Laccase immobilization on the electrode surface to design a biosensor for the detection of phenolic compound such as catechol.

Biosensors based on the coupling of a biological entity with a suitable transducer offer an effective route to detect phenolic compounds. Phenol and phenolic compounds are among the most toxic environmental pollutants. Laccases are multi-copper oxidases that can oxide phenol and phenolic compounds. A method is described for construction of an electrochemical biosensor to detect phenolic compounds based on covalent immobilization of laccase (Lac) onto polyaniline (PANI) electrodeposited onto a glassy carbon (GC) electrode via glutaraldehyde coupling. The modified electrode was characterized by voltammetry, Fourier transform infrared (FTIR) spectroscopy and atomic force microscopy (AFM) techniques. The results indicated that laccase was immobilized onto modified GC electrode by the covalent interaction between laccase and terminal functional groups of the glutaraldehyde. The laccase immobilized modified electrode showed a direct electron transfer reaction between laccase and the electrode. Linear range, sensitivity, and detection limit for this biosensor were 3.2 × 10(-6) to 19.6 × 10(-6)M, 706.7 mAL mol(-1), 2.07 × 10(-6)M, respectively.

Nazari M ，Kashanian S ，Rafipour R 《-》

An amperometric biosensor based on laccase immobilized onto Fe₃O₄NPs/cMWCNT/PANI/Au electrode for determination of phenolic content in tea leaves extract.

A method is described for the construction of an amperometric biosensor for detection of phenolic compounds based on covalent immobilization of laccase onto iron oxide nanoparticles (Fe₃O₄NPs) decorated carboxylated multiwalled carbon nanotubes (cMWCNTs)/polyaniline (PANI) composite electrodeposited onto a gold (Au) electrode. The modified electrode was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The biosensor showed optimum response within 3s at pH 6.0 (0.1 M sodium acetate buffer) and 35°C, when operated at 0.3 V vs. Ag/AgCl. Linear range, detection limit were 0.1-10 μM (lower concentration range) and 10-500 μM (higher concentration range), and 0.03 μM respectively. The sensor measured total phenolic content in tea leaves extract. The enzyme electrode lost 25% of its initial activity after its 150 uses over a period of 4 months, when stored at 4°C.

Rawal R ，Chawla S ，Devender ，Pundir CS ... -  《-》

Laccase biosensors based on mercury thin film electrode.

Kirgöz UA ，Tural H ，Timur S ，Pazarlioglu N ，Telefoncu A ，Pilloton R ... -  《ARTIFICIAL CELLS BLOOD SUBSTITUTES AND BIOTECHNOLOGY》

A novel amperometric catechol biosensor based on α-Fe(2)O(3) nanocrystals-modified carbon paste electrode.

Sarika C ，Shivakumar MS ，Shivakumara C ，Krishnamurthy G ，Narasimha Murthy B ，Lekshmi IC ... -  《-》

Polyphenol biosensor based on laccase immobilized onto silver nanoparticles/multiwalled carbon nanotube/polyaniline gold electrode.

Laccase purified from Ganoderma sp. was immobilized covalently onto electrochemically deposited silver nanoparticles (AgNPs)/carboxylated multiwalled carbon nanotubes (cMWCNT)/polyaniline (PANI) layer on the surface of gold (Au) electrode. A polyphenol biosensor was fabricated using this enzyme electrode (laccase/AgNPs/cMWCNT/PANI/Au electrode) as the working electrode, Ag/AgCl as the reference electrode, and platinum (Pt) wire as the auxiliary electrode connected through a potentiostat. The biosensor showed optimal response at pH 5.5 (0.1 M acetate buffer) and 35°C when operated at a scan rate of 50 mV s(-1). Linear range, response time, and detection limit were 0.1-500 μM, 6 s, and 0.1 μM, respectively. The sensor was employed for the determination of total phenolic content in tea, alcoholic beverages, and pharmaceutical formulations. The enzyme electrode was used 200 times over a period of 4 months when stored at 4°C. The biosensor has an advantage over earlier enzyme sensors in that it has no leakage of enzyme during reuse and is unaffected by the external environment due to the protective PANI microenvironment.

Rawal R ，Chawla S ，Pundir CS 《-》