Bioanalytical chemistry: basics and applications; nano-biotechnology; biosensorics and bioelectronics; microsystems and microsensors; novel signal-amplifying systems using LBL-encapsulated mediators; enzymes and dyes for amperometric sensors; ELISAs and other biotests; environmental chemistry; commercialization of biosensors and biotests (heart attack, stroke, viral and bacterial infections). 

1. Biotests: (i) An immunotest detects fatty acid-binding protein (FABP), which is a 15 kDa protein within 15 minutes. FABP is an early infarction marker and allows diagnosis or exclusion of acute myocardial infarction within half an hour after the onset of symptom. Conventional markers need 3-6 hours. In addition to life saving, the immunotest can be also used for detection of overtraining in athletes and horses. (ii) An InfectCheck barcode-style lateral flow assay for semi-quantitative detection of C-reactive protein (CRP) in distinguishing between bacterial and viral infections. The severity of bacterial infection can be assessed by simply counting the number of red lines. It is a one-step whole blood rapid test without any sample pre-treatment and the result is available within 15 min. This user friendly diagnostic tool can allow self-testing by interested individuals without any expensive reading device.

2. Biosensors: (i) Living yeast cells (Arxula adeninivorans) are immobilized at the top of Clark oxygen sensors and mass-produced thick-film sensors. Any change in cell respiration can be monitored in 70 seconds.  The cells are stable and can be reused for several months. As they are salt-tolerant, one can directly measure the biodegradable pollution in sea water samples within minutes instead of the 5-day- method (BOD5). (ii) Thick-film sensors and thin-film sensors produced by microsystem technology are used as transducers for immobilized lactate oxidase. By checking the lactate levels before and after training for humans and horses, one can evaluate fitness levels easily within seconds. It was demonstrated for subcutaneous in-vivo measurements during training. (iii) Cyanide fishing destroys nowadays many coral reefs in the Pacific Ocean. One million kilograms of cyanides have been used in the last 10 years in Pacific coral reefs to catch fishes mainly for consumption in Hong Kong. Using the oxygen binding abilities of porphyrines, a sensor is constructed for highly sensitive detection of cyanide in fish blood. We hope to help to stop cyanide fishing by developing a rapid test.

3. Signal amplification technologies: A SuperNova technology is based on a two-step approach for the preparation of the nanocrystal biolabels: (1) the fluorogenic precursor fluorescein diacetate (FDA) nanocrystals are firstly encapsulated by distearoylphosphatidylethanolamine (DSPE) lipids coupled to amino[poly-(ethylene glycol)] (PEG-Amine) and (2) subsequently coupled with biomolecules. High signal amplification can be achieved by conversion of the precursor FDA into mega releasable fluorescein molecules using a releasing reagent. The intensity of the fluorescence signal is proportional to the target analyte concentration. It has the potential to highly amplify the signal and can be a good alternative label for DNA hybridizations and immunoassays.

  
Representative Publications

Books :

"Biotechnology for Beginners”, Academic Press, New York (2008).

"Biosensing for the 21st Century" in: “Advances in Biochemical Engineering/Biotechnology Vol 109” (R Renneberg and F Lisdat, eds.) Springer, Berlin, Heidelberg (2008).

"Bioanalytics for Beginners" Springer, Heidelberg (2009).

"Katzenklon, Katzenklon" Spektrum Akademischer Verlag, Berlin, Heidelberg (2007).

Journal Papers :

"Human Heart-Type Fatty Acid-Binding Protein for On-Site Diagnosis of Early Acute Myocardial Infarction" International Journal of Cardiology 133 (3), 420-3, (2009).

"Diagnostic utility of CRP to neopterin ratio in patients with acute respiratory tract infections" Journal of Infection 58 (2), 123-30 (2009).

"Development of a creatinine enzyme-based bar-code-style lateral-flow assay" Analytical & Bioanalytical Chemistry 393 (4),1281-7 (2009).

"The missing link--light-induced (280-1,600 nm) free radical formation in human skin" Skin Pharmacology & Physiology 22 (1), 31-44 (2009).

"Development of enzyme-based bar code-style lateral-flow assay for hydrogen peroxide determination" Analytica Chimica Acta 634 (1), 89-95 (2009).

"Biotech history: Mexico, the father of the pill and the race for cortisone" Biotechnology Journal 3 (4), 449-451 (2008).

"InfectCheck CRP barcode-style lateral flow assay for semi-quantitative detection of C-reactive protein in distinguishing between bacterial and viral infections" Journal of Immunological Methods 336, 30-36 (2008).

"Frieder Scheller and the short history of biosensors"Advances in Biochemical Engineering/Biotechnology 109, 1-18 (2008).

"New trends in immunoassays" Advances in Biochemical Engineering/Biotechnology 109, 123-154 (2008).

"Biotech history: Yew trees, paclitaxel synthesis and fungi" Biotechnology Journal 2 10, 1207-1209 (2007).

"Value of serum procalcitonin, neopterin, and C-reactive protein in differentiating bacterial from viral etiologies in patients presenting with lower respiratory tract infections" Diagnostic Microbiology & Infectious Disease 59 (2), 131-136 (2007).

"Biofunctional organic nanocrystals for quantitative detection of pathogen deoxyribonucleic acid" Analytica Chimica Acta 584 (1), 7-11 (2007).

"A novel credit-card style assay for bedside determination of fatty acid-binding protein" IVD Technology Magazine 12 (2), 51 (2006).

"Detection of serum neopterin for early assessment of dengue virus infection" Journal of Infection 53 (3), 152-158 (2006).

 Lifesaver: CardioDetect^® FABP Rapid Test for Early Diagnosis of Acute Myocardial Infarction

 InfectCheck CRP barcode-style Rapid Test for Rapid Differentiation of Bacterial and Viral Infections

    A Novel Signal Amplification Technology － SuperNova System