NUS CHEMICAL & BIOMOLECULAR Engineering


	TRAU, Dieter W.
	Assistant Professor
	PhD (Chemistry.) HKUST, 2001 MEng (Chem.Eng./Biotechnology) AcUAS, German, 1994
	Contact information Blk EA, 9 Engineering Drive 1, #05-18L, Singapore 117576 Tel: (65) 6516 8052 Fax: (65) 6872 3069 Email: chetrau@nus.edu.sg
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RESEARCH

Nanoengineered Encapsulation

Encapsulated substances find an increasing number of applications in biotechnology, medicine and cosmetics. Encapsulation of protein crystals was achieved by sequential adsorption of oppositely charged polyelectrolytes. This extension of the so called Layer-by-Layer technique to crystalline materials leads to their encapsulation in a nanoscale polymer multilayer capsule of 15 nm thickness. The enzymes catalase and glucose-oxidase were successfully encapsulated in their solid state. The enzyme loaded µm-sized capsules represents a new class of µ-bioreactor with an extreme high loading density of bio-compound. Our approaches for the encapsulation of bio- and organic-crystalline materials demonstrate an alternative strategy to conventional encapsulation methods with the potential to create novel core-shell materials with tailored functionalities by incorporating optical, magnetic, or biorecognition properties into the encapsulate.

Integration of Biological Materials into Microfabrication

Microtechnology and Life Sciences are key areas for research, innovation and commercial development. A technology that provides an interface between the life science “bio world” and today's semiconductor and polymer based “electromechanical world” would open new avenues for research and potential product. A new technology was developed demonstrating for the first time the integration of biological materials (DNA) into microfabrication. The technique based on a passivation layer to protect biomolecules during the microfabrication process. The passivation layer can be applied and removed from the biomolecules under mild conditions. The method is photolithographic based and scalable for industrial mass production. Microelectronic/mechanic devices with integrated DNA or antibodies have a wide range of potential applications in bioanalytics, medicine and environmental monitoring.

Microcapsule-PCR

The polymerase chain reaction (PCR) is an important method in molecular biology with various applications in clinical research, diagnostics and biotechnology. Today, PCR reactions are carried out in reaction tubes or micro titer plates. Only 48 to 1539 reactions can be carried out in parallel. This number is to small to perform large screening projects, e.g. in pharmacological research in appropriate time. To perform a higher number of reactions in parallel, the integration density must be increased and the reaction volume decreased. This has limited chance to succeed by using the current technology. A totally new approach was introduced to overcome those limitations. The technology of “Microcapsule-PCR” allows performing millions of PCRs in parallel in a single reaction tube. “Microcapsule-PCR” is based on the encapsulation of PCR mixtures into microcapsules of ~50 µm in diameter by using our technique of matrix assisted encapsulation. Capsules create a compartment to separate individual PCRs from each other. They are not permeable for the PCR product but permeable for reactants (dNTPs). This allows feeding reactants from the outside while PCR product accumulates in the interior of capsules. Finally, individual capsules can be isolated and analyzed.

SELECTED PUBLICATIONS

Trau D., Jiang J., Sucher J.N.,"Preservation of the Biofunctionality of DNA and Protein during Microfabrication", Langmuir, 22, 877-881, 2006.

Trau D., Renneberg R., "Encapsulation of glucose oxidase microparticles within a nanoscale layer-by-layer film: immobilization and biosensor applications", Biosensors & Bioelectronics, 18, 1491-1499, 2003.

Trau D., Yang W., Lehmann M., Caruso F., Yu N.T., Renneberg R., "Nanoencapsulated Microcrystalline Particles for Superamplified Biochemical Assays", Analytical Chemistry, 74 (21), 5480-5486, 2002.

Trau D., Lee T.M.H., Lao A.I.K., Lenigk R., Hsing I.M., Ip N.Y., Carles M.C., Sucher N., "Rapid genotyping on a CMOS silicon PCR chip with integrated DNA microarray", Analytical Chemistry, 74 (13), 3168-3173, 2002.

Caruso F., Yang W., Trau D., Renneberg R., "Microencapsulation of Uncharged Low Molecular eight Organic Materials by Polyelectrolyte Multilayer Self-Assembly", Langmuir, 16 (23); 8932-8936, 2000.

Caruso F., Trau D., Möhwald H., Renneberg R., Enzyme "Encapsulation in Layer-by-Layer Engineered Multilayer Capsules", Langmuir, 16(4), 1485-1488, 2000.