Hydrogen Peroxide Biosensors Based on Direct Electron Transfer from Plant Peroxidases Immobilized on Self-Assembled Thiol-Monolayer Modified Gold Electrodes

Bioelectrocatalytical Detection of H2O2 with Different Forms of Horseradish Peroxidase Directly Adsorbed at Polycrystalline Silver and Gold

“…These electrode materials display a broad double layer region, where the faradaic currents resulting solely from direct ET from the electrode to HRP can be detected [21]. Since electrostatic interactions between the electrode and the surface of the enzyme can significantly affect both the adsorption and the efficiency of ET [22,23], optimal conditions for the bioelectrocatalysis of HRP were attained with polycrystalline gold bearing a slightly positive surface charge (potential of zero charge, pzc, close to À 80 mV [24]) and with silver electrodes suggesting a strongly positive surface charge (pzc of À 600 mV [24]). For this purpose, a chemical oxidative pretreatment of the electrodes was used providing surface charge and/or surface structure favorable for HRP adsorption and direct ET [16 ± 19, 22].…”

Tobacco Peroxidase as a New Reagent for Amperometric Biosensors

“…2). TOP was studied in an amperometric biosensor with a SAM at a gold electrode [17] on two different types of surfaces: positively and negatively charged (Fig. 3).…”

“…In addition to the fundamental studies of natural glycosylated TOP performed in 1996-1999 [3][4][5][6], which demonstrated a number of practically promising properties of this enzyme, the new enzyme was also tested for analytical purposes [7][8][9][10][11][12][13][14][15][16][17][18][19][20].…”

Uso analítico de tecidos e de extratos brutos vegetais como fonte enzimática

“…Gaspar et al [164][165][166] empregaram biossensores construídos com peroxidases obtidas e purificadas de tabaco (Nicotiana sylvestris) e batata doce (Ipomoea batatas) e fizeram um estudo comparativo empregando esses biossensores 164 com enzimas comerciais e aquelas obtidas no laboratório.…”