Devices with selectively permeable barriers

1. A device for allowing selective communication between a substrate and an outside environment, comprising:

a substrate including a sensor material that has an electrical property which varies when an analyte is present, a radio frequency identification (RFID) chip and an antenna, with the chip is electrically connected to the sensor material;

a first layer overlaying at least a portion of the substrate and having at least one first pore; and

a second layer overlaying at least a portion of the first layer and having at least one second pore, wherein

at least a portion of the first and/or second layers are movable with respect to each other between an open condition and a closed condition in response to a change in an environmental factor,

the first and second pores being substantially aligned in the open condition to allow fluid communication between the substrate and the outside environment such that when the at least one first and second pores are substantially aligned fluid passes through the at the least one first pore and the at least one second pore in the second layer,

the first and second pores being substantially misaligned in the closed condition to prevent fluid communication between the substrate and the outside environment; and

wherein the device has a perimeter that forms a fluid tight seal with the substrate.

2. The device of claim 1 , wherein the first and second pores are completely misaligned in the closed condition.

3. The device of claim 1 , further comprising an RFID chip and antenna associated with the substrate.

4. The device of claim 1 , wherein at least one of the first and second layers is comprised of a plastic material.

5. The device of claim 1 , wherein at least one of the first and second layers is comprised of aluminum.

6. The device of claim 1 , wherein said at least a portion of the first and/or second layers are movable with respect to each other between an open condition and a closed condition in response to a change in temperature.

7. The device of claim 1 , wherein said at least a portion of the first and/or second layers are movable with respect to each other between an open condition and a closed condition in response to a change in strain.

8. The device of claim 1 , wherein the first and second pores comprise laser-formed pores.

9. A method for exposing a sensor to an environment, comprising:

providing a sensor separated from an environment by a first layer having a first pore and a second layer having a second pore;

positioning the first and second pores substantially out of alignment with each other;

changing an environmental factor, thereby moving the first and second pores into substantial alignment with each other and exposing the sensor to the environment via the first and second pores; and wherein the sensor has a perimeter that forms a fluid tight seal with the substrate.

10. The method of claim 9 , wherein said positioning the first and second pores substantially out of alignment with each other includes positioning the first and second pores completely out of alignment with each other.

11. The method of claim 9 , wherein said changing an environmental factor includes changing the temperature of the first and/or second layers.

12. The method of claim 9 , wherein said changing an environmental factor includes applying a strain to the first and/or second layers.