Immobilization Techniques to Avoid Enzyme Loss from Oxidase-Based Biosensors: A One-Year Study

House, Jody L.; Anderson, Ellen M.; Ward, W. Kenneth

doi:10.1177/193229680700100104

Cited by 64 publications

(37 citation statements)

References 23 publications

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“…9 Other studies have shown that, while glucose sensors loaded with excess GO x could extend sensor lifetime, 172 any excess free (un-cross linked) GO x originally entrapped within the glutaraldehyde cross-linked enzyme layer can slowly leach out and contribute to a decline in sensitivity over time. 168 These factors should be taken into consideration to extend long-term in vivo sensor life. Enzyme denaturation is another concern for long-term enzymatic decay.…”

Section: Enzyme Degradationmentioning

confidence: 99%

Technologies for Continuous Glucose Monitoring: Current Problems and Future Promises

Vaddiraju

Burgess

Tomazos

et al. 2010

J Diabetes Sci Technol

230

224

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Devices for continuous glucose monitoring (CGM) are currently a major focus of research in the area of diabetes management. It is envisioned that such devices will have the ability to alert a diabetes patient (or the parent or medical care giver of a diabetes patient) of impending hypoglycemic/hyperglycemic events and thereby enable the patient to avoid extreme hypoglycemic/hyperglycemic excursions as well as minimize deviations outside the normal glucose range, thus preventing both life-threatening events and the debilitating complications associated with diabetes. It is anticipated that CGM devices will utilize constant feedback of analytical information from a glucose sensor to activate an insulin delivery pump, thereby ultimately realizing the concept of an artificial pancreas. Depending on whether the CGM device penetrates/breaks the skin and/or the sample is measured extracorporeally, these devices can be categorized as totally invasive, minimally invasive, and noninvasive. In addition, CGM devices are further classified according to the transduction mechanisms used for glucose sensing (i.e., electrochemical, optical, and piezoelectric). However, at present, most of these technologies are plagued by a variety of issues that affect their accuracy and long-term performance. This article presents a critical comparison of existing CGM technologies, highlighting critical issues of device accuracy, foreign body response, calibration, and miniaturization. An outlook on future developments with an emphasis on long-term reliability and performance is also presented.

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Section: Enzyme Degradationmentioning

confidence: 99%

Technologies for Continuous Glucose Monitoring: Current Problems and Future Promises

Vaddiraju

Burgess

Tomazos

et al. 2010

J Diabetes Sci Technol

230

224

View full text Add to dashboard Cite

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“…31 Subsequently, the GO x enzyme was immobilized by dip coating the Pt/PPh electrode from a solution of 140 mg/ml GO x , 56 mg/ml BSA, and 25% weight/volume glutaraldehyde, the latter of which enables enzyme cross linking, followed by a 2 h soak in phosphate-buffered saline (PBS) to remove the uncrosslinked proteins. 32 The next step involved dip coating the sensor with a polyurethane (PU) layer from a 3% (weight/weight) PU solution in 98% tetrahydrofuran/2% dimethylformamide (weight/weight). 33 Subsequently, a thin layer of catalase enzyme was added by coating it with a solution of catalase, BSA, and glutaraldehyde, followed by another 2 h soak in PBS to remove the uncross-linked proteins.…”

Section: Coil-type Glucose Sensorsmentioning

confidence: 99%

Design and Fabrication of a High-Performance Electrochemical Glucose Sensor

Vaddiraju

Legassey

Wang

et al. 2011

J Diabetes Sci Technol

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Abbreviations: (AP) acetaminophen, (BSA) bovine serum albumin, (FAD) flavin adenine dinucleotide, (GO x ) glucose oxidase, (PBS) phosphatebuffered saline, (PPh) polyphenol, (PU) polyurethane, (PVA) polyvinyl alcohol Keywords: bienzymatic, biosensor lag time, drug delivery coatings, foreign body response, implantable glucose sensors, outer membranes, selectivity Development of electrochemical sensors for continuous glucose monitoring is currently hindered by a variety of problems associated with low selectivity, low sensitivity, narrow linearities, delayed response times, hysteresis, biofouling, and tissue inflammation. We present an optimized sensor architecture based on layer stratification, which provides solutions that help address the aforementioned issues. Method:The working electrode of the electrochemical glucose sensors is sequentially coated with five layers containing: (1) electropolymerized polyphenol (PPh), (2) glutaraldehyde-immobilized glucose oxidase (GO x ) enzyme, (3) dip-coated polyurethane (PU), (4) glutaraldehyde-immobilized catalase enzyme, and (5) a physically cross linked polyvinyl alcohol (PVA) hydrogel membrane. The response of these sensors to glucose and electroactive interference agents (i.e., acetaminophen) was investigated following application of the various layers. Sensor hysteresis (i.e., the difference in current for a particular glucose concentration during ascending and descending cycles after 200 s) was also investigated. Results:The inner PPh membrane improved sensor selectivity via elimination of electrochemical interferences, while the third PU layer afforded high linearity by decreasing the glucose-to-O 2 ratio. The fourth catalase layer improved sensor response time and eliminated hysteresis through active withdrawal of GO x -generated H 2 O 2 from the inner sensory compartments. The outer PVA hydrogel provided mechanical support and a continuous pathway for diffusion of various participating species while acting as a host matrix for drug-eluting microspheres. Conclusions:Optimal sensor performance has been achieved through a five-layer stratification, where each coating layer works complementarily with the others. The versatility of the sensor design together with the ease of fabrication renders it a powerful tool for continuous glucose monitoring.

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“…This is due to the formation of proteins cross-linked by amino groups with strong azomethine (Fernandez-Lorente et al 2006;House et al 2007).…”

Section: Resultsmentioning

confidence: 99%

Residual Brewer’s Yeast Biomass and Bacterial Cellulose as an Alternative to Toxic Phenol-Formaldehyde Binders in Production of Pressed Materials from Waste Wood

Kadimaliev¹,

Kezina²,

Telyatnik³

et al. 2015

BioResources

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Pressed composites can be produced from wood sawdust waste using modified yeast biomass, waste as a bio-adhesive, ultra-dispersed bacterial cellulose (UBC) as a binder, and preliminary chemical crosslinking. The materials obtained were not inferior to traditional materials based on the required levels of toxic phenol-formaldehyde resin and physical and mechanical parameters. Physical and mechanical properties of the materials depended on the amount and viscosity of the binder, as well as on the chemical structure and conditions of chemical cross-linking and modified UBC application. The strengths of the best examples of the materials obtained were approximately 17 to 20 MPa, the densities were in the range of 1207 to 1255 kg/m 3 , and the water absorption was less than 20%. During hot pressing, notable changes were observed in the wood particles at FTIR-ATR spectra frequencies of 3620 cm -1 , 3600 to 3000 cm -1 , 2920 cm -1 , 2850 cm -1 , 1770 cm -1 , 1650 cm -1 , 1560 cm -1 , and 1089 cm -1 . This is mainly due to the chemical and structural changes in lignin, hemicellulose, and binder.

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Immobilization Techniques to Avoid Enzyme Loss from Oxidase-Based Biosensors: A One-Year Study

Cited by 64 publications

References 23 publications

Technologies for Continuous Glucose Monitoring: Current Problems and Future Promises

Technologies for Continuous Glucose Monitoring: Current Problems and Future Promises

Design and Fabrication of a High-Performance Electrochemical Glucose Sensor

Residual Brewer’s Yeast Biomass and Bacterial Cellulose as an Alternative to Toxic Phenol-Formaldehyde Binders in Production of Pressed Materials from Waste Wood

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