Valve for use in microfluidic structures

A recirculating pump for use in a microfluidics structure, comprising:

• a first layer of flexible material having a top side and a bottom side;
• a second layer of flexible material having a top side and a bottom side;
• a first spacer contacting said bottom side of said first layer and said top side of said second layer for separating said first and second layers, forming a first microfluidic channel;
• a third layer of flexible material having a top side and a bottom side;
• a second spacer contacting said bottom side of said second layer and said top side of said third layer for separating said second and third layers, forming a second microfluidic channel;
• wherein said second layer contains:
• a first slit forming a first actuator in said second layer, said first actuator shiftable between a first unactuated position in contact with said first spacer in which said first and second channels are isolated from one another and a second actuated position in which said first and second channels are in fluid communication with each other, and a second slit forming a second actuator in said second layer shiftable between a first unactuated position in contact with said second spacer in which said first and second channels are isolated from one another and a second actuated position in which said first and second channels are in fluid communication with each other;
• and activating means for shifting said first layer to a first pumping position from its normal position;
• whereby when said first layer is shifted to said first pumping position, said first actuator is shifted to said second actuated position while said second actuator is in said first unactuated position, thus forcing fluid from said first microfluidic channel into said second microfluidic channel.

A microfluidic device, comprising:

• a valve structure;
• a microfluidic inlet channel formed within said valve structure;
• a microfluidic outlet channel formed within said valve structure;
• an elastomeric structure separating said inlet and said outlet channels having a first unactuated position isolating said inlet channel from said outlet channel and a second actuated position whereby said inlet and said outlet channels are in fluid communication with each other, whereby when a fluid is introduced into said inlet channel, pressure within said inlet shifts said elastomeric structure from said first unactuated position to said second actuated position allowing fluid to flow from said inlet channel to said outlet channel, and when a fluid is introduced into said outlet channel, pressure holds said elastomeric structure in said first unactuated position, preventing flow between said inlet and outlet channels.