Transparent Biosensor Research Articles

Design of steering shaped optically transparent biosensor for the detection of tuberculosis cells

Design of steering shaped optically transparent biosensor for the detection of tuberculosis cells

Refractive index based optically transparent biosensor device design for early detection of coronavirus.

Refractive index based optically transparent biosensor device design for early detection of coronavirus.

A Conformable, Gas-Permeable, and Transparent Skin-Like Micromesh Architecture for Glucose Monitoring.

Monitoring the concentration of useful biomarkers via electronic skins (e-skins) is highly important for the development of wearable health management systems. While some biosensor e-skins with high flexibility, sensitivity, and stability have been developed, little attention has been paid to their long-term comfortability and optical transparency. Here, a conformable, gas permeable, and transparent skin-like Cu2 O@Ni micromesh structural glucose monitoring patch is reported. With its self-supporting micromesh structure, the skin-like glucose monitoring patch exhibits excellent shape conformability, high gas permeability, and high optical transmittance. The skin-like glucose biosensor achieves real-time monitoring of glucose concentrations with high sensitivity (15 420 µA cm-2 mM-1 ), low detection limit (50 nM), fast response time (＜2 s), high selectivity, and long-term stability. These desirable performance properties arise from the synergistic effects of the self-supporting micromesh configuration, high conductivity of the metallic Ni micromesh, and high electrocatalytic activities of the Cu2 O toward glucose. This work presents a versatile and efficient strategy for constructing conformable, gas permeable, and transparent biosensor e-skins with excellent practicability towards wearable electronics.

(Invited) Cavitas Sensors: Non-Invasive Bio/Chemical Sensing in Human Body Cavities for Medical and Healthcare

Introduction A non-invasive monitoring is important not only for medical inspection in hospitals but also healthcare management in daily life. For 30 years, we have developed several types of detachable sensors into human cavitas sites (conjunctiva, pharyngeal, oral cavity, etc.) with biocompatible materials and harmless device-techniques (Fig. 1). “Cavitas sensors” attached to body cavities such as a contact lens type and a mouthguard (“no implantable”, “no wearable”) are attracted attention for preventive medicine [1]. In this contribution, the cavitas sensors (soft contact-lens [SCL] and mouthguard [MG] biosensors) in human body cavities will be introduced as novel non-invasive biosensing devices. Soft contact lens type glucose sensor The soft contact lens type biosensor was designed for continuous glucose monitoring in tear fluids (Fig. 2) [2]. Biocom-patible poly(MPC-co-PMEH) (PMEH) (Fig. 3) [3,4] and polydimethyl siloxane (PDMS) were employed as the biosensor material. The biosensor consists of a flexible Pt working electrode and an Ag/AgCl reference/counter electrode, which were formed by micro-electro-mechanical systems (MEMS) technique. Glucose oxidase (GOD) was immobilized on the sensitive area by entrapping with PMEH polymer. The contact lens biosensor showed a good relationship between the output current and glucose concentration in a range of 0.03–5.0 mM, covering the reported tear glucose concentrations in normal and diabetic patients. Also, the biosensor was applied to a rabbit for the purpose of tear glucose monitoring. The basal tear glucose was estimated to 0.14 mM. Also, the change of tear glucose induced by the change of blood sugar level was assessed by the oral glucose tolerance test. As a result, tear glucose level increased with a delay of few min from blood sugar level (Fig. 4). The result showed that the contact lens biosensor is expected to provide further detailed information about the relationship between dynamics of blood glucose and tear glucose. Invisible Mouth guard type sensors with BLE transmitter The telemetric mouthguard-biosensor was developed with dental materials integrated with Bluetooth low energy (BLE) wireless module for measurement of saliva glucose [5]. The electrodes were formed on the thinner mouthguard surface which made of a polyethylene terephthalate glycol (PETG) using the same method as the contact lens one (Fig. 5). The BLE module, small potentiostat and battery were mounted and heat-sealed between upper and lower mouth guards. In the investigation of in-vitro characterization, the transparent biosensor showed excellent relationship between the output current and the glucose concentration (Fig. 6). In artificial saliva consisting of salts and proteins, the glucose sensor exhibits high-sensitive detection in a range of 5-1000 µmol/L including glucose concentration of human saliva. We demonstrated the capability of the sensor and wireless communication module to characterize an inclusion in oral phantom that imitative structure of human oral cavity. Stable and long-term monitoring (more than 1 day) using telemetry system was established. Monitoring of real-time changes of glucose concentration in artificial saliva with evaluation system of phantom jaw was demonstrated. The mouthguard device would be useful not only for monitoring of the oral chemical and physical information but also for unconstrained controlling of external device and system [6]. Future potential of cavitas sensors The self-detachable cavitas sensors are expected to allow the non-invasive bio/chemical monitoring, thus improving quality of life in view of the aging of society in near future.

(Invited) Cavitas Sensors: Non-Invasive Bio/Chemical Sensing in Human Body Cavities for Medical and Healthcare

Introduction A non-invasive monitoring is important not only for medical inspection in hospitals but also healthcare management in daily life. For 30 years, we have developed several types of detachable sensors into human cavitas sites (conjunctiva, pharyngeal, oral cavity, etc.) with biocompatible materials and harmless device-techniques (Fig. 1). “Cavitas sensors” attached to body cavities such as a contact lens type and a mouthguard (“no implantable”, “no wearable”) are attracted attention for preventive medicine [1]. In this contribution, the cavitas sensors (soft contact-lens [SCL] and mouthguard [MG] biosensors) in human body cavities will be introduced as novel non-invasive biosensing devices. Soft contact lens type glucose sensor The soft contact lens type biosensor was designed for continuous glucose monitoring in tear fluids (Fig. 2) [2]. Biocom-patible poly(MPC-co-PMEH) (PMEH) (Fig. 3) [3,4] and polydimethyl siloxane (PDMS) were employed as the biosensor material. The biosensor consists of a flexible Pt working electrode and an Ag/AgCl reference/counter electrode, which were formed by micro-electro-mechanical systems (MEMS) technique. Glucose oxidase (GOD) was immobilized on the sensitive area by entrapping with PMEH polymer. The contact lens biosensor showed a good relationship between the output current and glucose concentration in a range of 0.03–5.0 mM, covering the reported tear glucose concentrations in normal and diabetic patients. Also, the biosensor was applied to a rabbit for the purpose of tear glucose monitoring. The basal tear glucose was estimated to 0.14 mM. Also, the change of tear glucose induced by the change of blood sugar level was assessed by the oral glucose tolerance test. As a result, tear glucose level increased with a delay of few min from blood sugar level (Fig. 4). The result showed that the contact lens biosensor is expected to provide further detailed information about the relationship between dynamics of blood glucose and tear glucose. Invisible mouth guard type sensors with BLE transmitter The telemetric mouthguard-biosensor was developed with dental materials integrated with Bluetooth low energy (BLE) wireless module for measurement of saliva glucose [5]. The electrodes were formed on the thinner mouthguard surface which made of a polyethylene terephthalate glycol (PETG) using the same method as the contact lens one (Fig. 5). The BLE module, small potentiostat and battery were mounted and heat-sealed between upper and lower mouth guards. In the investigation of in-vitro characterization, the transparent biosensor showed excellent relationship between the output current and the glucose concentration (Fig. 6). In artificial saliva consisting of salts and proteins, the glucose sensor exhibits high-sensitive detection in a range of 5-1000 µmol/L including glucose concentration of human saliva. We demonstrated the capability of the sensor and wireless communication module to characterize an inclusion in oral phantom that imitative structure of human oral cavity. Stable and long-term monitoring (more than 1 day) using telemetry system was established. Monitoring of real-time changes of glucose concentration in artificial saliva with evaluation system of phantom jaw was demonstrated. The mouthguard device would be useful not only for monitoring of the oral chemical and physical information but also for unconstrained controlling of external device and system [6]. Future potential of cavitas sensors The self-detachable cavitas sensors are expected to allow the non-invasive bio/chemical monitoring, thus improving quality of life in view of the aging of society in near future.

Transparent In-Ga-Zn-O field effect glucose sensors fabricated directly on highly curved substrates

Fully transparent electronics are of increasing interest for biological applications, where the combination of sensing and imaging can potentially improve patient healthcare diagnostics. Herein, we report high-performance, fully-transparent amorphous In-Ga-Zn-O field-effect transistor (a-IGZO FET) based biosensors fabricated directly on highly-curved glass substrates. The a-IGZO channel and indium tin oxide electrodes were patterned directly on glass tubes (1.0 mm radius) by microcontact printing self-assembled monolayers and etching the metal oxide films. This approach led to a-IGZO FETs with excellent electronic performance, with high on/off drain current ∼1.3 × 106, high average electron mobility > 7.4 cm2/Vs, low on/off hysteresis ∼0.6, V and low gate leakage current ∼10−10 A. The back-channel of the a-IGZO FETs were functionalized with glucose oxidase to make fully transparent biosensors with very high sensitivity to glucose. We have determined that the glucose limit of detection is 170 μM. These results provide insight into new methods for fabricating a-IGZO FETs and a-IGZO FET biosensors on non-planar substrates, and may open a range of new applications, including transparent sensing catheters, flexible active transparent electrode sensing arrays, and integration of FET based biosensors on optical fibers.

Fast and cost-effective fabrication of large-area plasmonic transparent biosensor array.

Surface enhanced Raman-based sensors are widely used for chemical and biological species analysis; but to date the high cost, long production time, hazardous, and toxic content as well as small sensing area and opacity are limiting their capabilities for widespread applications in the medical and environmental fields. We present a novel cost-effective method for fast laser-based fabrication of affordable large-area and transparent periodic arrays of ligand-free metallic nanoparticles, offering a maximum possibility for the adsorption/immobilization of molecules and labeling. Further, we demonstrate a remarkable detection limit in the picomolar range by means of Raman scattering, thus evidencing a superior signal-to-noise ratio compared to other sensor substrates. The high sensitivity performance along with a fast and cheap fabrication procedure of reusable large-area transparent plasmonic devices opens the route for direct, in situ multimodal optical analysis with broad applications in the biomedical/analytical fields.

Transparent biosensor with micro channel array for optical and electrophysiological detection of luciferin–luciferase reaction

AbstractThis paper describes a transparent biosensor that was designed to detect both the optical and electrophysiological signals of the luciferin–luciferase reaction. By using microelectromechanical system (MEMS) technologies, we have studied and developed a ‘Micro Channel Array’ (MCA) integrated with suction holes and electrodes as planar patch‐clamp biosensors. A transparent biosensor was developed as an advanced MCA. The developed transparent biosensor employs an SU‐8‐based MCA structure for simultaneous multipoint sensing of optical and electrophysiological signals. In this study, we tested the newly developed biosensor using the mPer1‐luc slice culture, which has circadian rhythms and is a typical example of cells in which a luciferin–luciferase reaction occurs. We could measure the optical and electrophysiological signals of the mPer1‐luc slice culture. Here we describe the experimental results of this study, and describe the design and fabrication of the transparent biosensor with MCA. Copyright © 2007 Institute of Electrical Engineers of Japan© 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Transparent biosensor with micro channel array for optical and electrophysiological detection of luciferin–luciferase reaction

Transparent biosensor with micro channel array for optical and electrophysiological detection of luciferin–luciferase reaction

Composite films of Prussian blue and N-substituted polypyrroles: covalent immobilization of enzymes and application to near infrared optical biosensing

We demonstrate the feasibility of optical biosensing using a material which, in essence, is a modified inorganic film to which various enzymes were covalently attached. Thin and transparent blue films composed of Prussian blue and incorporated into a network of N-substituted polypyrroles are sensitive to pH in the 5–9 range at 720 nm wavelength and can be modified with enzymes to result in the respective biosensors. Several methods of enzyme immobilization, using bifunctional crosslinking reagents, and various enzymes were tested. The best results were obtained using the one-step carbodiimide method which resulted in highly active, stable and transparent biosensor films for optical determination of urea and acetylcholine. The operational stability exceeded 1 month and even after 2 months of dry storage at room temperature the activity did not drop. The biosensors allow optical determination of the respective substrates in the millimolar concentration range.