Fig. 1.

(a) Concept of the microfluidic chip for purification and enrichment of virus using hydroxyapatite chromatography. The microfluidic chip has a column for hydroxyapatite chromatography and a pair of switching valves. Hydroxyapatite particles are introduced into the column through inlet 1. The sample is introduced into the column through inlet 2 and both viruses and impurities in the sample are adsorbed onto the surface of hydroxyapatite particles. Then, an elution buffer is introduced into the column to elute the impurities such as proteins. Then, another elution buffer is introduced into the column to elute the viruses.

(b) The fabricated microfluidic chip. Upstream and downstream of the column, 50-μm-diameter cylindrical micropillars placed at 20-μm intervals hold the hydroxyapatite particles in the column. The diameter of the hydroxyapatite particles is 40 μm.