One of M2-Automaion's core technologies and part of every Microarray Spotter setup is our Microdispensing Technology. Providing a volume range from picoliter to microliter its suited for a variety of applications. Our contact and non-contact Dispensing Technology is capable of handling limited volumes of most sensitive aliquots, including experimental orientated Microarray Printing or a high throughput production of Diagnostic Chips.
If you have any questions or want to experience the possibilities of our Dispensing Technology for your Array Spotter, please do not hesitate to contact us.
The sample solution is transferred through the air towards the target as an individual small droplet, series thereof or a liquid jet. The main advantage of non-contact microdispensing is that the sample transfer does not depend on the properties of the target surface. The target surface is not touched - no damage, no contamination. The microdispenser and the properties of the sample liquid determine the spotting volume. Target surface structure and surface tension have no influence on the deposited volume. The wetted area on the target (spot size) is determined by the surface tension of both, the liquid and the target surface (e.g., hydrophobic versus hydrophilic). If up to a few hundred different samples need to be printed onto many targets, non-contact microarray spotting is the method of choice.
Our non-contact microdispenser can be classified by the target volume range (pL or nL) as well as the underlying functional principle. M2-Automation offers 3 lines of non-contact microdispenser:
pL-volume range - PDMD
Our non-contact Piezo-Driven MicroDispenser (PDMD) for the pL-volume range rely on ultrafast Volume Displacement (VD) and can dispense minimum 20 pL. PDMDs can dispense > 1000 droplets/s, therefore larger volumes can easily be transferred as well as a series of droplets in short time.
nL-volume range – M2MD04, SDMD
For the nL-volume range M2-Automation offers a whole range and two lines of microdispensers. These utilize either fast Volume Displacement (VD) as dispensing technique for maximum volume accuracy or, alternatively, employ a time-limited fast Flow-Based (FB) microdispensing for maximum flexibility. With the latter, two independent parameters, pressure and valve opening time, determine the droplet volume. If the pressure is raised to increase liquid ejection velocity, the valve opening time can be reduced to keep the ejection volume constant. Vice versa, if splashing occurs on the target surface, the liquid impact velocity can be reduced without reducing the volume. The fact that the flow velocity depends on the viscosity of the liquid limits the volume accuracy (5% variation if the ambient temperature varies by not more than 1%). This dependency is significantly reduced with VD enabling c.v. values of 2% or less for >50 nL dispense volume. For both techniques the minimum dispense volume is 10 nL.
Our proprietary M2-MicroDispenser generation 04 product line. These dispensers are available with both dispensing techniques. All include a solenoid valve and a shock wave generator producing pressure waves. An optional vial holder allows for bulk dispensing from an attached liquid reservoir (vial). Hydrophilic tapered glass capillaries as well as hydrophobic plastic tips are available as dispensing tips and can easily be exchanged by the user. With all these features M2MD04 offers maximum flexibility for non-contact liquid handling in the nL-volume range.
These dispensers utilize a very small solenoid valve with a directly attached short dispense capillary made of stainless steel. For that reason, our Solenoid valve-Driven MicroDispenser (SDMD) offer a minimum internal dead volume (< 35 µl), mostly of interest for bulk dispensing of precious (very expensive) liquids.
The sample solution is transferred from a pin to the target surface by a short contact. The main advantage of contact-based microdispensing is the ease of parallel spotting enabling high sample throughput. If a large number of sample solutions is to be spotted onto only a few targets contact-based microdispensing using many pins in parallel is the method of choice.
Our contact-based Pin-Driven Micro Dispenser (PinDMD) transfer the sample liquid with either blunt-end, split or capillary pins. The liquid is transferred as a small droplet hanging at the blunt end of a solid pin or the tapered end of a capillary (capillary pin). Both pin types are supported and custom-specific pins can be implemented upon request.
Pin is immersed in sample solution and after removal a small droplet hanging at the blunt end of the pin is transferred to the target surface. Only single transfers, after each sample deposition the pin needs to be immersed again in the sample solution.
The capillary provides a liquid reservoir that is filled by capillary force when the pin is immersed in sample solution. In contrast to split pins, the aspirated liquid is protected against solvent loss by evaporation enabling hundreds of sample depostions before the pin must be immersed again in the sample solution. Aliquots as little as 300 pL can be transferred.
Your microdispenser or
3rd party micro dispenser devices
M2-Automation offers custom-tailored solutions and is not limited to the use of its own micro-dispensers. Other companies on the market, for instance, offer non-contact microdispensing solutions for very viscous liquids and pastes (100-100.000mPas), which we do not have and might be necessary to meet your demands.
Or you have developed your own micro-dispenser and would like to get it implement in an M2-Automation microarray printing instrument. Another possible option is the implementation of our microdispensers or other components as well as software in your automation solution.