Biomarker detection via lab-on-a-chip integrated immunoaffinity approach for fluorescence and mass spectrometry readout

Abstract: The blood/plasma protein biomarker profile represents the pathological and physiological changes relating to human diseases. However, the plasma proteome reflects a high degree of complexity that results in a challenge for most analytical methods in clinical diagnostics. The focus in this thesis is the development and application of several integrated platforms to detect already established protein/peptide biomarkers from blood and plasma (Prostate Specific Antigen, PSA and Angiotensin I, Ang I). The integrated platforms that are described in the papers included in this thesis utilize protein/peptide immunoaffinity-capturing since it offers insights into dealing with the challenges of the plasma proteome analysis by reducing complexity and enriching the proteins/peptides of interest. Several integrated platforms were developed with the overall main aim of detecting biomarkers from complex biological samples: • porous silicon antibody microarray with signal amplification step (Paper I) • microfluidic whole blood immunoassay (Paper II and III) • integrated protein immunoaffinity capturing with microfabricated proteomic sample processing platform (ISET) enabling a direct interface to MALDI MS/MS analysis (Paper IV) • integrated peptide immunoaffinity capturing via porous silicon array-based immuno-MALDI (Paper V) enabling a direct interface to MALDI MS/MS analysis Ultimately, these platforms target future use in point-of-care settings (Paper I-III) and immuno-MALDI mass spectrometry immunoassays for identification and quantitative measurements of biomarkers using isotope labelled standards (Paper V) as well as outlook for use in the development of SRM/MRM assays (Paper IV).