# Hemocompatibility Evaluation of PEGylated Bovine Hemoglobin

## TL;DR

This study evaluates how well PEGylated bovine hemoglobin interacts with blood components, showing it is hemocompatible and suitable for use as an oxygen carrier.

## Contribution

The novel contribution is the detailed hemocompatibility evaluation of PEGylated bovine hemoglobin for potential clinical use.

## Key findings

- PEG-bHb preserved erythrocyte morphology and function without inducing eryptosis.
- PEG-bHb slightly disrupted coagulation parameters but did not compromise immunocompatibility.
- In vivo, PEG-bHb showed no adverse effects on erythrocyte function, coagulation, or inflammation.

## Abstract

Hemocompatibility is critical for intravenous hemoglobin-based oxygen carriers (HBOCs). We evaluated the hemocompatibility of polyethylene glycol-conjugated bovine hemoglobin (PEG-bHb) to facilitate its optimization and clinical translation. PEG-bHb was synthesized and characterized. In vitro hemocompatibility was assessed by incubating blood components with PEG-bHb (2.5–40 mg/mL), evaluating erythrocyte morphology/function, coagulation, complement activation, and leu kocyte phagocytosis. In vivo assessments in Wistar rats injecting PEG-bHb (50–100 mg/kg) included erythrocyte function, coagulation, complement activation, and histopathology. PEG-bHb exhibited increased hydrodynamic diameter, unaltered zeta potential, elevated colloidal osmotic pressure (COP) and viscosity, alongside a decreased P50 versus bovine hemoglobin (bHb). In vitro, PEG-bHb preserved erythrocyte morphology without inducing eryptosis, and oxygen supply efficiency was unaffected. Moreover, it slightly disrupted the activated partial thromboplastin time (APTT), the thrombin time (TT), and the platelet adhesion, while platelet activation and thromboelastography (TEG) remained unchanged. PEG-bHb did not activate complement and only mildly enhanced phagocytosis at 2.5 mg/mL. In vivo, PEG-bHb did not affect eryptosis, oxygen supply efficiency, coagulation, complement activation, and no inflammatory infiltration was observed. PEG-bHb maintains erythrocyte morphology and function, slightly perturb coagulation without compromising immunocompatibility, and demonstrated excellent hemocompatibility.