NaBH4was then added in 10 molar more than gold. analysis, transmission electron microscopy, matrix-assisted laser desorption/ionization-time of flight, and1H nuclear magnetic resonance analysis. Anti-FLAG and anti-HA antibodies were adhered to the surface of a QCM, and the response of each antibody upon exposure to HA, FLAG, and dual functionalized nanoparticles was compared with binding of Autiopronin nanoparticles and H5 HA proteins from influenza virus (H5N1). Results demonstrate that the immunoassay was capable of differentiating between nanoparticles presenting orthogonal epitopes in real-time with minimal nonspecific binding. The detection of H5 HA protein demonstrates the logical extension of using these nanoparticle mimics as a safe positive control in the detection of influenza, making this a vital step in improving influenza detection methodology. == Electronic supplementary material == The online version of this article (doi:10.1007/s00216-010-4419-8) contains supplementary material, which is available to authorized users. Keywords:Immunosensor, Nanoparticle, Quartz crystal microbalance, Viral simulant, ELISA, Influenza simulant, FLAG, Hemagglutinin, Epitope, PEG linkage, H5N1 == Introduction == Viruses are the smallest form of life on earth with the ability to replicate and spread within living cells [1]. As they pass from cell to cell, they adapt to evade host immunity and spread disease, creating some of the worst pandemics in history [2]. Improving diagnostics for viruses, such as influenza, would help slow the spread of infection in the event of an emerging virus. It is known that even with reassortment, a common viral defense mechanism, the majority of anti-hemagglutinin (anti-HA) antibodies recognize a specific nine amino acid sequence within the epitope, Rabbit polyclonal to LGALS13 AYDPVDYPY, which has been the focus of many assays to improve the detection of influenza [3]. Using this immunodominant Acetanilide sequence for the HA epitope, the influenza epitope can be mimicked with a functionalized nanoparticle yielding a comparable affinity to the linear peptide [4]. Another virus, Ebola, has also been effectively mimicked with a monolayer-protected cluster (MPC) through functionalization of the MPC with the antigenic determinant of the Ebola glycoprotein [5]. Integrating biology and materials chemistry using biomimicry in this way has allowed materials chemistry the opportunity to improve current diagnostic treatments, techniques, and limits of detection, but further improvements are still yet to be made [6]. The utilization of immuno-molecular recognition in the assembly of nanoscale sensors has applications in medical diagnosis, treatment, and the understanding of diseases [7]. Enzyme-linked immunosorbent assay (ELISA) is widely utilized in clinics and hospitals as an initial screening for several infectious diseases. While ELISA can be effectively employed in laboratory settings Acetanilide for common infectious agents, several obstacles inhibit the adaptation of this standard clinical assay to portable or select agent detection schemes. Unfortunately, pathogenic agent detection requires calibration with irradiated or otherwise attenuated samples of the organism. This requirement limits the widespread use of immunosensor diagnostics because of the scarcity of these agents and the logistic difficulty in safe transportation to remote locations. Recent cases like the development of meningitis and tularemia infections in researchers who were working with the causative agents of these diseases alert scientists to the hazards accompanying work with live calibrants [8]. The possibility of exposure and high cost are enough to warrant investigation into a safer positive control for these disease detection assays and devices. Without a positive control, Acetanilide the operational status of the sensor cannot be determined. Thus, the development of a nanoparticle mimic would be a safer alternative to current methodology and could be extended to address the needs of other assays that incorporate well-defined epitopes. Many traditional clinical assays lack.
