Fluidics

Typically, fluid needs to be stored either on-consumable or on-machine for any diagnostic device. There are a many factors that guide the implementation of a storage solution, some of which are:

Temperature – Is refrigeration or heating required?
Volatility – Does the fluid pose a fire risk or is evaporation a major concern?
Time-based effects – Will viscosity change, or will crystallization occur?
Volume – Are the volumes in the <1mL range and is wastage a commercial concern?
Throughput – How much and how often will the fluid be accessed?
User interaction – How are the fluids maintained or replaced?

Invetech’s fluidic experts have designed fluid storage solutions from large bulk containers that last for many days in a high to medium throughput setting, user-accessible bulks that contain medium value volatile reagent and low-volume extremely high value reagent containment and sensing systems that allow for the most precious of reagents to be used sparingly with minimal waste.

Blending, dissolving, emulsifying or suspending are just some of the many mixing methods that you may require when designing fluidic processes. Implementing these methods into an automated device can be achieved using a variety of technologies from simple stirring mechanisms all the way through to more advanced systems such as ultrasonic mixers or dedicated microfluidic mixing chips.

The challenges presented in mixing often focus on three areas:

• Homogeneity – Hard to mix fluids or fluid-solid suspensions may require more powerful mixing systems or variable workflows in order to achieve the desired results.

• Cross-contamination – Particularly prevalent in micro-fluidic applications, ensuring that mixing does not result in contamination of subsequent assay steps due to splashing, pumping or thermally driven flow is a risk that is controlled via geometric changes, active components such as valves or through workflow adjustments.

• Damage – Over-mixing may cause damage to the assay fluids or contained media such as cell or DNA fragments. Phenomena such as lysing of biological components may occur. Selecting the appropriate mixing method and apply a suitable amount of energy over time will minimize or eliminate damage effects.