Miyako Niimi

Virus purification and enrichment by hydroxyapatite chromatography on a chip

Abstract The spread of infectious diseases has become a global health concern. In order to diagnose infectious diseases quickly and accurately, next-generation DNA sequencing techniques for genetic analysis of infectious viruses have been developed rapidly. However, it takes a very long time to pretreat clinical samples for genetic analysis using next-generation sequencers. We have therefore developed a microfluidic chromatography chip that can purify and enrich viruses in a sample using hydroxyapatite particles packed in a micro-column. We demonstrated the purification of virus from a mixture of virus and FBS protein, and enrichment of the virus using this novel microfluidic chip.

Cell isolation system for rare Circulating Tumor Cell

For molecular analysis of the rare cells, such as Circulating Tumor Cells (CTCs), the rare cells isolation from the suspension which contains large population of other cells on the single cells level is required. In this paper, we fabricated and demonstrated a cell isolation system for rare CTCs. We utilized the technique of convective self-assembly, which is a technique for depositing uniform onto the microfluidic device, to array single CTCs. Under the suspended cancer cells experiments, we demonstrated that by using this system, the collection efficiency of cells which could be deposited on the microfluidic device was 98.3% while the flow rate was 57.1 μl/min. This system will be conducive to single rare cells analysis because the deposited cells could be picked up by glass pipette easily.

Isolation of Circulating Tumor Cells by convective self-assembly technique

The CTCs (Circulating Tumor Cells) isolation method enables to sort very rare single CTC from the whole blood. We utilized the technique of convective self-assembly, which is a technique for depositing cells onto the microfluidic channel, to isolate CTCs. Through the convective self-assembly processes, the cells including CTCs and blood cells are deposited in the channels of microfluidic chip. After giving the sheath flow, only the CTCs remain in the channels and the other cells are removed. As the result, it was indicated that a specific design of microchannel has the highest collection rate of about 90%.

Compiled chip for all pretreatment processes of virus gene analysis

In this research, we demonstrated a microfluidic chip to pretreat the samples for viral genome assay. The microfluidic chip has the following three functions; (1) Virus purification and enrichment, (2) Viral RNA extraction, and (3) Capture of the targeted virus genome. Hydroxyapatite chromatography, Boom method, and PNA (Peptide Nucleic Acid) were used for the above three functions, respectively. These three functions were integrated in one chip. Furthermore PNA immobilized on the glass can detect the targeted virus genome so that in situ virus detection would be possible by anybody, anywhere, anytime.