Highly Sensitive Detection Of Phosphopeptides With Functional Nanomaterials Enhanced Mass Spectrometry

Along with advances in life science and clinical research, there has been an increasing interest in the enrichment technologies for proteins with post-translational modifications. Abnormal variations in the protein phosphorylation lead to various types of diseases. Therefore, it is critical to investigate the protein phosphorylation for the early diagnosis of diseases. With the rapid progress of nanotechnologies, functional nanoparticles have successfully been used in bio-separation and biomedical fields. They can be designed to possess good biocompatibility, stable physical and chemical properties, and the flexible modification for different functions. This thesis is mainly related to the development of functionalized nanomaterials for enrichment and detection of phosphorylated peptides, including the two parts as follows:The first part is based on bacterial cellulose（BC）-derived nanomaterials. We synthesized BC@m Ti O₂ nanofibers to enrich the phosphopepetides, therefore facilitating their detection with mass spectrometry. Bacterial cellulose was feared with plenty of hydroxyl groups for the subsequent surface sol-gel process for the formation of the titanium dioxide layer. Highly ordered mesoporous structures of Ti O₂ with enhanced crystallinity were formed on the surface of BC by the hydrothermal and additional ammonia treatment. We demonstrated successfully the enrichment of phosphopeptides with BC@m Ti O₂ nanofibers. The sensitivity reached 1.7pmol, nearly two orders of magnitude better than the performance of the commercial tips.The second part is the development of superparamagnetic Fe₃O₄ nanoparticles coated with mesoporous Zr O₂. We synthesized zirconium dioxide layer on the surface of superparamagnetic Fe₃O₄ nanoparticle clusters through a sol gel process. The formation of the ordered mesoporous Zr O₂ structure was successfully realized by a hydrothermal processing method. The specific surface area of Fe₃O₄@m Zr O₂ reached to 338.3m²/g. We have optimized the sample treatment procedure by the development of in-situ elution, therefore reducing the loss of of the precious protein samples for better detection of limit with mass spectrometry（at the level of femtomole）.The good performance of our approach in detecting phosphopeptides was further verified using the lysis of cancer cells（A549 cell）In short summary, this thesis describes my efforts to develop functional nanomaterials for efficient enrichment and detection of phosphopepetides with mass spectrometry. Our research results lay a good foundation for application in the study of protein phosphorylation and the early diagnosis of the disease better of this kind of nanoparticles...