Proteins on a chip

Abstract

A technique of handling fluids at the submillimeter scale, microfluidics, plays an important role in chemistry and biology as a promising alternative for traditional analytics and diagnostics. The advantages of the microfluidic platforms, which include low sample consumption, precise control of fluids, and fast processing, have shown potential for high throughput screening in many scientific and industrial applications. Using the concept of miniaturization, we have designed and fabricated different microfluidic chips for the identification and characterization of proteins. In chapter 3 we developed the parallelization of microfluidic reactors for the kinetic studies of biotechnical reactions. In chapter 4 we developed a new microfluidic screening approach for the separation of biomolecules was shown. We automated all the processes of chromatographic separation, including reagent loading, pH gradient generation, particle packing in a column bed, stepwise elution, fraction collection, and on-chip detection in a single device for the process of on-chip pH gradient chromatofocusing. In chapter 5 a new microfluidic valve was established for particle and cell manipulation in a microfluidic chip. The v-type valve was designed to capture particles or cells in a fluid flow by focusing the flow in the center of a microchannel. In chapter 6 we present a microfluidic chip, which performs two sets of 9 parallel protein incubations with/without adsorbent particles to achieve an adsorption isotherm of a protein in a single experiment. In chapter 7 we developed a microfluidic protein aggregation device for the study of amyloid aggregation using 64 parallel reactors on a single microfluidic chip. The fibrillation of bovine insulin was investigated to evaluate the influence of protein concentration and sodium chloride (NaCl) concentration on the formation of fibrillar structures. In conclusion, we have developed various microfluidic devices for the separation, screening, and aggregation of proteins by the integration of microfluidic components such as microvalve, micromixer, and microstructures. The on-chip analysis with extremely low sample consumption is beneficial for the characterization of rare and expensive materials and identification of process conditions for bioprocessing. In addition, the flexibility of the device in handling reagents, as well as the parallelization, provides high potential for use in many different analytical separation applications. We believe that these integrated microfluidic platforms for high-throughput protein screening are a promising approach for fast biopharmaceutical process development.