Functionalized magnetic nanomaterials for electrochemical biosensing of cholesterol and cholesteryl palmitate

Abstract

Synthesis and functionalization of magnetite nanoparticles (Fe 3 O 4 ) was achieved with the view to covalently bind both cholesterol oxidase and cholesterol esterase biorecognition agents for the development of free and total cholesterol biosensors. Prior to enzyme attachment, Fe 3 O 4 was functionalized with 3-aminopropyltriethoxysilane (APTES) and polyamidoamine (PAMAM) dendrimer. Characterization of the material was performed by FT-IR and UV spectroscopy, SEM/EDX surface analysis and electrochemical investigations. The response to cholesterol and its palmitate ester was examined using cyclic voltammetry. Optimum analytical performance for the free cholesterol biosensor was obtained using APTES-functionalized magnetite with a sensitivity of 101.9 μA mM −1 cm −2 , linear range 0.1-1 mM and LOD of 80 μM when operated at 37 °C. In the case of the total cholesterol biosensor, the best analytical performance was obtained using PAMAM dendrimer-modified magnetite with sensitivity of 73.88 μA mM −1 cm −2 and linear range 0.1-1.5 mM, with LOD of 90 μM. A stability study indicated that the free cholesterol biosensors retained average activity of 98% after 25 days while the total cholesterol biosensors retained 85% activity upon storage over the same period.

Simple and Cost-effective Enzymatic Detection of Cholesterol Using Flow Injection Analysis

“…The performance of our FIA system was compared with other cholesterol sensors and the findings are shown in Table 1. Reproducibility, linear dynamic range, stability and detection limit are comparable to other designs described previously, 14,25,26,[36][37][38][39][40] and the good cost effectiveness of our FIA system was clearly realized considering its simple design, the use of a single enzyme and re-useability of enzymatic capillary reactor. Our enzymatic capillary reactor had operational and storage stability >30 days, which permitted the measurement of approximately 80 samples.…”

Surface-coated magnetic nanostructured materials for robust bio-catalysis and biomedical applications-A review

“…Both of the engineered ASNase revealed outstanding functioning stability after 17 consecutive batch cycles [31] . The MNPs surface was functionalized with aminopropyltriethoxysilane (APTES) and polyamidoamine (PAMAM) dendrimer to comprehend the covalent binding of cholesterol oxidase and esterase for the development of cholesterol biosensor [32] .…”

“…Another application of enzyme coated MNPs are the fabrication of biosensors involving sensitive biological entities like antibodies, cell receptors, enzymes, transducers and, detectors associated with signal processing and electronics [32] . Commonly used MNPs and enzymes-based biosensors are glucose sensor for blood-sugar tests.…”

(3-Aminopropyl) Triethoxysilane (APTES) Functionalized Magnetic Nanosilica Graphene Oxide (MGO) Nanocomposite for the Comparative Adsorption of the Heavy Metal [Pb(II), Cd(II) and Ni(II)] Ions from Aqueous Solution

“…APTES possess nitrogen-containing functional groups that have a strong coordination ability with heavy metal ions. Hence, modification of MGO with APTES enhances stability and improves other properties such as selective adsorption of metal ions from aqueous solution [22]. To the best of our knowledge, there are no previous literature studies on the comparative adsorption of the heavy metals Pb(II), Cd(II) and Ni(II) using APTES functionalized magnetic graphene oxide (MGO) nanocomposites.…”