CAPTURE-CONVERT: A functional polymer platform for heme colour reduction in absorbent products

Overview

CAPTURE-CONVERT is a two-stage functional material system designed to reduce the colour of menstrual fluid within absorbent hygiene products. The technology addresses a long-standing challenge: removing the intense red colour associated with hemoglobin and heme without resorting to harsh bulk treatments that could compromise safety, comfort, or product performance.

The system works by first sequestering hemoglobin and heme within a functional polymer or hydrogel matrix engineered with specific binding groups. This concentrates the colour-bearing species in a controlled location. A mild, immobilized redox or catalytic component then promotes controlled alteration or degradation of the porphyrin structure—the part of the heme molecule responsible for its strong colour—while limiting exposure of the bulk fluid to reactive chemistry. The same matrix is designed to retain residual coloured or reactive by-products, preventing their release.

This approach offers a practical pathway to integrate effective colour reduction into absorbent product architectures, with candidate materials designed for dry storage, activation on wetting, and compatibility with existing manufacturing processes.

Technical specifications

Key features:

• Functional polymer/hydrogel phase with hemoglobin/heme-binding groups for selective capture and concentration of colour-bearing species
• Immobilized, mild redox/catalytic component for localized porphyrin alteration or degradation
• Matrix designed to retain residual coloured or reactive by-products
• Materials engineered for dry storage, activation on wetting, and compatibility with absorbent hygiene-product formats
• Built on demonstrated expertise in hemin/porphyrin chemistry, redox analysis, heme functionalization, and hemin-loaded hyaluronan hydrogels

Validation approach:

• Screening of functional polymers for hemoglobin/heme capture using purified hemoglobin and blood-relevant matrices, with quantification of binding and colour changes via UV–Vis/Soret spectroscopy
• Evaluation of mild conversion chemistries to maximize colour reduction while limiting persistent coloured or reactive products
• Integration of lead systems into absorbent-compatible coatings or layers, with optimization of active loading, contact time, fluid uptake, leaching, and dry-storage stability
• Prototype validation in whole blood, menstrual-fluid simulant, and, where feasible, menstrual fluid using CIE Lab/ΔE colour metrics, Soret spectroscopy, and by-product assays

Technology readiness level

The technology is at an early development stage, with a structured 6–12 month validation plan progressing through four decision-gated stages: polymer screening, conversion chemistry evaluation, integration into absorbent-compatible formats, and prototype validation. The approach is supported by the research team's established expertise in heme and porphyrin chemistry and hydrogel functionalization, providing a direct experimental foundation for rapid screening and optimization.