Molecular imaging of membrane proteins and microfilaments using atomic force microscopy

Atomic force microscopy (AFM) is an emerging technique for a variety of uses involving the analysis of cells. AFM is widely applied to obtain information about both cellular structural and subcellular events. In particular, a variety of investigations into membrane proteins and microfilaments were performed with AFM. Here, we introduce applications of AFM to molecular imaging of membrane proteins, and various approaches for observation and identification of intracellular microfilaments at the molecular level. These approaches can contribute to many applications of AFM in cell imaging.

Development of Protein Chip for Diagnosis of Chlamydophia Pneumoniae / 결핵및호흡기질환

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.