TY - JOUR A1 - Beissenhirtz, Moritz Karl A1 - Kwan, R. C. H. A1 - Ko, K. M. A1 - Renneberg, Reinhard A1 - Scheller, Frieder W. A1 - Lisdat, Fred T1 - Comparing in vitro electrochemical measurement of superoxide scavenging activity with an in vivo assessment of antioxidant potential in Chinese tonifying herbs N2 - The in vitro superoxide scavenging activity (as determined by electrochemical measurement) and the in vivo antioxidant potential (as determined by a mouse model of carbon tetrachloride (CCl4) hepatotoxicity) of methanolic extracts prepared from 10 Chinese tonifying herbs were compared. Electrochemical measurement using a cytochrome c (Cyt. c) sensor showed that all of the tested herbal extracts exhibited a medium superoxide scavenging activity of different potency, as indicated by their IC50 values. The in vivo measurement demonstrated that 80% of the herbal extracts displayed in vivo antioxidant potential, as assessed by the percentage of protection of the activity of plasma alanine aminotransferases and the hepatic glutathione regeneration capacity under CCl4-intoxicated condition. Although the in vitro antioxidant activity did not correlate quantitatively with the in vivo antioxidant potential, for 8 out of 10 samples a similar tendency was found. The rapid amperometric assessment of antioxidant potential by Cyt. c sensor may offer a convenient and direct method for screening as well as the quality control of herbal products. Copyright (C) 2004 John Wiley Sons, Ltd Y1 - 2004 ER - TY - JOUR A1 - Mak, Karen K. W. A1 - Wollenberger, Ursula A1 - Scheller, Frieder W. A1 - Renneberg, Reinhard T1 - An amperometric bi-enzyme sensor for determination of formate using cofactor regeneration Y1 - 2003 ER - TY - JOUR A1 - Mak, Wing Cheung A1 - Cheung, Kwan Yee A1 - Trau, Dieter A1 - Warsinke, Axel A1 - Scheller, Frieder W. A1 - Renneberg, Reinhard T1 - Electrochemical bioassay utilizing encapsulated electrochemical active microcrystal biolabels N2 - A new approach to perform electrochemical immunoassay based on the utilization of encapsulated microcrystal was developed. The microcrystal labels create a "supernova effect" upon exposure to a desired releasing agent. The microcrystal cores dissolve, and large amounts of signal-generating molecules diffuse across the capsule wall into the outer environment. Layer-by-Layer (LbL) technology was employed for the encapsulation of electrochemical signal- generating microcrystals (ferrocene microcrystals). The encapsulated microcrystals were conjugated with antibody molecules through the adsorption process. The biofunctionalized microcrystals were utilized as a probe for immunoassays. The microcrystal-based label system provided a high-signal molecule to antibody (SIP) ratio of 10(4)-10(5). Microcrystal biolabels with different antibody surface coverage (1.60-5.05 mg m(-2)) were subjected to a solid-phase immunoassay for the detection of mouse immunoglobulin G (M-IgG) molecules. The microcrystal-based immunoassay for the detection of M-IgG performed with microcrystals having antibody surface coverage of 5.05 mg m(-2) showed a sensitivity of 3.93 nA g(- 1) L-1 with a detection limit of 2.82 g L-1 Y1 - 2005 SN - 0003-2700 ER - TY - JOUR A1 - Scheller, Frieder W. A1 - Yarman, Aysu A1 - Bachmann, Till A1 - Hirsch, Thomas A1 - Kubick, Stefan A1 - Renneberg, Reinhard A1 - Schumacher, Soeren A1 - Wollenberger, Ursula A1 - Teller, Carsten A1 - Bier, Frank Fabian ED - Gu, MB ED - Kim, HS T1 - Future of biosensors: a personal view JF - Advances in biochemical engineering, biotechnology JF - Advances in Biochemical Engineering-Biotechnology N2 - Biosensors representing the technological counterpart of living senses have found routine application in amperometric enzyme electrodes for decentralized blood glucose measurement, interaction analysis by surface plasmon resonance in drug development, and to some extent DNA chips for expression analysis and enzyme polymorphisms. These technologies have already reached a highly advanced level and need minor improvement at most. The dream of the "100-dollar' personal genome may come true in the next few years provided that the technological hurdles of nanopore technology or of polymerase-based single molecule sequencing can be overcome. Tailor-made recognition elements for biosensors including membrane-bound enzymes and receptors will be prepared by cell-free protein synthesis. As alternatives for biological recognition elements, molecularly imprinted polymers (MIPs) have been created. They have the potential to substitute antibodies in biosensors and biochips for the measurement of low-molecular-weight substances, proteins, viruses, and living cells. They are more stable than proteins and can be produced in large amounts by chemical synthesis. Integration of nanomaterials, especially of graphene, could lead to new miniaturized biosensors with high sensitivity and ultrafast response. In the future individual therapy will include genetic profiling of isoenzymes and polymorphic forms of drug-metabolizing enzymes especially of the cytochrome P450 family. For defining the pharmacokinetics including the clearance of a given genotype enzyme electrodes will be a useful tool. For decentralized online patient control or the integration into everyday "consumables' such as drinking water, foods, hygienic articles, clothing, or for control of air conditioners in buildings and cars and swimming pools, a new generation of "autonomous' biosensors will emerge. KW - Biosensors KW - Molecularly imprinted polymers KW - Personalized medicine Y1 - 2014 SN - 978-3-642-54143-8; 978-3-642-54142-1 U6 - https://doi.org/10.1007/10_2013_251 SN - 0724-6145 VL - 140 SP - 1 EP - 28 PB - Springer CY - Berlin ER - TY - BOOK A1 - Wollenberger, Ursula A1 - Renneberg, Reinhard A1 - Bier, Frank Fabian A1 - Scheller, Frieder W. T1 - Analytische Biochemie : eine praktische Einführung in das Messen mit Biomolekülen Y1 - 2003 SN - 3-527-30166-6 PB - John Wiley & Sons CY - Hoboken ER -