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Atomic Force Microscopy (AFM) has been shown not only high-resolution imaging of biological structures below the optical limit, but also evaluation of biophysical properties of the biomaterials and monitoring its dynamics and processes in real time. AFM technique promises direct access to the both structural and functional information of a biological sample at such high spatial resolution that no other current techniques can provide. Here, we utilize the AFM to monitor direct action of a Streptolysin O to an artificial membrane as well as a biological membrane in high resolution. Streptolysin O is a four-domain bacterial protein toxin that permeabilizes animal cell membranes. Protein first binds as a monomer to membrane cholesterol and subsequently assembles into oligomeric transmembrane pores, then Streptolysin O permeabilization is routinely used in the labs with suspension cell lines to deliver specific substances to the intracellular compartments. Most of the biomedical research has been focused either at the molecular level to investigate the interactions of enzymes and proteins in test tubes or at the tissue level by injecting drugs and chemicals into animals and observing the response. The "in vivo" and "in vitro" models to detect biological membrane metamorphoses will be especially useful for drug delivery testing. Drugs will surely interact with cell membranes; we can now observe in high resolution what happens when the drugs arrive in membranes. |