Device for dosing a liquid, and method of use

A device for dosing a liquid,

• wherein the device comprises a channel which ends in an opening of the device, for aspiration of a portion of the liquid through the opening and into the channel in an axial aspiration direction, wherein the channel is configured for capillary flow of the liquid portion therethrough,
• wherein the channel is formed along at least a part of its axial extension by a continuous array of channel portions, wherein at least two fixed-volume, advancement portions are in the axial aspiration direction each directly succeeded by a respective, fixed volume, pinning portion, each of the channel portions having a respective wall with an internal surface enclosing an internal volume of the channel portion,
• wherein the array of channel portions is formed such that at an axial boundary between each advancement portion of the array and the pinning portion succeeding the advancement portion in the axial aspiration direction, a shoulder is formed along substantially an entire circumference of the channel by a wall of the pinning portion flaring radially outwardly from a wall of the advancement portion at the axial boundary, at an angle with the advancement portion wall, seen in a diametrical cross-section of the channel,
• such that seen in the axial aspiration direction an expansion of the channel is formed at the shoulder at each axial boundary, for pinning of a meniscus of the liquid portion at the respective axial boundary,
• wherein of the shoulders for meniscus pinning in the axial aspiration direction, at least one of the shoulders which in the aspiration direction succeeds another one of the shoulders, the angle is larger than the angle at the other one of the shoulders.

A device for dosing a liquid,

• wherein the device comprises a channel which ends in an opening of the device, for dispension of a portion of the liquid through the opening and into the channel in an axial dispension direction,
• wherein the channel is configured for capillary flow of the liquid portion therethrough,
• wherein the channel is formed along at least a part of its axial extension by a continuous array of channel portions, wherein at least two fixed-volume, advancement portions are in the axial dispension direction each directly succeeded by a respective, fixed volume, pinning portion, each of the channel portions having a respective wall with an internal surface enclosing an internal volume of the channel portion,
• wherein the array of channel portions is formed such that at an axial boundary between each advancement portion of the array and the pinning portion succeeding the advancement portion in the axial dispension direction, a shoulder is formed along substantially an entire circumference of the channel by a wall of the pinning portion flaring radially outwardly from a wall of the advancement portion at the axial boundary, at an angle with the advancement portion wall, seen in a diametrical cross-section of the channel,
• such seen in the axial dispension direction an expansion of the channel is formed at the shoulder at each axial boundary, for pinning of a meniscus of the liquid portion at the respective axial boundary,
• wherein of the shoulders for meniscus pinning in the axial dispension direction at least one of the shoulders which in the dispension direction succeeds another one of the shoulders, the angle is larger than the angle at the other one of the shoulders.