Upon which targets can we dispense, print, spot?
The variety of possible targets that can be dispensed upon is infinite.
From the good old microscope slide to the highly complex biochemical sensor, from the simple nitrocellulose membrane to 3D structures in microfluidics: Our microdispensing instruments can handle any target.
The targets are often held in place by a vacuum table, but they are sometimes held in place using various customer-specific clamping mechanisms meant to prevent slippage during the highly dynamic movements of the axis system.
- Glass Slides
- Polymer Slides
- Silicon Wafers
- Biochemical Sensors
- Semiconductor Biochips
- Microtiter Plates
- Peptide Chips
- Functionalised Foils
- Diagnostic Membranes
- Microfluidic Cartridges
- Microfluidic Channels
- Lab-on-a-chip applications
- 3D-Printed Structures
The concept of implementing a lab on a chip has revolutionised diagnostics and expands the application of biosensors. The vision and motivation to be able to make a complete analysis or diagnosis on site, at the bed of a patient, based on a mere droplet of biofluid, is what has driven the development of lab-on-a-chip applications. And products are already available on the market. In most cases, all components, including the biomolecules needed for specific binding and detection, are implemented in one low-cost, plastic device. Non-contact liquid handling has proven to be very efficient when it comes to the insertion of biomolecules and other reagents into the tiny channels or cavities of the chip.
Produced by injection moulding, these chips are popular in the mass production of financially competitive, multi-parameter diagnostic tests. As the most expensive parts of such chips are the immobilised biomolecules, handling pL or nL aliquots during production is mandatory, as is high-speed liquid deposition. Non-contact liquid handling is essential in order to achieve both.
A common and traditional application in medical labs is the performance of ELISA tests in medium to large scale. Modern, more efficient applications analyse 10, 20 or even 100 parameters, instead of only one in each well. This can save a lot of money and time. The key technology enabling this is non-contact liquid handling. As our iONE spotters are equipped with three high-speed, linear, magnetic drives (XYZ), they are the preferred spotter for high-throughput production. This is because dispensing the liquid from above the wells (across at distance of 1 cm or more) yields poor spotting results, due to electrostatic charges residing on the plastic surface and flight paths that are too long.
Biosensors are related to lab-on-a-chip devices, but they also stand alone, and the worldwide market for them is growing. Size matters: the smaller and lighter they are, the better. Low production costs are important too. Their detection specificity and sensitivity are determined by the immobilised biomolecules. They specifically bind to and, thereby, capture the target molecules to be detected. Depositing them in a solution onto tiny electrodes is a challenging element of their production, and non-contact dispensing is the method of choice to master this process. Structures as small as 50 µm can be individually addressed, and liquid can be deposited onto them without making the neighbouring, forbidden surfaces wet.
Using membranes for immobilising biomolecules is a well-established method in biochemistry and molecular biology for the detection of proteins and nucleic acids. PVD and nitrocellulose are the most common materials used, and Western Blotting is the best-known application. Although they have been around for many years, their popularity has not declined. Both provide, on a microscopic level, a large surface to which many biomolecules bind very well without additional chemical help. Non-contact deposition of many different biomolecules in close proximity is possible, and it enables efficient analysis. Allergy tests that include several hundred instead of only a few known allergens are a prominent example.
Microscope slides are a standard carrier for a lot of different applications. Among them are immobilised microarrays of: oligonucleotides for gene-expression analyses, peptides for epitope mapping, proteins for autoantibody screening. Using hundreds or even thousands of different biomolecules in one experiment, instead of using only a few, opened the door for a new era of research. Today, DNA, peptide and protein microarrays are still powerful research tools. For their production, both contact-based and non-contact microdispensers are used to transfer the biomolecules onto the slide surface. If it’s for many different biomolecules on only a few slides, contact-based microdispensing using an array of pins is the best choice. If it’s for few biomolecules on many slides, then non-contact microdispensing is clearly superior, as no up and down moves are required for liquid deposition. This is one of the reasons we offer both techniques.
The surfaces of biochips and biosensors are anything but standard, in contrast to non-contact office printers where paper is the target surface. Custom-specific surfaces could be glass, ceramic or silicone, as well as all kinds of plastic. In many cases, those surfaces may have been activated by cold plasma treatment or other methods of surface modification. Additionally, the geometry surrounding the target surface is anything but standardised. That is why the microdispensing technique, the robotic platform, and the control software used for production must be adaptable and highly flexible.