Rapid Detection of Serum Procalcitonin by Immunochromatograghy Technology Based on Freeze-dried Up-conversion Nanoparticles/Antibody Conjugates

Procalcitonin (PCT) is a sensitive and specific biomarker for sepsis diagnosis and widely used as a biomarker to improve the diagnosis of bacterial infections and to guide the antibiotic therapy. In our work, an improved up-converting nanoparticle (UCP) technology based on the immunochromatographic assay (UPT-ICA) was developed for rapid and quantitative detection of PCT. In order to further improve the accuracy, sensitivity and stability of the assay on the basis of our previous study, the UCP coupling with monoclonal antibody of PCT (UCP-Ab1) was freeze-dried under certain conditions. And the detections of PCT levels with UCP-Ab1 conjugates before and after freeze-drying were evaluated. The results show that, compared to the UCP-Ab1 conjugates without freeze-drying, the detection sensitivity of freeze-dried UCP-Ab1 is slightly improved, having a lower immunochromatogragh background and better stability. This improved method can provide a rapid, accurate, and relatively easy way for the clinical detection of PCT.