A novel device for swift and efficient CD44 protein digestion of pipette tips in human serum

Abstract

For molecular diagnostics in modern biomedical research, electrospray ionisation mass spectrometry (ESI-MS) based on proteome profiling is important. Now a days, sample preparation such as proteolysis and protein extraction remain incredibly challenging and inefficient. Recent sample-preparation methods based on micro tips show promising results toward the aim “a proteome in an hour”. Proteolysis at the tip, is still infrequently observed and does not represent the processing of complex bio-samples. In this study, we outline a unique technique for detecting and extracting human serum CD44 biomarkers by ligand–protein interactions. This method employs macropores silica particles (MPSP) or (MOSF) modified with hyaluronic acid (HA). In order to assist in the profile of the human serum proteome, we limitations of immunoassays for rapid and multimodal proteolysis. For effective in situ proteolysis, in micropipette tips, MPSP were designed as nanoreactors with variable pore size and surface chemistry. In MS-based bottom-up proteome analysis, the device as-built demonstrated favourable sensitivity (LOD of 0.304 ± 0.007 ng/mL and LOQ of 0.973 ± 0.054 ng/mL), selectivity, durability (at −20 °C for 2 months), reuse (at least 10 times), and minimal memory impact. In addition, we examined into specific surface chemistries of nanoparticles for the absorption of proteins in serum and profiled the HA-binding serum proteome, setting a new preliminary benchmark for future databases. Our study not only helped establish a new platform for extracting/detection of CD44 and identifying the HA-binding proteome, but it also offered design recommendations for ligand affinity-based techniques for the antibody-free study of serum biomarkers with a view towards diagnostic applications.