Crosslinker-Free, Printable Alginate-Boronic Acid Hydrogel Adhesive with Enhanced Mechanical Performance for Soft...

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Regenerative Medicine

Background:

• Tissue adhesives offer advantages over sutures for minimally invasive wound closure.
• Existing cyanoacrylate adhesives have limitations, driving research into hydrogel alternatives.
• Alginate hydrogels are biocompatible but require modification for enhanced adhesive properties.

Purpose of the Study:

• To synthesize and characterize a novel alginate-aminophenylboronic acid (Alg-APBA) hydrogel adhesive.
• To optimize the hydrogel for bioprinting applications with controlled layer thickness.
• To evaluate the adhesive's mechanical properties, stability, and biocompatibility.

Main Methods:

• Alginate was conjugated with aminophenylboronic acid (APBA).
• Synthesis was confirmed using 1H NMR, FTIR, and UV-VIS spectroscopy.
• Rheological analysis, mechanical testing, and in vitro cell studies were performed.

Main Results:

• Successful conjugation of APBA to alginate with ~46% substitution was achieved.
• The Alg-APBA hydrogel exhibited shear-thinning, self-healing, and high print fidelity (0.99 ± 0.08).
• The adhesive demonstrated a shear strength of 19.0 ± 0.5 kPa, interfacial toughness of 58.0 ± 2.11 J/m², and stability in acidic conditions, outperforming fibrin adhesives. It was also biocompatible with keratinocytes and fibroblasts.

Conclusions:

• Alg-APBA hydrogel is a robust, biocompatible, and printable adhesive.
• Its pH-responsive bonding and excellent mechanical properties make it suitable for soft tissue applications.
• This hydrogel represents a significant advancement for bioprinted tissue adhesives and soft tissue fixation.