Fluid Sampling Device
In some implementations of this disclosure, a fluid sampling device includes an outer housing formed as a capsule, i.e., configured for swallowing by a patient, such as a mammalian patient. In such implementations, the fluid sampling device may be configured to sample fluids in the GI tract. In other embodiments, fluid sampling devices according to this disclosure may configured for insertion into a bodily cavity, or may be implanted or otherwise placed in the body
1 . A device for sampling contents in a cavity, the device comprising:
an outer housing comprising a sidewall extending between a first end and a second end spaced along an axis from the first end and an opening extending through the sidewall proximate the second end;
a sampling reservoir comprising a rigid housing defining a volume and a re-sealable portion, the sampling reservoir being disposed in the outer housing and moveable within the first housing, generally along the axis, between a sealed position, relatively closer to the first end of the outer housing, and a sampling position, relatively closer to the second end of the outer housing;
a biasing member disposed in the outer housing proximate the second end of the housing and configured to apply a biasing force to the sampling reservoir to bias the sampling reservoir toward the sealed position;
a gas generating cell disposed in the outer housing proximate the first end of the outer housing and configured to generate gas at an actuating rate sufficient to move the sampling reservoir from the sealed position to the sampling position, against the biasing force;
a sensor disposed to sense a condition of an environment external to the outer housing, the sensor being electrically connected to the gas generating cell to selectively control the gas generating cell to generate the gas; and
a hollow needle fixed relative to the outer housing and in fluid communication with the opening extending through the sidewall,
wherein the re-sealable portion of the sampling reservoir is pierced by the hollow needle when the sampling reservoir is in the sampling position and the re-sealable portion of the sampling reservoir is spaced from the piercing member when the sampling reservoir is in the sealed position.
2 . The device of claim 1 , further comprising an exhaust in the outer housing proximate the gas generating cell.
3 . The device of claim 2 , wherein the exhaust comprises a gas permeable membrane having a gas permeability that allows gas to flow through the gas permeable membrane at a rate lower than that actuating rate at which the gas generating cell generates gas.
4 . The device of claim 1 , wherein the sensor comprises a pH sensitive material that causes a signal at the sensor when a pH of the environment exceeds a threshold pH.
5 . The device of claim 1 , wherein the biasing member comprises a spring or a compressible material, the spring or the compressible material extending from an inner surface of the outer housing a distance greater than a distance the hollow needle extends from the inner surface of the outer housing when the sampling reservoir is in the sealed position and the spring or the compressible material being compressible to reduce the distance the compressible material extends from the inner surface of the outer housing so the distance the hollow needle extends from the inner surface is greater than the distance the compressible material extends from the inner surface of the outer housing when the reservoir is in the sampling position.
6 . A device for sampling contents in a cavity, the device comprising:
an outer housing comprising a sidewall extending between a first end and a second end spaced along an axis from the first end and an opening extending through the sidewall proximate the second end;
a sampling reservoir comprising a rigid housing defining a volume and a re-sealable portion, the sampling reservoir being disposed in the outer housing and moveable within the first housing, generally along the axis, between a sealed position, relatively closer to the first end of the outer housing, and a sampling position, relatively closer to the second end of the outer housing;
a biasing member disposed in the outer housing proximate the second end of the housing and configured to apply a biasing force to the sampling reservoir to bias the sampling reservoir toward the sealed position;
an actuator disposed in the outer housing proximate the first end of the outer housing and configured to move the sampling reservoir from the sealed position to the sampling position, against the biasing force; and
a piercing member disposed in the outer housing in fluid communication with the opening extending through the sidewall,
wherein the re-sealable portion of the sampling reservoir is pierced by the piercing member when the sampling reservoir is in the sampling position and the re-sealable portion of the sampling reservoir is spaced from the piercing member when the sampling reservoir is in the sealed position.
7 . The device of claim 6 , wherein the actuator comprises a gas generating cell and a gas generated by the gas generating cell moves the sampling reservoir from the sealed position to the sampling position.
8 . The device of claim 7 , further comprising a vent in the outer housing proximate the gas generating cell.
9 . The device of claim 8 , wherein the vent comprises a gas permeable membrane having a gas permeability lower than a rate at which the gas generating cell generates gas.
10 . The device of claim 6 , further comprising a sensor disposed to sense a condition of an environment external to the outer housing.
11 . The device of claim 10 , wherein the sensor comprises a threshold sensor responsive to a threshold pH of the environment.
12 . The device of claim 6 , further comprising a quencher disposed in the sampling reservoir.
13 . The device of claim 6 , wherein the biasing member comprises a spring or a compressible material.
14 . The device of claim 6 , wherein the piercing member comprises a hollow needle and further comprising a channel fluidly connecting the hollow needle to the opening.
15 . The device of claim 6 , wherein the actuator comprises a spring.
16 . The device of claim 15 , wherein the spring is retained in a compressed position by a supporting wire and the supporting wire is broken to release the spring to move the sampling reservoir to the sampling position.
17 . A device for sampling contents in a cavity, the device comprising:
an outer housing comprising a sidewall extending between a first end and a second end spaced along an axis from the first end and an opening extending through the sidewall to fluidly connect an interior of the outer housing with an exterior of the outer housing;
a sampling reservoir defining a volume disposed in the outer housing and moveable relative to the outer housing, between a sealed position and a sampling position, wherein, in the sampling position, fluids from an environment external to the outer housing enter the sampling reservoir through the outer housing; and
an actuator disposed in the outer housing proximate the first end of the outer housing and configured to move the sampling reservoir from the sealed position to the sampling position.
18 . The device of claim 17 , further comprising a hollow needle disposed in the outer housing and in fluid communication with the opening, wherein:
the sampling reservoir comprises a re-sealable portion, and
the actuator moves the sampling reservoir into contact with the hollow needle such that the hollow needle pierces the re-sealable portion, forming fluid communication via the hollow needle and the opening, between the volume and the exterior of the outer housing.
19 . The device of claim 17 , wherein:
the opening is formed through a portion of the sidewall,
the sampling reservoir comprises a rigid, cylindrical housing, a fin extending radially outwardly from an outer surface of the cylindrical housing, and a reservoir opening formed in a sidewall of the cylindrical housing,
the actuator comprises a gas generating cell, and
gas generated by the gas generating cell contacts the fin to rotate the sampling reservoir relative to the outer housing between the sealed position, in which the opening extending through the sidewall of the outer housing is rotationally spaced from the reservoir opening, and the sampling position, in which the opening extending through the sidewall of the outer housing aligns with the reservoir opening.
20 . The device of claim 17 , wherein:
the outer housing further comprises a vent formed therein, proximate the actuator,
the sampling reservoir comprises an expandable bag in fluid communication with the opening,
the actuator comprises a piezo pump spaced from the expandable bag,
the piezo pump pumps air in the outer housing between the expandable bag and the piezo pump, outside the expandable bag, out of the outer housing via the vent,
the expandable bag expands in response to the piezo pump pumping the air out of the outer housing, and
expansion of the expandable bag draws fluids external to the outer housing into the expandable bag through the opening.