Analysis application in biological field and prediction of human diseases with dual luminescence molecular of 3.5-generations polyamidoamine dendrimers–porphyrin

A new phosphorescence-labelling reagent (3.5-G-D–P labelling reagent) was developed, based on 3.5-generation polyamidoamine dendrimers (3.5-G-D) as internal acceptor to capture porphyrin (P) molecular. In the disturber of heavy atom, 3.5-G-D–P could emit room temperature phosphorescence (RTP) of 3.5-G-D and P on the surface of polyamide membrane (PAM), respectively. Products (3.5-G-D–P–WGA) of 3.5-G-D–P labelling triticum vulgaris lectin (WGA) could emit strong and stable RTP signal on the surface of PAM, and it also could take specific affinity adsorption reaction (AA) with alkaline phosphatase (ALP). The product of the AA reaction (3.5-G-D–P–WGA–ALP) could keep the RTP characteristics of 3.5-G-D–P very well, and the ΔIp of the system was linear correlation to the content of ALP. The ΔIp of the system with Tween-80 was once for P and twice for 3.5-G-D more than that without Tween-80. Thus, the affinity adsorption solid substrate-room temperature phosphorimetry (AA-SS-RTP) for the determination of trace ALP has been established using Tween-80–3.5-G-D–P to label WGA. The detection limit (LD) of this method was 0.12 fg spot−1 for 3.5-G-D and 0.18 fg spot−1 for P with direct method, 0.14 fg spot−1 for 3.5-G-D and 0.17 fg spot−1 for P with sandwich method, respectively, and the sensitivity was obviously high. This research showed that either using 3.5-G-D or P excitation/emission wavelength to determine the content of ALP in human serum, the results were coincided with ELISA, and the flexibility of AA-SS-RTP was obviously improved and the applicability was wider. Meanwhile, the reaction mechanism of determining ALP by direct method AA-SS-RTP was discussed.