Needleless syringe and method for delivering therapeutic particles

1. A needleless syringe for delivering therapeutic particles, comprising:

a gas source;

a cannon having a plurality of side openings shaped as slots, the side openings being positioned along a length of the cannon and transverse to a longitudinal axis of the cannon; and

a source of therapeutic particles located between the gas source and an entrance of the cannon;

wherein:

gas released from the gas source flows in the cannon and causes a propagation of the therapeutic particles through the cannon; and

each opening of the plurality of side openings is configured to allow a portion of the gas to be expelled laterally from the cannon, causing a corresponding local reduction of a pressure of the gas in the cannon and causing a corresponding local acceleration of a flow of the gas in the cannon, so that the pressure and a velocity of the gas in the cannon gradually decrease as the gas flows beyond successive ones of the side openings.

2. The needleless syringe as defined in claim 1 , comprising a puncturable membrane for releasably sealing the gas source.

3. The needleless syringe as defined in claim 2 , comprising a gas reservoir, a valve and a driver, wherein opening of the valve releases the gas from the gas reservoir into the driver, a pressure of the gas in the driver causing a puncture of the membrane.

4. The needleless syringe as defined in claim 1 , comprising a tube surrounding the cannon, the tube having an internal diameter sufficient for allowing release of gas from the cannon through the side openings, an end of the tube opposite from the gas source forming an injection site.

5. The needleless syringe as defined in claim 4 , wherein the end of the tube opposite from the gas source extends beyond an extremity of the cannon.

6. The needleless syringe as defined in claim 1 , wherein passage of the flow of the gas along each of the side openings creates a gas expansion fan within the cannon.

7. The needleless syringe as defined in claim 1 , wherein the plurality of side openings comprise one or more groups of slots, each group comprising two or more slots positioned circumferentially at a same axial length of the cannon.

8. The needleless syringe as defined in claim 1 , wherein the plurality of side openings comprises circular slots, the cannon being supported by at least a pair of structural stiffeners connected to the cannon between the circular slots.

9. A method for delivering therapeutic particles to a skin surface, comprising:

providing a gas source;

providing a cannon having a plurality of side openings shaped as slots, the side openings being positioned along a length of the cannon and transverse to a longitudinal axis of the cannon;

placing a source of therapeutic particles between the gas source and an entrance of the cannon; and

releasing gas from the gas source to cause the gas to flow in the cannon and to cause a propagation of the therapeutic particles through the cannon;

wherein each opening of the plurality of side openings allows a portion of the gas to be expelled laterally from the cannon, causing a corresponding local reduction of a pressure of the gas in the cannon and causing a corresponding local acceleration of a flow of the gas in the cannon, so that the pressure and a velocity of the gas in the cannon gradually decrease as the gas flows beyond successive ones of the side openings.

10. The method as defined in claim 9 , wherein the gas is released at a first pressure and wherein the gas exits the cannon at a second pressure lower than the first pressure.

11. Use of the method as defined in claim 9 on a patient's skin.

12. Use of the method as defined in claim 9 in vitro.

13. Use of the method as defined in claim 9 ex vivo.