Medical aspects

For peptide aptamers to be implementable in diagnostics and therapy, some challenges have to be accomodated. Antibodies comprise a dangerous threat for microorganisms displaying pathogen-associated molecular patterns (PAMPs). PAMPs are recognized by the antibodies FabFabfragment, antigen-binding-region and induces an immune response through the FcFcfragment, crystallizable-region, that binds effector cells of the immune system. The effector mechanisms include: OpsonisationOpsonisationOpson originates from Grece, where it referrers to a delicious side-dish. In this context it means that antibodies mark pathogens, making them more appetizing for phagocytes (i.e. neutrophils and macrophages), agglutinationAgglutinationAgglutinare is Latin and means "to glue". In the immune response it means that the antibodies bind multiple antigens, creating a cluster which is easier for the phagocytes to process in one portion instead of one by one. and complement activationComplement SystemWhen the system is activated, several proteases begin to cleave proteins that release certain cytokines, toxic to the pathogen. By a cascade of cleavage reactions the result is the production of a so called cell killing membrane attack complex that will destroy the given microbe. among other reactions.

Recently small gold nanoparticles (sAuNPs) have shown to be excellent tools for cancer therapy especially because of their high biocompatibily, large surface-to-volume ratio and strong diffusivity. Reference: Kim CS, et al. Cellular imaging of endosome entrapped small gold nanoparticles, 2015 Jun 10;2:306-15. doi: 10.1016/j.mex.2015.06.001. [PubMed] By attaching sAuNPs to the peptide aptamer it would be possible to detect and attack pathogenic organisms such as cancer cells.