Lectin-modified trifunctional nanobiosensors for mapping cell surface glycoconjugates.

Nanomaterial-based nanobiosensors (nanobiodevices or nanobioprobes) are increasingly emphasized. Here, quantum dots and gamma-Fe(2)O(3) magnetic nanoparticles were co-embedded into single swelling poly(styrene/acrylamide) copolymer nanospheres to fabricate fluorescent-magnetic bifunctional nanospheres. Subsequently, fluorescent-magnetic-biotargeting trifunctional nanobiosensors (TFNS) modified with wheat germ agglutinin (WGA), peanut agglutinin (PNA) or Dolichos biflorus agglutinin (DBA) were conveniently produced so as to bind with A549 cells which are surface-expressed with N-acetylglucosamine, d-galactosamine and N-acetylgalactosamine residues. The values of WGA, PNA and DBA on each nanobiosensor were calculated to be 40, 14 and 60, respectively. These three kinds of lectin-modified trifunctional nanobiosensors (lectin-TFNS) can be used for qualitative and quantitative analysis of the glycoconjugates on A549 cell surface. The fluorescence intensity of WGA-modified nanobiosensors related to N-acetylglucosamine on A549 cell surface was much higher than that of PNA-modified nanobiosensors corresponding to d-galactosamine and that of N-acetylgalactosamine-related DBA-modified nanobiosensors, which is consistent with the results detected by flow cytometry. Lectin-modified trifunctional nanobiosensors not only can quantify the different glycoconjugates on A549 cell surface, but also can recognize and isolate A549 cells. 0.5mg of WGA-modified fluorescent-magnetic trifunctional nanobiosensors could capture 7.0 x 10(4) A549 cells. Therefore, the lectin-modified trifunctional nanobiosensors may be applied in mapping the glycoconjugates on cell surfaces and for recognition and isolation of targeted cells.