Tangential flow filtration of hemoglobin

Area of Science:

• Biochemistry
• Biotechnology
• Biomaterials

Background:

• Hemoglobin (Hb) purification is crucial for developing Hb-based oxygen carriers.
• Traditional methods can be time-consuming and complex.
• Efficient purification is needed for therapeutic applications.

Purpose of the Study:

• To evaluate tangential flow filtration (TFF) for purifying bovine and human hemoglobin (Hb).
• To assess the purity, endotoxin levels, and oxygen-binding properties of purified Hb.
• To demonstrate TFF as a method for generating HPLC-grade Hb.

Main Methods:

• Purification of bovine and human hemoglobin (Hb) from red blood cells (RBCs) using tangential flow filtration (TFF) with hollow fiber (HF) membranes.
• Assessment of Hb purity using SDS-PAGE and HPLC.
• Measurement of endotoxin levels.
• Determination of oxygen affinity (P50) and cooperativity (n) from oxygen equilibrium curves.
• Molecular weight analysis of globin chains using LC-MS.

Main Results:

• TFF effectively purified Hb, with high concentrations achieved (318 mg/mL for bHb, 300 mg/mL for hHb).
• Purified Hb showed minimal methemoglobin (<1%) and significantly lower endotoxin levels than RBCs.
• SDS-PAGE and HPLC confirmed high purity, with accurate molecular weights for alpha and beta globin chains.
• Oxygen affinity and cooperativity of purified Hb were comparable to literature values.

Conclusions:

• Tangential flow filtration (TFF) is a fast, simple, and effective method for purifying bovine and human hemoglobin (Hb) to HPLC grade.
• The purified Hb retains functional oxygen-binding properties and exhibits high purity with low endotoxin levels.
• This TFF method is broadly applicable for Hb purification from various RBC sources, facilitating Hb-based oxygen carrier development.