Study of Glutathione S-transferase-P1 in cancer blood plasma after extraction by affinity magnetic nanoparticles and monitoring by MALDI-TOF, IM-Q-TOF and LC-ESI-Q-TOF MS.

Glutathione S-transferase P1 (GST-P1) is considered as a detoxification enzyme and can be upregulated in several cancers. Therefore, qualification and/or quantification of GST-P1 in biological fluids can be noteworthy in cancer diagnostic and/or prognostic methods. Whereas costly immunoassays methods are routinely used for clinical analysis, long analysis time per sample is still considered as their disadvantages. To create a fast, efficient, and economical GST-P1 qualification and/or quantification technique, we developed an affinity magnetic nanoparticle-MS method. In proposed method there is no need for any pretreatment for reducing the complexity of sample and depletion of high abundant proteins that are used in routinely immunoassays methods. After enrichment of GST-P1 from blood plasma samples by affinity magnetic nanoparticle (without any pretreatment), the final eluent was analyzed using MALDI-TOF, IM-Q-TOF and LC-ESI-Q-TOF MS. For the first time this study demonstrates the suitability of affinity magnetic nanoparticle-MS method for qualification/quantification of GST-P1 from acute lymphoblastic leukemia blood plasma samples with the limit-of-detection 0.0094 ppm in less than 5 h. Our finding showed that in these blood plasma samples the level of GST-P1 can be up to six times more than healthy children.

Conjugation of Single-Chain Variable Fragment Antibody to Magnetic Nanoparticles and Screening of Fig Mosaic Virus by MALDI TOF Mass Spectrometry.

The ability of mass spectrometry for discrimination between protein and peptide masses which are unique to specific pathogens provides an accurate and fast method for the detection of different types of pathogens, especially viruses. Capsid proteins are specific to each virus and can be used as a biomarker for detection of this pathogen. On the other hand, single-chain variable fragment (scFv) antibodies have been recently used to enhance the accuracy of immunoassay techniques. So conjugation of mass spectrometry and scFv antibody provides a very accurate and fast method for the detection of viruses. In this report, for the first time, we have immobilized scFv antibody of fig mosaic virus (FMV) on the magnetic nanoparticles (MNPs) to extract the virus capsid protein from complex biological media and subsequently identified this protein through both its intact molecular mass and peptide mass fingerprint (PMF) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).