EP-4737882-A1 - METHOD AND APPARATUS

EP4737882A1EP 4737882 A1EP4737882 A1EP 4737882A1EP-4737882-A1

Abstract

An aspect of the disclosure provides a method of characterising an analyte, the method comprising: providing a liquid system; administering, to the liquid system, a plurality of droplets wherein the droplets comprise the analyte; measuring, for each droplet of the plurality of droplets, an interface of at least one of (a) the droplet and (b) liquid system to provide a plurality of sets of interface behaviour data; determining, based on the sets of interface behaviour data, a variability of the interface behaviour; and determining a property of the analyte based on the variability of interface behaviour.

Inventors

ST. JOHN, Alexander Nicholas
CARAMAZZA, Piergiorgio
BOEHMKE, Alexandra Leigh

Assignees

Apoha Limited

Dates

Publication Date: 20260506
Application Date: 20241104

Claims (15)

A method of characterising an analyte, the method comprising: providing a liquid system; administering, to the liquid system, a plurality of droplets wherein the droplets comprise the analyte; measuring, for each droplet of the plurality of droplets, an interface of at least one of (a) the droplet and (b) liquid system to provide a plurality of sets of interface behaviour data; determining, based on the sets of interface behaviour data, a variability of the interface behaviour; and determining a property of the analyte based on the variability of interface behaviour.
A computer implemented method of characterising an analyte, the method comprising: obtaining a plurality of sets of interface behaviour data for each droplet of a plurality of droplets administered to a liquid system wherein the droplets comprise the analyte and the interface data comprises measurements of an interface of at least one of (a) the droplet and (b) the liquid system; determining, based on the sets of interface behaviour data, a variability of the interface behaviour; and determining a property of the analyte based on the variability of interface behaviour.
The method of claim 1 or 2 wherein determining variability comprises identifying a time window interval in the interface behaviour data and determining, based on the sets of interface behaviour data, a variability of the interface data at each of a plurality of times within the window interval.
The method of any preceding claim wherein the interface behaviour data comprises wave data, obtained from a wave evoked in the liquid system by the administering of the droplet, for example wherein the wave data comprises a plurality of measurements of a polarisation of a reflected light beam, reflected by a surface of the liquid system in the presence of the wave, for example wherein the measurements of polarisation comprise a first intensity of the reflected light beam, wherein the first intensity corresponds 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.
The method of any preceding claim wherein the interface behaviour data comprises droplet data obtained from the droplet during a window interval between its formation at a dispenser and coalescence of the droplet with the liquid system, for example wherein the window interval defines a time between contact of the droplet with the liquid system and coalescence of the droplet with the liquid system, for example wherein the droplet data comprises a time series indicating size of the droplet.
The method of any preceding claim wherein the variability comprises a statistical moment such as a variance or standard deviation.
The method of any of claims 1 to 5 wherein the variability comprises a measure of an envelope of the interface behaviour data.
The method of claim 6 or 7 wherein the variability comprises a measure of a change in the variability, such as a change in variability over a series of droplets.
The method of any preceding claim comprising combining the variabilities from each of the plurality of times to provide a combined variability metric, wherein the variability of interface behaviour is provided by the combined variability metric.
The method of any preceding claim wherein determining the property of the analyte based on the variability comprises comparing the variability of interface behaviour with variability of interface behaviour data of other analytes of the same type, for example wherein the comparing comprises identifying an analyte as an outlier from a distribution of variability of interface behaviour, for example wherein the distribution of variability of interface behaviour corresponds to variability of interface behaviour data of other analytes of the same type.
The method of any preceding claim wherein the analyte comprises a protein, such as an antibody.
The method of any preceding claim wherein the analyte comprises a candidate for inclusion in a medicament and the property comprises developability.
An apparatus for characterising an analyte, the apparatus comprising: a liquid system comprising a surfactant and a buffer configured to interact to cause a transition in state of the liquid system; a droplet dispenser, configured to administer droplets to the liquid system, the droplets comprising the analyte and the buffer; an interface measurement detector, configured to measure an interface of at least one of the droplets and the liquid system in response to the administration of droplets to the liquid system to acquire interface behaviour data for each droplet of a plurality of droplets administered to the liquid system; a controller configured to determine, based on the sets of interface behaviour data, a variability of the interface behaviour and to determine a property of the analyte based on the variability of interface behaviour.
The apparatus of claim 13 wherein the concentration of the buffer and/or the surfactant and content of the droplets are selected so that the interface behaviour data exhibits an N-stable response to the addition of a droplet.
The apparatus of claim 13 to 14 wherein the interface measurement detector comprises a droplet sensor configured to measure droplet data indicating a size of the droplet and/or wherein the interface measurement device comprises a detector configured to measure a wave evoked in the liquid system by the administering of the droplet, for example wherein the detector is configured to provide wave data based on a plurality of measurements of a polarisation of a reflected light beam, reflected by a surface of the liquid system in the presence of the wave.

Description

Field of invention The present disclosure relates to methods and apparatus for characterising an analyte, and more particularly for characterising an analyte based on the behaviour of an interface of a droplet or a liquid system to which the droplet is applied. 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 compression-rarefaction 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, lipidtype, 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 fluidair boundary). In a manner analogous to sound waves, shock waves may exist in Lucassen wave systems (e.g. two-dimensional shock waves). Lucassen shock waves may be characterised in the same way as Lucassen waves with t