contact-based, picolitre to nanolitre

Our contact-based Pin-Driven MicroDispensers (PinDMD) transfer the sample liquid with either blunt-end or capillary pins. The liquid is transferred as a small droplet, which hangs at the blunt end of a solid pin or the tapered end of a capillary. Both pin types are supported and custom-specific pins can be implemented upon request. M2-standard pin-heads can accommodate up to 36 pins (6x6).

Multiple pins are usually employed to increase sample throughput. The pins are held in place solely by gravity, and upon contact with the target surface, they can freely move upwards.  This ensures  that all pins contact the surface. The wettability of the target surface is a crucial parameter. It determines how much liquid is transferred, and it can even prevent it

contact based dispenser, pin head, pin spotting, pin holder, pin spotter

Key Features

  • 36 pins per head (6x6)
  • 4.5 mm dot-pitch
  • capillary or blunt end pins available
  • 80 µm to 500 µm tip diameter
  • single droplet volume 350 pL to 25 nL
  • absolute chemical inertness

Functional Principle

Blunt-end pins

The 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 are possible, as the pin needs to be immersed in the sample solution once again after each sample deposition.

Capillary pins

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 through evaporation, enabling hundreds of sample depositions to occur before the pin must be immersed in the sample solution again. Aliquots as little as 350 pL can be deposited. Important dispensing parameters are contact time and the acceleration of the upward movement assisting liquid transfer.

Capillary Pins

Sample aspiration and deposition with a capillary pin:

Capillary force fills the pin when immersed in liquid. Gravity ensures the liquid stays at the lower end during dispensing. Acceleration force of the upward movement assists the flow toward the surface.

Different Volumes

The orifice of the pin determines the transfer volume. Diameters between 80 and 500 µm are available for contact-based dispensing of 0.5 to 30 nL sample aliquots.