MicroSI Affinity Chromatography is a miniaturized version of conventional affinity chromatography and uses traditional chromatographic supports: Sepharose and Sephadex, commercially available with a wide variety of bioligands. These ligands can be specific so that the antibody binds to only one epitope, or may be a group type ligand such as nucleotide analogues or Protein A or Protein G that will capture a group of selected compounds.

Example assay includes production of Monoclonal Antibodies and quality control of IgG’s is carried out in real time on Protein A, or Protein G Sepharose 6B microcolumns, shown here (top photo, right) adjacent to a fiber optic flow cell integrated within “lab-on-valve” module. Separation and assay is completed within 120 seconds, with detection limit of 6ng mouse IgG, monitored at 280nm.

Target analytes are eluted from a microcolumn by 10 microliter pulse of eluant and monitored with UV-VIS spectrophotometry that provides quantification of native IgG at 280nm or of labeled biomolecules by absorbance or fluorescence measurement.

Separation of Mouse IgG from bovine serum albumin on renewable microcolumn of Protein A Sepharose 6B. Sample : IgG 2mg/mL, BSA 4.6mg/mL.. Mobile phase PBS, pH=7.4. Eluant 1M HCl, volume 5μL. Column capacity 20mg/mL, column volume 10μL. Flow cell volume 6μL, optical path 3mm.

MicroSI Affinity Chromatography is applicable for either online process monitoring (e.g., cell cultures and bioreactors), or serial assays of discrete samples supplied manually or from an autosampler, and is compatible with the MicroSIA, FIAlab-3200, FIAlab-3500, and FIAlab-4000 systems with the SI LOV manifold.