Methods of manufacture to optimize performance of transdermal sampling and analysis device
Methods and systems for manufacturing a transdermal sampling and analysis device for non-invasively and transdermally obtaining biological samples from a subject and determining levels of analytes of the obtained biological samples are provided. A method of manufacturing the device may improve performance and includes forming channel structures on the lid of the device, thereby making the spacer/channel support structures physically independent and separable from the sensing electrode. Other methods of manufacturing the device may improve performance and include forming at least one of the electrodes on each of the base and the lid, and forming a recessed second spacer layer over the channel support structures, thereby separating the channel support structures and the electrode on the lid to allow a larger area of the electrode to be exposed to the biological sample.
1. A transdermal sampling and analysis device adapted to be placed on skin, the transdermal sampling and analysis device comprising:
a substrate having a first side;
at least one disruptor mounted on the first side of the substrate, wherein the at least one disruptor is configured to generate a localized heat capable of altering permeability characteristics of barrier cells of an organism to become permeable when a voltage is applied across the at least one disruptor;
a reservoir on the first side of the substrate, wherein the reservoir comprises:
a circular collection portion configured to collect a biological sample that is obtained through permeable barrier cells, wherein the circular collection portion is substantially parallel to a plane of the skin; and
a sensing chamber portion configured to receive the biological sample from the circular collection portion, wherein the sensing chamber portion surrounds a periphery of the circular collection portion such that the sensing chamber portion is concentric with the circular collection portion substantially parallel to the plane of the skin;
a lid structure configured to enclose the reservoir;
a biological sensing element comprising at least a first electrode and at least a second electrode, wherein the biological sensing element is configured to determine a level of an analyte in the biological sample;
a first spacer layer disposed on the first side of the substrate; and
a second spacer layer disposed over the first spacer layer,
wherein the sensing chamber portion of the reservoir is configured to contain the biological sample between the at least first electrode and the at least second electrode.
2. The transdermal sampling and analysis device of claim 1 , wherein the first spacer layer comprises a plurality of channel support structures that form a plurality of channels in the sensing chamber portion.
3. The transdermal sampling and analysis device of claim 2 , wherein each of the plurality of channels in the sensing chamber portion comprise a channel height to width ratio of less than 20:1.
4. The transdermal sampling and analysis device of claim 3 , wherein the channel height to width ratio is approximately 3:1.
5. The transdermal sampling and analysis device of claim 3 , wherein the channel height to width ratio is approximately 1:1.
6. The transdermal sampling and analysis device of claim 3 , wherein the channel height is between 80 and 500 μm.
7. The transdermal sensing and analysis device of claim 2 , wherein the sensing chamber portion comprises a circular sensing chamber.
8. The transdermal sensing and analysis device of claim 2 , wherein the second spacer layer is further configured to be recessed back from an edge of at least one of the plurality of the channel support structures of the first spacer layer.
9. The transdermal sampling and analysis device of claim 1 , wherein the second spacer layer comprises a double-sided adhesive material that is pre-cut to form a shape recessed back from an edge of the first spacer layer.
10. The transdermal sampling and analysis device of claim 1 , further comprising:
an adhesive layer on a top surface of the second spacer layer, wherein the adhesive layer is configured to adhere the lid structure to the second spacer layer.
11. The transdermal sampling and analysis device of claim 1 , wherein a thickness of the first spacer layer is approximately equal to a thickness of the second spacer layer, wherein each of the first and second spacer layers are approximately 10-20 μm thick.
12. The transdermal sensing and analysis device of claim 1 , wherein one or more of the first spacer layer and second spacer layer comprise a photoresist material.
13. The transdermal sensing and analysis device of claim 12 , wherein the first spacer layer comprises a first photoresist material and the second spacer layer comprises a second photoresist material.