Ligands are immobilized in a matrix format (spots array). Different techniques are available to immobilize the ligands. We offer either contact spotting (SPRi-Arrayer) or flow printing (SPRi-CFM printer). For low-throughput applications, it is also possible to use manual spotters.
Contact spotting is very flexible and fast. It requires very low volumes, and up to several hundred different spots can be deposited. Different spot sizes can be chosen. The spot size depends on the number of spots on the surface of the prism and the type of needle used. The spot diameter can vary from 140 μm to 700 μm. Contact spotting can only be used with 2D surface chemistries.
Flow printing enables printing ligands in a 4x12 matrix in a single run. Up to three printings can be repeated on our SPRi-Biochip or SPRi-Slide. Each spot has its individual network of inlet and outlet tubes, reducing the risks for cross contamination. The ligand is immobilized using a back- and forth motion for increased spot homogeneity. Flow printing can be used with both 2D and 3D (Dextran-based) surface chemistries.
The user can randomly spot the biomolecules with a pipette by depositing a droplet of solution on the biochip surface. The imaging helps the user to select the spots easily. Two manual spotters are also available (Manual SPRi-Arrayer and Micropipette spotter).
The Manual SPRi-Arrayer is a manual, compact and easy-touse tool for printing molecules. It is a good start in microarray assays before scaling up to automatic printing. It allows carrying out a regular matrix at low cost.
The Micropipette spotter allows designing rapidly a 16-spot matrix thanks to a micropipette without cross contamination. This tool is adapted to SPRi-Biochips and SPRi-Slides.
To prepare a SPRi (Surface Plasmon Resonance imaging) experiment, there are several questions to consider beforehand:
An SPR experiment is composed of several steps, from ligands immobilization to data analysis. The choice of biochip surface chemistry, running buffer and regeneration solution depends on the nature of the ligands and potential analyte20.