Hydroxyapatite Microspheres: FAQs for Researchers

Hydroxyapatite Microspheres is a spherical calcium phosphate material widely used in chromatographic purification, drug delivery, and bone tissue engineering applications.

Chemical Name

Hydroxyapatite (calcium phosphate hydroxide)

Molecular Formula

Ca₁₀(PO₄)₆(OH)₂

Product Form

Spherical microspheres

Primary Applications

Protein/nucleic acid chromatography, drug delivery, bone scaffold fabrication

SKU

H128766

Material Class

Inorganic calcium phosphate ceramic

What Are Hydroxyapatite Microspheres?

Hydroxyapatite Microspheres (SKU: H128766) are spherical particles composed of hydroxyapatite (HA), a naturally occurring calcium phosphate mineral with the chemical formula Ca₁₀(PO₄)₆(OH)₂. HA is the primary inorganic constituent of bone and tooth enamel, giving it excellent biocompatibility and bioactivity. The microsphere morphology provides a high surface-area-to-volume ratio and improved flow characteristics compared with irregular granules, making these particles particularly suitable for column chromatography and controlled-release applications.

The material carries both positively charged calcium sites (C-sites) and negatively charged phosphate sites (P-sites) on its surface, enabling mixed-mode interactions with a wide variety of biomolecules including proteins, nucleic acids, lipids, and viral particles.

Key Applications of Hydroxyapatite Microspheres

Chromatographic Purification: HA microspheres are used as a stationary phase in hydroxyapatite chromatography (HAC) for the purification of monoclonal antibodies, plasmid DNA, recombinant proteins, and viruses. The dual-site (C-site and P-site) interaction mechanism offers selectivity complementary to ion-exchange and affinity chromatography, making HA chromatography a valuable polishing step in biopharmaceutical workflows.

Drug Delivery: The porous structure and surface chemistry of HA microspheres allow loading of small-molecule drugs, growth factors, and antibiotics. Controlled release from HA carriers is exploited in orthopedic and dental therapeutic applications.

Bone Tissue Engineering: Due to their compositional similarity to native bone mineral, HA microspheres serve as scaffolding materials and as injectable fillers that promote osteoblast adhesion, proliferation, and differentiation.

Cell Culture Microcarriers: HA microspheres can function as microcarriers supporting adherent cell growth in suspension bioreactor systems.

Handling, Storage, and Safety

Storage: Hydroxyapatite Microspheres should be stored in a cool, dry environment at room temperature, protected from moisture and mechanical shock. Keep the container tightly sealed when not in use to prevent adsorption of atmospheric CO₂, which can alter surface chemistry over time.

Handling: Standard laboratory personal protective equipment (PPE) — including gloves, safety glasses, and a laboratory coat — is recommended when handling the dry powder. Fine HA particles may become airborne; avoid generating dust and work in a well-ventilated area or use a fume hood when weighing or transferring the material.

Compatibility: HA microspheres are stable in aqueous buffer systems over a broad pH range (typically pH 5–9 for chromatographic use). Strong acids or chelating agents (e.g., EDTA, phosphate at high concentrations) can dissolve or degrade the material and should be avoided during equilibration and washing steps unless specifically required.

Disposal: Dispose of HA waste in accordance with local institutional and regulatory guidelines for inorganic laboratory materials.

Ordering and Specification Information

Hydroxyapatite Microspheres are available from Aladdin Scientific under SKU H128766. Researchers and procurement teams can place orders through the Aladdin Scientific website or by contacting the sales team directly. When placing an order, please confirm the required quantity, packaging size, and any project-specific purity or particle-size requirements.

For bulk quantities, custom particle size distributions, or surface-modified variants, please contact Aladdin Scientific technical support to discuss available options. A Safety Data Sheet (SDS) and product specification sheet are available upon request or downloadable from the product page.

Quality, Purity, and Grade Considerations

Hydroxyapatite Microspheres for research use are characterized by their Ca/P molar ratio, particle size distribution, specific surface area (BET), porosity, and phase purity as confirmed by X-ray diffraction (XRD). A stoichiometric Ca/P ratio of 1.67 is characteristic of pure hydroxyapatite. Deviations from this ratio may indicate the presence of secondary calcium phosphate phases such as tricalcium phosphate (TCP), which can affect chromatographic behavior and biological response.

For chromatographic applications, particle size uniformity and mechanical strength are critical to maintain consistent column back-pressure and resolution. For biological and tissue-engineering applications, sterility, endotoxin level, and absence of heavy-metal contaminants are important quality attributes. Please consult the product specification sheet or contact Aladdin Scientific for lot-specific analytical data.

Frequently asked questions

What is the chemical composition of Hydroxyapatite Microspheres?

Hydroxyapatite Microspheres are composed of calcium phosphate hydroxide with the formula Ca₁₀(PO₄)₆(OH)₂ and a stoichiometric Ca/P molar ratio of 1.67. This is the same mineral phase found in natural bone and tooth enamel, conferring inherent biocompatibility to the material.

Can Hydroxyapatite Microspheres be used for protein purification?

Yes. Hydroxyapatite Microspheres are widely used as a chromatography stationary phase for purifying proteins, including monoclonal antibodies and recombinant enzymes. The dual calcium (C-site) and phosphate (P-site) binding modes provide mixed-mode selectivity that is highly complementary to ion-exchange and affinity chromatography steps, making HA chromatography an effective polishing or intermediate purification method.

Are Hydroxyapatite Microspheres compatible with EDTA-containing buffers?

No. EDTA and other chelating agents bind calcium ions and will progressively dissolve or degrade the hydroxyapatite matrix, destroying the chromatographic medium and releasing calcium into your sample. Similarly, high concentrations of phosphate (typically above 200–500 mM) can displace bound molecules and may alter the material over time. These reagents should be excluded from mobile phases used with HA columns unless dissolution is specifically intended.

What particle size range is available for H128766?

Specific particle size data for SKU H128766 should be confirmed from the official Aladdin Scientific product specification sheet or by contacting technical support, as lot-specific values may vary. Particle size is a critical parameter for both chromatographic back-pressure and tissue-engineering scaffold architecture.

How should I store Hydroxyapatite Microspheres to maintain their performance?

Store Hydroxyapatite Microspheres in a sealed container at room temperature in a cool, dry location, away from moisture and CO₂. Prolonged exposure to atmospheric carbon dioxide can cause partial carbonate substitution on the HA surface, altering its chromatographic and biological properties. Once a container has been opened, reseal it promptly after each use.

How do I place an order for Hydroxyapatite Microspheres from Aladdin Scientific?

You can order Hydroxyapatite Microspheres (SKU: H128766) directly through the Aladdin Scientific website by searching for the product name or SKU. Alternatively, contact the Aladdin Scientific sales team by email or phone for assisted ordering, bulk pricing inquiries, or requests for a formal quotation. An SDS and certificate of analysis are available on request.

References

1. Kawasaki T. Hydroxyapatite as a liquid chromatographic packing. Journal of Chromatography A. 1991;544:149–168.
2. Bernardi G. Chromatography of proteins on hydroxyapatite. Methods in Enzymology. 1971;22:325–339.
3. Dorozhkin SV, Epple M. Biological and medical significance of calcium phosphates. Angewandte Chemie International Edition. 2002;41(17):3130–3146. doi:10.1002/1521-3773(20020902)41:17<3130::AID-ANIE3130>3.0.CO;2-1

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.