Microfluidic reaction vessel array with patterned films

Abstract

This disclosure describes various microfluidic devices that may be used in thermal cyclic fluid samples. Some of these devices may include a plurality of microwells that may be coupled by interconnected fluidic channels. These microwells may not be physically separated and yet may include features allowing for effective isolation of target molecules within each microwell. Other devices may include a plurality of microwells that may not be interconnected. The devices may also include mechanisms for causing a fluid to flow across the device. The devices may also include light-absorbing films for converting light energy to heat so as to allow for thermal cycling of samples within the microwells.

1 - 22 . (canceled) 
     
     
         23 . A method of thermal cycling on a microfluidic device, the method comprising:
 loading a plurality of microwells of a fluidic device with one or more sample fluids, wherein the fluidic device comprises a network of interconnected fluidic channels coupled to at least one sample inlet and the microwells, wherein the microwells are physically separated but connected to each other via the network of interconnected fluidic channels; and   thermal cycling a first microwell.   
     
     
         24 . The method of  claim 23 , wherein a first microwell is connected to a second microwell via a first fluidic channel, wherein the first microwell is separated from the second microwell by a first distance that is greater than a distance at which one or more molecules are capable of diffusing during thermal cycling. 
     
     
         25 . The method of  claim 24 , wherein the one or more molecules comprises nucleic acids, nucleotide molecules, or fluorescent dyes. 
     
     
         26 . The method of  claim 25 , wherein the distance is between about 100 μm to 1 mm. 
     
     
         27 . The method of  claim 23 , wherein the microwells are disposed in a first substrate mounted to a second substrate, wherein a plurality of films are arranged across regions of the second substrate that correspond to positions of the microwells, the films being configured to absorb photonic energy to increase a temperature of a corresponding microwell, and wherein thermal cycling the first microwell comprises:
 applying a first photonic energy to a first film corresponding to the first microwell such that the first film absorbs the photonic energy to increase a temperature of the first microwell by a first amount.   
     
     
         28 . The method of  claim 27 , wherein the fluidic device comprises a number of photonic energy sources corresponding to a number of the microwells of the fluidic device. 
     
     
         29 . The method of  claim 27 , further comprising applying a second photonic energy to a second film corresponding to a second microwell such that the second film absorbs the photonic energy to increase a temperature of the second microwell by a second amount. 
     
     
         30 . The method of  claim 29 , wherein fluid in the first microwell and the second microwell is thermally cycled, and wherein fluid in a first fluidic channel connecting the first microwell to a second microwell remains substantially not thermally cycled. 
     
     
         31 . The method of  claim 29 , wherein the first photonic energy is emitted by a first source, and wherein the second photonic energy is emitted by a second source different from the first source. 
     
     
         32 . The method of  claim 29 , wherein the first amount is different from the second amount. 
     
     
         33 . The method of  claim 32 , wherein the first film and the second film are patterned films, wherein the first film is of a different pattern than the second film. 
     
     
         34 - 50 . (canceled) 
     
     
         51 . A microfluidic device for thermal cycling portions of a fluid sample comprising a liquid and a plurality of cells, the microfluidic device comprising:
 a sample inlet;   a plurality of microwells each fluidically coupled to the sample inlet by a respective fluidic channel, wherein each microwell is isolated from other microwells and each fluidic channel is isolated from other fluidic channels;   a plurality of interconnected circulation channels each disposed around at least a portion of a perimeter of each of the plurality of microwells;   a suction source coupled to each of the circulation channels and configured to evacuate the circulation channels to cause a gas within the fluidic channels to diffuse into the circulation channels and thereby draw the fluid sample into the plurality of microwells; and   a plurality of discrete light-absorbing regions disposed adjacent to the plurality of microwells, wherein each discrete light-absorbing region is configured to absorb light energy from a light source to increase a temperature of an adjacent microwell.   
     
     
         52 . The microfluidic device of  claim 51 , wherein each microwell is sized to retain a volume of the fluid sample determined to statistically limit the number of cells present in the volume to a predetermined number. 
     
     
         53 . The microfluidic device of  claim 52 , wherein each microwell is 600 micrometers×600 micrometers×50 micrometers. 
     
     
         54 . The microfluidic device of  claim 52 , wherein each microwell has an internal volume of 16 nanoliters. 
     
     
         55 . The microfluidic device of  claim 51 , wherein each of the plurality of discrete light-absorbing regions is disposed adjacent to a single microwell of the plurality of microwells. 
     
     
         56 . The microfluidic device of  claim 51 , wherein the plurality of discrete light-absorbing regions is disposed on a substrate beneath or above the plurality of microwells. 
     
     
         57 . The microfluidic device of  claim 51 , wherein the plurality of discrete light-absorbing regions is disposed within the plurality of microwells. 
     
     
         58 . The microfluidic device of  claim 51 , wherein the suction source is a syringe pump. 
     
     
         59 . The microfluidic device of  claim 51 , wherein the suction source is a vacuum source. 
     
     
         60 . The microfluidic device of  claim 51 , wherein one or more of the plurality of fluidic channels are shaped to have a meandering pathway. 
     
     
         61 . A method of thermal cycling portions of a fluid sample comprising a liquid and a plurality of cells on a microfluidic device, the method comprising:
 engaging a suction source to draw the fluid sample into a plurality of microwells that are fluidically coupled to each other via a plurality of fluidic channels, wherein each of the plurality of microwells has a trapping region configured to trap a single cells;   trapping, within each trapping region of one or more of the plurality of microwells, a single cell of the plurality of cells;   causing a flushing solution to flow through the plurality of microwells to flush away untrapped cells; and   directing light energy toward a plurality of discrete light-absorbing regions disposed adjacent to the plurality of microwells so as to cause the discrete light-absorbing regions to absorb the light energy and increase a temperature of an adjacent microwell.