Chemical heating system for diagnostic devices

Abstract

The present invention relates to a chemical heating system for molecular diagnostic tests, comprising an air-activatable chemical heating composition, and a water-activatable chemical heating composition.

Claims

1. A device comprising: a diagnostic platform, and a chemical heating system comprising: both an air-activatable chemical heating composition which comprises a transition metal powder, and a water-activatable chemical heating composition which comprises a component which is selected from an alkaline earth metal oxide, an alkaline earth metal alloy, an alkali metal oxide, and an alkali metal alloy.

2. The device according to claim 1, wherein the alkaline earth metal oxide is calcium oxide, or magnesium oxide or a mixture thereof; or wherein the alkaline earth metal alloy is a magnesium-based alloy comprising at least one alloying element which is selected from Fe, Co, Cu, Ni, Zn, or Al or a combination of at least two of these alloying elements.

3. The device according to claim 1, wherein the transition metal is iron or zinc.

4. The device according to claim 1, wherein the air-activatable chemical heating composition further comprises one or more solid additives which are selected from the group consisting of carbon, an inorganic salt, a silicate mineral, and a combination of at least two of these solid additives.

5. The device according to claim 1, wherein the water-activatable chemical heating composition comprises an alkaline earth metal oxide, and the air-activatable chemical heating composition and the water-activatable chemical heating composition are not in direct contact with each other.

6. The device according to claim 1, wherein the water-activatable chemical heating composition comprises an alkaline earth metal alloy, and the air-activatable chemical heating composition and the water-activatable chemical heating composition are in direct contact with each other in the form of a powder blend.

7. The device according to claim 1, wherein no phase change material is present.

8. The device according to claim 1, wherein the diagnostic platform is a platform for molecular diagnostic testing, enzymatic testing, or immunological testing.

9. The device according to claim 1, being free of any electrical heating elements and electronic temperature control means.

10. The device according to claim 1, wherein the chemical heating system is positioned in a casing and the molecular diagnostic platform is fixed to the casing.

11. The device according to claim 10, wherein the casing has one or more inlets by which air and optionally water can enter the casing.

Description

(1) The invention is described in further detail by the following Examples:

EXAMPLE 1

(2) A blend of iron powder (4.5 g), activated carbon (1.7 g) and sodium chloride (0.9 g), representing the air-activatable chemical heating composition, is provided in a plastic casing. Calcium oxide (2.0 g), representing the water-activatable chemical heating composition, is shrink-wrapped in a water-soluble foil which is then also provided in said plastic casing.

(3) The casing topside contains several openings by which air and water can enter the casing.

(4) A molecular diagnostic platform is fixed to the plastic casing.

(5) The device is vacuum-packed so that no air can enter the casing which contains the chemical heating system. By removing the vacuum package, air enters the casing. Then, water (4 ml) is added for activating the water-activatable composition and promoting the oxidation of the metal powder in the air-activatable composition.

(6) The water-soluble foil is at least partly dissolved and an exothermic reaction between CaO and water is initiated. Furthermore, the water is promoting the exothermic redox reaction between the metal powder and the atmospheric oxygen. The reaction heat is transferred to the molecular diagnostic platform fixed to the casing wall.

(7) Temperature at the platform as a function of time is measured. The temperature curve is shown in FIG. 1.

(8) As demonstrated by the measured curve, there is an extremely sharp increase of temperature to about 61° C. and said temperature is maintained within a relatively narrow range for more than 40 minutes. Under these temperature conditions, a loop-mediated isothermal amplification (LAMP) can be carried out. No phase change material is needed.

(9) By varying the amounts of the water-activatable and air-activatable compositions, the temperature to which the diagnostic platform is heated up can be adjusted, depending on the type of isothermal diagnostic test to be carried out.

EXAMPLE 2

(10) The air-activatable heating composition was a mixture of iron powder, activated carbon, and sodium chloride. The water-activatable composition was a magnesium-iron alloy (Fe content: 13 at %).

(11) The air-activatable and water-activatable heating compositions were mixed, thereby obtaining a final blend containing iron powder (4.2 g), activated carbon (2.4 g), sodium chloride (0.9 g) and the magnesium-iron alloy (0.2 g).

(12) The blend was positioned in the same plastic casing as used in Example 1. A molecular diagnostic platform is fixed to the plastic casing.

(13) By removing the vacuum package, air enters the casing. Then, water was added (3 ml). An exothermic reaction between magnesium and water is initiated. Furthermore, the water is promoting the exothermic reaction between the iron powder and the atmospheric oxygen. The reaction heat is transferred to the molecular diagnostic platform fixed to the exterior of the casing.

(14) Similar to Example 1, temperature at the molecular diagnostic platform was increasing to a value of about 65° C. within a short period of time and said temperature was maintained within a relatively narrow range for at least 15 minutes. Under these temperature conditions, a loop-mediated isothermal amplification (LAMP) can be carried out. No phase change material is needed.

(15) By varying the amounts of the water-activatable and air-activatable compositions, the temperature to which the diagnostic platform is heated up can be adjusted, depending on the type of isothermal diagnostic test to be carried out.