Biomolecular engineering: a new frontier in biotechnology

"Smart" polymeric microfluidics fabricated by plasma processing: controlled wetting, capillary filling and hydrophobic valving

We demonstrate a mass-production-amenable technology for fabrication, surface modification and multifunction integration in polymeric microfluidic devices, namely direct lithography on the polymeric substrate followed by polymer plasma etching, and selective plasma deposition. We apply the plasma processing technology to fabricate polymeric microfluidics in poly(methyl methacrylate) (PMMA) and poly(ether ether ketone) (PEEK). First, deep anisotropic O(2) plasma etching is utilized to pattern the polymer via an in situ, highly etch-resistant, thin, Si-containing photoresist, or via a thick organic photoresist. Absolute control of surface roughness (from smooth to very rough), and the production of stable-in-time (slowly ageing) superhydrophilic microchannels are demonstrated. Second, we demonstrate the spontaneous capillary pumping through such rough, superhydrophilic plasma-etched microchannels in contrast to smooth ones, even 5 weeks after fabrication. Third, by using C(4)F(8) fluorocarbon plasma deposition through a stencil mask, we produce superhydrophobic patches inside the microchannels, and use them as passive valves. Our approach proposes "smart" multifunctional microfluidics fabricated by a plasma technology toolbox.

Application of Scintillation Proximity Assay in Drug Discovery

Scintillation proximity assay (SPA), characterized by its speed, sensitivity, reliability, and the fact that no separation step is required, has become an important technique in high-throughput screening (HTS) for new drugs, and for investigating their biological interactions. The SPA technique now plays a key role in HTS, in that it can be used in many assay formats including radioimmunoassays (RIAs), ligand-receptor binding assays, and enzyme assays. The SPA-based enzyme assay is usually designed in three formats corresponding to different enzymes: signal removal format for hydrolytic enzymes, signal addition format for polymerase and transferase enzymes, and product capture format for antibodies, DNA probes, receptors or other specific binding proteins. The use of SPA in RIAs has been facilitated by new carriers, such as membranes that can be configured in various shapes and sizes, allowing the assay to be performed on samples from many sources including tissue, serum, plasma or cells. This review presents the principles of SPA, discusses supporting materials and quenching effects, as well as detailed examples of the latest advances.

Know-how and know-why in biochemical engineering

This contribution analyzes the position of biochemical engineering in general and bioprocess engineering particularly in the force fields between fundamental science and applications, and between academia and industry. By using culture technology as an example, it can be shown that bioprocess engineering has moved slowly but steadily from an empirical art concerned with mainly know-how to a science elucidating the know-why of culture behavior. Highly powerful monitoring tools enable biochemical engineers to understand and explain quantitatively the activity of cellular culture on a metabolic basis. Among these monitoring tools are not just semi-online analyses of culture broth by HPLC, GC and FIA, but, increasingly, also noninvasive methods such as midrange IR, Raman and capacitance spectroscopy, as well as online calorimetry. The detailed and quantitative insight into the metabolome and the fluxome that bioprocess engineers are establishing offers an unprecedented opportunity for building bridges between molecular biology and engineering biosciences. Thus, one of the major tasks of biochemical engineering sciences is not developing new know-how for industrial applications, but elucidating the know-why in biochemical engineering by conducting research on the underlying scientific fundamentals.

Developments in microarray technologies

The focus of high-throughput drug discovery has progressed through the genome and the transcriptome and is now moving towards more difficult problems in assessing the proteome, glycome and metabolome. Microarrays are currently the major tool in the assessment of gene expression via cDNA or RNA analysis; however, they are also used to screen libraries of proteins and small molecules. Microarrays have helped to extract more information from smaller sample volumes and enabled the incorporation of low-cost high-throughput assays in the drug discovery process. The technology continues to develop and is being rapidly transferred into more challenging areas, with the potential to further aid and enhance the drug discovery process through the development of, for example, proteomic, glycomic and tissue arrays.