Hydroxyapatite is formed from the chemical combination of calcium and phosphate salts. The crystalline material so derived is widely used in analytical and preparative biomolecule research, as well as in industrial production of biologically active substances. However, the fragility of the crystals limits flow rates and column longevity. In the 1980s, scientists discovered how to agglomerate and sinter the crystals at high temperature to form robust spherical, macroporous beads that could withstand very high flow rates and pressures without breakage. This is the material that is manufactured today and used for the fractionation and purification of a wide variety of biological molecules as described in this guide. Product descriptions and specifications are provided in Chapter 2. Two types of chemically pure ceramic hydroxyapatite, CHT™ ceramic hydroxyapatite Types I and II, are produced. The duration and temperature of the sintering step determine whether the ceramic hydroxyapatite is CHT Type I or Type II. CHT is a mixed-mode resin. Details of the binding mechanism are described in Chapter 3.
CHT is a leading purification medium of biomolecules in today's demanding downstream process industry. Its mixed-mode support offers unique selectivities and often separates biomolecules that appear homogeneous with other chromatographic methods. The diverse binding capabilities of CHT for host cell proteins, leached protein A, antibody dimers and aggregates, nucleic acids, and viruses allow its use at any stage from initial capture to final polishing.
The properties of CHT ceramic hydroxyapatite improve efficiency, yield, and financial value through:
- Excellent capture at elevated flow rates enabling processing at all scales
- Large capacity for higher-titer upstream feedstocks
- Exceptional selectivity allowing for a two-step chromatographic process
This is a guide for the use of CHT as a media support in your purification process. The guide is organized into five main topics:
- Product Description
- Regeneration, Sanitization, and Storage
- Column Packing Protocols
- Case Studies
Throughout this guide, we have incorporated recommendations ranging from method scouting and optimization to column packing techniques that represent feedback from process chromatographers worldwide. Should you have further questions, contact either your local Bio-Rad process chromatography sales representative or the Bio-Rad chromatography technical support department at 1-510-741-6563 or 1-800-876-3425 extension 6563. You can also send an email to Isg_techserv_us@bio-rad.com.