Application Research Of New Techniques In Clinical Laboratory Based On MALDI-TOF MS And LC-MS/MS

Due to high speed,high sensitivity,wide detection range and high throughput,mass spectrometry has wide applications in clinical laboratory.Among all the mass spectrometry techniques,MALDI-TOF MS and LC-MS/MS are the most widely used mass spectrometer in clinical practice.Therefore,our research is preliminary application of new techniques in clinical laboratory based on MALDI-TOF MS and LC-MS/MS,which provide a solid foundation for the clinical application of mass spectrometry.Part1:Nanoporous silica coupled MALDI-TOF MS and its application indetection of urine Bence-Jones proteinsBence-Jones protein is a biomarker in urine for multiple myeloma.Traditional methods for the detection of urine Bence-Jones protein are either less-sensitive or laborious.Herein,we describe a new method for the detection of urine Bence-Jones protein using nanoporous materials and MALDI-TOF MS.Macroporous ordered silica foams(MOSF)were used to enrich proteins from urine,and then the materials-proteins composites were analyzed by MALDI-TOF MS.Based on the presence of a pair of specific MALDI-TOF mass spectrometric signals,Bence-Jones proteins can be detected for the diagnosis of multiple myeloma.Twenty-one multiple myeloma patients’ and twenty-seven healthy volunteers’urine samples were analyzed by our method.High sensitivity(95.24%,20/21)and specificity(100%,27/27)for the diagnosis of multiple myeloma were achieved.Compared to other methods for the detection of urine Bence-Jones proteins,e.g.immunofixation electrophoresis and immunonephelometry,our approach is rapid,economical and convenient,which can be a new choice for the clinical diagnosis of Bence-Jones proteins related diseases.Part 2:LC-MS/MS based label-free quantitative metaproteomics and its application in the research of CRC patients’ gut microbiotaMetaproteomics are commonly used to study the functional characteristics of gut microbiota.Colorectal cancer is one of the most common tumors.Alterations in gut microbiota have been implicated in the pathogenesis of Colorectal Cancer(CRC).Previous studies have focused on the taxonomy abundance variations and microbial compositions,however the functional activity changes in CRC patients’ gut bacteria remain largely unknown.Herein,we collected fecal samples from 14 newly diagnosed CRC patients and 14 healthy volunteers,and characterized the microbiota using label-free quantitative metaproteomic method.A total of 30545 protein groups and 84217 peptides from 178 genera of microbials were quantified.From the results of metaproteomics,there are 332 differential proteins between colorectal cancer group and healthy control group(P<0.05,fold change(P/H)>2 or fold change(P/H)<0.05).Among the 332 differential proteins,bacterial proteins related to iron intake/transport,oxidative stress,and DNA replication,recombination and repair are significantly alternated in abundance.There are 25 differential proteins related to iron intake/transport and 30 related to oxidative stress,which suggests that the high local concentration of iron and high oxidative stress in the large intestine of CRC patients.Through metaproteomics’ analysis,we also suggest some taxonomy variations and bacterial protein biomarkers new to CRC.Our study demonstrates that gut bacteria involve in CRC pathogenesis not only via taxonomy but also functional activity variations.