A dual enzyme functionalized nanostructured thulium oxide based interface for biomedical application

Abstract

In this paper, we present results of the studies related to fabrication of a rare earth metal oxide based efficient biosensor using an interface based on hydrothermally prepared nanostructured thulium oxide (n-Tm2O3). A colloidal solution of prepared nanorods has been electrophoretically deposited (EPD) onto an indium-tin-oxide (ITO) glass substrate. The n-Tm2O3 nanorods are found to provide improved sensing characteristics to the electrode interface in terms of electroactive surface area, diffusion coefficient, charge transfer rate constant and electron transfer kinetics. The structural and morphological studies of n-Tm2O3 nanorods have been carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopic techniques. This interfacial platform has been used for fabrication of a total cholesterol biosensor by immobilizing cholesterol esterase (ChEt) and cholesterol oxidase (ChOx) onto a Tm2O3 nanostructured surface. The results of response studies of the fabricated ChEt-ChOx/n-Tm2O3/ITO bioelectrode show a broad linear range of 8-400 mg dL(-1), detection limit of 19.78 mg (dL cm(-2))(-1), and high sensitivity of 0.9245 μA (mg per dL cm(-2))(-1) with a response time of 40 s. Further, this bioelectrode has been utilized for estimation of total cholesterol with negligible interference (3%) from analytes present in human serum samples. The utilization of this n-Tm2O3 modified electrode for enzyme-based biosensor analysis offers an efficient strategy and a novel interface for application of the rare earth metal oxide materials in the field of electrochemical sensors and bioelectronic devices.

Potential of Gelatin‐Zinc Oxide Nanocomposite as Ascorbic Acid Sensor

“…This may be due to high surface coverage of the immobilized enzyme on the GB‐ZnO/ITO electrode. The surface concentration of AsOx/GB‐ZnO/ITO was higher than that of reported in literature 48, 49.…”

“…where I p is the peak current of the bioelectrode ( I pa anodic and I pc cathodic), n is the number of electrons involved or electron stoichiometry (1), A is the surface area of the bioelectrode (0.25 cm 2 ), C is the concentration of redox species (5 mM) and v is the scan rate (20 mV/s). The D value obtained was 3.75×10 −5 cm 2 s −1 , which is higher than reported in the literature 48,49.…”

Kaempferol mediated synthesis of gold nanoparticles and their cytotoxic effects on MCF-7 cancer cell line

“…Metal and metal oxide nanoparticles stabilized with bioactive substances may find application in diverse areas like gene and drug delivery, as biosensors, as bio-catalysts and in diagnosis and therapeutics [1][2][3]. Gold nanoparticles (AuNPs) for example, can act as a carrier moiety delivering a drug in a controlled manner by enhancing its bioavailability and overcoming side effects and non-specificity [1,4].The classical methods of synthesis of gold nanoparticles (AuNPs) which employ chemical agents like sodium citrate, CTAB etc.…”

Influence of NH3 plasma and Ti doping on pH-sensitive CeO2 electrolyte-insulator-semiconductor biosensors

“…Over the past decade, various types of metal oxides such as Nb 2 O 5 9 , HfO 2 10 , and TiO 2 11 have been used as the sensing insulator in an EIS structure. Recently, some rare earth oxides, with advantages including wide band gaps, large band offsets on Si, and high dielectric constants have been demonstrated as good sensing insulators for EIS biosensing devices 12, 13 . Among these rare earth oxides, CeO 2 , with a wide bandgap of 3.19 eV and a high dielectric constant, has been used as the sensing material for EIS biosensing devices 14, 15 .…”