Noncovalent functionalization of carbon nanotubes with lectin for label-free dynamic monitoring of cell-surface glycan expression.

A kind of concanavalin A functionalized multiwalled carbon nanotube (ConA-MWCNT) was constructed by noncovalent assembly of ConA on carboxylated MWCNT with poly(diallyldimethylammonium) as a linker. The novel nanomaterial was characterized with scanning electron microscopy and atomic force microscopy. It incorporated both the specific recognition ability of lectin for cell-surface mannosyl groups and the unique electronic and mechanical properties of MWCNT. An electrochemical label-free method for cytosensing was proposed by constructing a ConA-MWCNT interface on a glassy carbon electrode, which showed a linear response to K562 cells ranging from 1 × 10(4) to 1 × 10(7) cellsmL(-1). The ConA-MWCNT interface could be further used for monitoring of dynamic variation of glycan expression on K562 cells in response to drugs. A facile and high-throughput optical method for the analysis of dynamic glycan expression on living cells was also developed by constructing an array of ConA-MWCNT spots on a glass slide. This method showed acceptable rapidity and low cost. The noncovalent functionalization of MWCNTs with lectins could be potentially applied in cell biological studies based on cell-surface glycan expression.