Design of Enzyme Electrodes for Extended Use and Storage Life

Design and optimization of a lactate amperometric biosensor based on lactate oxidase cross-linked with polymeric matrixes

“…These activity measurements exhibit a rapid increase in LOD catalytic behavior from pH 5.0-7.0, after which slow decrease in enzyme activity is observed. The highest sensitivity corresponds to the data obtained at pH 7.0, which is in agreement with other previously reported LOD-based electrochemical sensors [8][9][10]12,36,37]. Fig.…”

“…The stability is of great importance for the success of these devices as analytical instruments, and is mainly dependent on the lifetime, or the rate of denaturation or inactivation, of the enzyme employed [2,10,11]. The use of novel immobilization methods [8,9,[12][13][14][15][16] or media [17][18][19][20][21] is usually employed in order to enhance the enzyme stability by optimizing the surrounding microenvironment. The sensor-to-sensor reproducibility is also a major problem concerning the reliability of these devices.…”

Immobilization of horseradish peroxidase on O-carboxymethylated chitosan/sol–gel matrix

“…Though it has been reported that when the glutaraldehyde cross-linking process was performed in wet conditions, parts of the enzyme activity would be lost [30]. However, when the process was processed in dry conditions, the activity of the enzyme could be retained [31]. On the other hand, more stable and reactive enzyme layers could be obtained in the presence of the amino presented compounds such as bovine serum albumin (BSA), collagen, or gelatin [32].…”

Biosensors : the stabilité problem

“…It is thought that the hydrophobic environment of the carbon paste reduces the relative water activity of the enzyme surface, thus mimicking the stabilisation effects seen with enzymes in organic solvents [18]. Khan and Wernet reported the formation of a multilayer composite lactate sensor having a shelf-stability of over 2 years at -18°C and about a year at room temperature [19]. The membranes were stored dry and assayed for enzyme activity using the amperometric responses to 5µl injections of ethanol (2.5g.l -1 ) in a YSI model 27 glucose analyser.…”

“…Unpolarised biosensors remained active for far longer than polarised ones [53]. Khan and Wernet also reported a loss of stability at higher polarisation potentials [19].…”