The Virtual Laser Valve (VLV) technology enables the SpinX™ gCards™ to be user-programmed to suit a broad range of applications. A VLV connects two microfluidic structures at a precise location on the gCard which defines a precise volume of liquid. By applying centrifugal force at a controlled time, liquid moves through this newly created connection to a new chamber, where it can be combined with other liquids to create precise dilutions or biochemical reactions for controlled incubation times.
Creating VLVs
The VLV technology relies on focusing a high-radiance laser beam onto a microscopic area on the surface of a thin film which is specially designed to strongly absorb laser light. The film separates two plastic substrates containing microfluidic structures. A single laser shot, lasting no more than a few microseconds, is sufficient to perforate the film. This perforation creates a channel between microfluidic components (either channels or chambers) facing the film. This closed-to-open transition, when combined with the controlled application of centrifugal force, functions as a valve, allowing precise volumes of liquids to flow at precise times. The movement of liquid through the valves is robust because there are no moving parts or external mechanical or electrical contacts. And because the valves are created optically, there is no marginal cost for each valve.
Each gCard has the potential for 200,000 discrete valves, allowing for a great deal of assay flexibility.
Biologically Friendly Thanks to both the highly absorbent nature and the thinness of the film, the amount of energy required to achieve perforation is minimal. If the equivalent energy were absorbed in one microliter of water and fully converted into thermal energy, the temperature of the water would rise by less than 0.001 degrees. The wavelength used to create the valve is poorly absorbed by water or by the vast majority of biochemical substances. This explains why perforation can occur in the presence of the liquid, without inducing any measurable effect on the liquid. It has been experimentally verified that the Virtual Laser Valve is compatible with genomic DNA, proteins, bacteria, yeast, and mammalian cells.
It has been experimentally verified that the VLV is compatible with all biochemical samples of interest, specifically for genomic DNA, proteins, bacteria, yeast, and mammalian cells. In this example, Src kinase was loaded into microfluidic chambers which were then perforated with 600 VLVs. The enzyme was then collected and its activity compared to control.
