Table 2.

Novel bio-inks for 3D printings based on chitosan.

Chitosan Blends	Material Dedication	Rheology	Toxicity/ Cell Proliferation	Biodegradability Swelling Ratio	Comments	Bibliography
Carboxymethyl Chitosan-Based Bioink: Ethylenediaminetetraacetic acid (EDTA) stabilized with 0.5 M calcium chloride	Cartilage tissue	Storage modulus G′ at 23 °C: 112 kPa	Rabbit chondrocytes; flow cytometry; 95:9 ± 1:3% After 36 h seeded on mesh; similar proliferation rate between the control group (9:9 ± 0:7%)	Swelling ratio: 14–22% weight increase after 22 days in water	Bioprinting of scaffolds for cells	[277]
Cell-Laden Thermosensitive Chitosan Hydrogel Bioink: β-glycerophosphate Potassium phosphate Sodium bicarbonate	Development of chitosan-based bioink	Storage modulus G′ at 36 °C: around 1000 Pa	Human periodontal ligament stem cells; WST (Colorimetric assay for the nonradioactive quantification of cell proliferation, cell viability, and cytotoxicity )assay showed that there was no significant difference in cell viability until day five	Lack of information	Cell encapsulation is associated with minimal cytotoxicity	[278]
Cell-laden hydrogels, bioink: Potato starch	3D bioprinting scaffolds for neural cell growth		Neuro-2a, mouse neuroblastoma cells LDH (Lactate Dehydrogenase)assay kit and fluorescent microscopy: viability after 10 days-10% and lower	Degradation time is decreasing with the addition of the potato starch component	Chitosan dissolution and crosslinking must be optimized	[279]
BMSCs-laden gelatin/sodium alginate/carboxymethyl chitosan hydrogel: Gelatin Sodium alginate Carboxymethyl chitosan	3D bioink for tissue scaffolds	Young modulus: 80–120 mPa	Bone mesenchymal stem cells (BMSC); Live/Dead cells staining: 85% of the printed cells were viable at 0 and 2 days of culturing	Biodegradation in 60 days in the physiological environment: 35–50% mass loss	Bioink showing antimicrobial properties towards E.coli	[280]
Fabrication of hydroxybutyl chitosan/oxidized chondroitin sulfate hydrogels: Hydroxybutyl chitosan (HBC) Oxidized chondroitin sulfate via Shift base reaction	Cell delivery system for cartilage tissue engineering	Turn into stabile hydrogel at 35 °C–40 °C, Storage modulus G′: −150–300 Pa for 50 mg/mL HBC concentration	Mesenchymal stem cells, Live/ Dead assay after via fluorescent microscopy; Cell viability was verified inside the hydrogels in 14 days, showing gradually spreading in the hydrogel with the appearance of pseudopodia	Lack of information	Injectable hydrogel with a porous structure of average 100 µm pore size was developed to form a microporous hydrogel	[281]
DLP printing photocurable chitosan: Methacrylic anhydride Lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP)	Photocurable bioink for digital light processing (DLP) technology for tissue engineering	Stress-strain for CHIMA (methacrylated derivative of chitosan) 33.6% 80 kPa; CHIMA 44.6% 33.6% −150 kPa	Human umbilical vein endothelial cells (HUVECs); LIVE/DEAD Viability/Cytotoxicity kit: Viability for 4 examined samples oscillated around 90% after 3 days from incubation	The swelling ratios of hydrogels 11.7–33.6% DS exhibit a decreased trend from 500% to 150% 2 during the incubation time	The CHI-MA (1 wt%) with 33.6% DS was selected as the photocuring bioink for DLP	[282]
Photocurable chitosan as bioink Methacrylated chitosan Β-glycerol phosphate salt (β-GP)	Bioink for cellularized therapies towards personalized scaffold architecture	40 s of exposition at 37 °C initiate crosslinking bioink: Storage modulus G’: −90–100 Pa	NIH, 3T3, Saos-2, SH-SY5Y cell lines; LIVE/DEAD Viability/Cytotoxicity kit, fluorescence microscopy: viability: around 95–115% compering to control, after 24 h	Decreased mass of 55% after 14 days of incubation in the cultured medium at 37 °C; thermogravimetric analysis	Bioink did not adversely affect the hosting cells and allowed cell proliferation and organization towards tissue formation.	[196]
Chitosan ducts fabricated by extrusion-based 3D printing Formic acid Acetic acid Glycolic acid Lactic acid	Soft tissue restoration	Young modulus: 12.38 ± 1.19 MPa	MTT test on L929 mouse fibroblast cell line for 24 h cell viability of CS ducts prepared by 30% GA close to 90%	Stable after soaking in two weeks in Tris-HCl with the addition of lysozyme	The 30 wt.% GA was optimal based on tensile properties and preliminary cytotoxicity	[283]
Chitosan-calcium phosphate inks: Calcium Phosphate Acetic acid orthophosphate solutions	Bioinks as potential bone substitute	For all other inks, Loss modulus G″ were higher than G′ from the start, thus the inks were liquid-like	Not tested	Lack of information	More printable inks are obtained with higher chitosan concentration (0.19 mol·L−1).	[284]
Cell-Laden Nanocellulose/Chitosan-Based Bioinks: Glycerophosphate Hydroxyethyl cellulose Cellulose nanocrystals	Bioprinting and enhancing cell differentiation for bone tissue	Viscosity in the range of 30 Pa·s–6 × 104 Pa·s; Yield stress 412.35 ± 45.35 pa	MC3T3, a pre-osteoblast cell line; Live/Dead cell staining kit; after 7 days incubation in media at 37 °C there is neither significant proliferation nor cell toxicity	The shrinkage of scaffolds after 24 h incubation in DMEM (Dulbecco’s Modified Eagle Medium) at 37 °C ranges between 30–34%		[285]
Natural based poly(gamma-glutamic acid)/Chitosan bioink: Poly(gamma-glutamic acid)	Alternative to other materials used in 3D bioprinting	Storage modulus G′ around 50 Pa and 30 Pa for 4.5% and 6% Chitosan hydrogels	Human adult fibroblast: Cell viability after 14 days incubation of DMEM on bioink around 80%	35% Mass loss after 35 days incubation in cell medium	FTIR analysis demonstrated Gamma-PGA/Cs interpolyelectrolyte complex formation	[286]
A writable bioink under serum culture media: Catechol Vanadyl ions	Polymer for 3D printing	Storge modulus G′ value of the V-Chi-C gels at 1 Hz was gradually enhanced up to 6 ± 0.5 × 106 Pa at 168 hrs from 69 ± 18 Pa at 0 hr	LIVE⁄DEAD® Viability/Cytotoxicity Kit; 90% L929 cells viability after 5 days incubation on scaffolds	Weight loss down to 50% of initial mass at 12 h of incubation in PBS, and remained constant (40%) for next 7 days		[281]