Amperometric inhibition biosensors based on horseradish peroxidase and gold sononanoparticles immobilized onto different electrodes for cyanide measurements
“…Tyrosinase (Tyrs) was immobilized onto the electrode surface by cross‐linking with glutaraldehyde (GA) and bovine serum albumin (BSA) as reported in previous works . A mixture of 15 μL of (104 unit/μL) Tyrs solution, 7.5 μL of 1 % BSA and 7.5 μL of 0.25 % GA was prepared; 7.5 μL of this mixture was pipetted onto the surface of the carbon nanopowder paste electrode and allowed to dry for 2 h at ambient temperature.…”
Herein, we report an electrochemical biosensor for the measurement of proteins and protease activity using carbon nanopowder paste electrode modified with tyrosinase. The measurement of proteins is based on the amperometric measurement of the enzymatic product, tyrosine, at low applied potential (i.e +0.05 V vs. Ag/AgCl), in a linear range from 1 μg/mL to 10 μg/mL for casein and albumin bovine serum. This biosensor is also used to assess the enzymatic activity of the enzymes namely trypsin and proteinase K, observing a detection limit of 0.02 mU/mL (S/N=3). The ability of this assay to monitor the trypsin activity is exploited to investigate its inhibition by leupeptin. The trypsin kinetic interactions reveal uncompetitive binding of leupeptin with 50 % inhibition equal to 3.75 μM, a dynamic range of 0.25–10 μM, and a detection limit of 0.25 μM. The assay developed can be considered as general activity assay of any protease with the advantages of good storage stability (few weeks), low detection limit and ability to analyse turbid and colored samples.
“…Tyrosinase (Tyrs) was immobilized onto the electrode surface by cross‐linking with glutaraldehyde (GA) and bovine serum albumin (BSA) as reported in previous works . A mixture of 15 μL of (104 unit/μL) Tyrs solution, 7.5 μL of 1 % BSA and 7.5 μL of 0.25 % GA was prepared; 7.5 μL of this mixture was pipetted onto the surface of the carbon nanopowder paste electrode and allowed to dry for 2 h at ambient temperature.…”
Herein, we report an electrochemical biosensor for the measurement of proteins and protease activity using carbon nanopowder paste electrode modified with tyrosinase. The measurement of proteins is based on the amperometric measurement of the enzymatic product, tyrosine, at low applied potential (i.e +0.05 V vs. Ag/AgCl), in a linear range from 1 μg/mL to 10 μg/mL for casein and albumin bovine serum. This biosensor is also used to assess the enzymatic activity of the enzymes namely trypsin and proteinase K, observing a detection limit of 0.02 mU/mL (S/N=3). The ability of this assay to monitor the trypsin activity is exploited to investigate its inhibition by leupeptin. The trypsin kinetic interactions reveal uncompetitive binding of leupeptin with 50 % inhibition equal to 3.75 μM, a dynamic range of 0.25–10 μM, and a detection limit of 0.25 μM. The assay developed can be considered as general activity assay of any protease with the advantages of good storage stability (few weeks), low detection limit and ability to analyse turbid and colored samples.
“…Due to its powerful catalytic activity, through electron transfer mechanisms, peroxidase has found application in a variety of biosensors, mainly electrochem- ical ones, in which distinct types of responses can be recorded and treated to give accurate information on a specific analyte. Attar et al [65] constructed a biosensor based on horseradish peroxidase to detect cyanides, which consist of extremely poisonous substances and is present in surface and ground-waters. In their proposal, peroxidase enzymatic activity is inhibited, and the decrease is inversely proportional to cyanide concentration increase.…”
Section: Supramolecular Compounds For Electrochemical Biosensorsmentioning
It is incontestable that the interactions and bonds that keep molecules united to generate unique supramolecular compounds, with individual properties, morphologies and behaviour, are of special dynamics and singular forces. Therefore, it is necessary to discuss and consider the types of interactions that may occur in a determined system, their dynamics and number, which directly act on the energetic balance that strengthen the union between participants and give rise to a supramolecule.In this chapter, a number of such supramolecular systems that find application as any component of a biosensor are presented and discussed, considering intermolecular interaction forces that confer them shape, function and unique properties. To better understand their structural dynamics and the mechanisms through which they can be used in biosensing, a brief explanation on the interaction thermodynamics, types of intermolecular interactions that compete against each other and the energetic equilibrium that originate and stabilize supramolecular systems is given. To explain how this balance of forces can be extensively exploited to develop methods to produce supramolecular compounds, an overview on supramolecular strategies is presented and their contribution is explored in each example presented in this text, to evidence the importance of planning and developing methodologies of preparation, based on
“…With the development of nanotechnology, more and more nanomaterials such as modified carbon nanotubes, nanocomposite material, modified gold nanoparticles, and QDs have been widely employed in the electrode modification and electrochemical sensor development. [28][29][30][31][32][33][34][35] It is that significantly improves the sensitivity, detection limit and stability in OP and CB pesticide determination. In this review, we have combined with the latest research papers and summarized the use of biosensors for detection of OPs and CBs based on various nanomaterials and different enzymes (AChE, ChE, etc.…”
Recent research progress is reviewed in development of rapid detection of Organosphorous (OPs) and carbamates (CBs) pesticide based on acetylcholinesterase (AChE) inhibition principle. Enzyme biosensors have properties that can provide conveninent, rapid, sensitive and cheap on-field detection with AChE. In recent years, effective monitoring of OPs and CBs pesticides has been done successfully by using nanomaterials-based AChE sensors. More and more nanomaterials such as modified carbon nanotubes, nanocomposite material, modified gold nanoparticles, quantum dots(QDs) are applied to enzyme biosensors, the modified electrodes can promote significant enhancements of determinations of pesticide residues.
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