Biochip for cellomics and proteomics

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We have developed biochips for retaining a single biological cell for long-term monitoring of cellular changes and reactions. In particular, we have carryied out measurements of intracellular calcium in a yeast, a heart muscle cell and a cancerous cell as they were stimulated by various reagents. We have also assembled polymeric chips to conduct DNA probe immobilization and sample hybridization in a microarray format. This is achieved using all microfluidic operations without using any spotting procedures. The objectives of this proposed research is to extend these methods for the basic studies of cellular transport processes and protein-small molecule interactions. First, the biochip that achieves single-cell retention for long-term cellular monitoring allows us to study various essential biochemical processes. For instance, the mechanistic study of drug efflux from a single cancerous cell will benefit the elucidiation of the kinetics of multi-drug resistance of chemotherapeutic drugs. To date, the conventional method of flow cytometry only allows the measurements of a batch of cells for the study of excretion and accumulation of drugs. The biochip method can be used to monitor the kinetic process of a drug when it enters a cancerous cell, and then leaves it upon excretion. Such a process as mediated by a cellular membrane excretory protein  will be studied in detail in the single-cell format. Second, the biochip that has been developed for DNA microarray will be exploited to construct cell microarray for cell-drug interaction studies and small molecule array for enzyme binding studies. In addition, the complex channel network on the microfluidic chip will be employed to carry out protein separation. For instance, one radial and numerous spiral channels will be constructed on the biochip to conduct 2-dimensional separation for cellular proteins. This biochip protein separation will link the extraction of proteins from a single cell on the one end, and the subsequent analysis of separated proteins on the other.We envision that our approach of on-chip study of proteins in general and cellular proteins in particular will be highly significant in the field of proteomics and cellomics.