Construction of an immunochromatographic determination system for N¹,N¹²-diacetylspermine

N(1),N(12)-diacetylspermine (DiAcSpm) is a recently identified tumor marker. Its concentration increases in the urine of cancer patients at early clinical stages. To utilize this characteristic feature and thus contribute to the early detection of cancer, we developed an immunochromatographic determination system for DiAcSpm.

We examined the factors that affect the performance and stability of our determination system, including antibody selection and the conditions for the formation of stably dispersed antibody-coated gold nanoparticles. We then tested the performance of the system by determining the DiAcSpm concentration in human urine samples.

We constructed an immunochromatographic strip using anti-DiAcSpm antibody-coated gold nanoparticles in the conjugate pad and an acetylspermine-protein conjugate (a DiAcSpm mimic) immobilized on the analyzing membrane. The use of the immunochromatographic strip and an immunochromato-reader allowed for the quantitative determination of DiAcSpm in the range of 20 to 700 nM. The analytical values obtained by this method were well correlated with those determined by a colloidal gold aggregation procedure using an automatic biochemical analyzer. The immunochromatographic strip was stable for at least 8 weeks at 50°C.

A competitive immunochromatographic device for DiAcSpm determination was developed in this study. This simple device will contribute to increasing the opportunities for early cancer detection and timely care.