Apparatus and method for heating microfluidic volumes and moving fluids

A method for concentrating and measuring microfluidic volumes comprising the steps of:

• providing a laminar body comprising:
• a substrate having a first surface and a second surface;
• at least one heating element disposed on the first surface;
• the heating element comprising:
• a conductive layer patterned into at least two electrodes in spaced relation to each other;
• a resistive layer comprising a resistive material having a resistance temperature coefficient such that resistance changes with temperature;
• the resistive layer being disposed between the electrodes to permit current to flow through the resistive material between the electrodes;
• and
• at least one fluid-receiving location corresponding to the location of the at least one heating element wherein the heating element is in thermal communication with the fluid-receiving location;
• placing a volume of fluid at the fluid-receiving location;
• providing an electronics component having at least signal detection circuitry and control circuitry connected to the at least one heating element;
• applying a voltage across the at least one heating element;
• obtaining at least one electrical information from at least one of the heating elements;
• the electrical information being a function of the variable resistance of the resistive material;
• monitoring the electrical information of the at least one heating element;
• controlling the at least one heating element based on the electrical information calibrated to correspond to a known fluid volume or temperature;
• and
• determining the fluid volume or temperature.

A method for moving microfluids comprising the steps of:

• providing a laminar body comprising:
• a substrate having a first surface and a second surface;
• at least one heating element disposed on the first surface;
• the heating element comprising:
• a conductive layer patterned into at least two electrodes disposed in spaced relation to each other;
• a resistive layer comprising a resistive material having a resistance temperature coefficient such that resistance changes with temperature;
• the resistive material being disposed between the electrodes to permit current to flow through the resistive material between the electrodes;
• and
• providing at least a first receiving location interconnected to a second receiving location;
• the heating element being located next to the first receiving location;
• placing a volume of fluid in the second receiving location;
• placing a volume of gaseous fluid in the first receiving location;
• heating the volume of gaseous fluid to expand and exert pressure on the volume of fluid in the second receiving location to move the volume of fluid in the second receiving location;
• and
• moving the volume of fluid.