WO2010088259A1

WO2010088259A1 - Syringe actuator

Info

Publication number: WO2010088259A1
Application number: PCT/US2010/022209
Authority: WO
Inventors: Bart Borghuis; Fred Letterio; Jean Bennett
Original assignee: The Trustees Of The University Of Pennsylvania
Priority date: 2009-01-27
Filing date: 2010-01-27
Publication date: 2010-08-05

Abstract

A syringe having a bore and a plunger therein, comprising a first biasing element for biasing the plunger, a shaft extending along the outside of the syringe, wherein the shaft has a proximal end, a distal end, and a pivot therebetween, wherein the pivot is adapted for attaching to the syringe, a stopping element operably coupled to the distal end of the shaft for engaging with the plunger, and a second biasing element operably coupled to the shaft for biasing the stopping element toward the plunger, wherein upon the proximal end of the shaft, pivots with respect to the distal end, the stopping element disengages from the plunger, thereby allowing the plunger to move within the bore by the force of the first biasing element.

Description

SYRINGE ACTUATOR

CROSS REFERENCE TO RELATED APPLICATIONS

[001] This application claims priority to United States Provisional Patent Application 61/147,509, filed January 27, 2009, which is incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

[002] The present invention generally relates to a syringe controlled with one hand from the needle or dispensing end thereof. Specifically, the invention relates to means for actuating a long syringe with one hand.

BACKGROUND OF THE INVENTION [003] Reference is made to Fig. 1, which is a side view drawing of a Hamilton syringe 2. The syringe 2 shown is a Hamilton Company syringe purchased from Fisher Scientific. This syringe may be used for precision fluid measuring in the life sciences and medical research fields. [004] Operating the syringe 2 for releasing material requires two hands, one hand to apply a force against the plunger 4 at the distal end of the syringe for dispensing material and one hand for stabilizing the syringe at the proximal end 6 thereof for a targeted release of the material. This limitation may prevent the free use of one hand in procedures, for example, to manipulate and stabilize the injected tissue, vial or specimen.

[005] In general, there are two classes of syringe systems: manual and pump-driven. Manual syringes, such as the constant rate syringe from the Hamilton Company, have a spring driven plunger that is released by pressing a latch (not shown) at the plunger or distal end of the syringe. The Hamilton Company also sells the PB600 repeating dispenser manual syringe, having a button at the plunger-end of the syringe for advancing the plunger by a small, preset amount. These manual syringes are controlled for dispensing by one hand at the distal end of the syringe and thus, require a second hand for stabilizing the syringe 2 at the proximal end thereof. Examples of pump-driven syringes include the EDOS 5222 (EPPENDORF™), the UltraMicroPump II (WORLD PRECISION INSTRUMENTS™), and the Nanoject II (HARVARD APPARATUS™). These pump-driven syringes are designed for injecting nanoliter volumes into e.g. stemcells and oocyte expression systems and use glass micropipettes. They are electrically powered and in some cases controlled by microprocessors. For one-handed injection, pump-driven syringes typically use a foot pedal control. However, these syringes still require an additional appendage to one hand (in this case a foot) for operation. [006] Accordingly, a need exists for a syringe operable using one hand.

SUMMARY OF THE INVENTION

[007] In one embodiment, the invention provides a syringe having an axial bore and a plunger disposed therein, comprising: a first biasing element for biasing said plunger; a shaft extending along the outside of the syringe, wherein said shaft has a proximal end, a distal end, and a pivot point disposed therebetween, wherein said pivot point is adapted for attaching to the syringe; a stopping element operably coupled to said distal end of said shaft for engaging with the plunger; and a second biasing element operably coupled to said shaft for biasing said stopping element toward said plunger, whereupon pivoting said proximal end of said shaft with respect to said distal end, said stopping element disengages from the plunger, thereby allowing the plunger to move within the bore by the force of said first biasing element.

[008] In another embodiment, the invention provides an actuator adapted for attaching onto a syringe, wherein the syringe has an axial bore and a plunger disposed therein, comprising: a shaft having a proximal end, a distal end, and a pivot point disposed therebetween, wherein said pivot point is adapted for attaching to the syringe; a stopping element operably coupled to said distal end of said shaft for engaging with the plunger; and a biasing element operably coupled to said shaft, whereupon pivoting of said proximal end of said shaft with respect to said distal end, said stopping element disengages from the plunger thereby allowing the plunger to move within the bore. [009] In one embodiment, the invention provides a method for dispensing a liquid from a syringe with one hand, comprising the steps of: using a syringe operably coupled to an actuator, said syringe comprising: an actuator adapted for attaching to the syringe, wherein the syringe having an axial bore and a plunger therein, comprising: a shaft having a proximal end, a distal end, and a pivot point disposed therebetween, wherein the pivot point is adapted for attaching to the syringe; a stopping element operably coupled to the distal end of the shaft for engaging with the plunger; and a biasing element operably coupled to the shaft for moving the stopping element toward the plunger, drawing a liquid by moving the plunger against the biasing element; pivoting the proximal end of the shaft with respect to the distal end; and disengaging said stopping element from the plunger, thereby allowing the plunger to move within the bore by the force of the biasing element thereby dispensing the liquid using one hand.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Various embodiments of the present invention are illustrated in the following drawings, which are meant to be exemplary only and are not limiting on the scope of the present invention, and in which [0011] Fig. 1 is a side view drawing of a conventional Hamilton syringe;

[0012] Fig. 2 is a side view drawing of a syringe in accordance with one embodiment of the present invention;

[0013] Fig. 3 is a picture of a prototype of the syringe of Fig. 2, in accordance with one embodiment of the present invention; [0014] Fig. 4 is a side view drawing of a stopping mechanism for the graded expansion and contraction, respectfully, of a container portion of the syringe of Fig. 2, in accordance with one embodiment of the present invention;

[0015] Fig. 5 is a side view drawing of a syringe in accordance with one embodiment of the present invention; [0016] Fig. 6 is a side view drawing of a syringe in accordance with one embodiment of the present invention;

[0017] Fig. 7 is a picture of a prototype of a syringe of Figures 5 or 6 in accordance with one embodiment of the present invention; and

[0018] Fig. 8 is a picture of a prototype of a syringe of Figures 5 or 6 in accordance with one embodiment of the present invention.

[0019] It will be appreciated that for simplicity and clarity of illustration, elements shown in the drawings have not necessarily been drawn accurately or to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity or several physical components included in one functional block or element. Further, where considered appropriate, reference numerals may be repeated among the drawings to indicate corresponding or analogous elements. Moreover, some of the blocks depicted in the drawings may be combined into a single function.

DESCRIPTION OF THE PREFERRED EMBODIMENT [0020] In the following description, various aspects of the present invention will be described. For purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the present invention. However, it will also be apparent to one skilled in the art that the present invention may be practiced without the specific details presented herein. Furthermore, well known features may be omitted or simplified in order not to obscure the present invention.

[0021] Reference is made to Fig. 2, which is a side view drawing of a syringe 8 in accordance with one embodiment of the present invention. Syringe 8 may comprise structures, possibly separable, for example, a bore 12 and a plunger 10, connected by a first biasing element 14. The first biasing element 14 (e.g., a coil or spring) may bias the plunger. In some embodiments, the first biasing element 14 is a coil or spring (e.g., compressed spring) disposed inside the body of syringe 8. In other embodiments, the first biasing element 14 is a coil or spring (e.g., compressed spring) disposed outside the body of syringe 8.

[0022] Syringe 8 may comprise an actuator comprising a shaft 16 extending along the outside of the syringe 8 and a stopping element 24 operably coupled to the distal end 20 of the shaft 16 for engaging with the plunger 10. The shaft 16 may have a proximal end 18, a distal end 20, and a pivot 22 therebetween. The pivot 22 may be adapted for attaching to the syringe 8. Syringe 8 may comprise a second biasing element 26 operably coupled to shaft 16 for biasing the stopping means 24 from moving toward the plunger 10. In some embodiments, the second biasing element 26 is operably coupled to shaft 16 by being disposed on lower side of shaft 16. In other embodiments, the second biasing element 26 is operably coupled to shaft 16 by being disposed on upper side of shaft 16. In one embodiment, the second biasing element 26 is coupled to pivot 22. In one embodiment, when the proximal end 18 of the shaft 16 pivots with respect to the distal end 20 of the shaft 16, the stopping element 24 disengages from the plunger 10, thereby allowing the plunger 10 to move within the bore 12 by the force of the first biasing element 14. The syringe may comprise a container portion 32 for holding and dispending material. [0023] Accordingly and in one embodiment, provided herein is a syringe 8, an actuator adapted for attaching to a syringe, a syringe system, and a method for the operation thereof comprising a bore 12 and a plunger 10 therein, comprising a first biasing element 14 for biasing the plunger 10, a shaft 16 extending along the outside of the syringe, wherein the shaft 16 has a proximal end 18, a distal end 20, and a pivot 22 therebetween, wherein the pivot 22 is adapted for attaching to the syringe 8, a stopping element 24 operably coupled to the distal end 20 of the shaft 16 for engaging with the plunger 10, and a second biasing element 26 operably coupled to the shaft 16 for biasing the stopping means toward the plunger 10, wherein upon the proximal end 18 of the shaft 16, pivots with respect to the distal end 20, the stopping element 24 disengages from the plunger 10, thereby allowing the plunger 10 to move within the bore 12 by the force of the first biasing element 14.

[0024] The syringe 8 may comprise inner walls (not shown) mating with the plunger 10 for creating a inflation or suction in the container portion 32 when the plunger 10 is moved towards and away from the body of the syringe 8, respectively. The syringe 8 may provide a controlled release of a spring loaded plunger 10 from the needle or proximal end thereof. [0025] Movement of the plunger 10 may be controlled by friction at a point 40 between a shaft 36 of the plunger 10 and the stopping element 24. The stopping element 24 may connect the shaft 36 of the plunger 10 to the shaft 16. The first biasing element 14 may force the stopping element 24 against the shaft 36 of the plunger 10, for example, by a coil spring mechanism through along the inner walls of the body of the syringe 8. The shaft 16 may be rotated by pushing down on the proximal end 18 thereof. The shaft 16 may rotate about an axis fixed relative to the body, releasing the stopping means 24 and thus releasing the plunger 10. The force exerted by the first biasing element 14 on the plunger 10 may then move the plunger 10 toward the proximal end direction of syringe 8. This movement may narrow the container portion 32 and any material contained thereby may be dispended. [0026] In one embodiment, there may be a balance of forces for mediating the syringe 8 intaking and dispensing material. For example, arrows in Fig. 2 may indicate first and second biasing force directions (1, 3, respectively) and the release force direction (5). In one example, there may be a force (1) exerted by the first biasing element 14 toward the proximal end direction of syringe 8 and a force (3) exerted by the second biasing element 14 perpendicular to force (1) and toward syringe 8. Each of these forces may be countered by a relatively stronger opposing force of the stopping element 24 (e.g., friction at point 40 or a latching by notched grooves 28 described hereinbelow). When the stopping element 24 is released, the force provided thereby no longer opposes biasing forces (1 and 3). Thus, the biasing forces propel the plunger 10, towards the proximal or needle end of the syringe 8 for dispensing material contained therein. [0027] In one embodiment, an actuator may be adapted for attaching to the syringe 8. The syringe 8 has a bore 12 and a plunger therein 10. The actuator comprises a shaft 16 having a proximal end 18, a distal end 20, and a pivot 22 therebetween. The pivot 22 may be adapted for attaching to the syringe 8. The actuator comprises a stopping means 24 operably coupled to the distal end 20 of the shaft 16 for engaging with the plunger 10. The actuator comprises a biasing element 14 operably coupled to the shaft 16 for moving the stopping means 24 toward the plunger 10. When the proximal end 18 of the shaft 16 pivots with respect to the distal end 20, the stopping means 24 disengages from the plunger 10 thereby allowing the plunger 10 to move within the bore 12. [0028] A person skilled in the art will recognize that the actuators described herein, which in certain embodiments are used in the methods provided may be operable when more than a single actuator is attached to the syringe. Accordingly and in another embodiment the syringe 8 has an axial bore 12 and a plunger disposed therein 10, the plunger 10 is adapted to engage a third biasing element. In another embodiment, an actuator comprises a shaft 16 having a proximal end 18, a distal end 20, and a pivot 22 therebetween. The pivot 22 operably linked to the syringe 8. The actuator comprises a stopping element 24 operably coupled to the distal end 20 of the shaft 16 for engaging with the plunger 10. The actuator comprises a third biasing element on the plunger 10 for moving the stopping element 24 toward the plunger 10. When the proximal end 18 of the shaft 16 pivots with respect to the distal end 20, the stopping element 24 disengages from the plunger 10 thereby allowing the plunger 10 to move within the bore 12 and wherein the third biasing element affect movement of the plunger in an opposite direction to the first biasing element 14. In certain embodiments, the operation of each actuator is independent, such that operating one actuator results in expelling of the bore 12 content, while operating another actuator results in filling of the bore 12. [0029] Reference is made to Fig. 3, which is a picture of a prototype of the syringe of Fig. 2, in accordance with one embodiment of the present invention. [0030] Figures 5 and 6 illustrate syringe 8 in accordance with one embodiment of the present invention. In some embodiments, the elements of syringe 8 are connected to one another by connecting mechanisms 21, 23 (e.g., screw, washer, etc.). Any connecting mechanism known to one of skilled in the art may be used to connect the elements of syringe 8. In some embodiments, as shown in Fig. 6, the shaft 16 may comprise logo 25. Figures 7 and 8 show a prototype of a syringe illustrated in Figures 5 and 6, in accordance with one embodiment of the present invention. [0031] Reference is made to Fig. 4, which is side view drawing of a stopping mechanism for the graded expansion and contraction, respectfully, of a container portion of the syringe of Fig. 2, in accordance with one embodiment of the present invention. In each of Fig. 4, the syringe 8 may comprise an actuator comprising a shaft 16 extending along the outside of the syringe 8 and a stopping element 24 operably coupled to the shaft 16 for engaging with the plunger 10. According to an exemplary embodiment of the invention, the plunger 10 may comprise notched grooves or ridges 28 in contact with the stopping element 24.

[0032] When a force is applied to the proximal end 18 of the shaft 16 toward the syringe 8, the stopping element 24 is forced against the notched grooves 28. The notched grooves 28 may comprise a stop, latch, or hook that may prevent the relative movement of the plunger 10 in a specific direction (e.g., toward the proximal end and distal end of the syringe 8, in Fig. 4). Thus, material may be securely held or released, as shown in Figs. 4.

[0033] In one embodiment, the stopping element 24 may be disengaged by the first biasing element 14 providing a counter force that overwhelms the holding force of the notched grooves 28, or by a release mechanism (not shown). [0034] In Fig. 4, when a force is applied, the stopping element 24 moves across the notched grooves 28, providing a graded motion, which may be used for indexing the expansion of a container portion of the syringe 8 for measuring the amount of material taken in. [0035] In another embodiment, the notched grooves 28 may be disposed in a mirrored configuration to that shown in Fig. 4. In such embodiments, when a force is applied, the stopping element 24 moves across the notched grooves 28, providing a graded motion, which may be used for indexing the contraction of a container portion of the syringe 8 for measuring the amount of material dispensed or intaken.

[0036] When a force is applied to the first biasing element 14 for moving the plunger 10 away from the body of the syringe 8, the stopping element 24 moves across the notched grooves 28. In one embodiment, the distance 30, denoted by, d, between the notched grooves 28 may be proportional to the volume of container portion 32 of the same length. For example, if the container portion 32 is shaped as a cylinder with a radius, r, the volume of the container portion 32 is πr²d . Thus, when the plunger 10 moves across the distance 30 (e.g., for dispensing or intaking material), the volume of the container portion 32 changes proportionally (e.g., with a proportionality constant of m² in the example above). Thus, in certain embodiments the user may index the amount or volume of material dispensing or intaking (e.g., the change in volume of the container portion 32) by the number of notched grooves 28 across which the plunger 10 moves. In one embodiment, indicators or marks (not shown) may be disposed on the surface of the syringe 8 body indicating the placement of the notched grooves 28 for a user to visualize the notched grooves 28. [0037] In one embodiment, the movement of the stopping element 24 forced across the notched grooves 28 may provide a sound, such as, a click or tap or a change in force felt by the hand caused by a jump or bounce of the stopping element 24 across the notched grooves 28. For example, an administrator may index the plunger distance, the volume of the container portion 32 (e.g., proportional thereto), and thus, and amount of material being dispensed or intaken by counting clicks or feeling the jump of the stopping element 24 across the notched grooves 28. The material may be injected at once or in steps, for example, instantaneous or gradually.

[0038] In another embodiment, the syringe 8 may comprise a dispensing or uptake counter (not shown) for automatically keeping track of the index, volume, or other measures of the amount of material dispensed or taken in by the syringe 8 and /or the position of the plunger 10 or size of the container portion 32.

[0039] The syringe 8 may be used to dispense or intake a predetermined, measured, or calibrated volume of material. In one embodiment, for each amount dispensed or taken in, the plunger 10 may move a predetermined or calibrated distance (e.g. proportional to the desired volume of material for dispensing or intaking). In one embodiment, dispensing or intaking a measured volume of material may comprise an administrator counting a number of sounds (e.g., clicks) or feelings (e.g., the jumps of the stopping element 24 moving across the notched grooves 28) to measure the volume. In another embodiment, the syringe 8 may comprise a stopper (not shown) positioned between the shaft 16 and the syringe 8. The stopper may be spaced a predetermined distance from the shaft 16 for stopping the shaft 16 from pivoting towards the syringe 8 after the predetermined space. This may limit the syringe 8 to dispense or intake the predetermined amount of material. The stopper may be advanced (e.g., automatically of manually) after each amount dispensed or intaken for recalibrating the predetermined amount of material to be dispensed or intaken. [0040] The syringe 8 may comprise various materials or layers of material. For example, the container portion 32 may be composed of a plastic, glass, or other material that is preferably transparent and rigid. The rod 12, the plunger 10, the shaft 16, the plunger shaft 36, and may be composed of a metal (e.g., surgical steel) or other material that is substantially rigid for moving the plunger 10, for example, by force. The syringe 8 may comprise a textured surface for increase the friction for gripping the syringe 8. The textured surface may preferably comprise areas adapted for handling by a user, such as the proximal end 18 of the shaft 16 and the proximal end of the syringe 8.

[0041] For providing sufficient friction and smooth relative motion between rod 12 and plunger shaft 36, the plunger shaft 36, may be 'roughened up' with fine grain metal sandpaper and lubricated, for example, with machine oil. [0042] Container portion 32 may comprise one or more measuring scale(s) 34. An embodiment of the measuring scale 34 is shown in Figs. 1-3. The measuring scale 34 may be for example a volumetric scale useful for determining the quantity of material within container portion 32. The measuring scale 34 may be a liquid scale with labels such as nanoliters (nL), microliters (// L), milliliter (mL) or the like. Other measurement scales or devices may be used. [0043] Since the actuating member of the syringe 8 is controlled near the proximal end thereof, the same single hand (e.g., positioned at the proximal end) may be used for administering (e.g., controlling or dispensing material) and stabilizing the syringe 8. Thus, the other hand may be used for other tasks, such as, manipulating the tissue or anatomical structures to be injected. [0044] In another embodiment, provided herein is a method for dispensing a liquid from a syringe 8, single handedly, whereby the syringe comprises an actuator adapted for attaching to a syringe, wherein the syringe 8 has a bore 12 and a plunger 10 therein, comprising a shaft 16 having a proximal end 18, a distal end 20, and a pivot 22 therebetween, wherein the pivot 22 is adapted for attaching to the syringe 8, a stopping element 24 operably coupled to the distal end 20 of the shaft 16 for engaging with the plunger 10, and a first biasing element 14 operably coupled to the shaft 16 for moving the stopping means 24 toward the plunger 10, comprising the steps of: Drawing a liquid by moving the plunger 10 against the first biasing means 14; pivoting the proximal end of the shaft 16 with respect to the distal end 20; and disengaging said stopping element 24 from the plunger 10, thereby allowing the plunger 10 to move within the bore 12 by the force of the first biasing element 14 thereby dispensing the liquid. [0045] The syringe 8 may be a modified version of the Hamilton Company syringe 2 described in reference to Fig. 1. Other syringes may be used. The syringe 8 may be used for procedures in fields, such as, life sciences and medical research that require precise injection of small volumes (e.g., 0.1 - 25 μ L), e.g. microsurgic procedures in humans and animals. For example, the syringe 8 may be used in the field of gene therapy where typically 0.5 - 5 μ L of virus-containing solutions are injected into the eye or brain.

[0046] The syringe 8 is the only manually-driven syringe for one-handed injecting. Compared with pump-driven syringes, the syringe 8 is a relatively high-performance, low-cost (e.g., less than 1/lOth of the cost; at $80 excluding labor) precision microinjection instrument. Compared with pump- driven syringes that use glass micropipette (e.g., which are typically undesirable for visually guided medical applications), the syringe 8 may use a standardized gauge, commercially available, surgical steel needle.

[0047] The syringe 8 may be substantially precise. For example, when the syringe 8 is modified (e.g., from the Hamilton syringe), the syringe 8 is as precise as the original syringe. The syringe 8 may be self-contained, autoclaveable, low tech, low maintenance, and may require no external controller, pump, or foot pedal.

[0048] While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made. Embodiments of the present invention may include other apparatuses for performing the operations herein. Such apparatuses may integrate the elements discussed, or may comprise alternative components to carry out the same purpose. It will be appreciated by persons skilled in the art that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

Claims

CLAIMS WHAT IS CLAIMED IS:

1. A syringe having an axial bore and a plunger disposed therein, comprising: a. a first biasing element for biasing said plunger; b. a shaft extending along the outside of the syringe, wherein said shaft has a proximal end, a distal end, and a pivot point disposed therebetween, wherein said pivot point is adapted for attaching to the syringe; c. a stopping element operably coupled to said distal end of said shaft for engaging with the plunger; and d. a second biasing element operably coupled to said shaft for biasing said stopping element toward said plunger, whereupon pivoting said proximal end of said shaft with respect to said distal end, said stopping element disengages from the plunger, thereby allowing the plunger to move within the bore by the force of said first biasing element.

2. An actuator adapted for attaching onto a syringe, wherein the syringe has an axial bore and a plunger disposed therein, comprising: a. a shaft having a proximal end, a distal end, and a pivot point disposed therebetween, wherein said pivot point is adapted for attaching to the syringe; b. a stopping element operably coupled to said distal end of said shaft for engaging with the plunger; and c. a biasing element operably coupled to said shaft for moving said stopping element toward said plunger, whereupon pivoting of said proximal end of said shaft with respect to said distal end, said stopping element disengages from the plunger thereby allowing the plunger to move within the bore.

3. The actuator of claim 2, wherein the plunger comprises a plunger biasing element, for forcing the plunger to move into the bore.

4. The actuator of claim 3, whereby upon pivoting the proximal end of said shaft, with respect to said distal end, said stopping element disengages from the plunger, thereby allowing the plunger to move within the bore by the force of said plunger biasing element.

5. The actuator of claim 3, whereby the syringe plunger defines notched grooves in contact with said stopping element.

6. The actuator of claim 5, wherein each notch defines a predetermined volume to be expelled from the syringe, whereupon pivoting the proximal end of said shaft, with respect to said distal end, said stopping element disengages from the plunger, thereby allowing the plunger to move within the bore by the force of said plunger biasing element allowing indexing of the volume expelled by the syringe.

7. The syringe of claim 1 or actuator of claim 2, wherein the stopping element engaging the plunger comprises a second biasing element.

8. The actuator of claim 7, wherein the second biasing element is capable of being modulated with respect to the biasing force of the stopping element engaging the plunger.

9. The syringe of claim 1 or actuator of claim 2, whereby the biasing element is a spring, an air actuator, an electromagnetic device or their combination.

10. A method for dispensing a liquid from a syringe with one hand, comprising the steps of: a. using a syringe operably linked to an actuator, said syringe comprising: an actuator adapted for attaching to the syringe, wherein the syringe having an axial bore and a plunger therein, comprising: i. a shaft having a proximal end, a distal end, and a pivot point disposed therebetween, wherein the pivot point is adapted for attaching to the syringe; ii. a stopping element operably coupled to the distal end of the shaft for engaging with the plunger; iii. and a biasing element operably coupled to the shaft for moving the stopping element toward the plunger, drawing a liquid by moving the plunger against the biasing element; b. pivoting the proximal end of the shaft with respect to the distal end; and c. disengaging said stopping element from the plunger, thereby allowing the plunger to move within the bore by the force of the biasing element thereby dispensing the liquid using one hand.

11. The method of claim 10, whereby the biasing element forces the plunger to move into the bore.

12. The method of claim 10, whereby the syringe plunger defines notched grooves in contact with said stopping element.

13. The method of claim 12, wherein each notch defines a predetermined volume to be expelled from the syringe, whereupon pivoting the proximal end of said shaft, with respect to said distal end, said stopping element disengages from the plunger, thereby allowing the plunger to move within the bore by the force of said plunger biasing element allowing indexing of the volume expelled by the syringe.

14. The method of claim 10, wherein the stopping element engaging the plunger comprises a second biasing element.

15. The method of claim 14, wherein the second biasing element is capable of being modulated with respect to the biasing force of the stopping element engaging the plunger.

16. The method of claims 10 or 14, whereby the biasing element is a spring, an air actuator, an electromagnetic device or their combination.