Miniaturized thermal system formed with semiconductor material with medical applications
In a first embodiment, a portable, battery-operated, minimally invasive small fiber neuropathy testing and diagnostic device, microcontrolled and interfacing with wireless powering to a wireless communications device is being disclosed. Said device is constructed out of an intra-epidermal thermal stimulus consisting of an electronically heated temperature-controlled polymer covered semiconductor material 101 lowered inside the skin through a probe 108 configured with three miniaturized electrodes 109 while a nerve impulse response measurement system records and identifies nerve action potential pulses through a proprietary algorithm. The invention also discloses a detection and characterization method of action potential pulses from neuron cells with respect to their timing such as pulse repetition statistics and rates from a single-point of measurement as diagnostically relevant for determining neuropathies. In an alternate embodiment, a medical device is constructed for biological tissue treatment for achieving a collagen denaturing effect or thermal tissue ablation.
1. A probe for assessing nerve function in small-fiber nerve nociceptors in a patient's epidermis, the probe comprising:
a probe body having a tip, the tip having a size and shape for insertion intra-epidermally into the patient's skin;
an electrical power source;
a heat source electrically coupled to the electrical power source and disposed at the tip of the probe so as to conduct thermal energy into an intra-epidermal region of the patient's skin, the heat source electrically insulated so as to isolate the patient from the power source;
at least one electrode disposed at the probe tip; and
the at least one electrode disposed so as to detect action potential pulses generated by small-fiber nerves in response to being heated by the heat source.
2. The probe for assessing nerve function in small-fiber nerve nociceptors in a patient's epidermis of claim 1 , wherein the heat source comprises a thermistor.
3. The probe for assessing nerve function in small-fiber nerve nociceptors in a patient's epidermis of claim 1 , wherein the heat source has a negative temperature coefficient.
4. The probe for assessing nerve function in small-fiber nerve nociceptors in a patient's epidermis of claim 1 , wherein the heat source comprises an indium antimonide heating element.
5. The probe for assessing nerve function in small-fiber nerve nociceptors in a patient's epidermis of claim 1 , wherein the heat source comprises a heating element and at least one magnet disposed to apply a magnetic field to the heating element.
6. The probe for assessing nerve function in small-fiber nerve nociceptors in a patient's epidermis of claim 1 , wherein the heat source comprises a heating element enclosed in an insulator coating.
7. The probe for assessing nerve function in small-fiber nerve nociceptors in a patient's epidermis of claim 1 , wherein the tip is disposable.
8. The probe for assessing nerve function in small-fiber nerve nociceptors in a patient's epidermis of claim 1 , further comprising:
a temperature sensor disposed in the probe adjacent to the heat source so as to sense the temperature of the heat source; and
a feedback circuit in electrical communication with the temperature sensor and a heater control circuit, the heater control circuit in electrical communication with the heat source so as to control the temperature of the heat source.
9. The probe for assessing nerve function in small-fiber nerve nociceptors in a patient's epidermis of claim 8 , wherein the heater control circuit comprises:
a voltage regulator having a power input, a power output, and a feedback input, the power output electrically coupled to the heat source;
a power source coupled to the regulator power input;
a feedback element electrically coupled between the regulator output and the regulator feedback input and defining a feedback node;
an resistor coupled between the regulator feedback input and ground;
an active circuit electrically coupled between the regulator feedback node and ground; and
a control input coupled to the active circuit, the active control circuit controllable drawing feedback current from the feedback node in response to a signal on the control input.
10. The probe for assessing nerve function in small-fiber nerve nociceptors in a patient's epidermis of claim 1 , wherein the power source is a DC power source.
11. The probe for assessing nerve function in small-fiber nerve nociceptors in a patient's epidermis of claim 10 , where the power source is a battery.
12. A system for assessing small fiber neuropathy in a patient, comprising:
a probe having a tip comprising a heat source and at least one sensing electrode, the tip configured to penetrate the patient's skin;
a sampling circuit electrically coupled to the sensing electrode and configured to acquire a plurality of samples of electrical output from the at least one sensing electrode; and
a sample processing circuit to detect a plurality of action potential pulses from the sensing electrode samples, and then to determine a time relationship between two of the action potential pulses from among the plurality of action potential pulses.
13. The system for assessing small fiber neuropathy in a patient of claim 12 , wherein the at least one sensing electrode comprises a plurality of sensing electrodes disposed so as to encircle the heat source.
14. The system for assessing small fiber neuropathy in a patient of claim 12 , further comprising a control circuit having a controllable voltage source electrically coupled to the heat source and configured to heat the heat source to a temperature of at least 40 degrees Celsius and less than 46 degrees Celsius.
15. The system for assessing small fiber neuropathy in a patient of claim 12 , wherein the sampling circuit further comprises a digital-to-analog converter electrically coupled to the at least one sensing electrode to digitally sample the electrical output from the at least one sensing electrode.