Systems and Methods for Monitoring Chemical and Biological Activity using Differential Measurements

Abstract

A system operable to monitoring bio/chemical activities includes a first measurement probe, a second measurement probe and a comparator. The first measurement probe is operable to interrogate one or more physical properties of a sample at a first location of the sample, and to output, in response, a first measurement signal. The second measurement probe is operable to interrogate one or more physical properties of the sample at a second location of the sample, and to output, in response, a second measurement signal. The comparator is coupled to receive the first and second measurement signals, the comparator configured to output a difference signal comprising the difference between the first and second measurement signals, the difference signal corresponding to the difference in one or more bio/chemical activities occurring at the first location of the sample relative to the second location of the sample.

1 . A system operable to monitor one or more bio/chemical activities within a sample, the system comprising:
 a first measurement probe operable to interrogate one or more physical properties of a sample at a first location of the sample, and to output, in response, a first measurement signal;   a second measurement probe operable to interrogate one or more physical properties of the sample at a second location of the sample, and to output, in response, a second measurement signal; and   a comparator coupled to receive the first and second measurement signals, the comparator configured to output a difference signal comprising the difference between the first and second measurement signals, the difference signal corresponding to the difference in one or more bio/chemical activities occurring within the sample at the first location relative to the second location.   
     
     
         2 . The system of  claim 1 , wherein the first and second measurement probes are operable to interrogate the sample's electrical properties at the respective first and second locations. 
     
     
         3 . The system of  claim 1 , wherein the first and second measurement probes are operable to interrogate the sample's optical properties at the respective first and second locations. 
     
     
         4 . The system of  claim 1 , wherein the first and second measurement probes are operable to interrogate the sample's mass properties at the respective first and second locations. 
     
     
         5 . The system of  claim 1 , wherein the first and second measurement probes are operable to interrogate the sample's chemical properties at the respective first and second locations. 
     
     
         6 . The system of  claim 1 , wherein the first and second measurement probes are operable to interrogate the sample's mass and charge properties at the respective first and second locations. 
     
     
         7 . The system of  claim 1 , wherein the first and second measurement signals are non-DC formatted signals, the system further comprising a DC converter configured to convert the first and second measurement signals to respective DC formatted signals. 
     
     
         8 . The system of  claim 1 , wherein the first and second measurement signals comprise DC signals, and wherein the difference signal comprises a DC formatted signal at a voltage level which corresponds to the difference between the first and second measurement signals. 
     
     
         9 . The system of  claim 1 , wherein the comparator comprises a differential amplifier having a first input coupled to the first measurement probe, a second input coupled to the second measurement probe, and an output for providing the difference signal. 
     
     
         10 . The system of  claim 1 , further comprising a correlator having an input coupled to receive the difference signal, and memory operable to retain one or more stored difference signals, each stored difference signal corresponding to a predetermined activity, wherein the correlator compares the difference signal against one or more of the stored difference signals and identifies as occurring with the sample, the activity of the stored difference signal which has the closest correlation to the difference signal. 
     
     
         11 . The system of  claim 1 , further comprising:
 a first reference element coupled to the first measurement probe; and   a second reference element coupled to the second measurement probe, wherein the first measurement probe, the first reference element, the second measurement probe, and the second reference element comprise are coupled together in a bridge circuit configuration.   
     
     
         12 . The system of  claim 11 , wherein the first and second reference elements comprise resistors. 
     
     
         13 . The system of  claim 11 , wherein:
 the first reference element comprises a third measurement probe operable to interrogate one or more physical properties of the sample at a third location of the sample, and to output, in response, a third measurement signal; and   the second reference element comprises a fourth measurement probe operable to interrogate one or more physical properties of the sample at a fourth location of the sample, and to output, in response, a fourth measurement signal.   
     
     
         14 . The system of  claim 11 , wherein the comparator comprises:
 a first differential amplifier having a first input coupled to the first measurement probe, a second input coupled to the first reference element, and an output;   a second differential amplifier having a first input coupled to the second measurement probe, a second input coupled to the second reference element, and an output; and a third differential amplifier having a first input coupled to the output of the first differential amplifier, a second input coupled to the output of the second differential amplifier, and an output for providing the difference signal.   
     
     
         15 . The system of  claim 14 , wherein the comparator further comprises a phase meter having a first input coupled to the output of the first differential amplifier, and a second input coupled to the output of the second differential amplifier, the phase meter operable to output the relative phase difference between the first and second differential amplifier output signals. 
     
     
         16 . The system of  claim 11 , further comprising a first signal ground coupled to the sample at a third location proximate to the first measurement probe, wherein the first measurement probe interrogates the sample by transmitting a signal between the first measurement probe and the first signal ground. 
     
     
         17 . The system of  claim 16 , further comprising a second signal ground coupled to the sample at a fourth location proximate to the second measurement probe, wherein the second measurement probe interrogates the sample by transmitting a signal between the second measurement probe and the second signal ground. 
     
     
         18 . The system of  claim 13 , further comprising:
 a signal probe coupled to the sample at a fifth location of the sample, the signal probe configured to apply a test signal to the sample; and   a signal ground coupled to the sample at a sixth location of the sample, the signal ground operable to provide a ground potential to the applied test signal.   
     
     
         19 . A system operable to monitor one or more bio/chemical activities within a sample, the system comprising:
 a first measurement probe coupled to the sample at a first location of the sample, the first measurement probe configured to interrogate one or more physical properties of the sample at the first location and to output, in response, a first measurement signal;   a second measurement probe coupled to the sample at a second location of the sample, the second measurement probed configured to interrogate one or more physical properties of the sample at the second location, and to output, in response, a second measurement signal; and   a comparator coupled to receive the first and second measurement signals, the comparator configured to output a difference signal comprising the difference between the first and second measurement signals, the difference signal corresponding to the difference in one or more bio/chemical activities occurring at the first location relative to the second location.   
     
     
         20 . The system of  claim 19 , wherein the first and second measurement probes are operable to interrogate the sample's electrical properties at the respective first and second locations. 
     
     
         21 . The system of  claim 19 , wherein the first and second measurement probes are operable to interrogate the sample's optical properties at the respective first and second locations. 
     
     
         22 . The system of  claim 19 , wherein the first and second measurement probes are operable to interrogate the sample's mass properties at the respective first and second locations. 
     
     
         23 . The system of  claim 19 , wherein the first and second measurement probes are operable to interrogate the sample's chemical properties at the respective first and second locations. 
     
     
         24 . The system of  claim 19 , wherein the first and second measurement probes are operable to interrogate the sample's mass and charge properties at the respective first and second locations. 
     
     
         25 . The system of  claim 19 , wherein the first and second measurement signals are non-DC formatted signals, the system further comprising a DC converter configured to convert the first and second measurement signals to respective DC formatted signals. 
     
     
         26 . The system of  claim 19 , wherein the first and second measurement signals comprise DC formatted signals, and wherein the difference signal comprises a DC formatted signal at a voltage level which corresponds to the difference between the first and second measurement signals. 
     
     
         27 . The system of  claim 19 , wherein the comparator comprises a differential amplifier having a first input coupled to the first measurement probe, a second input coupled to the second measurement probe, and an output for providing the difference signal. 
     
     
         28 . The system of  claim 19 , further comprising a correlator having an input coupled to receive the difference signal, and memory operable to retain one or more stored difference signals, each stored difference signal corresponding to a predetermined activity, wherein the correlator compares the measured difference signal against one or more of the stored difference signals and identifies as occurring with the sample, the activity of the stored difference signal which has the closest correlation to the measured difference signal. 
     
     
         29 . The system of  claim 19 , further comprising:
 a first reference element coupled to the first measurement probe; and   a second reference element coupled to the second measurement probe,   wherein the first measurement probe, the first reference element, the second measurement probe, and the second reference element comprise are coupled together in a bridge circuit configuration.   
     
     
         30 . The system of  claim 29 , wherein the first and second reference elements comprise resistors. 
     
     
         31 . The system of  claim 29 , wherein:
 the first reference element comprises a third measurement probe coupled to the sample at a third location, the third measurement probe configured to interrogate one or more physical properties of the sample at the third location of the sample, and to output, in response, a third measurement signal; and   the second reference element comprises a fourth measurement probe coupled to the sample at a fourth location of the sample, the fourth measurement probe configured to interrogate one or more physical properties of the sample at the fourth location, and to output, in response, a fourth measurement signal.   
     
     
         32 . The system of  claim 29 , wherein the comparator comprises:
 a first differential amplifier having a first input coupled to the first measurement probe, a second input coupled to the first reference element, and an output;   a second differential amplifier having a first input coupled to the second measurement probe, a second input coupled to the second reference element, and an output; and   a third differential amplifier having a first input coupled to the output of the first differential amplifier, a second input coupled to the output of the second differential amplifier, and an output for providing the output difference signal.   
     
     
         33 . The system of  claim 32 , wherein the comparator further comprises a phase meter having a first input coupled to the output of the first differential amplifier, and a second input coupled to the output of the second differential amplifier, the phase meter operable to output the relative phase difference between the first and second differential amplifier outputs. 
     
     
         34 . The system of  claim 29 , further comprising a first signal ground coupled to the sample at a third location proximate to the first measurement probe, wherein the first measurement probe interrogates the sample by transmitting a signal between the first measurement probe and the first signal ground. 
     
     
         35 . The system of  claim 34 , further comprising a second signal ground coupled to the sample at a fourth location proximate to the second measurement probe, wherein the second measurement probe interrogates the sample by transmitting a signal between the second measurement probe and the second signal ground. 
     
     
         36 . The system of  claim 31 , further comprising: a signal probe coupled to the sample at a fifth location of the sample, the signal probe configured to apply a test signal to the sample; and a signal ground coupled to the sample at a sixth location of the sample, the signal ground operable to provide a ground potential to the applied test signal. 
     
     
         37 - 56 . (canceled) 
     
     
         57 . A system operable to monitor bio/chemical activities within a plurality of samples, the system comprising:
 three or more measurement probes operable to interrogate one or more physical properties of a respective three or more samples, and to output, in response, a respective three of more measurement signals;   a comparator coupled to receive at least two of the three of more measurement signals, the comparator configured to output a difference signal corresponding to the difference in bio/chemical activity occurring within a first sample relative to a second sample, whereby the interrogation of the first sample produces one of the at least two measurement signals, and the interrogation of the second sample produces the second of the at least two measurement signals.   
     
     
         58 . The system of  claim 57 , further comprising a switch having an input coupled to receive at least two of the three of more measurement signals, the switch operable to selectively output one or more of the at least two received measurement signals. 
     
     
         59 . The system of  claim 58 , wherein the comparator is coupled to receive the first measurement signal, and the input of the switch is coupled to receive the second and third measurement signals, and wherein the switch is operable to selectively output either the second measurement signal or the third measurement signal. 
     
     
         60 . The system of  claim 58 , further comprising:
 a first reference element coupled to the first measurement probe; and   a second reference element coupled to the second measurement probe, wherein the first measurement probe, the first reference element, the second measurement probe, and the second reference element comprise are coupled together in a bridge circuit configuration.   
     
     
         61 . The system of  claim 59 , wherein the first and second reference elements comprise resistors. 
     
     
         62 . The system of  claim 57 , further comprising a switch having an input coupled to receive all of the three of more measurement signals, the switch operable to selectively output two or more of the received three or more measurement signals. 
     
     
         63 . The system of  claim 62 , wherein the three of more measurement probes comprises four measurement probes operable to interrogate one or more physical properties of a respective four samples, and to output, in response, a respective four measurement signals. 
     
     
         64 . The system of  claim 63 , further comprising a switch having an input coupled to receive the four measurement signals and two or more outputs coupled to the comparator, the switch operable to selectively output two or more of the four measurement signals to the comparator. 
     
     
         65 . The system of  claim 62 , wherein the three of more measurement probes comprises five or more measurement probes operable to interrogate one or more physical properties of a respective five or more samples, and to output, in response, a respective five or more measurement signals. 
     
     
         66 . The system of  claim 65 , further comprising a switch having an input coupled to receive the five or more measurement signals and four outputs coupled to the comparator, the switch operable to selectively output four of the five or more measurement signals to the comparator.