Determination of Procalcitonin in Serum with Immunochromatographic Strips Based on NaYF4: Yb,Er Upconverting Nanophosphors

Upconverting nanophosphors(UCP) NaYF4: Yb,Er were synthesized and surface functional modified. The prepared UCP were taken as fluorescent marker in the immunochromatographic strips for rapid determination of procalcitonin (PCT) in serum. The optimized conditions for immunochromatographic reaction were as follow: 15 mg·g-1 of labeled antibody, 40 μg of immune complexe (UCP), 1.0 μL·cm-1 of antibody zoned film on detection line and 5 min of incubation time. The linearity range of PCT was 0.05-50 μg·L-1 with the detection limit (3s/k) of 0.020 μg·L-1. The prepared immunochromatographic strips were used to determine PCT in serum, giving results in consistent with those obtained by Roche ECLIA and RSDs (n=3) less than 23%.