Precise and Low Volume Sampling Using Microfluidic Device

We report a microfluidic device platform to precisely sample low volumes of fluids such as blood for disease diagnosis. It comprises a custom-engineered T-channel, a microfabricated PDMS device. The sampling rate (Q2) is controlled by the design of the sampling channels and the withdrawal rate (Q
1
) of continuous flow using a syringe pump in the main channel. Three devices with a flow rate ratio (Q
1
/Q
2
) of 10, 50, and 100 were designed and tested. The minimum experimental Q2 was found to be 160 nl/min against Q
1
of 1.7 µ1/min. The reported device has the capability to reduce the dead volumes, and precisely sample low volumes from regions where the sample volume is limited such as cerebrospinal fluid.