Determination of alkaline phosphatase based on affinity adsorption solid-substrate room temperature phosphorimetry using rhodamine 6G–dibromoluciferin luminescent nanoparticle to label lectin and prediction of diseases

In the presence of heavy atom perturber LiAc, the silicon dioxide nanoparticle containing rhodamine 6G (R) and dibromoluciferin (D) (R-D-SiO2) can emit strong and stable solid-substrate room temperature phosphorescence signal of R (λex/λem = 481/648 nm) and D (λex/λem = 457/622 nm) on the surface of acetyl cellulose membrane (ACM). R-D-SiO2 is used to label triticum vulgare lectin (WGA). Then two types of affinity adsorption reactions, R-D-SiO2-WGA- alkaline phosphatase (ALP) (direct method) and WGA-ALP-WGA-R-D-SiO2 (sandwich method), are carried out on ACM. The conditions and the analytical characteristics for the determination of ALP using affinity adsorption solid-substrate room temperature phosphorimetry (AA-SS-RTP) were studied. For a 0.40-μl drop of sample, results show that the detection limits of the sandwich method are 0.16 ag spot−1(457/622 nm) and 0.17 ag spot−1(481/648 nm), and the detection limits of the direct method are 0.41 ag spot−1 (457/622 nm) and 0.44 ag spot−1 (481/648 nm). The contents of ALP in human serum correlated well with those obtained by enzyme-linked immunoassay. This study shows that AA-SS-RTP whether by the sandwich method or the direct method, can combine very well the characteristics of both high sensitivity of SS-RTP and specificity of the immunoreaction. Simultaneously, whether the phosphorescence excitation/emission wavelength of either R or D in R-D-SiO2 is chosen to determine ALP, this can promote the agility and widen the adaptability of AA-SS-RTP.