Immobilization of GOD and HRP enzymes on nanostructured substrates

Abstract

The study of the entrapment of glucose oxidase (GOD) and horseradish peroxidase (HRP) enzymes on different solid-state substrates has been carried out. By using conventional methods, these enzymes have been immobilized on the following substrates: commercial Si wafers, thin films of nanostructured TiO 2 and gold nanotubes grown on polycarbonate membranes. Surface chemical composition and morphology of the samples have been investigated by means of X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Peak-fitting analysis of the main XPS signals permitted identification of the fingerprints of GOD and HRP enzymes and comparison of their entrapment on different substrates. The highest amount of attached enzymes was registered on the nanostructured TiO 2 films prepared by using the sol-gel technique. Moreover, the surface impurities, remaining on the samples after the immobilization of the phosphate buffer solution, were identified, and their removability by sample washing in deionized water was demonstrated.

Advanced characterization of immobilized enzymes as heterogeneous biocatalysts

“…2). Table 1 shows a set of emerging techniques that are applied to a direct quantification of the protein amount attached to the solid phase [20][21][22][31][32][33][34][35][36][37][38][39][40][41]. Measurements from within solid material are increasingly used and they complement the traditionally used measurements from the liquid phase.…”

“…3a. Table 1 summarizes the analytical methods for measurement of the distribution of bound proteins on surfaces and more specifically inside porous supports [22,[31][32][33][34][35][36][51][52][53][54][55][56][57][58]. Level of application, strengths and limitations are pointed out.…”

Immobilization of laccase on polyacrylamide and polyacrylamide – κ – carragennan-based semi-interpenetrating polymer networks

“…Many methods are available for enzyme immobilization, including adsorption to insoluble materials (Tomotani and Vitolo 2006), entrapment in polymeric gels (Curulli et al 2006), encapsulation in membranes (Patel et al 2006), crosslinking with bi-functional reagents (Simiddy et al 2006), or covalent linking onto insoluble carriers (Gao et al 2006). Entrapment, one of the immobilization techniques, can be defi ned as physical restriction of the enzyme within a confi ned space or network.…”

α-MoO3 nanowire-based amperometric biosensor for l-lactate detection

“…Recently, glassy carbon electrodes modified with a molybdenum oxide layer were found to give a good response to the anodic oxidation of nitrite at relatively moderate positive potentials. The use of molybdenum oxidemodified electrodes as amperometric sensors for monitoring nitrite enhanced the sensitivity of detection compared to what had previously been achieved [17]. Herein, we propose a simple and sensitive biosensor using MoO 3 nanowires for Llactate detection.…”

“…The immobilization of LOx on a sensing layer has been achieved by methods such as physical adsorption, chemical cross-linking, self-assembly, covalent bonding, and sol-gel immobilization [12][13][14][15]. Recently, the immobilization of LOx on electrodes through the use of transition metal oxide nanostructures has gained attention because of their diverse physical, chemical, and electrical properties [16,17]. Among the different transition metal oxides, molybdenum trioxide (MoO 3 ) nanostructures possess the most desirable characteristics in terms of high specific surface area, optical transparency, chemical and photochemical stability, electrochemical activity, and ease of fabrication [18,19].…”