Determination of calprotectin in gingival crevicular fluid by immunoassay on a microchip

Gingival crevicular fluid (GCF) contains calprotectin, which appears to be a useful biomarker for periodontal diseases because of its high level in GCF from periodontally diseased pockets. To determine calprotectin in GCF that has a very small volume, sandwich enzyme-linked immunosorbent assay (ELISA) on a microchip was performed and its utility was estimated. Anti-calprotectin primary antibody was discharged on a microchip using a piezoelectric inkjet printing system. Calprotectin standard and calprotectin in GCF samples from eleven subjects were determined by the ELISA method with the prepared microchip and their values were compared with those obtained by conventional ELISA. Using the ELISA on a microchip, a reasonable standard curve of calprotectin protein (1.56–100ng/mL) was obtained. Calprotectin in GCF samples was quantified and showed reasonable values in accordance with the condition of periodontal diseases. The values determined by the microchip method and conventional ELISA showed a significant linear relationship (R2=0.981). Calprotectin in GCF was determined using the ELISA on a microchip with high efficiency and this ELISA method for calprotectin determination may become a useful method for diagnosing periodontal diseases. ► Calprotectin in gingival crevicular fluid (GCF) is a biomarker for periodontitis. ► We determined calprotectin in GCF using the ELISA on a microchip. ► This method has advantages of small GCF volume and shorter time for assay. ► The ELISA method using a microchip may be useful for diagnosing periodontitis.