System and method for tool feedback sensing

1. A microneedle application device for moving a microneedle array toward a target skin location, the microneedle application device comprising:

a portion of the microneedle application device adapted for skin contact at least prior to microneedle application; and

a feedback sensor operably connected to the microneedle application device, wherein the feedback sensor is capable of generating an output corresponding to forces between the target skin location and the portion of the microneedle application device at least prior to microneedle application;

wherein the microneedle array comprises two or more microneedles each comprising a height of no greater than about 250 micrometers; and wherein the feedback sensor comprises one or more sensor regions positioned to sense the force between the portion of the microneedle application device adapted for skin contact and the target skin location and

further comprising an additional sensor region operably connected to a piston of the microneedle application device.

2. The microneedle application device of claim 1 , further comprising an indicator operably connected to the sensor regions, wherein the indicator is capable of indicating when the microneedle application device is in a desired orientation relative to the target application site for microneedle application.

3. The microneedle application device of claim 1 further comprising at least two additional sensor regions, each force sensing element being operably connected to the portion of the microneedle application device adapted for skin contact at least prior to microneedle application.

4. The microneedle application device of claim 3 , wherein at least one of the sensor regions is located at or near a perimeter of the portion of the microneedle application device adapted for skin contact at least prior to microneedle application.

5. The microneedle application device of claim 3 , wherein the sensor regions are positioned about an axis and are substantially equally spaced apart along a circumference defined around the axis.

6. The microneedle application device of claim 4 , wherein the sensor regions each provide an output indicating desirability of an orientation of the microneedle application device relative to the target application site.

7. The microneedle application device of claim 1 , wherein the sensor regions provide a quantitative output indicating force sensed.

8. The microneedle application device of claim 1 , further comprising a processor operatively connected to the sensor regions for processing data from the force sensing element.

9. The microneedle application device of claim 1 , further comprising a lockout for preventing application of the microneedle array under conditions determined as a function of the output generated by the feedback sensor.

10. The microneedle application device of claim 1 , wherein each microneedle of the microneedle array comprises a height of at least about 100 micrometers.

11. A method of microneedle application, the method comprising:

providing a microneedle applicator device of claim 1

providing a microneedle array, wherein the microneedle array is mountable relative to the microneedle applicator device;

positioning a locating portion of the microneedle applicator device in contact with skin at least prior to microneedle application to substantially define a target application site on the skin for application of the microneedle array;

sensing a force between the target application site and a first portion of the microneedle applicator device;

positioning the microneedle applicator device such that the microneedle array can be moved into contact with the skin along a path that is substantially orthogonal relative to the target application site; and

moving the microneedle array toward the target application site.

12. The method of claim 11 , wherein the first portion of the microneedle applicator device corresponds to a microneedle array deploying piston.

13. The method of claim 11 , wherein the first portion of the microneedle applicator device corresponds to the locating portion.

14. The method of claim 13 and further comprising sensing a force between the target application site and a second portion of the microneedle applicator device.

15. The method of claim 14 , wherein the second portion of the microneedle applicator device corresponds to a microneedle array deploying piston.

16. The method of claim 15 and further comprising correlating force sensed between the target application site and the first portion of the microneedle applicator device to force sensed between the target application site and the second portion of the microneedle applicator device.

17. The method of claim 11 , further comprising providing an indication to an operator whether or not the microneedle applicator device is positioned for proper microneedle array application.