Dopamine-Modified Alginate Beads Reinforced by Cross-Linking via Titanium Coordination or Self-Polymerization and Its Application in Enzyme Immobilization

Abstract

Two novel kinds of dopamine-modified alginate beads were developed by using titanium(IV) coordination or self-polymerization, besides the conventional Ca2+ ion cross-linking. Alginate was modified with dopamine (AlgDA) via EDC/NHS chemistry. Fourier transform infrared spectroscopy (FTIR) and circular dichroism (CD) characterization confirmed that dopamine was covalently attached preferentially to the mannuronic acid residues of alginate; thus, gel-forming ability of the as-prepared AlgDA was well retained. The titanium(IV) coordination-reinforced alginate beads [Ca–Ti(AlgDA)] were prepared by cross-linking with Ti4+ and Ca2+. Covalently cross-linking-reinforced alginate beads (Ca–AlgPDA) were also prepared by self-polymerization of dopamine and cross-linking with Ca2+. The swelling of Ca–AlgPDA and Ca–Ti(AlgDA) were both obviously inhibited, and the mechanical properties were enhanced by 3 times compared to those of Ca–Alg beads. The as-prepared beads were utilized for immobilization of alcohol dehydrogenase (YADH). The immobilization efficiency of Ca–Ti(AlgDA) and Ca–AlgPDA reached up to 100% and 89%, respectively, both notably higher than that of Ca–Alg (67.4%). Stabilities of the immobilized YADH in Ca–AlgPDA and Ca–Ti(AlgDA) toward pH, storage, and recycling were all improved compared with those immobilized in Ca–Alg.

Regulatory parameters of self-healing alginate hydrogel networks prepared via mussel-inspired dynamic chemistry

“…39 Moreover, the characteristic new absorbance at 280 nm was used with the aid of a calibration curve to quantify the conjugation of DOPA onto the biopolymer (the absence of peaks at 4400 nm indicates no oxidation products). 20 In agreement with previous studies, 45 the characteristic IR peaks of the G and M residues of the alginate backbone in the region 810-950 cm À1 as well as those around 1120 cm À1 and 1610 cm À1 (stretching of hydroxyl and carboxylic groups, respectively) were also present in the Alg-DA samples. Moreover, a new peak at around 1080 cm À1 emerged upon functionalization and was attributed to the C-N stretching vibration.…”

Biodegradable Nanoparticles Enhanced Adhesiveness of Mussel‐Like Hydrogels at Tissue Interface

“…The wide range of dopamine grafting is achieved by altering the molar ratios of alginate to dopamine. The UV–visible absorption spectroscopy at 280 nm of the alginate–dopamine polymer revealed a dopamine content of 26%, which is close to the dopamine content in Mfp‐3, and also is within the range of dopamine content reported in other dopamine conjugated alginate polymers …”

“…The chemical structure of periodate oxidized alginate was confirmed by aldehyde CO stretching at 1720 cm −1 in the oxidized alginate spectrum (Figure S1B, Supporting Information). The alginate–dopamine polymer structure was verified by CC aromatic stretching and CN amine stretching at 1520 and 1091 cm −1 , respectively (Figure S1B, Supporting Information) . The dopamine content in mussel foot proteins (Mfps) varies from 10% to 15% in Mfp‐1, 2% to 4% in Mfp‐2, 25% in Mfp‐3, 5% in Mfp‐4, and 30% in Mfp‐5, whereas Mfp‐3 and Mfp‐5 are the proteins that contact the surface and help mussels adhere to wet surfaces .…”

“…The dopamine content in mussel foot proteins (Mfps) varies from 10% to 15% in Mfp‐1, 2% to 4% in Mfp‐2, 25% in Mfp‐3, 5% in Mfp‐4, and 30% in Mfp‐5, whereas Mfp‐3 and Mfp‐5 are the proteins that contact the surface and help mussels adhere to wet surfaces . Some research groups reported that the dopamine contents incorporated into alginate ranged from 10% to 42% . The wide range of dopamine grafting is achieved by altering the molar ratios of alginate to dopamine.…”

Polydopamine functionalized hydrogel beads as magnetically separable antibacterial materials

“…21, 22 Use of Ca 2+ to prepare alginate hydrogels and microbeads for cell or protein encapsulation and drug delivery has been reported. [22][23][24][25][26][27] Thaya et al demonstrated antibacterial activity of Ca 2+ cross-linked alginate/chitosan microspheres. 28 El-Aassar and Mo tested antibacterial activity of alginate microbeads containing silver nanoparticles (AgNPs).…”