Structure of lactate oxidase from Enterococcus hirae revealed new aspects of active site loop function: Product-inhibition mechanism and oxygen gatekeeper.

l-Lactate oxidase (LOx) is a flavin mononucleotide (FMN)-dependent triose phosphate isomerase (TIM) barrel fold enzyme that catalyzes the oxidation of l-lactate using oxygen as a primary electron acceptor. Although reductive half-reaction mechanism of LOx has been studied by structure-based kinetic studies, oxidative half-reaction and substrate/product-inhibition mechanisms were yet to be elucidated. In this study, the structure and enzymatic properties of wild-type and mutant LOxs from Enterococcus hirae (EhLOx) were investigated.

Development of a POCT type insulin sensor employing anti-insulin single chain variable fragment based on faradaic electrochemical impedance spectroscopy under single frequency measurement.

To improve glycemic control managed through insulin administration, recent studies have focused on developing hand-held point-of-care testing (POCT) electrochemical biosensors for insulin measurement. Amongst them, anti-insulin IgG-based sensors show promise in detecting insulin with high specificity and sensitivity. However, fabrication of electrochemical sensors with IgG antibodies can prove challenging because of their larger molecular size.

Faradaic electrochemical impedance spectroscopy for enhanced analyte detection in diagnostics.

Electrochemical impedance spectroscopy (EIS) is a widely implementable technique that can be applied to many fields, ranging from disease detection to environmental monitoring. EIS as a biosensing tool allows detection of a broad range of target analytes in point-of-care (POC) and continuous applications. The technique is highly suitable for multimarker detection due to its ability to produce specific frequency responses depending on the target analyte and molecular recognition element (MRE) combination.

Correction to: Project honeybee: Clinical applications for wearable biosensors.

The original version of this article unfortunately contained a mistake.

Electrochemical Detection of Fertility Hormones.

Fertility hormone levels are constantly changing, but it is crucial for a woman to be able to monitor her fertility levels if she is interested in conceiving. Women and physicians often have a difficult time determining ovulation windows due to fluctuating menstrual cycles and inaccurate interpretations of hormone levels. Current methods of fertility monitoring include physical or vaginal exams, laparoscopy, ultrasound scans, as well as evaluation of hormone levels.

An Experimental Platform for Characterizing Cancer Biomarkers with Capabilities in Noninvasive and Continuous Screening.

Early detection is crucial to the proper and effective treatment of two metastatic cancers, prostate cancer and small cell lung cancer. Currently, preventative screenings for these conditions are restricted to high-risk populations and extremely expensive. The discovery of clinically indicative biomarkers has been revolutionary in advancing screening and diagnostic capabilities.

Toward a Label-Free Electrochemical Impedance Immunosensor Design for Quantifying Cortisol in Tears.

Cortisol is a viable biomarker for monitoring physiological, occupational, and emotional stress and is normally present in tear fluid at approximately 40 nM, or higher as a result of stress. We present characterization and quantification of cortisol via several electrochemical methods versus the standard enzyme-linked immunosorbent assay, commonly known as ELISA. We also present a prototyped design of a disposable test strip and handheld sensor based on label-free electrochemical impedance spectroscopy to quantify cortisol levels in tear fluid within approximately 90 seconds.

Multi-Biomarker Detection Following Traumatic Brain Injury.

The Centers for Disease Control and Prevention estimates almost two million traumatic brain injuries (TBIs) occur annually in the U.S., resulting in nearly $80 billion of economic burden.

Development of Electrochemical Methods to Enzymatically Detect Lactate and Glucose Using Imaginary Impedance for Enhanced Management of Glycemic Compromised Patients.

Lactate is an important biological marker that can provide valuable information for patients who have experienced a traumatic injury. Additionally, when coupled with glucose, the severity and likely prognosis of a traumatic injury can be determined. Because monitoring various markers proves useful in diagnosis and treatment of trauma patients, monitoring both glucose and lactate simultaneously may be especially useful for diabetic patients who have suffered a traumatic injury.

Development Toward a Triple-Marker Biosensor for Diagnosing Cardiovascular Disease.

Cardiovascular disease (CVD) is the leading cause of death in the United States and is responsible for 30% of all deaths globally. The diagnosis and management of CVD requires monitoring of multiple biomarkers, which comprehensively represents the state of the disease. However, many assays for cardiac biomarkers today are complicated and laborious to perform.

Feasibility of Commercially Marketed Health Devices for Potential Clinical Application.

Concerns have been raised regarding the lack of validation on consumer-marketed health-monitoring devices. An investigation to characterize current health monitoring devices was carried out in the laboratory using widely accepted clinical and industry criteria. In total, 16 unique devices were examined.

Proof of Concept for a Universal Identification System for Medical Devices.

Medical devices need a unified way of accessing information that uniquely identifies them. This can provide traceability to specifications, lot numbers, recalls, and the like. Such a system would have applications for devices both in and out of the body.

Non-Contact Type Pulse Oximeter.

Heart rate and through-body blood perfusion are vital measurements in all stages of patient care, be it predictive, in the clinical setting, or outpatient monitoring. Irregular, underachieving, or overperforming heart rate is the main precursor of most cardiovascular diseases that have severe long-term complications. In addition to heart rate, the shape of the pulse waveforms can indicate the heart's valve health and electrophysiology health.

Toward the Development of a Wearable Optical Respiratory Sensor for Real-Time Use.

Respiration rate is an important vital sign that can provide insight into a patient's status and health progression. This information is used from critical care to sports and human performance evaluation. The current state of the art has demonstrated effectiveness in monitoring respiration rate with the use of wearable sensors.

Staggered Nitinol Wire Actuator Array for High Linear Displacement and Force-to-Mass Ratio.

We present the design and performance of a unique Nitinol (NiTi) actuator design for high linear displacement and force generation through joule heating. The device is comprised of a staggered linear array of NiTi in wire form that, as a shape memory alloy, can achieve linear displacement through material phase change when heated. This change allows the crystal lattice within the material to displace/adjust.

A Comparison of Force Sensing for Applications in Prosthetic Haptic Feedback.

The current study presents a comparison of two load sensor designs that can be applied toward haptic feedback sensing in upper limb prosthetics. A lab-standard capacitive load cell sensor is discussed, which is succeeded by the proposal of an electrochemical sensor. Experiments were conducted primarily as a proof-of-principle study to evaluate sensor characteristics for prosthetic applications.

BODDEE BUDDEE: Evaluation of Different Foams and Thermoplastics to Develop a Biofidelic Manikin for Cardiopulmonary Resuscitation.

Cardiopulmonary resuscitation (CPR) is an emergency course of action developed to sustain oxygenated blood flow in persons suffering from cardiac arrest by manually compressing the heart in the chest and providing rescue ventilations. The best-selling CPR manikins, an integral part of training, are costly investments that lack biofidelic characteristics in appearance, feel, and response; as a result, the rescuer's learning experience suffers. The objective of the present study was to test the compressibility properties of different foams and thermoplastics in order to determine which material would most accurately imitate a human chest response.

Project honeybee: Clinical applications for wearable biosensors.

Please provide an abstract of 150 to 250 words. The abstract should not contain any undefined abbreviations or unspecified references. The Project Honeybee Observational Clinical Trials were 12-month studies designed to validate the use of commercially available ambulatory medical devices costing $50-$300 for clinical applications.

Third generation impedimetric sensor employing direct electron transfer type glucose dehydrogenase.

Faradaic electrochemical impedance spectroscopy (faradaic EIS) is an attractive measurement principle for biosensors. However, there have been no reports on sensors employing direct electron transfer (DET)-type redox enzymes based on faradaic EIS principle. In this study, we have attempted to construct the 3rd-generation faradaic enzyme EIS sensor, which used DET-type flavin adenine dinucleotide (FAD) dependent glucose dehydrogenase (GDH) complex, to elucidate its characteristic properties as well as to investigate its potential application as the future immunosensor platform.

Designer fungus FAD glucose dehydrogenase capable of direct electron transfer.

Fungi-derived flavin adenine dinucleotide glucose dehydrogenases (FADGDHs) are currently the most popular and advanced enzymes for self-monitoring of blood glucose sensors; however, the achievement of direct electron transfer (DET) with FADGDHs is difficult. In this study, a designer FADGDH was constructed by fusing Aspergillus flavus derived FADGDH (AfGDH) and a Phanerochaete chrisosporium CDH (PcCDH)-derived heme b-binding cytochrome domain to develop a novel FADGDH that is capable of direct electron transfer with an electrode. A structural prediction suggested that the heme in the CDH may exist in proximity to the FAD of AfGDH if the heme b-binding cytochrome domain is fused to the AfGDH N-terminal region.

Facilitating Earlier Diagnosis of Cardiovascular Disease through Point-of-Care Biosensors: A Review.

Cardiovascular disease (CVD) accounts for 30% of all global deaths and is predicted to dominate in the coming years, despite vast improvements in medical technology. Current clinical methods of assessing an individual's cardiovascular health include blood tests to monitor relevant biomarker levels as well as varying imaging modalities such as electrocardiograms, computed tomography, and angiograms to assess vasculature. As informative as these tools are, they each require lengthy scheduling, preparation, and highly trained personnel to interpret the results before any information is accessible to patients, often leading to delayed treatment, which can be fatal.

A Disposable Tear Glucose Biosensor-Part 5: Improvements in Reagents and Tear Sampling Component.

A tear glucose (TG) sensor with an integrated tear sampler can provide a noninvasive method for calibrating the continuous TG contact lens and monitoring glucose. Expanding from previous work, an improved TG sensor that implements dried reagents, genetically modified glucose dehydrogenase (GDH), and a tear sampler was developed and compared against the TG sensor prepared with commercial GDH. It was found that neither sensor was affected by the tear interferents: ascorbic acid, acetaminophen, and uric acid.

Direct Measurement of a Biomarker's Native Optimal Frequency with Physical Adsorption Based Immobilization.

The optimal frequency (OF) of a biomarker in electrochemical impedance spectroscopy (EIS) is the frequency at which the EIS response best reflects the binding of the biomarker to its molecular recognition element. Commonly, biosensors rely on complicated immobilization chemistry to attach biological molecules to the sensor surface, making the direct study of a biomarker's native OF a challenge. Physical adsorption presents a simple immobilization strategy to study the native biomarker's OF, but its utility is often discouraged due to a loss in biological activity.

The electrochemical behavior of a FAD dependent glucose dehydrogenase with direct electron transfer subunit by immobilization on self-assembled monolayers.

Continuous glucose monitoring (CGM) is a vital technology for diabetes patients by providing tight glycemic control. Currently, many commercially available CGM sensors use glucose oxidase (GOD) as sensor element, but this enzyme is not able to transfer electrons directly to the electrode without oxygen or an electronic mediator. We previously reported a mutated FAD dependent glucose dehydrogenase complex (FADGDH) capable of direct electron transfer (DET) via an electron transfer subunit without involving oxygen or a mediator.

Minimizing the effects of oxygen interference on l-lactate sensors by a single amino acid mutation in Aerococcus viridansl-lactate oxidase.

l-lactate biosensors employing l-lactate oxidase (LOx) have been developed mainly to measure l-lactate concentration for clinical diagnostics, sports medicine, and the food industry. Some l-lactate biosensors employ artificial electron mediators, but these can negatively impact the detection of l-lactate by competing with the primary electron acceptor: molecular oxygen. In this paper, a strategic approach to engineering an AvLOx that minimizes the effects of oxygen interference on sensor strips was reported.