Abstract: There is provided a liquid droplet monitoring and measuring apparatus (1) for a liquid droplet dispensing system having a nozzle (5) with a dispensing tip (7). The apparatus (1) comprises an inner chamber (2) surrounded by an outer shield (3), preferably not in contact with each other. An RF oscillator electrically energises the liquid through an electrode (11). The inner chamber (2) is connected through pre-amplifiers (16), band pass filters (17), rectifier (18), low pass filter (19) and signal conditioning amplifier (20) to a signal read-out device (21). The operation of the apparatus is based on the measurement of the capacitance between the nozzle (5) and the inner chamber (2). As a droplet (15) grows on the dispensing tip (7), the capacitance between the nozzle (5) and the inner chamber (2) increases. Therefore, the signal detected and received by the signal read-out device (21) changes. This change is directly related to the volume of the droplet which can therefore be measured.

Abstract: A liquid outlet link assembly is provided for liquid delivery output rates below 10 &mgr;l per minute so as to smooth out the flow from a positive displacement pump which has an immediate step pumping rate which is relatively substantially larger than the delivery rate required through the liquid outlet means. Essentially, this liquid link assembly has a bubble of air or some other pressure activated expansion means which initially contracts on the step pump such as a syringe pump operation and then gradually expands over time, allowing a steady output rate through the link assembly.

Abstract: Biological assays using various constructions of biochips are disclosed to mirror in vivo situations. The biochip 50 comprises a microchannel 51 having a liquid outlet port 1, bubble release port 2 and a liquid outlet port 3 with an associated bubble release port 4. A multiplicity of tests can be performed often by coating the bore of the microchannel 50 which various adhesion mediating proteins or the use of chemoattractants. The assay assembly 60 comprises a syringe pump feeding the biochip 50. An inverted microscope 65, digital camera 66 and recorder 67 are provided. A sample liquid containing cells in suspension is injected slowly through the biochip and the effect of the assay recorded over a long period.

Abstract: Biological assays using various constructions of biochips are disclosed to mirror in vivo situations. The biochip 50 comprises a microchannel 51 having a liquid outlet port 1, bubble release port 2 and a liquid outlet port 3 with an associated bubble release port 4. A multiplicity of tests can be performed often by coating the bore of the microchannel 50 which various adhesion mediating proteins or the use of chemoattractants. The assay assembly 60 comprises a syringe pump feeding the biochip 50. An inverted microscope 65, digital camera 66 and recorder 67 are provided. A sample liquid containing cells in suspension is injected slowly through the biochip and the effect of the assay recorded over a long period.

Abstract: A dispensing assembly for liquid droplets that includes a dispenser connected to a liquid carrying pipe which in turn is connected to a source of pressurized liquid. The dispenser has an elongated body member having a main bore connected to the liquid carrying pipe. At the other end, the main bore has a valve seat that is connected to a nozzle having a nozzle bore terminating in a dispensing tip. An elongated valve boss of ferromagnetic material covered with a soft polymer is mounted in the main bore and has a cross-sectional area less than that of the main bore. A separate valve boss actuating coil assembly has upper and lower coils that are separate from the main body that can be unplugged from both coils and from the liquid carrying pipe. As such, the main body can be a disposable member.

Abstract: A dispensing assembly for liquid droplets that includes a dispenser connected to a liquid carrying pipe which in turn is connected to a source of pressurized liquid. The dispenser has an elongated body member having a main bore connected to the liquid carrying pipe. At the other end, the main bore has a valve seat that is connected to a nozzle having a nozzle bore terminating in a dispensing tip. A valve boss of ferromagnetic material covered with a soft polymer is mounted in the main bore and has a cross-sectional area less than that of the main bore. A separate valve boss actuating coil assembly has upper and lower coils that are separate from the main body that can be unplugged from both coils and from the liquid carrying pipe. As such, the main body can be a disposable member.

Abstract: A dispenser (1) for liquid droplets of the order of 30 &mgr;l or less in volume. The dispenser (1) comprises a metering valve body (2) having a main bore (3) connected by a pipe (4) to a pressurised liquid delivery source (not shown). The body (2) comprises a base (5) from which is mounted a nozzle (6) projecting above the base (5) to form a valve seat (7). An actuating coil assembly (11) is mounted on the exterior of the body (2) for moving a floating valve boss (15) of a ferromagnetic material. Sensing coils (20, 21) are mounted around and spaced-apart along the body (2) forming part of a valve boss detector. The valve boss detector acts as a positional movement detector so that the opening and closing of the valve can be accurately controlled and bouncing of the valve boss (15) either against an end stop (9) or on the valve seat (7) can be greatly minimized, if not prevented fully, by careful operation of the actuating coil assembly (11).

Abstract: A multi nozzle dispensing head for a dispensing assembly for liquid droplets of 10 &mgr;l or less. The dispensing assembly comprises a pressurised liquid delivery source feeding a dispenser including a metering valve and the multi nozzle dispensing head. The multi nozzle dispensing head comprises a bored primary nozzle feeding a manifold forming a split channel which in turn feeds bored secondary nozzles. The aggregate resistance to flow in all the secondary nozzle bores is greater than the resistance to flow in the split channel, generally by a factor of 10.

Abstract: A liquid outlet link assembly is provided for liquid delivery output rates below 10 &mgr;l per minute so as to smooth out the flow from a positive displacement pump which has an immediate step pumping rate which is relatively substantially larger than the delivery rate required through the liquid outlet means. Essentially, this liquid link assembly has a bubble of air or some other pressure activated expansion means which initially contracts on the step pump such as a syringe pump operation and then gradually expands over time, allowing a steady output rate through the link assembly.

Abstract: A dispenser (1) for liquid droplets of the order of 30 &mgr;l or less in volume. The dispenser (1) comprises a metering valve body (2) having a main bore (3) connected by a pipe (4) to a pressurised liquid delivery source (not shown). The body (2) comprises a base (5) from which is mounted a nozzle (6) projecting above the base (5) to form a valve seat (7). An actuating coil assembly (11) is mounted on the exterior of the body (2) for moving a floating valve boss (15) of a ferromagnetic material. Sensing coils (20, 21) are mounted around and spaced-apart along the body (2) forming part of a valve boss detector. The valve boss detector acts as a positional movement detector so that the opening and closing of the valve can be accurately controlled and bouncing of the valve boss (15) either against an end stop (9) or on the valve seat (7) can be greatly minimized, if not prevented fully, by careful operation of the actuating coil assembly (11).

Abstract: A conventional syringe pump (10) is used to dispense liquids of less than 5 &mgr;l in volume in a dispensing assembly (1). There is a divider barrier formed by a flexible elastomer membrane (5) clamped between an inner part (3) and an outer part (4) of a dispenser (2). The dispenser (2) has a bore divided into a system liquid reservoir (6) and a sample liquid reservoir (7). The system liquid reservoir (6) connects to the pump (10) and the sample liquid reservoir (7) communicates with a nozzle (15) having a dispensing tip (16). The membrane (5) is virtually incompressible and therefore the pump (10) can dispense accurately. Electrostatic drop detachment using an electrode (25) electrically coupled to the dispensing tip (16) and a conducting plate (19) forming a receiving electrode below a substrate (20).

Abstract: Biological assays using various constructions of biochips are disclosed to mirror in vivo situations. The biochip 50 comprises a microchannel 51 having a liquid outlet port 1, bubble release port 2 and a liquid outlet port 3 with an associated bubble release port 4. A multiplicity of tests can be performed often by coating the bore of the microchannel 50 which various adhesion mediating proteins or the use of chemoattractants. The assay assembly 60 comprises a syringe pump feeding the biochip 50. An inverted microscope 65, digital camera 66 and recorder 67 are provided. A sample liquid containing cells in suspension is injected slowly through the biochip and the effect of the assay recorded over a long period.