Self-powered Glucose Sensor Research Articles

A true continuous healthcare system for type 1 diabetes

Continuous monitoring of vital signs and timely treatment are the future trends for wearable and implantable healthcare systems, which inevitably require ceaseless power supply. Discharged batteries could be detrimental to the health of people, such as those with type 1 diabetes, whose glucose levels should be monitored and controlled through timely insulin injections. Here, we demonstrate a feasible true continuous healthcare system for type 1 diabetes by combining a low-energy micropump, self-powered glucose sensor, and ceaseless power supply. By converting body heat into electricity to charge a battery for 790.1 s, we acquired 136.8 mJ (100%) of energy, which was used to operate the micropump and sensor for 74.6 mJ (54.5%) and 25.3 mJ (18.5%), respectively; the surplus 36.9 mJ (27.0%) was stored in the battery. These findings can help realize a true continuous healthcare system in the future.

A Self-Charging Supercapacitor for a Patch-Type Glucose Sensor

Wearable electronic medical devices measuring continuous biological signals for early disease diagnosis should be small and lightweight for consecutive usability. As a result, there has been an increasing need for new energy supply systems that provide continuous power without any interruption to the operation of the medical devices associated with the use of conventional batteries. In this work, we developed a patch-type self-charging supercapacitor that can measure biological signals with a continuous energy supply without batteries. The glucose oxidase coated on the surface of the microneedle-type glucose sensor encounters glucose in the interstitial fluids of the human body. Electrons created by glucose oxidation operate the self-powered system in which charging begins with the generation of potential differences in supercapacitor electrodes. In an 11 mM glucose solution, the self-powered solid-state supercapacitors (SPSCs) showed a power density of 0.62 mW/cm2, which resulted in self-charging of the supercapacitor. The power density produced by each SPSC with a drop of 11 mM glucose solution was higher than that produced by glucose-based biofuel cells. Consequently, the all-in-one self-powered glucose sensor, with the aid of an Arduino Uno board and appropriate programming, effectively distinguished normal, prediabetic, and diabetic levels from 0.5 mL of solutions absorbed in a laboratory skin model.

A self-powered glucose sensor based on BioCapacitor principle with micro-sized enzyme anode employing direct electron transfer type FADGDH

Diabetes mellitus is a disorder in which the body does not produce enough or respond normally to insulin; consequently, blood glucose levels increase to become abnormally high. Accordingly, the primary treatment of diabetes is to control glycemic levels continuously. To continuously control glycemic levels, several medical devices have been developed to monitor blood glucose levels, represented by sensors and monitors for the self-monitoring of blood glucose. The ultimate goal for those engaged in research to develop medical devices is to develop implantable biodevices, namely self-powered autonomously operated artificial pancreas systems. One of the most challenging issues in realizing an implantable artificial pancreas is the long-term continuous supply of electricity, which is currently dependent on rechargeable batteries, requiring periodical replacement. In this work, we report the development of a direct electron transfer type enzyme-based miniaturized self-powered glucose sensor based on the BioCapacitor principle with a micro-sized enzyme anode area (0.15 mm × 0.75 mm), which has only 0.1 mm2 of electrode surface. As a result, a BioCapacitor utilizing a biofuel cell with a micro-sized enzyme anode was operated by self-power. In addition, the glucose concentration was detected within the range from 13 mM to 100 mM based on the frequency of charge/discharge cycles of the BioCapacitor. Although further improvement of the current density of the micro-sized anode is necessary to monitor a glucose concentration range lower than 13 mM, this self-powered glucose sensor with a micro-sized electrode based on the BioCapacitor principle was operated continuously for 6.6 h at 37 °C in 100 mM potassium phosphate buffer (pH 7.0). Our success indicates the potential to realize self-powered, autonomous, and implantable sensing modules for bio devices such as glucose-sensing systems for an artificial pancreas.

Development of a Sensitive Self-Powered Glucose Biosensor Based on an Enzymatic Biofuel Cell.

Biofuel cells allow for constructing sensors that leverage the specificity of enzymes without the need for an external power source. In this work, we design a self-powered glucose sensor based on a biofuel cell. The redox enzymes glucose dehydrogenase (NAD-GDH), glucose oxidase (GOx), and horseradish peroxidase (HRP) were immobilized as biocatalysts on the electrodes, which were previously engineered using carbon nanostructures, including multi-wall carbon nanotubes (MWCNTs) and reduced graphene oxide (rGO). Additional polymers were also introduced to improve biocatalyst immobilization. The reported design offers three main advantages: (i) by using glucose as the substrate for the both anode and cathode, a more compact and robust design is enabled, (ii) the system operates under air-saturating conditions, with no need for gas purge, and (iii) the combination of carbon nanostructures and a multi-enzyme cascade maximizes the sensitivity of the biosensor. Our design allows the reliable detection of glucose in the range of 0.1–7.0 mM, which is perfectly suited for common biofluids and industrial food samples.

Multi-functional NiO/g-C3N4 hybrid nanostructures for energy storage and sensor applications

A multi-functional NiO/g-C3N4 (NC) hybrid nanostructure was synthesized by a hydrothermal process using melamine and Ni(OH)2 as precursors followed by thermal treatment. The optimal conditions were determined by studying the process conditions, such as the Ni(OH)2 to melamine ratio and thermal treatment temperature. The NC prepared in this study exhibited both excellent glucose sensing properties and supercapacitor properties. A very high glucose sensitivity, as high as 5,387.1 µA mM−1cm−2, and excellent energy density of 49.6 Wh kg−1 at a power density of 1,064.2 W kg−1 were obtained when NC was used as the electrode material for glucose sensing and symmetric supercapacitor, respectively. A flexible glucose sensing device using a flexible substrate and self-powered glucose sensor system that used the same material (NC) for the both power supply and sensing devices were also demonstrated.

Paper-Based Disk-Type Self-Powered Glucose Biosensor Based on Screen-Printed Biofuel Cell Array

There is an increasing need for wearable diagnostic sensor devices and for enzymatic biofuel cells (EBFCs) as efficient power sources. In this study, a six-glucose/O2 biofuel cell array connected in series was fabricated by screen printing as a self-powered glucose sensor exhibiting an electromotive force of 3.2 V. Porous carbon electrodes were formed by screen printing of MgO-templated carbon on water-repellent paper to improve the performance of the cathode and thus prevent it from being the limiting step. The bioanode contained glucose oxidase as a catalyst and tetrathiafulvalene as a mediator, and the cathode contained bilirubin oxidase as an oxygen reduction catalyst. A good linear relationship was obtained between the output of EBFCs and glucose concentration (1–25 mM), which contains the range of urine glucose levels. The artificial urine components did not interfere with the output of the EBFC, but it was limited by low ion conductivity and low buffer capacity.

Highly Selective and Sensitive Self-Powered Glucose Sensor Based on Capacitor Circuit

Enzymatic glucose biosensors are being developed to incorporate nanoscale materials with the biological recognition elements to assist in the rapid and sensitive detection of glucose. Here we present a highly sensitive and selective glucose sensor based on capacitor circuit that is capable of selectively sensing glucose while simultaneously powering a small microelectronic device. Multi-walled carbon nanotubes (MWCNTs) is chemically modified with pyrroloquinoline quinone glucose dehydrogenase (PQQ-GDH) and bilirubin oxidase (BOD) at anode and cathode, respectively, in the biofuel cell arrangement. The input voltage (as low as 0.25 V) from the biofuel cell is converted to a stepped-up power and charged to the capacitor to the voltage of 1.8 V. The frequency of the charge/discharge cycle of the capacitor corresponded to the oxidation of glucose. The biofuel cell structure-based glucose sensor synergizes the advantages of both the glucose biosensor and biofuel cell. In addition, this glucose sensor favored a very high selectivity towards glucose in the presence of competing and non-competing analytes. It exhibited unprecedented sensitivity of 37.66 Hz/mM.cm2 and a linear range of 1 to 20 mM. This innovative self-powered glucose sensor opens new doors for implementation of biofuel cells and capacitor circuits for medical diagnosis and powering therapeutic devices.

BaTiO3 nanoparticles as biomaterial film for self-powered glucose sensor application

A facile M (metal)-S (semiconductor)-M (metal) structure was fabricated and glucose bio-sensing property of barium titanate nanoparticles (BTO NP’s) film has been reported for the first time. It is highly desirable for developing solid-state glucose biosensors (non-enzymatic) with multifunctional materials having extended application from diagnostics to therapeutics. In our present work, the glucose sensor (I–V curves) deviated from ohmic nature to non-ohmic nature with the introduction of glucose (0μM–1mM) indicating glucose molecules as an electron donor to BTO semiconductor. Sensing mechanism is attributed to the change in resistance across the device by the reduction of depletion layer width across metal-semiconductor interface as depicted schematically by an energy band diagram. Further, we demonstrated self-powered glucose sensor by utilizing piezoelectric nanogenerator’s output (BTO nanocubes/polyvinylidene fluoride [PVDF]) for driving BTO NP’s film based glucose sensor under different glucose concentrations and the obtained voltage measured across the sensor varied from 2V (absence of glucose) to few mV (1mM glucose) at a frequency of 11Hz with constant mechanical load (11N). The proposed sensor has good selectivity, reasonable sensitivity (23.79μA/mMcm2), eco-friendly and detection limits down to 7.94μM having linear relationship with glucose concentrations.

Microneedle-based self-powered glucose sensor

A microneedle-based self-powered biofuel-cell glucose sensor is described. The biofuel cell sensor makes use of the integration of modified carbon pastes into hollow microneedle devices. The system displays defined dependence of the power density vs glucose concentration in artificial interstitialfluid. An excellent selectivity against common electroactive interferences and long-term stability are obtained. The attractive performance of the device indicates considerable promise for subdermal glucose monitoring.

Fabrication of a Self-Powered Glucose Sensor Using Carbon Nanotube-Based Nanomesh and Direct Electron Transfer: A Prospective Approach for Energy Harvesting in Sensor Networks

This study demonstrates a new design concept of a glucose/oxygen biofuel cell (BFC) involving direct electron transfer between the active sites of the enzyme, glucose oxidase (GOx), and the electrode surface modified with multiwall carbon nanotube―polyaniline nanomesh (MWNT@PANI(NM)). GOx and catalase were immobilized independently into MWNT@PANI(NM) to fabricate the bioanode and biocathode, respectively, for the glucose BFC. The MWNT@PANI(NM)/GOx bioanode exhibited excellent electrochemical sensor characteristics towards glucose in phosphate buffer (pH 7) over a wide concentration range (1―30 mM) with a high sensitivity (1.66 μA/mM). The fabricated glucose BFC, MWNT@PANI(NM)/GOx//MWNT@PANI(NM)/Cat, provides a maximum power density of 35.7 μW/cm ―2 at a potential that is close to the formal potential of GOx. Thus, MWNT@PANI(NM)/GOx functions as a mediator-less bioanode for the generation of electrical power. The present investigation conceptually provides a platform for resolving limitations that are related to the energy harvesting and power management issues in electronic healthcare devices such as wireless body area network (WBAN). We presume that the present work would be beneficial in resolving restrictions on the limited capacity of energy resources for the sensors in a WBAN.