Wu Zou,Fuchun Gong,Xuejiao Chen,Zhong Cao,Jiaoyun Xia,Tingting Gu,Zhizhang Li
Intrinsically fluorescent polymer nanoparticles (F-PNPs) were synthetized from 2-hydroxy-5-methylisophthalaldehyde and melamine by solvothermal method . F-PNPs can emit strong yellow green fluorescence at 542 nm without the conjugation to any external fluorescent agent and surface modification. Owing to the abundant amino and hydroxyl groups on their surface, the F-PNPs possess multiple binding sites, good biocompatibility and excellent water-solubility. Addition of Zn 2+ to the F-PNPs solution resulted in a blue shift (Δλ=40 nm) with obvious enhancement in the fluorescence intensity at 502 nm; while there was negligible change in the presence of other metal ions . The subsequent treatment with pyrophosphate (PPi) can cause fluorescence recovery of F-PNPs by pulling the Zn 2+ out of the coordination cavity of F-PNPs-Zn 2+ nanocomposites. No interference was observed from other anions and nucleotides, making the F-PNPs-Zn 2+ ensembles highly sensitive and selective nanoprobes for PPi. The detection limit is 2.75 × 10 −8 M/L and 7.63 × 10 −8 M/L for Zn 2+ and PPi, respectively. The proposed nanoprobes were then used for detecting the recovery of Zn 2+ and PPi in rabbit serum samples, which were found to be 99.4–104.2% and 98.6–104.7%, respectively. The present strategy for the fabrication of nanoparticles may offer a new sight for the preparation of polymer nanostructures . The F-FNPs based probes can provide an accurate method for the detection of Zn 2+ and PPi in serum samples.
In view of the biological significance and micro-heterogeneity of protein glycosylation for human health, specific enrichment of N -glycosylated proteins/peptides from complex biological samples is a prerequisite for the discovery of disease biomarkers and clinical diagnosis. In this work, we propose a “grafting-from” N-glycoprotein enriching method based on the in-situ growth of thermoresponsive polymer brushes from the N -glycosylated site of proteins. The initiator was first attached to the pre-oxidized glycan moieties by hydrazide chemistry , from which the thermoresponsive polymers can be grown to form giant protein-polymer conjugates (PPC). The thermosensitive PPC can be precipitated and separated by raising the temperature to above its lower critical solubility temperature (LCST). Mass spectrometry verified 210 N -glycopeptides corresponding to 136 N-glycoproteins in the rabbit serum. These results demonstrate the capability of the tandem thermoprecipitation strategy to enrich and separate N-glycoprotein/glycopeptide. Due to its simplicity and efficiency specifically, this method holds the potential for identifying biomarkers from biological samples in N -glycoproteome analysis.
Two kinds of new immunogens and coating antigens had been designed and synthesised by methods of lively ester (DCC) and carbodiimide (EDC), respectively. Preliminary immunosorbent assays indicated that the two target conjugates presented good inhibition ratio against the haptens of cypermethrin in vivo. The results showed that the best efficient titres of anti-cypermethrin rabbit serum in methods of DCC and EDC were 1:32000 and 1:64000, the IC50 of them were 18.907µg/L and 16.877µg/L against the haptens of cypermethrin, respectively. The data indicated that the anti-cypermethrin antibodies in method of EDC had higher sensitivity and higher selectivity than the anti-cypermethrin antibodies in method of DCC. Thus, we can synthesise antigens and anti-bodies with method of EDC. The antibodies of high quality can be effectively used in the field of the rapid detection of pyrethroid pesticide residues in the research of the reagent strips.
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