Enzyme biosensors immobilization

Enzymatic bioreactor Immobilized enzyme biosensor Immobilized enzyme reactor Immobilized microfluidic enzyme reactor (IMER) Membrane reactor... 

Fig. 2. Schematic of an electrochemical biocatalytic biosensor showing enzyme E immobilized onto the electrode where S is the substrate (target) and P is...

Gautier S.M., Blum L.J., Coulet P.R., Fiber-optic sensor with Co-immobilized bacterial bioluminescence enzymes, Biosensors 1989 4 181. 

The first enzyme biosensor was a glucose sensor reported by Clark in 1962 [194], This biosensor measured the product of glucose oxidation by GOD using an electrode which was a remarkable achievement even though the enzyme was not immobilized on the electrode. Updark and Hicks have developed an improved enzyme sensor using enzyme immobilization [194], The sensor combined the membrane-immobilized GOD with an oxygen electrode, and oxygen measurements were carried out before and after the enzyme reaction. Their report showed the importance of biomaterial immobilization to enhance the stability of a biosensor. 

A.L. Crumbliss, J.Z. Stonehuerner, R.W. Henkens, J. Zhao, and J.P. O Daly, A carrageenan hydrogel stabilized colloidal gold multi-enzyme biosensor electrode utilizing immobilized horseradish peroxidase and cholesterol oxidase/cholesterol esterase to detect cholesterol in serum and whole blood. Biosens. Bioelectron. 8, 331-337 (1993). 

Immobilized catalases, for textile bleaching effluent treatment, 4 68—69 Immobilized cells, 3 670 Immobilized enzyme biosensors,... 

Many different types of techniques for protein immobilization have been developed using, in most cases, enzyme sensors. Early studies of enzyme biosensors often employed thick polymer membranes (thickness 0.01-1 mm) in which enzymes are physically entrapped or chemically anchored. The electrode surface was covered with the enzyme-immobilized polymer membranes to prepare electrochemical enzyme sensors. Although these biosensors functioned appropriately to... 

The enzyme is immobilized on a nylon mesh, which also acts as a diffuse reflector for the light. The dynamic range of this sensor is between 1(T5 and 10 3M. Although the primary process that determines the steady-state concentration of the p-nitrophenoxide ion is the diffusion-reaction mechanism (which is governed by concentrations of all participating species), the detection of its concentration is again subject to the limitations of optical sensing of ionic species (Section 9.4.1). There are many similar optical enzyme biosensor schemes that utilize detection of... 

Acetylcholineesterase Biosensors were fabricated from filter-supported solventless bilayer lipid membrane (BLM) and used for the analysis of the substrates of hydrolytic enzymes in a flowthrough system. The codeposition of lipid (dipalmitoyl-phosphatidic acid) and protein solutions to form a BLM on a microporous glass fiber or polycarbonate ultra-filtration membrane disc was described. Enzyme was immobilized on the membrane by incorporation of protein solution into the lipid matrix at the air-electrolyte interface before BLM formation. 

Keywords bio-application, biocompatability, biosensor, carbon nanotube, direct electron transfer, electroconductivity, enzyme, functionalization, immobilization, quantum dot... 

By using a resonant mirror biosensor, the binding between YTX and PDEs from bovine brain was studied. The enzymes were immobilized over an aminosilae surface and the association curves after the addition of several YTX concentrations were checked. These curves follow a typical association profile that fit a pseudo-first-order kinetic equation. From these results the kinetic equilibrium dissociation constant (K ) for the PDE-YTX association was calculated. This value is 3.74 p,M YTX (Pazos et al. 2004). is dependent on YTX structure since it increases when 44 or 45 carbons (at C9 chain) group. A higher value, 7 p,M OH-YTX or 23 p,M carboxy-YTX, indicates a lower affinity of YTXs analogues by PDEs. 

When constructing biosensors, which are to be used continuously in vivo or in situ, maintaining sensor efficiency while increasing sensor lifetime are major issues to be addressed. Researchers have attempted various methods to prevent enzyme inactivation and maintain a high density of redox mediators at the sensor surface. Use of hydrogels, sol-gel systems, PEI and carbon paste matrices to stabilize enzymes and redox polymers was mentioned in previous sections. Another alternative is to use conductive polymers such as polypyrrole [123-127], polythiophene [78,79] or polyaniline [128] to immobilize enzymes and mediators through either covalent bonding or entrapment in the polymer matrix. Application to various enzyme biosensors has been tested. 

Immobilization of Enzymes Biosensors for Hydrogen Peroxide, Glufosinate, Glyphosate, Fluoxetine and Setraline... 

The enhanced chemiluminescense obtained with the horseradish peroxidase-H202-luminol (139) system was applied to the development of a CLD biosensor for p-iodophenol, coumaric acid (26), 2-naphthol and hydrogen peroxide. The enzyme was immobilized by microencapsulation in a sol-gel matrix. LOD for the phenolic compounds were 0.83 p,M, 15 nM and 48 nM, respectively. A remote version of the enhanced biosensor was designed by directly immobilizing the enzyme on the tip of an optical fiber. This model was used for H2O2 assay. LOD was 52.2 p,M, with RSD 4.7% (w = 4) °. A bioluminescent response was obtained for phenols with pA a > 7 in the presence of a recombinant Escherichia coli strain, DPD2540, containing a fabA luxCDABE fusion this behavior may have analytical applications. 

Schuhmann, W. Amperometric enzyme biosensors based on optimized electron-transfer pathways and non-manual immobilization procedures. Rev. Mol. Biotechnol. 2002, 82, 425-441. 

---