Controlled Fabrication of pH-Visualised Silk Fibroin-Sericin Dual-Network Hydrogels for Urine Detection in Diapers

Area of Science:

• Biomaterials Engineering
• Medical Diagnostics
• Smart Materials

Background:

• Urine pH monitoring is crucial for detecting systemic acid-base balance and renal disorders.
• Current methods are instrument-dependent or manual, posing challenges for infants and the elderly.
• A need exists for accessible, real-time urine pH monitoring solutions.

Purpose of the Study:

• To develop a pH-responsive smart hydrogel for integration into diapers.
• To enable equipment-free, real-time, and visually interpretable urine pH monitoring.
• To create a user-friendly diagnostic tool for vulnerable populations.

Main Methods:

• Fabrication of a dual-network hydrogel using silk fibroin-sericin and visible light photo-crosslinking.
• Optimization of sericin content for improved gelation time, mechanical strength, and water absorption.
• Incorporation and fine-tuning of natural anthocyanins for distinct colorimetric pH indication.

Main Results:

• The hydrogel exhibited rapid gelation (≤15 min) with enhanced mechanical properties (54 kPa max stress, 168% strain) and high water absorption (566%).
• Four distinct color changes (green, reddish-purple, blue) were achieved in response to varying urine pH levels, with improved color differentiation (ΔE).
• The hydrogel demonstrated a clear visual output: green for normal pH, and reddish-purple or blue for abnormal acidity or alkalinity.

Conclusions:

• The developed intelligent hydrogel system offers a promising, equipment-free platform for continuous body fluid monitoring.
• Its combination of rapid gelation, robust mechanical properties, and sensitive visual pH response addresses limitations of current monitoring methods.
• This technology has significant potential for early diagnosis and management of urinary and renal disorders, particularly in at-risk groups.