Amino Acid Ionic Liquid Modified Mesoporous Carbon: A Tailor‐made Nanostructure Biosensing Platform

Abstract

A novel nanocomposite based on ordered graphitized mesoporous carbon (GMC) and amino acid ionic liquids (AAIL) is obtained through controlled surface modification of GMC with hydrophilic AAILs (1-ethyl-3-methylimidazolium alanine, EMIM[Ala]), which is used as a platform for a tyrosinase biosensor to detect phenol. The GMC-AAIL nanocomposite possesses a better biocompatibility and improved aqueous-phase dispersion than hydrophobic GMC alone, owing to the introduction of hydrophilic and biocompatible AAILs. Comparative studies revealed that the catalytic activity of tyrosinase for phenol in phosphate buffer solution (PBS) containing EMIM[Ala] was about ten times higher than that in pure PBS. By entrapping tyrosinase molecules into the mesopores of GMC, making use of the synergy effect of GMC and AAIL (the "interspace confinement effect", the anti-fouling ability, and the biocompatible microenvironment), the GMC-AAIL-based biosensors display superior analytical performance to GMC-based ones in terms of signal-to-noise ratio, stability, repeatability, and working life. After 21-day storage, the electrode retained more than 90% of its initial response, indicating that surface modification of GMC with hydrophilic and biocompatible AAILs could significantly prolong the life of tyrosinase in vitro. The GMC10-EMIM[Ala]-based biosensor demonstrates a linear response for phenol concentrations from 0.1 to 10 µmol L(-1) with a low detection limit of 20 nmol L(-1) and sensitivity of 1385 mA cm(-2) M(-1). The GMC-AAIL nanocomposite proves to be a promising platform for enzyme-based biosensors and biocatalysis.

3D metal-organic framework as highly efficient biosensing platform for ultrasensitive and rapid detection of bisphenol A

“…The effective immobilization of enzyme molecules is one of the key factors in developing high performance enzyme biosensor. To seek for better immobilization matrixes, a variety of materials including graphene (Wang et al, 2010), mesoporous carbon (Wu et al, 2012b), metal nanoparticle (Saei et al, 2013), carbon nanotube (Vashist et al, 2011), metal oxide (Lu et al, 2008) and conducting polymer (Zhai et al, 2013) have already been explored to modify the electrodes for improving the loading amount as well as the bioactivity of the enzymes.…”

Direct Electrochemical Tyrosinase Biosensor based on Mesoporous Carbon and Co3O4 Nanorods for the Rapid Detection of Phenolic Pollutants

“…As shown, GMC exhibits a highly ordered porous structure with a pore diameter of 10 nm, which is indicative of the formation of an ordered mesoporous structure. These spherical pores are interconnected by adjacent smaller windows, which could provide mass‐transfer channels for the enzyme‐catalyzed substrate and product 21. More importantly, the mesopores with a pore size of 10 nm could provide a favorable microenvironment to accommodate the Tyr molecules.…”

“…Our previous study revealed that GMC with proper pore‐size matching for enzyme molecules could accommodate enzyme molecules into their mesopores thus to provide a protective microenvironment to prevent enzyme deactivation 16. 21 As for Co 3 O 4 , it has good hydrophilicity and biocompatibility 19. The combination of Co 3 O 4 with GMC resulted in the formation of a novel nanocomposite with improved hydrophilicity and biocompatibility.…”

“…Second, the pore size (pore diameter of 10 nm) of GMC matched the size of the Tyr molecules (6.5×9.8×5.5 nm), so GMC could provide a protective microenvironment for the immobilized proteins to prevent inactivation 16. 21 With the addition of Co 3 O 4 nanorods, a pair of more distinct redox peaks was observed on GMC/Co 3 O 4 ‐Tyr‐Chi/GCE (Figure 3 a, curve a), which indicated that more Tyr molecules on GMC/Co 3 O 4 ‐Tyr‐Chi/GCE could participate in direct electron transfer between the active center of the Tyr molecule and the electrode. Nanostructured metal oxides can provide a biocompatible electroactive surface for enzyme immobilization 25.…”

“…The graphitized ordered mesoporous carbon was prepared by a template‐assisted method according to our previously reported method 21. Briefly, monodisperse silica nanospheres (10 nm) were synthesized through the Stöber method reported by Yokoi with minor revision 37.…”