Development of an Amperometric Cholesterol Biosensor Based on Graphene−Pt Nanoparticle Hybrid Material

Abstract

We describe the development of a highly sensitive amperometric biosensor based on the hybrid material derived from nanoscale Pt particles (nPt) and graphene for the sensing of H 2 O 2 and cholesterol. The biosensing platform was developed using the hybrid material and enzymes cholesterol oxidase and cholesterol esterase. Chemically synthesized graphene has been decorated with nanosized Pt particles. The electron microscopic measurements show that the Pt nanoparticles on graphene have an average size of 12 nm and are randomly distributed throughout the surface. The Pt nanoparticle based hybrid material modified electrode efficiently catalyzes the electrochemical oxidation of H 2 O 2 at the potential of 0.4 V, which is >100 mV less positive with respect to the bulk Pt electrode. The sensing platform is highly sensitive and shows linear response toward H 2 O 2 up to 12 mM with a detection limit of 0.5 nM [S/N (signal-to-noise ratio) ) 3] in the absence of any redox mediator or enzyme. The combination of electronically highly conductive graphene and catalytically active Pt nanoparticle favors the facilitated electron transfer for the oxidation of H 2 O 2 . The cholesterol biosensor was developed by immobilizing cholesterol oxidase and cholesterol esterase on the surface of graphene-nanoparticle hybrid material. The bienzyme integrated nanostructured platform is very sensitive, selective toward cholesterol, and it has a fast response time. The sensitivity and limit of detection of the electrode toward cholesterol ester are 2.07 ( 0.1 µA/µM/cm 2 and 0.2 µM, respectively. The apparent Michaelis-Menten constant (K m app ) was calculated to be 5 mM. The sensor does not suffer from the interference due to other common electroactive species and is highly stable. The analytical performance of the hybrid material was further evaluated using screen-printed electrodes with 50 µL of electrolyte.

Synthesis of 3D porous CeO2/reduced graphene oxide xerogel composite and low level detection of H2O2

“…A reliable, fast, accurate, and low level detection of H 2 O 2 has been the central task in various fields of analytical chemistry from environmental protection [23,24] to biosensors utilizing enzymes [25][26][27][28][29][30]. There are several disadvantages of the enzyme-modified electrodes, such as instability, high cost of enzymes and complicated immobilization procedure.…”

Fabrication of multiwalled carbon nanotube–polyaniline/platinum nanocomposite films toward improved performance for a cholesterol amperometric biosensor

“…It is observed that four interfering substances did not cause observable interference. Because the oxidation of ascorbate and urate on the unmodified electrode occurs at more positive potential (>0.40 V), the coexistence of these analytes would interfere the measurement of H 2 O 2 [39]. Obviously, the excellent selectivity of the biosensor was attributed to the contribution of a low-operating potential amperometric detection of cholesterol.…”

Development of Biosensors from Polymer Graphene Composites

“…It should be noted here that, most of the cases GO/rGO mixed with ethanolic Nf solution either by ultrasonication or by stirring at room temperature to form homogeneous mixture and directly coated on electrode surface for further use [61][62][63][64][65][66]. Nf also can be used as layer film over the modified electrode to stabilized the electrode material [67].…”