Abstract: A microfabricated device is fabricated by depositing a first metal layer on a substrate to provide a first electrode of an electrostatic actuator, depositing a first structural polymer layer over the first metal layer, depositing a second metal layer over said first structural polymer layer to form a second electrode of the electrostatic actuator, depositing an insulating layer over said first structural polymer layer, planarizing the insulating layer, etching the first structural polymer layer through the insulating layer and the second metal layer to undercut the second metal layer, providing additional pre-formed structural polymer layers, at least one of which has been previously patterned, and finally bonding the additional structural layers in the form of a stack over the planarized second insulating layer to one or more microfluidic channels. The technique can also be used to make cross over channels in devices without electrostatic actuators, in which case the metal layers can be omitted.

Abstract: A method is provided for controllably delivering an additive fluid into a host fluid in a target system at a desired volumetric flow rate. The method comprises: providing a binary supply injector connected in an additive fluid delivery system between a pressurized supply of the additive fluid and the target system. The binary supply injector is controllable between an ON state which permits flow of the additive fluid therethrough and an OFF state which prevents flow of the additive fluid therethrough. The method involves iteratively repeating: estimating a volumetric flow rate of the additive fluid between the pressurized supply and the target system; and if the estimated volumetric flow rate of the additive fluid is greater than the desired volumetric flow rate, controlling the supply injector to its OFF state; or if the estimated volumetric flow rate of the additive fluid is less than the desired volumetric flow rate, controlling the supply injector to its ON state.

Abstract: An integrated microfluidic check valve has a first chamber having inlet and outlet ports and divided by a barrier the said inlet and outlet ports into first and second subchambers. A membrane forms a wall of the first chamber and co-operates with the barrier to selectively permit and prevent fluid flow between the inlet and outlet ports. A second chamber adjoining the first chamber and has a wall formed by the membrane. A microfluidic channel establishes fluid communication between the second chamber and the first subchamber. The membrane deflects to permit fluid flow around the barrier when the pressure in the first subchamber is lower than the pressure in the second subchamber. Two such valves can be combined into a peristaltic pump.

Abstract: A microfabricated device is fabricated by depositing a first metal layer on a substrate to provide a first electrode of an electrostatic actuator, depositing a first structural polymer layer over the first metal layer, depositing a second metal layer over said first structural polymer layer to form a second electrode of the electrostatic actuator, depositing an insulating layer over said first structural polymer layer, planarizing the insulating layer, etching the first structural polymer layer through the insulating layer and the second metal layer to undercut the second metal layer, providing additional pre-formed structural polymer layers, at least one of which has been previously patterned, and finally bonding the additional structural layers in the form of a stack over the planarized second insulating layer to one or more microfluidic channels. The technique can also be used to make cross over channels in devices without electrostatic actuators, in which case the metal layers can be omitted.

Abstract: An integrated microfluidic device has at least at least one active element controlled by pneumatic signals, and at least one electrostatic actuator integrated in the device for generating the pneumatic signals within the device from an external supply of pressure or vacuum. In one embodiment the pressure supply may be generated internally on chip using an integrated pump.

Abstract: A method is provided for controllably delivering an additive fluid into a host fluid in a target system at a desired volumetric flow rate. The method comprises: providing a binary supply injector connected in an additive fluid delivery system between a pressurized supply of the additive fluid and the target system. The binary supply injector is controllable between an ON state which permits flow of the additive fluid therethrough and an OFF state which prevents flow of the additive fluid therethrough. The method involves iteratively repeating: estimating a volumetric flow rate of the additive fluid between the pressurized supply and the target system; and if the estimated volumetric flow rate of the additive fluid is greater than the desired volumetric flow rate, controlling the supply injector to its OFF state; or if the estimated volumetric flow rate of the additive fluid is less than the desired volumetric flow rate, controlling the supply injector to its ON state.

Abstract: Provided is a method for characterizing a polypeptide, which method comprises the steps of: (a) optionally reducing cysteine disulphide bridges in the polypeptide to form free thiols, and capping the free thiols; (b) cleaving the polypeptide with a sequence specific cleavage reagent to form peptide fragments; (c) optionally deactivating the cleavage reagent; (d) capping one or more ?-amino groups that are present with a lysine reactive agent; (e) analyzing peptide fragments by mass spectrometry to form a mass fingerprint for the polypeptide; and (f) determining the identity of the polypeptide from the mass fingerprint.

Abstract: An optical modulator comprises first and second optical waveguides having first and second electrodes respectively associated therewith, and an electrically conductive region associated with both waveguides. The electrodes have inputs for an electrical signal at input ends thereof, and outputs for the electrical signal at opposite output ends thereof. The conductive region is electrically connected to the output ends of the first and second electrodes such that an electric field created by the electrical signal between the first electrode and the conductive region is substantially equal in magnitude to an electric field created by the electrical signal between the second electrode and the conductive region. The balancing of the electric fields experienced by the waveguides enables the modulation of light in the two waveguides to be balanced.

Abstract: Provided is a method for characterising a polypeptide, which method comprises the steps of; (a) optionnally reducing cysteine disulphide bridges in the polypeptide to form free thiols, and capping the free thiols; (b) cleaving the polypeptide with a sequence specific cleavage reagent to form peptide fragments; (c) optionally deactivating the cleavage reagent; (d) capping one or more ?-amino groups that are present with a lysine reactive agent; (e) analysing peptide fragments by mass spectrometry to form a mass fingerprint for the polypeptide; and (f) determining the identity of the polypeptide from the mass fingerprint.

Abstract: An improved method is provided for fabricating a polarisation rotator in a rib waveguide having a propagation axis and opposite side walls. The method includes etching a pit in the substrate surface to form a recess in one of the side walls of the waveguide, during formation of the waveguide on the substrate surface, so as to provide an asymmetric waveguide section for imparting polarisation rotation to radiation propagated along the propagation axis. Preferably the pit is formed by a wet etching step forming an upper side surface within the recess that is inclined relative the waveguide side walls, and the waveguide side walls are formed by a dry etching step to extend perpendicularly to the substrate surface. In addition the dry etching step forms a lower side surface adjoining the upper side surface within the recess and tilted relative to the upper side surface.

Abstract: A photonic integrated device having a substrate layer, epitaxial layers formed on said substrate layer and a guiding layer formed by one of the epitaxial layers. An optical waveguide is formed within the guiding layer. In the waveguide are a splitter (4) having at least two outputs, each output being transmitted to a Mach-Zehnder modulator (6, 8), the phase of the output of at least one modulator being shiftable, the signals being recombined to provide an optical phase shift key (PSK) output (14) wherein a trench is etched into the substrate layer between each pair of modulators to isolate the modulators from one another.

Abstract: An array of hybridization probes, each of which comprises a mass label linked to a known base sequence of predetermined length, wherein each mass label of the array, optionally together with the known base sequence, is relatable to that base sequence by mass spectrometry.

Abstract: Provided is a method for characterising a polypeptide or a population of polypeptides, which method comprises the steps of: (a) contacting a sample comprising one or more polypeptides with a lysine reactive agent to cap ?-amino groups; (b) optionally reacting the sample of polypeptides with an amine reactive reagent to block ?-amino groups; (c) digesting the sample of polypeptides with a cleavage reagent to produce peptide fragments; (d) optionally deactivating the cleavage reagent; (e) removing those peptides having uncapped or unblocked amino groups; and (f) recovering the N-terminal peptides.