A Partially Graphitic Mesoporous Carbon Membrane with Three-Dimensionally Networked Nanotunnels for Ultrasensitive Electrochemical Detection

Abstract

A hierarchically porous partially graphitic carbon (HPGC) membrane with three-dimensionally networked nanotunnels is prepared and applied as a monolithic matrix for electrochemical (bio)sensing. The walls of the nanotunnels (∼40−80 nm in diameter) are composed of partially graphitic carbon with ordered mesopores (∼6.5 nm in diameter). After modification with polydopamine, the HPGC membrane can be decorated with nanoparticles (i.e., Au NPs) and subsequently functions as a three-dimensional matrix for enzyme (i.e., glucose oxidase) immobilization. The Au NPs can accelerate electron transfer between the membrane electrode and enzyme and synergistically work with the enzyme in catalyzing glucose oxidation, thus considerably enhancing the sensitivity of the sensor. The signal intensity of the HPGC monolithic membrane electrode is ∼700 times higher than that obtained from mesoporous carbon/Nafion paste electrode counterparts. The limit of detection of the biosensor is 0.48 × 10 −11 M toward glucose detection, 4 orders of magnitude lower than that achieved by conventional nanostructured glucose sensors. The HPGC membrane shows potential in preparing monolithic electrodes for diverse electrochemical applications such as electrochemical detection, energy storage, and electrochemical catalysis.

Biosensors—Recent Advances and Future Challenges in Electrode Materials

“…More recent developments are focusing on the preparation of OMC with large mesopores and graphite walls. A hierarchically porous partially graphitic carbon membrane with three-dimensionally networked nanotunnels was used as a monolithic electrode matrix for the construction of a glucose biosensor [ 105 ]. The nanotunnels (~40–80 nm in diameter) are composed of partially graphitic carbon with ordered mesoporous (~6.5 nm in diameter).…”

Recent Trends on Electrochemical Sensors Based on Ordered Mesoporous Carbon

“…They can serve as hosts for the biomolecules and associated cofactors and mediators, and the abundant interconnected pores in the OMC can facilitate mass transport and offer large accessible surface area for reactants and electrons. The various biosensing applications involving OMC materials [ 194 , 195 , 196 , 197 , 198 , 199 , 200 , 201 , 202 , 203 , 204 , 205 , 206 , 207 , 208 , 209 , 210 , 211 , 212 , 213 , 214 , 215 , 216 , 217 , 218 , 219 , 220 , 221 , 222 , 223 , 224 , 225 , 226 , 227 , 228 , 229 , 230 , 231 , 232 , 233 , 234 , 235 , 236 , 237 , 238 , 239 , 240 , 241 , 242 , 243 , …”

“…OMC materials with hierarchical pore structures and/or large mesopores [ 214 , 220 , 221 , 222 , 223 , 226 , 231 ] seem to be the most promising ones (ensuring high enzyme loadings and fast transport of reagents). Graphitized or partially graphitic mesoporous carbons are also attractive because of their high conductivity [ 200 , 232 ]. The bioelectrode configuration most often implied the use of Nafion to confine OMC particles onto the electrode surface, this polymer offering at the same time a way of durable enzyme immobilization.…”

“…Other strategies for improved performance and lifetime involve ship-in-a-bottle approaches (e.g., enzyme cross-linking in bottleneck pore structures [ 234 , 267 ]) or the covalent bonding of GOD to the OMC surface [ 230 ]. Metal nanoparticles-decorated OMC enable to further improve charge transfer kinetics by providing a higher number of active sites (Pt, Au and Pd NPs have been used for that purpose [ 142 , 216 , 217 , 218 , 219 , 224 , 232 ], and even alloyed NiFe 2 NPs [ 233 ]), which could also lead to electrical contacting of redox proteins for advanced bioelectrocatalysis [ 268 , 269 ]. Note that if the overall conductivity of the composite continuously increases with NPs loading amounts (e.g., from 5% to 50% Pt NPs, for instance), due to better interconnectivity, the dependence of the electrocatalytic response (i.e., to H 2 O 2 ) on NPs loading follows an inverted V-shaped profile, with an optimal situation where Pt NPs are well-dispersed on OMC with little interconnection [ 235 ].…”

Immobilization of Enzymes on a Phospholipid Bionically Modified Polysulfone Gradient-Pore Membrane for the Enhanced Performance of Enzymatic Membrane Bioreactors

“…The important properties during the choice of a membrane are appropriate pore structure and permeability, which are vital to enhance the amount of enzyme loading and the timely separation of the product [ 21 , 22 , 23 ]. Therefore, membranes with perfect radial gradient pores, the size of which reduces gradually from the inner side to the outer side, meet the demands and hence, have been selected as supports.…”