Apparatus and method for heating microfluidic volumes and moving fluids

Abstract

A device and method for the temperature control, concentration, volume measurement and transport of microfluidic volumes are provided. The device includes one or more heating elements having a resistive material that varies with temperature. The heating elements are formed into a laminar body that may be formed into a variety of geometries and/or easily married to a second body including micro-well plates, micro-centrifuge tubes and microfluidic circuits.

1 . 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.    
   
   
       2 . The method of  claim 1  wherein the step of monitoring the electrical information includes monitoring the electrical information of one or more of the heating elements.  
   
   
       3 . The method of  claim 1  wherein the step of determining the volume of fluid includes calculating the fluid volume as a function of the resistance of the at least one heating element.  
   
   
       4 . The method of  claim 1  further including the step of: 
 positioning the at least one heating element along a surface of the fluid-receiving location at locations corresponding to known graduations of one or more fluid volumes;    determining the level of the fluid based on at least one electrical information of the at least one heating element.    
   
   
       5 . The method of  claim 1  further including the step of evaporating the fluid volume.  
   
   
       6 . The method of  claim 1  wherein the step of monitoring an electrical information includes monitoring the voltage or current across the at least one heating element.