Large molecules pass the biological membranes through accessory elements, either carriers (ionophores) and/or water channels. Ionophores shield the charge of the target ion, enabling it to cross the membrane to be released on the other side. This may consume time and some huge structures need a bulky ionophore. However, water channels enable the passage of many ions with a high rate without the need of carriers that may limit the ion transfer rate.
Simulation of living cell membrane in engulfing large molecules through channels is a very interesting mechanism to enhance permselectivity of fabricated polyvinyl chloride (PVC) membrane sensors. Green synthesis of carbonaceous nanoparticles to play this role was fulfilled in nano carbon dots (CD).
The polymerization of β-cyclodextrin with acrylates, either imprinted with the target molecule (in molecularly imprinted polymer, MIP) or not (in non-imprinted polymer, NIP) provided a good enhancement of binding selectivity, in comparison with β-cyclodextrin alone as ionophore.
Application of both inventions in fabrication of three sensors (1; CD/βCD, 2; CD/NIP and 3; CD/MIP) enabled trace analysis of azoxystrobin fungicide in ranges (10-11 -10-4, 10-13 -10-4 and 10-13 -10-4 M), respectively, with high selectivity.