Proteomics is one of the most important issues in the post-genomic area, because it can greatly contribute to identifying protein biomarkers for disease diagnosis and drug screening. Protein array is a key technology for proteome researches and has been analyzed by various methods including fluorescence, mass spectrometry, atomic force microscopy and surface plasmon resonance (SPR). SPR biosensor is a promising technology in proteomics, since it has various advantages including real-time measurement of biomolecular interactions without labeling and the simple optical system for the device. SPR biosensors have a strong potential for analyzing proteomes by SPR imaging and SPR spectroscopic imaging, even though the challenge is to produce proteins on a proteomic scale.
Animals ; *Biosensing Techniques ; Humans ; Protein Array Analysis ; *Proteomics ; Research Support, Non-U.S. Gov't ; *Surface Plasmon Resonance/instrumentation/methods

BACKGROUND: The diagnosis of chlamydial infection is based on serology. The current gold standard of diagnosis is MIF(microimmunofluorescence), but this modality is subjective and time-consuming. Protein microarray with using a SPR(surface plasmon resonance) sensor has recently been suggested as a method for detecting infection. For developing a protein chip to diagnose chlamydial infection, EBs(elementary bodies) were immobilized on a gold chip and the interaction between an antibody for Chlamydophila pneumoniae and the EBs(elementary bodies) immobilized on the surface of the gold chip was measured by using an SPR sensor. METHODS: For the surface antigen, the EBs of Chlamydophila pneumoniae LKK1 were purified. Charged arrays were prepared by using PDDA(polydiallyldimethylammonium chloride) which has a positive charge. After immobilization of the chlamydial EBs on the PDDA surface, the investigation of the surface was done with using atomic force microscopy. After the antibody for C. pneumoniae was applied on chip, we monitored the SPR wavelength-shift to detect any antigen-antibody interaction with using a self-assembled SPR sensor. RESULTS: The chlamydial EBs on the positively charged PDDA were visible on the surface with using atomic force microscopy. The SPR wavelength increased after interaction of antibody for C. pneumoniae with the EBs immobilized on charged gold surface. The wavelength-shift was correlated with the concentration of antigens. CONCLUSION: The surface immobilization of EBs on the gold surface with the charged arrays was identified and the antigen-antibody interaction on the gold chip was detected via the SPR sensor. Further investigations are needed to apply this technique to the clinical field.
Antigens, Surface ; Chlamydial Pneumonia ; Chlamydophila pneumoniae ; Diagnosis* ; Immobilization ; Microscopy, Atomic Force ; Pneumonia* ; Protein Array Analysis*