A rapid-response ultrasensitive biosensor for influenza virus detection using antibody modified boron-doped diamond.

According to the World Health Organization (WHO), almost 2 billion people each year are infected worldwide with flu-like pathogens including influenza. This is a contagious disease caused by viruses belonging to the family Orthomyxoviridae. Employee absenteeism caused by flu infection costs hundreds of millions of dollars every year. To successfully treat influenza virus infections, detection of the virus during the initial development phase of the infection is critical, when tens to hundreds of virus-associated molecules are present in the patient's pharynx. In this study, we describe a novel universal diamond biosensor, which enables the specific detection of the virus at ultralow concentrations, even before any clinical symptoms arise. A diamond electrode is surface-functionalized with polyclonal anti-M1 antibodies, which then serve to identify the universal biomarker for the influenza virus, M1 protein. The absorption of the M1 protein onto anti-M1 sites of the electrode change its electrochemical impedance spectra. We achieved a limit of detection of 1 fg/ml in saliva buffer for the M1 biomarker, which corresponds to 5-10 viruses per sample in 5 minutes. Furthermore, the universality of the assay was confirmed by analyzing different strains of influenza A virus.

Influence of different amino substituents in position 1 and 4 on spectroscopic and acid base properties of 9,10-anthraquinone moiety.

A series of novel 1-amino and 1,4-diamino-9,10-anthraquinones, substituted with different alkyl groups, were synthesized as the result of alkylation with amino substituents. All the obtained aminoanthraquinone derivatives were characterized by NMR, IR spectroscopy and mass spectrometry. The spectroscopic properties of these compounds were determined by using UV-Vis spectroscopy in acetonitrile, and in the mixture of acetonitrile and methanol at different pH ranges. The effects of various substituents present in the newly developed anthraquinone derivatives and their ability to form hydrogen bonds between the carbonyl oxygen atom of anthraquinone moiety and nitrogen atom of N-H group in 1-aminoanthraquinone (1-AAQ) and 1,4-diaminoanthraquinone (1,4-DAAQ) were studied. Additionally, the effects of hydrogen bond formation between O-H group in hydroxyethylamino substituent and the carbonyl oxygen atom of anthraquinone were investigated. The spectroscopic behavior of the studied derivatives strongly depended on the solvent-solute interactions and the nature of solvent. The values of pKa for the new anthraquinones were determined by the combined potentiometric and spectrophotometric titration methods.

1,5-Bis(piperidin-1-yl)-9,10-anthraquin-one.

In the centrosymmetric title compound, C24H26N2O2, the piperidine ring adopts a chair conformation and is inclined at a dihedral angle of 37.5 (1)°to the anthracene ring system. In the crystal, adjacent mol-ecules are linked through C-H⋯π and π-π [centroid-centroid distances = 3.806 (1) Å] inter-actions, forming a layer parallel to the bc plane.

1-(Piperidin-1-yl)-9,10-anthraquinone.

In the title compound, C(19)H(17)NO(2), the piperidine ring adopts a chair conformation. The mean planes of the piperidine ring and the anthracene ring system are inclined at a dihedral angle of 38.7 (1)°. In the crystal, adjacent mol-ecules are linked through C-H⋯π and π-π [centroid-centroid distance = 3.782 (1) Å] inter-actions, forming a layer parallel to the bc plane.