International Journal of Nanomedicine (Mar 2020)
Simultaneous Real-Time Detection of Pregnancy-Associated Plasma Protein-a and -A2 Using a Graphene Oxide-Based Surface Plasmon Resonance Biosensor
Abstract
Shi-Yuan Fan,1 Nan-Fu Chiu,2 Chie-Pein Chen,1,3 Chia-Chen Chang,4 Chen-Yu Chen1,3 1Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan; 2Institute of Electro-Optical Science and Technology, National Taiwan Normal University, Taipei, Taiwan; 3Department of Medicine, Mackay Medical College, New Taipei City, Taiwan; 4Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan City, TaiwanCorrespondence: Chen-Yu ChenDepartment of Medicine, Mackay Medical College, No. 46, Section 3, Zhongzheng Road, Sanzhi District, New Taipei City 252, TaiwanTel +886 2 2636 0303Email [email protected]: Pregnancy-associated plasma protein-A and -A2 (PAPP-A and -A2) are principally expressed in placental trophoblasts and play a critical role in the regulation of fetal and placental growth. PAPP-A2 shares 45% amino acid similarity with PAPP-A. This study aimed to investigate the efficacy of real-time detection of PAPP-A and PAPP-A2 using a novel surface plasmon resonance (SPR) biosensor based on graphene oxide (GO).Methods: Traditional SPR and GO-based SPR chips were fabricated to measure PAPP-A and PAPP-A2 concentrations. We compared SPR response curves of PAPP-A and PAPP-A2 between traditional SPR and GO-SPR biosensors. We also performed interference tests and specificity analyses among PAPP-A, PAPP-A2, and mixed interference proteins.Results: The time to detect PAPP-A and PAPP-A2 was about 150 seconds with both traditional SPR and GO-SPR biosensors. Approximately double SPR angle shifts were noted with the GO-SPR biosensor compared to the traditional SPR biosensor at a PAPP-A and PAPP-A2 concentration of 5 μg/mL. The limit of detection of the GO-SPR biosensor was as low as 0.5 ng/mL for both PAPP-A and PAPP-A2. Interference testing revealed that almost all of the protein bonded on the GO-SPR biosensor with anti-PAPP-A from the mixture of proteins was PAPP-A, and that almost no other proteins were captured except for PAPP-A2. However, the SPR signal of PAPP-A2 (5.75 mdeg) was much smaller than that of PAPP-A (13.76 mdeg). Similar results were noted with anti-PAPP-A2, where almost all of the protein bonded on the GO-SPR biosensor was PAPP-A2. The SPR signal of PAPP-A (5.17 mdeg) was much smaller than that of PAPP-A2 (13.94 mdeg).Conclusion: The GO-SPR biosensor could distinguish PAPP-A and PAPP-A2 from various mixed interference proteins with high sensitivity and specificity. It could potentially be used to measure PAPP-A and PAPP-A2 in clinical blood samples during pregnancy.Keywords: pregnancy-associated plasma protein-A, pregnancy-associated plasma protein-A2, graphene oxide, surface plasmon resonance, biosensor
