Endoscope for analyte consumption rate determination with single cell resolution for in vivo applications
Novel methods and devices including modified endoscopes that employ fiber optic technology and multiple extrinsic optical sensors for enablement of simultaneous determination of change rates of biological analytes in vivo with single-cell resolution. The devices employ dynamic oscillatory actuation to determine the gradient of analytes of interest along one or multiple directions with respect to the cell. The change rate or flux of the analyte of interest can be easily determined by applying the first Fick's law that relates the flux with the concentration gradient. The dual operation mode of the device markedly increases measurement sensitivity and accuracy.
1. A modified endoscope utilizing fiber optics for simultaneous measurement of changes in multiple biological analytes in vivo with single cell resolution comprising:
a proximal end and a distal end, wherein the proximal end is adapted to be placed outside a body and the distal end is adapted to be placed inside the body;
at least two different optical sensors on the distal end, wherein the sensors respond to concentration changes of different analytes of interest with at least one of different light emission signal amplitudes, emission temporal characteristics, or spectral characteristics;
a sensor button on the distal end, wherein the sensor button can be actuated back and forth to regulate the exposure of the sensors to the analytes;
a piezo actuator on the distal end, wherein the actuator is coupled to a light guide on one end, to the sensor button on the other end, and is positioned to control the displacement of the sensors at the distal end;
a sensitive detector on the proximal end, wherein the detector is configured to detect the emitted light of each of the sensors; and
a light guide configured to serve as a light delivery medium from a light source to the sensors at the distal end and as a emission light delivery medium from the sensors to the detector at the proximal end.
2. The modified endoscope of claim 1 , wherein the light guide is surrounded by a tubing that is flexible and operative for analyte delivery to the distal end.
3. The modified endoscope of claim 2 , wherein the flexible tubing and the light guide are configured to enable in vivo applications under complex geometrical confinements.
4. The modified endoscope of claim 2 , wherein the endoscope is configured to determine analyte flux by measuring an analyte gradient along one or several directions with regard to a single cell in vivo.
5. The modified endoscope of claim 4 , wherein the analyte gradient can be actively controlled by flowing analytes through the flexible tubing at a known concentration and flow rate.
6. The modified endoscope of claim 5 , wherein a combination of external analyte concentration with an oscillatory actuation of the optical sensors significantly increases the measurement sensitivity as compared to measurements with no active modulation of the external analyte concentration.
7. The modified endoscope of claim 6 , wherein the external flux of the analyte through the flexible tubing is modulated in a sinusoidal or other well-defined pattern such that alterations in both phase and amplitude result from cellular activity.
8. The modified endoscope of claim 7 , wherein change rates of the analyte due to cellular activity are calculated from displacement of the optical sensors and changes in modulation depth and phase shift of external analyte flux.
9. The modified endoscope of claim 1 , wherein the endoscope is equipped with in vivo imaging capability.
10. The modified endoscope of claim 1 , wherein the endoscope is equipped with biopsy material collection capability.
11. A method for simultaneous measurement of changes in multiple biological analytes with single cell resolution in vivo comprising:
positioning a distal end of a modified endoscope inside the body at a place of interest;
delivering light through a light guide from a proximal end of the endoscope to at least two optical sensors at the distal end;
actuating a sensor button at the distal end to expose the sensors to the analytes of interest;
transmitting a light emission signal amplitude of each of the sensors corresponding to a change in concentration gradient of the analytes; and
measuring the analytes concentration gradient change transmitted by the sensors with a sensitive detector.