How to make the PDMS Channel Plate
The casting set mainly comprises the casting station, Polycarbonate carriers, liquid PDMS and syringes. In addition, you will need a “Master Chip” introducing your particular channel layout.
The master chip is made from Teflon coated silicon and made at GeSiM on request. Basically we accept any layout provided by a CAD drawing; a set of typical channel layouts is on the shelf. Please ask.
The Hydrogel Valve – Properties and Function
To add liquid, to start and stop reactions, a dead volume free microvalve (GeSiM patent) can be placed into the flow system.
The valve is made from a silicon chip but comes with different housings for convenient handling. Most popular version is called “HG-7″, based on a PEEK-housing with 1/16” fitting.
The valve chip incorporates a small but well defined amount of a hydrogel immobilized in a liquid transparent chamber. The surrounding heater controls the temperature of the chamber in a limited range around the swelling temperature of the hydrogel.
For operation of the valve nothing but 250 mW power is required. The Fluid Processor provides full control of the device.
The sample liquid gets in contact with the enclosed hydrogel. Therefore the valve is mainly made for aqueous solutions but tolerates <15 % methanol, acetone.
Measurement of Tiny Flows
The GeSiM flow sensors has been designed for flow rates in the range of 0…100 Microliters per minute. It is a thermocalorimetric sensor measuring the heat transfer in a very tiny chamber. The fluid sample is negligibly heated whereas the surroundig temperature distribution is monitored.
As larger the heat transport through the chamber as more precisely the measurement result will be. In other terms, as more time is allowed for a single measurement as better the accuracy.
The sensor can be used along with the MicCell Fluid Processor (See next article) but is available for standalone operation too. The sensor is cascadable, it allows to measure several independent fluid flows simultaneously. Up to four stacked sensors can be managed by a single controller. The controller connects to a PC through serial interface, a dedicated software displays the measurement result.
Please download the flyer (right) for more information.
Controlling of Complex Setups
The GeSiM Fluidprocessor is a racked unit combining several types of valves and syringe pumps. It is usually built to a particular application.
In addition, a Windows based software (“MicCell-Software”) is available for controlling
- Hydrogel Valves
- Piezoelectric Dispensers
- Flow Sensors