The proposed instrument consists of a hand held base unit and a disposable cartridge or labcard that will carry out a Real Time Polymerase Chain Reaction automatically, from sample preparation, to detection. The labcard, made of SU-8 on a plastic film, contains all the disposable components, whereas the base unit has all the standard electronics and optics. This approach will avoid any cross contamination between measurements.
Fabrication process of 3D microchannels and its components
The labcard is divided in six building blocks:
Sample injection block consisting of pumps, a mixer and reagent reservoirs. This block will carry ouy the sample injection by touching the inlet with an impregnated swab containg raw sample. Then fluid will be mixed with the sample and pumped into the labcard.
Separation block containing a reservoir with metallic electrodes for cell separation and purification of the inserted sample.
Thermolysing block: a reservoir with metallic electrodes working as resistors will break the membranes of the cells by a surge of temperature. This will release their DNA.
Real Time PCR block containing a mixer and a reservoir with metallic electrodes working as resistors to heat the extracted DNA.
Detection block containing a laser, filters and photodetector. A continuous reading system must be developed in order to measure cycle by clycle the amplified DNA. The integration of developed waveguides and filters will be carried out depending on their performance.
Flood block consisting of a reservoir full with an alkaline solution to flood the channels.
The base unit will have the electronics plus two photodiodes and a standard laser to excite the dye laser. Neither the light source nor detectors are demanding high quality alignment (dye laser feature) to provide easy replacement of the disposable labcard due to fluorescence allows multimode waveguiding (large waveguides). The alignment of the labcard with the laser source and photodiodes can be realistically done by mechanical alignment marks.