sensor architecture itself. Therefore, this review aims to give an unpack different aspects of the integration of optical fiber biosensors into packaging platforms to bring them closer to actual clinical use. Particularly, the paper discusses how optical fiber sensors are integrated into flow cells, organized into microfluidic chips, inserted into catheters, or otherwise encased in medical devices to meet requirements of the prospective applications.

Nano-Photonic Crystal D-Shaped Fiber Devices for Label-Free Biosensing at the Attomolar Limit of Detection.

Maintaining both high sensitivity and large figure of merit (FoM) is crucial in regard to the performance of optical devices, particularly when they are intended for use as biosensors with extremely low limit of detection (LoD). Here, a stack of nano-assembled layers in the form of 1D photonic crystal, deposited on D-shaped single-mode fibers, is created to meet these criteria, resulting in the generation of Bloch surface wave resonances. The increase in the contrast between high and low refractive index (RI) nano-layers, along with the reduction of losses, enables not only to achieve high sensitivity, but also a narrowed resonance bandwidth, leading to a significant enhancement in the FoM. Preliminary testing for bulk RI sensitivity is carried out, and the effect of an additional nano-layer that mimics a biological layer where binding interactions occur is also considered. Finally, the biosensing capability is assessed by detecting immunoglobulin G in serum at very low concentrations, and a record LoD of 70 aM is achieved. An optical fiber biosensor that is capable of attaining extraordinarily low LoD in the attomolar range is not only a remarkable technical outcome, but can also be envisaged as a powerful tool for early diagnosis of diseases.

Advances in Plasmonic Photonic Crystal Fiber Biosensors: Exploring Innovative Materials for Bioimaging and Environmental Monitoring

AbstractThis review paper comprehensively analyzes recent advancements in optical fiber‐based biosensors, focusing on conventional fiber and photonic crystal structures. This paper overviews the significant applications of optical fiber biosensors, including bioimaging, quality analysis, food safety, and field environment monitoring, setting the stage for subsequent discussions. The primary objective of the review is to systematically evaluate recent literature concerning optical fiber‐based biosensors, emphasizing their sensitivities and resolutions. The second section explores integrating plasmonic materials such as graphene, TDMC, germanium, black phosphorus, and silicon within optical fiber biosensors, elucidating their roles in enhancing sensitivity and resolution in biosensing applications. A detailed examination of photonic crystal fibers (PCF) follows, categorizing them into internally and externally metal film‐coated biosensors, highlighting their distinct advantages and limitations. Comparative analyses in two tables delineate the performance and sensitivity of optical fiber‐based biosensors, mainly focusing on different coating strategies. The final section of the review discusses emerging trends and applications in optical fiber biosensing technologies, underscoring their potential to transform biomedical and environmental monitoring fields. By synthesizing recent developments and challenges, this review aims to offer researchers and practitioners a comprehensive understanding of optical fiber‐based biosensors, facilitating informed decision‐making and driving further advancements in the field.

An Efficient Bio-Receptor Layer Combined with a Plasmonic Plastic Optical Fiber Probe for Cortisol Detection in Saliva.

Cortisol is a clinically validated stress biomarker that takes part in many physiological and psychological functions related to the body's response to stress factors. In particular, it has emerged as a pivotal tool for understanding stress levels and overall well-being. Usually, in clinics, cortisol levels are monitored in blood or urine, but significant changes are also registered in sweat and saliva. In this work, a surface plasmon resonance probe based on a D-shaped plastic optical fiber was functionalized with a glucocorticoid receptor exploited as a highly efficient bioreceptor specific to cortisol. The developed plastic optical fiber biosensor was tested for cortisol detection in buffer and artificial saliva. The biosensor response showed very good selectivity towards other hormones and a detection limit of about 59 fM and 96 fM in phosphate saline buffer and artificial saliva, respectively. The obtained detection limit, with a rapid detection time (about 5 min) and a low-cost sensor system, paved the way for determining the cortisol concentration in saliva samples without any extraction process or sample pretreatment via a point-of-care test.

Detection of 17-[formula omitted]-Ethinylestradiol with Bio-Functionalized tapered optical fiber sensor

This paper presents the utilization of tapered optical fiber (TOF) biosensor for the detection of 17-α-ethinylestradiol (EE2), an estrogen hormone. TOF with a waist diameter of 12 μm was fabricated from single mode fiber using heat and pull method. The tapered area was used as the sensing interface between the evanescent waves propagating around the fiber due to its unique geometry and the attached molecules on the tapered surface. EE2 antibodies were used as biorecognition molecules towards the targeted analyte, EE2. When tested with different concentrations of EE2 within the range of 0.1 ng/L – 1 mg/L, the developed sensor attained a detection limit of 1 ng/L with a sensitivity value of 1.088 nm/ngL-1 within the operation range of 1 – 10 ng/L. The specificity of the sensor was validated by testing the developed sensor with estrone (E1) and no significant wavelength shift was observed. These findings highlight the potential of our approach for sensitive and selective detection of EE2.

Optical fiber LSPR sensor for SARS-CoV-2 N gene detection based on AuNRs

A novel SARS-CoV-2 N gene optical fiber biosensor based on ASO-coated gold nanorods is proposed in this work. A fiber probe prepared by AuNRs self-assembly was used to detect N gene by complementary base pairing method. The detected material was processed into AuNRs-ASO2-N gene coupler by cross-linking, and the pairing of N gene with ASO1 connected to AuNRs on the surface of the optical fiber formed the hydrogen bonding. The coupling of AuNRs resulted in a left shift of the peak position and a decrease in absorbance in the LSPR spectrum. In this manuscript, it is verified for the first time by simulation and experimental characterization that the coupling mode of AuNRs on the surface of the optical fiber is side by side, which leads to a left shift of the peak position of the LSPR absorption peak on the optical fiber. It is also proved that sandwich method is superior to the traditional method of changing the refractive index. The response time of the sensor is 10 min, and the detection limit is 1 pM, and the results show that the optical fiber sensor based on ASO-coated AuNRs has excellent RNA detection performance in artificial body fluids and is very suitable for RNA detection.

Four-core fiber-based multi-tapered WaveFlex biosensor for rapid detection of Vibrio parahaemolyticus using nanoparticles-enhanced probes

Infections caused by Vibrio parahaemolyticus (V. parahaemolyticus) can be highly fatal, making rapid and sensitive detection of them is essential. A new optical fiber biosensor based on localized surface plasmon resonance (LSPR) phenomenon is developed in this paper. A tapered-in-tapered fiber structure based on MFM is constructed by using four-core fiber (FCF) and multi-mode fiber (MMF) to qualitatively detect different concentrations of V. parahaemolyticus. The sensor successfully excites the LSPR phenomenon and increases the attachment point of biomolecules on the probe surface by fixing gold nanoparticles (AuNPs), molybdenum disulfide nanoparticles (MoS2-NPs) and cerium dioxide nanorods (CeO2-NRs). The functionalization of polyclonal antibodies on the probe surface can improve the specificity of the sensor. The linear detection range of the developed sensor was 1 × 100-1 × 107 CFU/mL, the sensitivity was 1.61 nm/[CFU/mL], and the detection limit was 0.14 CFU/mL. In addition, the reusability, reproducibility, stability, and selectivity of the sensor probe are also tested, which shows that the sensor has great application prospects.

Design of Terahertz Refractive Index-Based Spiral Hollow-Core Photonic Crystal Biosensor Using Enhanced Probabilistic Pyramid Neural Networks for Brain Tumor Detection

Cancer diagnosis is difficult and costly due to the complexity of the brain. Photonic technology-based biosensors show potential for identifying malignant tissues, including brain tumors, but they are often costly, time-consuming, and computationally difficult. To address these challenges, we propose an enhanced probabilistic pyramid neural networks (EPPNN)-based hollow-core photonic crystal fiber (PCF) biosensor with terahertz refractive index (THzBio-ECPPN) for detection of cancerous brain tumors. The approach is divided into two stages: biosensor design and brain tumor detection. Initially, PCF geometry with suspended cladding and a spiral-shaped hollow-core in the terahertz (THz) band is proposed. The PCF biosensors’ characteristics are then calculated using the EPPNN model. The EPPNN model’s hyperparameters are modified using the circle-inspired optimization algorithm to maximize accuracy and minimize effective mode loss. The proposed biosensor is then used to identify brain tumors. Experimental evaluations utilizing MATLAB show that the suggested strategy surpasses earlier methods, with a higher sensitivity (98%). The sensor has exceptional performance characteristics, such as a high figure of merit of 1.25–1.35 RI range and sensitivity of 50000 nm RIU−1, indicating its potential for precise detection of changes in refractive index. This combination of photonic crystal structures and neural networks has enormous potential for improving cancerous tumor accuracy to 99.92%, precision to 99.23%, specificity to 99.73%,and sensitivity to 99.36% of brain tumor diagnosis.

Surface plasmon resonance photonic crystal fiber biosensor: Utilizing silver-phosphorene nanoribbons for Near-IR detection

In recent years, the utilization of two-dimensional materials in photonic crystal fiber structures has developed the capabilities of biosensors in biological and biochemical applications. A photonic crystal fiber biosensor based on surface plasmon resonance with silver and phosphorene layers is proposed in this paper. Phosphorene helps with the prevention of oxidation of the silver layer used as a plasmonic active metal. The sensor performance can be optimized by changing the structural parameters. The maximum wavelength sensitivity obtained was 1800 nm/RIU in the dynamic index range of 1.39–1.45, and the proposed sensor also showed the maximum amplitude sensitivity of 268 RIU−1 with an analyte refractive index of 1.40. The performance of the proposed sensor was analyzed using the finite element method. The results show that using phosphorene may open a new window for the study of online biomolecular interaction.

High‐performance photonic crystal fibre biosensor for identifying Jurkat cells by refractive index analysis

AbstractJurkat cells are immortalised lines of human T lymphocyte cells widely used in research to study leukaemia, signalling of T cells, and immune responses. These cells can be used as models to define the mechanisms of leukaemia and to develop mechanism‐based therapies. Jurkat cells can be detected with remarkable accuracy using the recently created Photonic Crystal Fibre (PCF). The suggested design has a hybrid arrangement on its clad surface and a rectangular core. The recently released PCF analyser displays a maximum Relative Sensitivity are 95.81% for Jurkat (type I) and 94.93% for Jurkat (type II), respectively. The Effective Material Loss of 0.0070 cm−1, 0.0080 cm−1, and the Confinement Loss of 9.11 × 10−9 dB/m, 9.15 × 10−8 dB/m were also examined for the previously described units. Jurkat cells represent a model of leukaemia that is very malignant and proliferative, representative of aggressive T‐cell acute lymphoblastic leukaemia with the ability to progress rapidly and hence poor prognosis for patients. The benefit of applying a suggested PCF sensor to Jurkat cell detection lies in the high sensitivity to refractive index changes, allowing label‐free and real‐time monitoring of cell interaction. This PCF sensor can offer high light‐matter interaction, custom geometry, and biocompatibility for specific and reliable detection of deadly Jurkat cells in biomedical research and clinical diagnostics.

Label-free optical fiber biosensor for the detection of CD44-expressing breast cancer cells

Increased level of CD44, transmembrane glycoprotein, is observed in several cancers such as breast, colorectal, head and neck, gastric, and ovarian cancer. Current methods for analyzing CD44 expressing cells are time-consuming, semi-quantitative, use labeled reagents for analysis or are not suitable for in situ analysis. Therefore exploring novel methods which are label-free and fast with the in situ detection capability for the quantification of these cells is of importance.Using optical fiber as a sensing element in biosensors offers low cost, high sensitivity, chemical inertness, and immunity to electromagnetic interference, and possibility of being used in in situ applications. This study reports the first label-free optical fiber biosensor for detection of CD44-expressing cancer cells. A fiber-optic ball resonator (BR) sensor was fabricated and then functionalized with CD44 antibodies. Different concentrations of the cells were incubated with the biosensor to measure the reflected light using optical backscatter reflectometer. The biosensor was able to detect cancer cells with a limit of detection of 335 cells/mL. The presence of the cells on the sensor surface was demonstrated by fluorescent and scanning electron microscope analysis. The work is the first proof-of-concept biosensor based on optical fibers for CD44 cancer cells and acts as a promising tool for in situ detection of cancer cells.

Ammonia-trapping multilayer polymer urease film amplifier coated surface plasmon resonance sensor for ultra-sensitive urea detection

In this paper, we have developed a new urea signal amplification technology based on a multilayer urease polymer film self-assembly structure for the first time, enabling the realization of ultra-accurate urea optical detection. We demonstrate the effectiveness of this technique based on surface plasmon resonance (SPR) platform. When the urea signal amplifier is combined with SPR sensors, multilayer urease polymer film contacts with urea molecules, the urea molecules are oxidated into NH3 and CO2, causing the pH increase, which weakens the electrostatic interaction between different polymer layers and induces the RI reduction of the multilayer urease film, thereby causing the shift of the SPR spectrum. Experiment results confirm that urea sensitivity has been improved 12-fold, and the limit of detection (LOD) has been optimized to less than 10−3 mmol/L. Furthermore, the anti-interference has been improved 22.8-fold and is kept even the interference signal strength increases by 100 times. Moreover, multilayered urease polymer leads to the increase of urease on the sensor surface, thus expanding the detection range of urea by 3.5 times. This provides a new way to solve the contradiction between high sensitivity and large measurement range of optical fiber biosensor. Importantly, the concept of using enzyme-loaded polymer films for signal amplification can be adapted for the detection of various other biomolecules by replacing the enzyme with a specific recognition element for the target molecule. This opens doors for developing highly sensitive and specific biosensors for diverse applications in healthcare, environmental monitoring, and food safety.

Structure Design and Sensitivity Optimization of Optical Fiber Biosensor Based Au Nano Column - TiO2 Heterostructure

An investigation on a single mode optical fiber sensor-based surface plasmon resonance was carried out in this work. A titanium dioxide (TiO2) coated gold Nano-column (Au) are deposited on the proposed sensor and theoretically analyzed using COMSOL Muliphysics software 5.3. Presence of TiO2 over the Au Nano-column can improve the sensitivity of the sensor and tune the resonance peak of transmission spectrum from visible region to near-infrared region. The size effect of TiO2 nanoparticles on the sensor performance is studied. The optimum parameters of such as Au size and separation width between the Au Nano-column have been selected to enhance the performance of the sensor. In comparison, the sensor with TiO2 over Au Nano-column is significantly improve the sensitivity and develop the sensor performance. The greater sensitivity of 5243.76 nm/RIU (refractive index unit) is obtained of sensor with TiO2 over Au Nano-column when the external refractive index of analyte is varying from 1.33 to 1.39, while sensitivity of the sensor coated with Au Nano-column is obtained to be 4643.17 nm/RIU for the same analyte range. Above results can be used to predict the best parameters values of the sensor that corresponding to the greatest sensitivities of detection and finally opening new study in the field of gas sensors. HIGHLIGHTS Optical fiber biosensors are a devices that use to measure the analyte by using the optical field Optical fiber biosensors have a high detection speed and low-cost, compared to congenital sensors The optical fiber sensors based SPR are widely used for biosensor applications The novelty in this research is the fabricate of optical fiber sensor coated with TiO2 over Au Nano-column based SPR foe gas detection GRAPHICAL ABSTRACT

A microfiber biosensor for detection of AKT protein in human embryonic kidney cell lysate based on the vernier effect

The AKT protein is closely related to the cancer and diabetes. Rapid detection of AKT is very important in medical diagnosis. This paper proposed a parallel connected tapered seven-core fiber (PTSCF) biosensor to utilize vernier effect to improve sensitivity. Experimental results showed that 5.99 times improvements have been achieved in the refractive index sensing in the ranges of 1.333–1.337. By functionalizing AKT-Ab on the PTSCF sensor surface, a fast detection (<40 min) and an ultra-low limit of detection (LoD) of 0.044 ng/mL have been achieved for AKT protein solutions. The proposed PTSCF biosensor has been applied to detect AKT proteins in human embryonic kidney cell lysates and compared with those obtained by the western blotting (WB) method. Experimental results showed that the LoD of the PTSCF biosensor is 400-fold less than that of WB method. The proposed PTSCF biosensor holds great potential for applications in various medical fields, including intra-operative rapid detection, animal experiments, and pathological research.