Encapsulation of tyrosinase within liposome bioreactors for developing an amperometric phenolic compounds biosensor

Tyrosinase Biosensor for Phenol Monitoring in Water

“…The minisensor developed has been successfully validated for tap and lake water samples. The detection limit achieved with the sensor (at S/N=3) was 1.24 ng/L, significantly lower that the detection limits reported for chromatographic [5][6][7][8][9] and biosensor [12][13][14] approaches. The proposed sensor exhibits high tolerance to interfering ions and can detect concentrations of 2.5 μg/L in surface water for drinking purposes and 6.1 μg/L in lake water.…”

“…The enzyme is rather unstable; it can be inactivated by its substrate, and, further, the sensor performance can be altered by the formation of radicals during electrochemical reduction of the enzymatically generated quinones, causing electrode fouling [12]. These disadvantages have been extensively discussed in literature, whereas various solutions have been proposed with bi-enzyme systems or complex multilayer designs [12][13][14]. Since the goal of the present work was to construct a simple and reliable sensor based only on phenol hydroxylation and avoiding completely the catechol oxidase activity of the enzyme, the authors studied the response of the tyrosinase-containing membrane within the pH-range 5.0-8.5 with a view to highlighting a suitable pH value.…”

“…The utilization of the enzyme in biosensor development has been limited to amperometry, investing on the redox character of the cascade reactions or the subsequent quinone reduction. A variety of problems reported refer mainly to (i) the immobilisation of the enzyme onto the sensor's surface [14], (ii) the leaching of enzyme to the solution [13], and (iii) the fouling of the electrode surface by the products of phenol oxidation [12]. This paper presents a novel phenol minisensor, built on a solid supported bilayer lipid membrane (s-BLM) platform incorporated with tyrosinase.…”

“…Although chromatography offers supreme precision, accuracy and resolution, none of these methods can be packed into field instrumentation, while their high detection limits necessitate laborious sample pre-treatment, such as solid-phase extraction. Potential alternatives rely on capillary electrophoresis [10], immunoassays [11] and biosensors [12][13][14].…”

Enzyme Immobilization by Microencapsulation: Methods, Materials, and Technological Applications

“…1a). The assembly of OmpF porines into the liposomes was achieved by various strategies, among them rehydration of the dried lipid film with porine solution containing 1% detergent, or consecutive freeze and thaw cycles (28,29). -Lactamase encapsulated in POPC liposomes showed no conversion of ampicillin owing to inhibited permeation before insertion of OmpF into the liposomal membrane.…”