Patent ID: 7452726

Claim:
A method for perfusing cells with a reagent comprising the steps of: (a) providing a microfluidic device having (i) a cell growth chamber, a cell inlet in communication with said chamber, said cell inlet having an inlet valve in operable communication therewith to control fluid flow through said cell inlet into said chamber, wherein said cells can pass through said cell inlet into said chamber when said inlet valve is open, but cannot pass through said cell inlet when said inlet valve is closed; and, (ii) a reagent inlet for inputting said reagent into said chamber, said reagent inlet having a reagent valve in operable communication with said reagent inlet for controlling fluid flow through said reagent inlet into said chamber, said cell inlet and/or said chamber having a retention mechanism for retaining said cells in said chamber while permitting flow of said reagent into said chamber when said reagent valve is open; wherein when said cells are loaded into said chamber, and said inlet valve is closed, said cells are retained in said chamber by the retention mechanism while said reagent valve is open and closed; (b) opening said cell inlet valve and introducing said cells into said chamber; (c) closing said cell inlet valve; (d) opening said reagent valve to introduce said reagent into said chamber; and, (e) introducing said reagent into said chamber while retaining said cells inside of said chamber thereby perfusing said cells with said reagent.