System and method for controlling thermal cycler modules

Abstract

Systems and methods for processing and analyzing samples are disclosed. The system may process samples, such as biological fluids, using assay cartridges which can be processed at different processing locations. In some cases, the system can be used for PCR processing. The different processing locations may include a preparation location where samples can be prepared and an analysis location where samples can be analyzed. To assist with the preparation of samples, the system may also include a number of processing stations which may include processing lanes. During the analysis of samples, in some cases, thermal cycler modules and an appropriate optical detection system can be used to detect the presence or absence of certain nucleic acid sequences in the samples. The system can be used to accurately and rapidly process samples.

1 . A computer readable medium, comprising code, executable by a processor, for implementing a method for operating a thermal cycler module, the method comprising:
 obtaining a predetermined temperature vs. time profile associated with a selected thermal cycler module in an array of thermal cycler modules, the array of thermal cycler modules comprising the selected thermal cycler module and a set of thermal cycler modules; and   controlling, by a processor, the thermal cycler modules in the set of thermal cycler modules so that their performance matches the predetermined temperature vs. time profile, each of the thermal cycler modules in the set of thermal cycler modules being controlled using a source of variation between the thermal cycler modules in the array.   
     
     
         2 . The computer readable medium of  claim 1  wherein the source of variation comprises an ambient temperature of the thermal cycler module, or a physical characteristic of the thermal cycler module. 
     
     
         3 . The computer readable medium of  claim 1  wherein controlling the thermal cycler modules comprises, for each module, adjusting h a , which is a thin film heater output at ambient temperature (° C./second) and k, which is a rate of heat transfer, using the following equation:
     dB/dt=h   a   +k ( Ta−B ( t )), where 
 dB/dt=change in block temp in degrees per second, 
 Ta=ambient temperature (° C.), 
 h a =thin film heater output at ambient temperature (° C./second), 
 k=rate of heat transfer, and 
 B(t)=the temperature of the thermal block at a given time t, 
 wherein dB/dt 
 
     
     
         4 . The computer readable medium of  claim 3  wherein B(t)=(B(0)−(h a /k)−Ta)e kt +(ha/k)+Ta, where B(0)=starting block temperature at time=0. 
     
     
         5 . The computer readable medium of  claim 3  wherein k is adjusted using a blower. 
     
     
         6 . A computer readable medium, comprising code, executable by a processor, for implementing a method of driving a first thermal cycler in a predetermined thermal profile (B(t)), the first thermal cycler including a thermal block, a heater thermally coupled to the thermal block, and a blower to direct air to the thermal block, the method comprising:
 determining the rate of change of the thermal block temperature with respect to time (dB/dt) as a function of heater output (h a ), of blower heat transfer (k), and of ambient temperature (Ta);   measuring the thermal block temperature;   measuring the ambient temperature at the thermal cycler; and   adjusting one of the heater output and the blower heat transfer according to a modeled relationship of:
     dB/dt=h   a   +k ( Ta−B ( t )). 
   
     
     
         7 . The computer readable medium of  claim 6  wherein the step of adjusting one of the heater output and the blower heat transfer includes adjusting the heater output and the blower heat transfer. 
     
     
         8 . The computer readable medium of  claim 7  wherein the first thermal cycler further includes a processor having a memory, the processor sensing the thermal block temperature and the ambient temperature and controlling the heater output and the blower heat transfer, and the memory including a representation of the predetermined thermal profile and a representation of the modeled relationship. 
     
     
         9 . The computer readable medium of  claim 8  wherein the processor controls the blower heat transfer by adjusting the power supplied to the blower. 
     
     
         10 . The computer readable medium of  claim 9  wherein the same predetermined thermal profile is determined through evaluation of the rate of change of the thermal block temperature with respect to time as a function of heater output, of blower heat transfer, and of ambient temperature of a plurality of thermal cyclers and selection of a thermal profile achievable by each of the plurality of thermal cyclers as the predetermined profile. 
     
     
         11 . The computer readable medium of  claim 10  wherein the response of the first thermal cycler matches the response of a second thermal cycler. 
     
     
         12 . The computer readable medium of  claim 11  wherein first thermal cycler is disposed adjacent the second thermal cycler.