Table 1:

Summary of materials, methods, and results from studies incorporating nanomaterials into 3DP scaffolds

Material(s)	Cell Type/ Animal Model	Method	Results	Citation #
HA scaffold. PCL NPs containing BMP-2	primary MSCs, rabbit model	Dip-coated particles onto scaffold	Improved ALP activity in MSCs; improved bone regeneration in rabbit calvarial defect	44
PEGDA/GelMA scaffold. PLGA nanospheres containing TGF-β1	primary MSCs	Mixed nanospheres with liquid ink before printing	Increased expression of genes associated with chondrogenic differentiation	51
PCL scaffold, polydopamine coating, PLGA NPs containing IGF-1	primary MSCs, primary rabbit chondrocytes	Coated scaffold with polydopamine before co-incubation with NPs	Enhanced cell viability; increased expression of chondrogenic markers	52
PEGDA scaffold, PLGA NPs containing BSA	PC-12 neural cells, primary cortical neurons	Mixed NPs with liquid ink before printing	Increased average neurite length and total neurite length in PC-12 cells	54
PVA and bioglass scaffold, chitosan/pDNA NPs	primary MSCs, rhesus monkey model	Added NPs and cells to printed scaffolds prior to surgical implantation	Improved bone regeneration in rhesus monkey mandibular model	53
PLLA scaffold, tubular and spherical polypyrrole NPs	L929 fibroblasts	Dissolved PLLA in solvent with NPs before printing, then lyophilized printed scaffolds	Inclusion of NPs was minimally cytotoxic; enhanced conductivity	55
PLLA scaffold, CaP NPs, BMP-2 and BSA protein	primary MSCs	PLLA emulsion mixed with CaP NPs and protein solutions before printing on a cryogenic stage, then lyophilized printed scaffolds	Improved compressive strength with addition of CaP NPs; trend of improved attachment and differentiation	59
Poly(ester urea) scaffold, HA nanocrystals	MC3T3-E1 cells	Dissolved poly(ester urea) in solvent with HA nanocrystals before drying and melting into filament, printed filament into scaffolds	Improved cell viability in 30% HA scaffolds; enhanced ALP activity; increased expression of both osteocalcin and bone sialoprotein	60
Alginate gel scaffold, SiO2 NPs	primary MSCs	Mixed NPs with liquid ink before extrusion	Improved compressive modulus and MSC viability; reduced swelling and degradation	61
Alginate gel scaffolds, ZnO NPs	MITC-STO fibroblasts, S. epidermis	Mixed NPs with liquid ink before extrusion	Increased stiffness; antimicrobial properties; no cell toxicity observed	63
PCL scaffold, CNTs	H9C2 myoblast cells	Mixed CNTs with PCL in solvent before printing	Inclusion of CNTs did not impact cell viability; increased elastic modulus conductivity, maximum load, and hardness of scaffolds	45
Methacrylated collagen, alginate, and hybrid scaffolds, CNTs	primary endothelial cells	Mixed CNT solution with liquid ink before printing	Inclusion of CNTs did not impact cell viability; conductivity and mechanical properties were improved	65
PCL/polyethylene oxide scaffold, CNTs	H9C2 myoblast cells	Mixed CNTs with PCL/polyethylene oxide solution before printing	CNTs decreased cell attachment; cells could still proliferate and align with scaffold	66
PEGDA scaffold, CNTs	neural stem cells	Mixed CNTs with liquid ink before printing	Increased average neurite length; electrical stimulation induced neuronal gene expression	67
PCL scaffold, CNTs	primary MSCs	Mixed CNTs with melted PCL before printing	CNTs improved hardness, elastic modulus, compressive modulus, and viability	68
PPF scaffold, ssDNA/CNT nanocomplexes	MC3T3-E1 cells	Printed PPF scaffolds which were then ammonolyzed and coated with ssDNA-CNT complexes	Toxicity and aggregation of CNTs reduced; increased scaffold conductivity; enhanced expression of osteogenic markers	69
PEEK scaffold, silver NPs, polydopamine coating	MG-63 osteoblast-like cells, E. coli, S. aureus	Sequentially dip-coated with polydopamine and then silver nitrate, followed by UV exposure to form silver NPs	Silver NPs conferred antibacterial activity; slight decrease in cell viability	46
Alginate gel scaffold, iron oxide NPs	primary endothelial cells	Mixed NPs with liquid ink before printing	NPs can be magnetically manipulated within cells and within scaffold; NPs are trackable with μCT	72
PCL scaffold, TiO2 NPs	MC3T3-E1 cells	Mixed NPs with polymer solution before casting in 3DP-derived scaffold cast	Improved mechanical properties; no effect on ALP activity	73
GelMA scaffold, gold NPs	primary MSCs	Mixed NPs with liquid ink before printing	NPs were visible with μCT; no effect on cell viability	74