TY  - JOUR
A1  - Sellrie, Frank
A1  - Beck, Michael
A1  - Hildebrandt, Niko
A1  - Micheel, Burkhard
T1  - A homogeneous time-resolved fluoroimmunoassay (TR-FIA) using antibody mediated luminescence quenching
N2  - The determination of low-molecular weight substances (haptens) is demonstrated with a homogeneous time-resolved immunoassay using antibody-induced luminescence quenching. Our novel assay technology uses the newly developed monoclonal antibody (G24-BA9) to quench the luminescence of europium trisbipyridine (EuTBP). We performed a competitive biotin immunoassay including an EuTBP-biotin conjugate, the anti-EuTBP antibody G24-BA9 and streptavidin as assay components. Steric hindrance allows only the binding of either G24-BA9 (to the EuTBP moiety) or streptavidin (to the biotin moiety) to the EuTBP-biotin conjugate. Addition of the analyte biotin resulted in the binding of streptavidin to biotin and a concomitant preferred binding of G24-BA9 to EuTBP-biotin. Since G24-BA9 quenches the luminescence of EuTBP within the conjugate, the luminescence signal could be used to indicate and quantify the presence of free biotin in the system. All experiments were carried out in solution in the presence of 5% serum demonstrating the possibility of using our novel assay for a very fast determination of low molecular weight substances in biological fluids.
Y1  - 2010
UR  - http://www.rsc.org/Publishing/Journals/AY/Index.asp
U6  - https://doi.org/10.1039/C0ay00306a
SN  - 1759-9660
ER  - 
TY  - JOUR
A1  - Beck, Michael
A1  - Stiel, H.
A1  - Leupold, Dieter
A1  - Winter, Bernd
A1  - Pop, D.
A1  - Vogt, U.
A1  - Spitz, Christian
T1  - Evaluation of the energetic position of the lowest excited singlet state of ß-carotene by NEXAFS and photoemission spectroscopy
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Legall, Herbert
A1  - Stiel, Holger
A1  - Beck, Michael
A1  - Leupold, Dieter
A1  - Gruszecki, Wieslaw I.
A1  - Lokstein, Heiko
T1  - Near edge X-ray absorption fine structure spectroscopy (NEXAFS) of pigment-protein complexes : peridinin- chlorophyll a-protein (PCP) of Amphidinium carterae
N2  - Peridinin-chlorophyll a protein (PCP) is a unique water soluble antenna complex that employs the carotenoid peridinin as the main light-harvesting pigment. In the present study the near edge X-ray absorption fine structure (NEXAFS) spectrum of PCP was recorded at the carbon Kedge. Additionally, the NEXAFS spectra of the constituent pigments, chlorophyll a and peridinin, were measured. The energies of the lowest unoccupied molecular levels of these pigments appearing in the carbon NEXAFS spectrum were resolved. Individual contributions of the pigments and the protein to the measured NEXAFS spectrum of PCP were determined using a "building block" approach combining NEXAFS spectra of the pigments and the amino acids constituting the PCP apoprotein. The results suggest that absorption changes of the pigments in the carbon near K-edge region can be resolved following excitation using a suitable visible pump laser pulse. Consequently, it may be possible to study excitation energy transfer processes involving "optically dark" states of carotenoids in pigment-protein complexes by soft X-ray probe optical pump double resonance spectroscopy (XODR).
Y1  - 2007
UR  - http://www.sciencedirect.com/science/journal/0165022X
U6  - https://doi.org/10.1016/j.jbbm.2006.08.005
SN  - 0165-022X
ER  - 
TY  - JOUR
A1  - Hildebrandt, Niko
A1  - Charbonniere, Loïc J.
A1  - Beck, Michael
A1  - Ziessel, Raymond F.
A1  - Löhmannsröben, Hans-Gerd
T1  - Quantum dots as efficient energy acceptors in a time-resolved fluoroimmunoassay
Y1  - 2005
SN  - 1433-7851
ER  - 
TY  - JOUR
A1  - Gruszecki, Wieslaw I.
A1  - Stiel, H.
A1  - Niedzwiedzki, Dariusz
A1  - Beck, Michael
A1  - Milanowska, J.
A1  - Lokstein, Heiko
A1  - Leupold, Dieter
T1  - Towards elucidating the energy of the first excited singlet state of xanthophyll cycle pigments investigated by x-ray absorption spectroscopy
Y1  - 2005
ER  -