Hemolysis Assay

The rapid expansion of hydrogel-based therapeutics—from wound dressings to 3D bioprinting inks—has made hemocompatibility a critical determinant of clinical success. Unlike rigid materials, hydrogels possess unique physicochemical properties such as high water content, swelling capabilities, and potential for degradation, which present specific challenges in biocompatibility testing. Hemolysis, the rupture of red blood cells (RBCs) and release of hemoglobin, serves as a primary indicator of acute toxicity under international standards like ISO 10993-4 and ASTM F756.

At Matexcel, we specialize in overcoming the technical artifacts common in testing "soft matter." Our Hemolysis Assay Services are engineered to provide precise, regulatory-compliant data that accounts for the osmotic and mechanical behaviors of hydrogels, ensuring that safety assessments reflect true physiological interactions rather than experimental errors.

Service Overview

Matexcel provides a comprehensive suite of hemolysis testing services designed to characterize the interaction between hydrogel biomaterials and erythrocytes. We employ a Lifecycle Assessment Approach, evaluating materials in their nascent, equilibrated, and degrading states to capture all potential toxicity profiles. Our protocols are adaptable to various stages of development, from early R&D screening to GLP-compliant validation for regulatory submissions.

Technical Principles

The core of our assay is the quantitative measurement of intracellular hemoglobin released into the plasma or supernatant following contact with the test material.

• Biological Mechanism: Hemolysis in hydrogels is typically driven by three mechanisms:

Osmotic Lysis: Hydrogels may rapidly absorb water from the blood suspension, creating a hypertonic environment that dehydrates and ruptures RBCs. Conversely, hypotonic elution can cause cell swelling.

Chemical Lysis: Residual monomers, photo-initiators, or surfactants can act as detergents, solubilizing the RBC lipid bilayer.

Surface-Mediated Lysis: Cationic surface charges (common in chitosan or antimicrobial gels) can attract and disrupt negatively charged RBC membranes via electrostatic interaction.

• Detection Method: We utilize the Cyanmethemoglobin (Drabkin's) Method for quantification. This converts all hemoglobin forms into a stable complex absorbing at 540 nm, ensuring accuracy. For turbid samples common with hydrogel degradation, we employ the Harboe Method (multi-wavelength correction) to subtract interference.

Technical Classifications

Our services are categorized based on the method of contact and regulatory requirements:

• Direct Contact Method (ASTM F756): The hydrogel is placed directly into the blood suspension. This is ideal for evaluating surface topography and charge-mediated toxicity.
• Extract (Elution) Method (ISO 10993-4): An extract of the material is generated using saline or culture media and then added to RBCs. This isolates the effect of leachable chemicals (e.g., crosslinkers) from physical surface effects.
• Dynamic/Mechanical Hemolysis: For materials used in blood flow environments (e.g., coatings), we circulate blood over the material to assess shear-induced hemolysis, differentiating it from chemical toxicity.

Applications

• Wound Dressings: Verification that hemostatic or exudate-absorbing gels do not lyse clots or cause secondary tissue damage.
• Injectable Hydrogels: Evaluation of liquid precursors and in-situ gelling systems for toxicity during the sol-gel transition.
• 3D Bio-inks: Ensuring printability parameters do not compromise cell membrane integrity, serving as a proxy for cytocompatibility.
• Blood-Contacting Coatings: Testing hydrophilic coatings on catheters for durability and hemocompatibility under flow.

Our Services

Matexcel offers robust testing packages comparable to industry leaders, tailored for the specific needs of hydrogel developers:

• Standard ASTM F756 & ISO 10993-4 Panels: Direct Contact & Extract Assays Performed with fresh human or rabbit blood. Report Including Hemolytic Index (HI) calculation and classification (Non-hemolytic: 0-2%, Slightly hemolytic: 2-5%, Hemolytic: >5%).
• Dynamic Flow Loop Testing: Custom circuits to simulate physiological shear stress for coatings and vascular implants.
• Degradation Product Analysis: Time-course hemolysis testing (24h, 48h, 72h) of hydrogel degradation products to detect delayed toxicity.
• Custom "Soft Matter" Protocols: Adjusted blood-to-material ratios for highly absorbent materials, spectral scanning (200-700 nm) to identify drug interference in drug-eluting gels.

Company Service Advantages

• Scientific Problem Solving: We do not just report failures; we perform Root Cause Analysis (e.g., checking for osmotic shock vs. chemical toxicity) to help guide your formulation.
• High-Throughput Screening: Rapid screening of multiple hydrogel formulations (e.g., varying crosslinker %) using 96-well plate formats for early-stage R&D.
• Regulatory Support: Our reports are formatted for direct inclusion in FDA 510(k) and CE Mark technical files, complete with validation data (LOD/LOQ) and statistical analysis.

Contact us

Hemolysis testing for hydrogels requires more than a standard protocol; it demands a deep understanding of polymer physics and hematology. Matexcel provides the expertise to navigate these complexities, ensuring your biomaterials are rigorously validated for safety. By controlling for artifacts like swelling and turbidity, we deliver data that is not only compliant but scientifically robust, accelerating your path to clinical application.

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