We have developed a target-molecule-functionalized magnetic nanoparticle (MNP)-based method to facilitate the study of biomolecular recognition and separation. The superparamagnetic property of MNPs allows the corresponding biomolecules to be rapidly separated from crude biofluids with a significant improvement in recovery yield and specificity. Various MNPs functionalized with tag molecules (chitin, heparin, and amylose) were synthesized for recombinant protein purification, and several probe-functionalized MNPs, such as nitrilotriacetic acid (NTA)@MNP and P(k)@MNP, exhibited excellent extraction efficiency for proteins. In a cell recognition study, mannose-functionalized MNPs allowed specific purification of Escherichia coli with FimH adhesin on the surface. In an immunoprecipitation assay, the antibody-conjugated MNPs reduced the incubation time from 12 to 1 h while maintaining a comparable efficiency. The functionalized MNPs were also used in a membrane proteomic study that utilized the interaction between streptavidin-functionalized MNPs and biotinylated cell membrane proteins. Overall, the functionalized MNPs were demonstrated to be promising probes for the specific separation of targets from proteins to cells and proteomics.

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Ephedrine (EH) and pseudoephedrine (PEH), which are chiral enantiomers commonly used clinically, have different pharmacological actions and treatment effects due to their chiral nature. In the presence of Pd2+, the reaction system of Ery B (erythrosin B)‐Pd2+ has a strong resonance Rayleigh scattering (RRS) intensity. Adding EH into this system reduced the RRS intensity, but PEH could not produce this phenomenon. The chiral recognition of these enantiomers could be achieved according to this spectral difference. At the same time, reduction in RRS strength of the reaction system is proportional to the concentration of EH. Under optimized conditions, the linear range is 40–960 ng/ml, and the detection limit is 3.9 ng/ml. A new method for the rapid detection of EH enantiomers can be established. Based on this assay, a new method for the determination of the chiral enantiomers of EH and PEH can be developed.

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In this study, a novel method for chiral recognition of phenylglycinol (PG) enantiomers was proposed. Firstly, water-soluble N-acetyl-l-cysteine (NALC)-capped CdTe quantum dots (QDs) were synthesized and experiment showed that the fluorescence intensity of the reaction system slightly enhancement when added PG enantiomers to NALC-capped CdTe quantum dots (QDs), but the R-PG and S-PG could not be distinguished. Secondly, when there was Ag presence in the reaction system, the experiment result was extremely interesting, the PG enantiomers cloud make NALC-capped CdTe QDs produce different fluorescence signal, in which the fluorescence of S-PG+Ag+NALC-CdTe system was significantly enhanced, and the fluorescence of R-PG+Ag+NALC-CdTe system was markedly decreased. Thirdly, all the enhanced and decreased of the fluorescence intensity were directly proportional to the concentration of R-PG and S-PG in the linearly range 10-10mol·L, respectively. So, the new method for simultaneous determination of the PG enantiomers was built too. The experiment result of the method was satisfactory with the detection limit of PG can reached 10mol·L and the related coefficient of S-PG and R-PG are 0.995 and 0.980, respectively. The method was highly sensitive, selective and had wider detection range compared with other methods.