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Updated: Jul 7, 2026

Synthesis, Hemoglobin Encapsulation and Biorthogonal PEGylation in Hierarchically Porous UiO-66 Nanoparticles for Oxygen Delivery Applications
Published on: May 8, 2026
Modulation of O2 Affinity and Enzymatic Activity of Core‒Shell Structured Hemoglobin Nanoparticles
Ryo Hoshiya1, Tomoka Araki1, Teruyuki Komatsu1
1Department of Applied Chemistry, Graduate School of Science and Engineering, Chuo University, Bunkyo-ku, Tokyo, Japan.
None:
Hemoglobin-based O2 carriers (HBOCs) are promising substitutes for red blood cells (RBCs), but their performance depends critically on optimized O2 affinity and stability of oxygenated hemoglobin (oxy Hb). In this study, we report the precise modulation of both O2 affinity and enzymatic (antioxidant) activity in core-shell structured stroma-free Hb nanoparticles (X-SFHbNPs, X = human serum albumin (HSA) or poly(2-ethyl-2-oxazoline) (POx)). Low-affinity nanoparticles (X-SFHbNPLs) were prepared from deoxy Hb (T-state), and circular dichroism (CD) analysis indicated that the core Hb retains a T-state-like structure even under oxygenated conditions. Blending high- and low-affinity nanoparticles enabled fine tuning of O2 affinity. POx-SFHbNP preserved the intrinsic catalase (Cat), superoxide dismutase (SOD), and carbonic anhydrase (CA) activities of the parent SFHb. Moreover, POx-Hb(Cat/SOD/CA)NPs, prepared by incorporating elevated levels of these enzymes into purified Hb, exhibited enhanced enzymatic activities. Both X-SFHbNPs and X-Hb(Cat/SOD/CA)NPs showed excellent resistance to oxidation, with negligible metHb formation after 2 h in aqueous H2O2. These multifunctional Hb nanoparticles provide a versatile platform for advanced HBOCs with tunable O2 transport and antioxidant capabilities. Furthermore, X‒SFHbNPs showed reduced binding affinities toward haptoglobin, a Hb-binding plasma protein.
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