Methods, systems, and computer program products for detecting a droplet

Patent metadata

Field	Value
Publication number	US-2018015452-A1
Application number	US-201715719007-A
Country	US
Kind code	A1
Filing date	Sep 28, 2017
Priority date	Aug 15, 2014
Publication date	Jan 18, 2018
Grant date	—

Abstract

This invention relates to methods, systems, and computer program products for detecting a droplet.

First claim

What is claimed is:

1 . A method for detecting the formation of a droplet comprising:
estimating a plurality of rate of change in pipette pressure values during a given time interval; and detecting formation of the droplet at a distal end of a pipette tip attached to a pipette, responsive to at least one of the plurality of rate of change in pipette pressure values being greater than or equal to an upper pressure related threshold and at least one of the plurality of rate of change in pipette pressure values being less than or equal to a lower pressure related threshold.

2 . The method of claim 1 , wherein estimating the plurality of rate of change in pipette pressure values during the given time interval comprises:
measuring a pipette pressure at an internal portion of a pipette at given sampling time intervals to generate a plurality of pipette pressure values; determining a plurality of pressure differences relative to at least one previously measured pipette pressure value; and mathematically weighting each of the plurality of pressure differences to provide the plurality of rate of change in pipette pressure values.

3 . The method of claim 2 , wherein mathematically weighting each of the plurality of pressure differences to provide the plurality of rate of change in pipette pressure values comprises:
weighting a most recently determined pressure difference to provide a weighted pressure difference; weighting at least one previously calculated rate of change in pipette pressure value to provide a weighted previously calculated rate of change in pipette pressure value; and summing the weighted pressure difference and the weighted previously calculated rate of change in pipette pressure value.

4 . The method of claim 3 , wherein the most recently determined pressure difference is weighted by about 0% to 49% and the at least one previously calculated rate of change in pipette pressure value is weighted by about 51% to about 100%.

5 . The method of any one of claims 1 - 4 , wherein the plurality of rate of change in pipette pressure values changes over a period of time.

6 . The method of any one of claims 1 - 5 , wherein the upper pressure related threshold and/or the lower pressure related threshold is/are determined using a given rate of dispense.

7 . The method of any one of claims 1 - 6 , wherein the droplet has a volume in a range of about 0.5 μL to about 3.5 μL.

8 . The method of any one of claims 1 - 7 , wherein at least one of the plurality of rate of change in pipette pressure values corresponds to a rate of change in pipette pressure while the pipette is dispensing a gas and at least one of the plurality of rate of change in pipette pressure values corresponds to a rate of change in pipette pressure while the pipette is dispensing a liquid.

9 . The method of any one of claims 1 - 8 , further comprising, responsive to detecting the formation of the droplet, stopping dispensing of liquid from the pipette tip.

10 . The method of any one of claims 1 - 9 , further comprising detecting a clog in the pipette tip attached to the pipette.

11 . The method of claim 10 , wherein detecting the clog in the pipette tip attached to the pipette comprises:
determining that a given number of rate of change in pipette pressure values of the plurality of rate of change in pipette pressure values are greater than or equal to a first clog related threshold, or determining that an updated pressure difference corresponding to a most recently measured pipette pressure value of the plurality of pipette pressure values is greater than a second clog related threshold.

12 . The method of claim 11 , wherein the given number of rate of change in pipette pressure values of the plurality of rate of change in pipette pressure values corresponds to a given period of time.

13 . The method of any one of claim 11 or 12 , further comprising estimating the updated pressure difference.

14 . The method of claim 13 , wherein estimating the updated pressure difference comprises selecting a minimum pipette pressure value from the plurality of pipette pressure values and subtracting the minimum pipette pressure value from the most recently measured pipette pressure value of the plurality of pipette pressure values.

15 . The method of any one of claims 11 - 14 , wherein the second clog related threshold corresponds to a cumulative rise in pressure of a given value.

16 . The method of any one of claims 11 - 15 , wherein the first clog related threshold and/or the second clog related threshold is/are determined using a given rate of dispense.

17 . The method of any one of claims 1 - 16 , further comprising detecting that the pipette tip does not contain a liquid.

18 . The method of claim 17 , wherein detecting that the pipette tip does not contain the liquid comprises estimating a plurality of changes in pressure over a given period of time.

19 . The method of claim 18 , wherein detecting that the pipette tip does not contain the liquid further comprises determining that a portion of the plurality of changes in pressure indicate no significant change in pressure.

20 . The method of claim 19 , wherein the portion of the plurality of changes in pressure that indicates no significant change in pressure is at least 50%.

21 . The method of any one of claims 18 - 20 , wherein estimating the plurality of changes in pressure over the given period of time comprises measuring the pipette pressure at an initial point in time and estimating the plurality of changes in pressure at a given point in time after the initial point in time.

22 . A method for detecting the formation of a droplet comprising:
measuring a pipette pressure at an internal portion of the pipette including a pipette tip attached thereto to generate a plurality of pipette pressure values; determining a pressure difference relative to at least one previously measured pipette pressure value; providing a plurality of pressure difference values; comparing a portion of the plurality of pressure difference values with an upper pressure related threshold and a lower pressure related threshold; and responsive to determining that at least one pressure difference value of the portion of the plurality of pressure difference values is greater than or equal to the upper pressure related threshold and that at least one pressure difference value of the portion of the plurality of pressure difference values is less than or equal to the lower pressure related threshold, detecting the formation of the droplet.

23 . The method of claim 22 , wherein comparing the portion of the plurality of pressure difference values with the upper pressure related threshold and the lower pressure related threshold comprises comparing a portion of a plurality of rate of change in pipette pressure values with the upper pressure related threshold and the lower pressure related threshold.

24 . The method of any one of claim 22 or 23 , further comprising estimating a rate of change in pipette pressure and providing a plurality of rate of change in pipette pressure values.

25 . The method of claim 24 , wherein estimating the rate of change in pipette pressure comprises mathematically weighting the pressure difference to provide a weighted pressure difference.

26 . The method of claim 25 , wherein estimating the rate of change in pipette pressure comprises

Assignees

• Bio Merieux Inc

Inventors

• Luebbert Daniel Oliver
• Pingel Daniel Joseph
• Harrison Joel Patrick
• Pionke Jeremey Joseph

Classifications

• G01N35/1009

  Characterised by arrangements for controlling the aspiration or dispense of liquids · CPC title

• B01L2300/0681

  Filter · CPC title

• B01L2400/02

  Drop detachment mechanisms of single droplets from nozzles or pins · CPC title

• G01N2035/1018

  Detecting inhomogeneities, e.g. foam, bubbles, clots · CPC title

• B01L2300/0627

  Sensor or part of a sensor is integrated · CPC title