Nagel, T.T.NagelEhrentreich-Förster, E.E.Ehrentreich-FörsterSingh, M.M.SinghSchmitt, K.K.SchmittBrandenburg, AlbrechtAlbrechtBrandenburgBerka, A.A.BerkaBier, F.F.Bier2022-03-042022-03-042008https://publica.fraunhofer.de/handle/publica/21535610.1016/j.snb.2007.10.009We describe a new and rapid method for diagnosing tuberculosis-specific antibodies in undiluted human blood serum by surface sensitive biosensors. An integrated optical grating coupler, an interferometric biosensor and a device based on the reflectometric interference spectroscopy (BIAffinity, Analytik Jena AG) were used to determine tuberculosis-specific antibodies, which are present in blood serum of infected persons. The specific sensor surface was generated by immobilized 38-kDa tuberculosis antigen and real-time detection was performed without any label in all cases. Unspecific binding effects caused by serum proteins were suppressed by appropriate coupling chemistry. 1,4-Phenylenediisothiocyanate was used as a crosslinker for the coupling of the antigen achieving the effect of complete surface coverage. This enables label-free serodiagnosis of tuberculosis infection with a specificity of 100% and a sensitivity of 75%. Based on our results, we anticipate that a label-free detection procedure with one or more marker antigens is possible for a rapid, economical and accurate routine diagnosis of tuberculosis and other infectious diseases in the future.enMycobacterium tuberculosislabel-freeblood serumgrating couplerinterferometric biosensorRIfS621610620541journal article