Hemoglobin-based high-throughput assessment of lyoprotectant efficacy

Area of Science:

• Biopharmaceutical stabilization
• Lyoprotectant characterization
• Protein formulation science

Background:

• Biologics require lyoprotectants to prevent degradation during drying.
• Existing assays for lyoprotectant efficacy are limited.
• Hemoglobin serves as a model protein for studying desiccation damage.

Purpose of the Study:

• To develop a high-throughput assay for screening lyoprotectant efficacy.
• To quantitatively assess the protective properties of various compounds during freeze-drying.
• To elucidate the mechanisms by which lyoprotectants stabilize proteins.

Main Methods:

• Developed a hemoglobin oxidation assay as a high-throughput screening platform.
• Quantified lyoprotectant efficacy using the IC50 (concentration for 50% inhibition of oxidation).
• Employed all-atom molecular dynamics simulations to study protein-carbohydrate interactions.

Main Results:

• Raffinose showed the strongest molar protection, while mass-based concentrations revealed similar efficacy across tested carbohydrates.
• Molecular dynamics simulations indicated larger carbohydrates form more hydrogen bonds and surface coverage on hemoglobin.
• These sugars displace water and form a protective coat, suggesting water replacement and surface coverage are key stabilization mechanisms.

Conclusions:

• The integrated experimental-computational framework provides a quantitative method for evaluating lyoprotectants.
• Water replacement and surface coverage are identified as principal mechanisms for sugar-mediated stabilization during drying.
• This approach can advance the discovery and design of optimal stabilizers for freeze-dried biologics, including red blood cells.