02434nas a2200241   4500000000100000008004100001260000900042100001400051700001300065700001600078700001800094700001500112700001500127700001600142700001400158700002000172700001400192245011700206300001100323490000700334520183700341022001402178       2010                            d  c20101 aGoulart L1 aVieira C1 aFreschi APP1 aCapparelli FE1 aFujimura P1 aAlmeida JF1 aFerreira LF1 aGoulart I1 aBrito-Madurro A1 aMadurro J00aBiomarkers for serum diagnosis of infectious diseases and their potential application in novel sensor platforms.  a201-220 v303 aNanotechnological tools and biomarkers for diagnosis and prognosis, as well as strategies for disease control and monitoring populations at higher risk, are continuous worldwide challenges for infectious diseases. Phage display and monoclonal antibody combinatorial libraries are important sources for biomarker discovery and for improved diagnostic strategies. Mimetic peptides were selected against polyclonal antibodies from patients with dengue fever, leprosy, and leishmaniasis as model diseases, and from immunized chickens with total antigens from all three pathogens. Selected single or combined multi-epitope peptide biomarkers were further associated with four different sensor platforms, classified as affinity biosensors, that may be suitable as general protocols for field diagnosis. We have also developed two methods for nanoparticle agglutination assays (a particle gel agglutination test and a magnetic microparticle [MMP]-enzyme-linked immunosorbent assay [ELISA]) and two electrochemical biosensors (impedimetric and amperometric) for DNA and antibody detection. For the agglutination tests, micro- and nanoparticles were coupled with filamentous bacteriophages displaying the selected mimotopes on their surfaces, which has favored the formation of the antigen-antibody or peptide-protein complexes, amplifying the optical detection in ELISA assays or after the chromatographic separation of the microagglutinates. We have also demonstrated a proof-of-concept for the electrochemical biosensors by using electrodes modified with novel functionalized polymers. These electrochemical biosensors have proven to be fast, very sensitive, and specific for the detection of pathogen DNA and circulating antibodies of patients, which may become important in a wide range of diagnostic devices for many infectious agents.  a1040-8401