WO-2026093762-A1 - METHOD AND APPARATUS

WO2026093762A1WO 2026093762 A1WO2026093762 A1WO 2026093762A1WO-2026093762-A1

Abstract

An aspect of the disclosure provides an apparatus comprising: a droplet dispenser configured to deliver a droplet to a liquid system to generate a wave in the liquid system, light beam optics for illuminating an area of the liquid system with a light beam, and a light collector coupled to a detector and positioned for receiving a reflected light beam provided by reflection of the light beam by the liquid system, and the light collector being configured to sense: a first intensity of the reflected light beam corresponding to a first polarisation component of the reflected light beam; a second intensity of the reflected light beam corresponding to second polarisation component of the light beam after reflection; and, the apparatus further comprising a liquid motion sensor configured to sense further parameters of liquid motion associated with the delivery of the droplet to the liquid system.

Inventors

SHRIVASTAVA, Shamit

Assignees

APOHA LIMITED

Dates

Publication Date: 20260507
Application Date: 20251031
Priority Date: 20241104

Claims (20)

1 . An apparatus compri sing : a droplet di spenser configured to deliver a droplet to a liquid system to generate a wave in the liquid system, light beam optics for illuminating an area of the liquid system with a light beam, and a light collector coupled to a detector and positioned for receiving a reflected light beam provided by reflection of the light beam by the liquid system, and the light collector being configured to sense : a first intensity of the reflected light beam corresponding to a first polari sation component of the reflected light beam; a second intensity of the reflected light beam corresponding to second polari sation component of the light beam after reflection ; and, the apparatus further comprising a liquid motion sensor configured to sense further parameters of liquid motion as sociated with the delivery of the droplet to the liquid system .
2 . The apparatus of claim 1 wherein the liquid motion sensor compri ses at least one of : a beam deflection sensor configured to sense deflection of the reflected light beam from a beam direction as sociated with specular reflection of the light beam from an undisturbed surface of the liquid system; and a droplet sensor , configured to sense delivery of the droplet to the liquid system .
3 . The apparatus of claim 2 wherein the liquid motion sensor compri ses the beam deflection sensor , for example wherein the beam deflection sensor i s integrated into the light collector .
4 . The apparatus of any preceding claim wherein the beam deflection sensor is configured to provide a signal indicating at least one of a magnitude and a direction of said deflection .
5 . The apparatus of claim 3 or 4 wherein the light collector compri ses a divided detector comprising a plurality of light sensitive detector elements spatially arranged for sensing said deflection .
6 . The apparatus of claim 3 , 4 or 5 wherein the divided detector i s segmented and the light sensitive elements are arranged in di f ferent segments of the segmented detector .
7 . The apparatus of claim 6 wherein the detector segments compri ses four segments which provide quadrants of a quadrant detector .
8 . The apparatus of claim 5 , 6 or 7 wherein the light collector compri ses a beam splitter arranged to direct the first polari sation component of the reflected beam to the divided detector and to direct the second polarisation component to a second detector , for example wherein the second intensity corresponds to the total intensity sensed by the divided detector .
9 . The apparatus of any preceding claim wherein the liquid motion sensor comprises the droplet sensor .
10 . The apparatus of claim 9 wherein the droplet sensor i s configured to provide droplet data indicating parameters of contact between the droplet and the liquid system.
11 . The apparatus of claim 10 wherein the parameters of contact compri se a time series indicating si ze of the droplet .
12. The apparatus of claim 11, wherein the apparatus is configured to provide one such time series for each droplet, wherein the time series corresponds to an interval between formation of the droplet and coalescence of the droplet with the liquid system, such as an interval between contact of the droplet with the liquid system and coalescence of the droplet.
13. The apparatus of claim 11 or 12 wherein the droplet sensor comprises an optical sensor configured to provide optical data obtained from the droplet at the surface of the liquid system.
14. The apparatus of claim 13 wherein the optical sensor is provided by one of: (a) a camera, wherein the optical data is based on images of the droplet; and (b) a detector and a light beam illuminating the detector wherein the droplet is formed in the path of the light beam to the detector and the optical data comprises a time series of detected intensity of the light beam.
15. The apparatus of any preceding claim further comprising a controller configured to characterise the analyte based on wave data comprising a time series of measurements of the first intensity, the second intensity, and the parameters of liquid motion .
16. The apparatus of claim 15 wherein the controller is configured to determine a characteristic of the analyte based on the wave data .
17. A method of characterising an interaction between a droplet of an analyte and a liquid system, the method comprising: obtaining wave data comprising (iii) parameters of liquid motion associated with the delivery of the droplet to the liquid system; and ( iv) a time series of measurements of a wave generated in a liquid system by the droplet , wherein the time series of measurements compri se a plurality of measurements of : a first intensity of a reflected light beam, reflected by the surface of the liquid system, wherein the first intensity corresponds to a first polari sation component of the reflected light beam; a second intensity of the reflected light beam corresponding to second polari sation component of the light beam after reflection ; and, the method further compri sing : characteri sing the analyte based on the time series of measurements of the first intensity, the second intensity, and the parameters of liquid motion .
18 . The method of claim 17 wherein the parameters of liquid motion compri se at least one of : ( a ) deflections of the reflected light beam from a beam direction as sociated with specular reflection of the light beam from an undi sturbed surface of the liquid system; and (b ) parameters of contact between the droplet and the liquid system .
19 . The method of claim 18 wherein the parameters of contact compri se a time series indicating si ze of the droplet .
20 . The method of claim 19 , comprising obtaining wave data for a plurality of droplets and providing, for each droplet , a time series of droplet data indicating si ze of the droplet , wherein the time series corresponds to an interval between formation of the droplet and coalescence of the droplet with the liquid system .

Description

Method and Apparatus Field of invention The present disclosure relates to methods and apparatus for characterising an interaction between a stimulus and a liquid system, and more particularly to methods and apparatus for characterising such interactions based on properties of surface waves in the liquid system. Background. The surface of a material has a thermodynamic potential that is independent of its volume. The physical and chemical properties of a surface are derived from its thermodynamic potential. For example, the response of the surface to a mechanical perturbation is given by properties such as surface tension and lateral compressibility. Similarly, the response of the surface to an electromagnetic perturbation is given by properties such as surface dipole moment. As a result of these perturbation, different types surface waves may be generated on a surface e.g. a surface of a fluid (e.g. a liquid) forming an interface with another fluid (e.g. air) . Some example types of surface waves are: Rayleigh waves; Gravity waves; Capillary waves; Lucassen waves. The physics of these waves have been described in Nonlinear fractional waves at elastic interfaces Julian Kappler, Shamit Shrivastava, Matthias F. Schneider, and Roland R. Netz Phys. Rev. Fluids 2, 114804 - Published 20 November 2017. These waves may be hydrodynamically coupled. Rayleigh waves are characterised by elliptical motion of a notional fluid particle in a plane which is perpendicular to the surface at equilibrium and parallel to the direction of propagation of the wave . Gravity waves are characterised by a displacement from equilibrium of a notional fluid particle at the surface wherein the displacement of the notional particle is characterised by having a restoring force of gravity or buoyancy. Capillary waves are characterised by a displacement from equilibrium of a notional fluid particle wherein the displacement of the notional fluid particle is in a direction transverse to the surface at equilibrium and transverse to the direction of propagation of the wave and have a restoring force of surface tension . Lucassen waves are characterised by a displacement from equilibrium of a notional fluid particle at a surface of a wave-medium by oscillation in a direction parallel to that surface at equilibrium and parallel to the direction of propagation of the wave. In Lucassen waves this notional particle is subject to a restoring force resulting from the surface elastic modulus of the surface of the wave-medium. Put another way Lucassen waves are compressionrarefaction waves which occur in the plane of a boundary (an interface) between a wave-medium and an adjacent medium such as air . Lucassen waves have been observed in lipid monolayers and in other types of liquid systems. Shamit Shrivastava , Matthias F. Schneider Opto-Mechanical Coupling in Interfaces under Static and Propagative Conditions and Its Biological Implications describes how a wave can be generated in a lipid monolayer mechanically with a dipper and how parameters of the generated wave, such as the intensity of fluorescent particles therein and the lateral pressure of the surface wave, can be measured, for example using a photo detector and a Wilhemly balance respectively . Shrivastava S, Schneider MF. 2014 Evidence for two-dimensional solitary sound waves in a lipid controlled interface and its implications for biological signalling. J. R. Soc. Interface 11: 20140098 describes a method in which Lucassen waves can be generated in a lipid monolayer and how parameters of said waves may be measured (e.g. fluorescence energy transfer (FRET) measurements; a piezo cantilever) . The document also describes how the state of a lipid monolayer may be characterised by a variety of thin film parameters (e.g. surface density of lipid molecules, temperature, pH, lipid-type, ion or protein adsorption, solvent incorporation, etc. ) and also how the state of the lipid monolayer can affect parameters of waves which propagate in the lipid monolayer . Bernhard Fichtl, Shamit Shrivastava & Matthias F. Schneider, Protons at the speed of sound: Predicting specific biological signaling from physics Nature Scientific Reports describes how Lucassen waves can be generated in a lipid interface in response to a change in pH of the system and that the speed of these waves can be controlled by the compressibility of the interface. The document describes how parameters of these waves depend on the degree of change in pH. The document also describes how mechanical and electrical changes at the lipid interface can be measured (e.g. using a Kelvin probe) . Lucassen waves may be described as interfacial compression waves and may be considered two-dimensional sound waves (sound waves confined to a surface which forms a boundary between two phases e.g. a fluid-air boundary) . In a manner analogous to sound waves, shock waves may exist in Lucassen wave systems (e.g. two- dimensional shock waves) . Lucassen sho