Microfluidic device and microfluidic apparatus using the same

Abstract

To improve temperature distribution of fluid in a flow channel of a microfluidic device in which a resistive element disposed in substrate as that in which the channel is formed is heated to control the temperature in accordance with resistance of the element, provided is a microfluidic device including: a substrate; a flow channel disposed in the substrate for flowing through fluid therein; a first resistive element for primarily heating the fluid; and multiple second resistive elements for supplementarily heating the fluid, the elements being disposed at positions different from position where the first element is disposed. A microfluidic apparatus operating the device stores a relational expression between a temperature of the fluid and resistance of the first element, and a fixed value of a ratio between a heat energy input into the first and second element, and controls the temperature in accordance with the expression and the value.

1 . A microfluidic device, comprising:
 a substrate;   a flow channel disposed in the substrate for flowing through fluid therein;   a first resistive element for primarily heating the fluid in the flow channel; and   a second resistive element for supplementarily heating the fluid in the flow channel, the second resistive element being disposed at a position different from a position where the first resistive element is disposed.   
     
     
         2 . The microfluidic device according to  claim 1 , wherein the first resistive element and the second resistive element are electrically independent from each other. 
     
     
         3 . A microfluidic device, comprising:
 a substrate;   multiple flow channels disposed in parallel to one another in the substrate for flowing through fluid therein;   first resistive elements for primarily heating the fluid in the multiple flow channels, the first resistive elements being disposed independent from one another so as to correspond to the number of the multiple flow channels; and   a second resistive element for supplementarily heating the fluid in the multiple flow channels, the second resistive element being electrically independent from the first resistive elements and disposed in a region of the substrate exterior to an outermost first resistive element in the substrate among the first resistive elements.   
     
     
         4 . The microfluidic device according  claim 1 , wherein the first resistive element is disposed on the flow channel and the second resistive element is disposed apart from the flow channel. 
     
     
         5 . A microfluidic apparatus, comprising the microfluidic device according to  claim 1  for measuring a temperature of fluid in a flow channel based on a resistance value of a first resistive element and adjusting a heat energy input into the first resistive element to control the temperature of the fluid in the flow channel, wherein
 the microfluidic apparatus stores a relational expression between the temperature of the fluid in the flow channel and the resistance value of the first resistive element, and a fixed value of a ratio between a heat energy input into the first resistive element and a heat energy input into a second resistive element; and 
 the microfluidic apparatus controls the temperature of the fluid in the flow channel in accordance with the relational expression and the fixed value. 
 
     
     
         6 . The microfluidic apparatus according to  claim 5 , further comprising an arithmetic unit for calculating the fixed value of the ratio between the heat energy input into the first resistive element and the heat energy input into the second resistive element, wherein
 the arithmetic unit calculates the fixed value by using a size of the microfluidic device and an environmental condition of the microfluidic apparatus as input parameters.   
     
     
         7 . The microfluidic device according to  claim 1 , wherein the first resistive element and the second resistive element have the same shape and the same area. 
     
     
         8 . The microfluidic device according to  claim 7 , wherein the first resistive element and the second resistive element have voltages applied thereto, the voltages exhibiting values different from each other so that temperature distribution of the fluid in the flow channel becomes uniform. 
     
     
         9 . The microfluidic device according to  claim 1 , wherein the first resistive element and the second resistive element have one of shapes and areas different from each other. 
     
     
         10 . The microfluidic device according to  claim 9 , wherein the first resistive element and the second resistive element are formed to have the one of the shapes and the areas different from each other so that temperature distribution of the fluid in the flow channel becomes uniform. 
     
     
         11 . A method of heating fluid in flow channel with use of the microfluidic device according to  claim 1 . 
     
     
         12 . The method according to  claim 11 , comprising applying different voltages to the first resistive element and the second resistive element, respectively. 
     
     
         13 . A method of heating fluid in flow channel with use of the microfluidic device according to  claim 3 . 
     
     
         14 . The method according to  claim 11 , wherein the first resistive element is disposed on the flow channel and the second resistive element is disposed apart from the flow channel. 
     
     
         15 . A method of treating fluid comprising the method of heating fluid in flow channel according to  claim 11 . 
     
     
         16 . The method of treating fluid according to  claim 15 , wherein the heating comprises subjecting the fluid in the flow channel to a temperature cycle to perform PCR. 
     
     
         17 . A method of controlling a temperature of fluid in flow channel with use of the microfluidic device according to  claim 1 , the method comprising:
 measuring the temperature of the fluid in the flow channel based on a resistance value of a first resistive element;   adjusting a heat energy input into the first resistive element;   storing a relational expression between the temperature of the fluid in the flow channel and the resistance value of the first resistive element, and a fixed value of a ratio between a heat energy input into the first resistive element and a heat energy input into a second resistive element; and   controlling the temperature of the fluid in the flow channel in accordance with the relational expression and the fixed value.   
     
     
         18 . The method of controlling a temperature of fluid in flow channel according to  claim 17 , further comprising an arithmetic unit for calculating the fixed value of the ratio between the heat energy input into the first resistive element and the heat energy input into the second resistive element, wherein
 the arithmetic unit calculates the fixed value by using a size of the microfluidic device and an environmental condition of the microfluidic apparatus as input parameters.