Abstract:
In this paper, through the novel one-step strategy, once mechanical mixing between chitosan polymer (dissolved in Fe
3+ solution with predetermined concentration, termed as CS-Fe) and 3,4-dihydroxybenzaldehyde (DBA) solution was completed, a brown hydrogel (termed as CS-DBA-Fe) could be instantly prepared
in situ as results of Schiff base reaction between CS and DBA, plus oxidation-coordination interaction between Fe
3+ and catechol groups. Multiple interactions, including coordination bond, covalent bond, hydrogen bond, π-π and π-cation interaction inside the CS-DBA-Fe crosslinking system were achieved simultaneously, leading to drastic versatile adhesion. What’s more, the obtained hydrogels also exhibited various merits, including tunable gelation time, adhesion strength and rheological properties, as well as outstanding surface adaptability and stability, rendering it a promising candidate of tissue adhesion materials for emergent situation. Lastly, though several traditional methods like reductive amination strategy (RA strategy) were developed, they usually involve prolonged reaction time, harsh reaction conditions and complicated purifying procedures. Herein, hydrogels prepared by RA strategy (termed as CCS-Fe) were used as the benchmark to further evaluate the adhesion strength of CS-DBA-Fe adhesives. Compared with the RA strategy, adhesives obtained by this method not only had better bonding strength (up to 48.8 kPa), and the preparation time was greatly shortened (from 72 h to less than 10 min). The one-step
in-situ preparation of tissue adhesive provides an important alternative for the facile preparation of biomimetic tissue adhesives.