Table 2.

Biopolymer-based electrodeposition.

Acid-base Mechanisms	Details/Comments
Cathodic neutralization
Chitosan	Co-deposit various components (ceramics, nanoparticles, proteins) [42,149–152]
Chitosan derivatives (3,4-dihydroxybenzaldehyde) [153]	Co-deposit with gelatin for conformal coatings [96], osteoblast adhesion [154] and acetylsalicylic acid incorporation [155]
Collagen	Couple migration and assembly with calcium phosphate mineralization [156, 157]
Anodic neutralization
Alginic acid [142]	Deposition through anodic neutralization
Silk	Anodic gelation [158–164]
Hyaluronic acid	Anodic deposition of gentamicin-loaded silk fibroin coating [95] Co-deposit with nanoparticles and proteins [165–167]
Anodic Ca2+ solubilization
Ca2+-alginate [171, 172]	Co-deposit with cells [143,168–170] Co-deposit with agarose[173]
Modified alginate (RGD peptide for cell sheet fabrication) [168]
Anodic conversion of WO42− into isopoly-tungstic acid	Reversible complexation-based crosslinking of Konjac glucomannan polysaccharide [174,175]
Oxidation-Reduction Mechanisms	Details/Comments
Reduction
Ruthenium complex, Ru(bpy)2Cl2	Irreversible deposition [146]
Electroclick (Copper)	Coupling through azide and alkyne reactions [139]
Oxidation
Chitosan	Co-deposition with enzyme conjugation [176,177]
Catechol oxidation to quinone [144, 178]	Poly(allylamine hydrochloride) [145]
Fe (II) to Fe (III)	Tannic acid-Fe(III) complex [179]
	Fe3+ alginate assembly (can be reversed by electrochemical reduction of Fe3+ to Fe2+) [148] Poly(acrylic acid)—reversible [180]
Ferrocene as a mediator	Mediated oxidation of catechols to quinones to crosslink proteins [181]
[Fe(CN)6]4− to [Fe(CN)6]3−	Electrostatic interactions with cationic polyelectrolytes [182, 183]
Copper plate oxidation to Cu2+ ions	Electrostatic crosslinking of carboxymethylcellulose (CMC) [184]
	Coordination with chitosan for deposition [147]