Table 1.

Summary of wound healing studies evaluating the antimicrobial properties of CS-based NPs, CMCSNPs, and CS-modified metal NPs in vitro.

NP formulation	Active ingredient	Encapsulation efficiency	Size	Surface charge	Microbe	Key findings	Ref.
Blank CS-based NPs
CSNPa	–	–	141.20 nm†	–	S. aureus, P. aeruginosa	• Dose-dependent antibacterial activity was observed against S. aureus. • Consistent antibacterial activity was observed for all concentrations of CSNPs against P. aeruginosa (63% – 69%).	[113]
CSNPa	–	–	77 nm†	> +30.00 mV	S. aureus, E. coli	• CSNPs displayed dose-dependent bacterial inhibition. • Higher inhibitory effects were observed against S. aureus (<50% survival) compared to E. coli (>50% survival).	[112]
CSNPa	–	–	208.40 ± 15.70 nm†	+24.20 ± 3.90 mV	S. aureus, E. coli	• CSNP-loaded calcium alginate hydrogels exhibited a dose-dependent antibacterial effect with greater effects against S. aureus than E. coli. • CSNP-loaded calcium alginate hydrogels had significantly higher antibacterial activity than CS-calcium alginate hydrogels.	[75]
Therapeutic compound loaded CS-based NPs
Lecithin-coated CSNPa	Tigecycline (TGC)	22%	235 ± 20 nm†	+19 ± 5 mV	S. aureus	• TGC-loaded CSNPs had significantly lower minimum inhibitory concentration (MIC) values than TGC-loaded lecithin-coated CSNPs. • Unloaded CSNPs had consistently lower MIC values than unloaded lecithin-coated CSNPs. • The MIC values for unloaded CSNPs, TGC-loaded CSNPs, lecithin-coated CSNPs, and TGC-loaded lecithin-coated CSNPs were 0.3, 0.1, 1.2, and 0.4 mg, respectively.	[125]
CSNPb	SSD	89.71% ± 11.01%	51.67 ± 12.55 nm†	–	S. aureus, P. aeruginosa, E. coli, B. subtilis, C. albicans	• SSD-loaded CSNPs showed higher antibacterial activity against Gram-positive bacteria than Gram-negative bacteria. • Antifungal activity of SSD-loaded CSNPs ranged from 20.35% – 36.85% reduction rates.	[126]
CSNPa	Cefazolin (CEZ)	94.80% ± 0.47%	227.40 nm†	+48.80 mV	S. aureus	• Sodium alginate and pectin films containing the CEZ-loaded CSNPs achieved 100% inhibition at 24 h incubation.	[127]
CSNPa	CUR	99.93% ± 3.43%	279.70 ± 20.30 nm†	+52.40 ± 1.50 mV	S. aureus, P. aeruginosa	• Similar inhibitory activity was observed for both S. aureus and P. aeruginosa for all treatment groups. • CUR-loaded CSNPs had significantly higher inhibitory activity than blank CSNPs. • At 1000 µg, CUR-loaded CSNPs had a ZOI of ∼25 mm while the positive control, gentamicin had a ZOI of 25 – 30 mm for both S. aureus and P. aeruginosa	[128]
Gelatin/CSNPc	EGCG	45.80% ± 3.70%	236.60 ± 7.80 nm†	+28.90 ± 1.20 mV	S. aureus, P. aeruginosa, E. coli	• EGCG-loaded gelatin/CSNPs with gentamicin had significantly larger ZOI than commercial AquacelⓇ Ag+ dressings. • Largest ZOI was observed in P. aeruginosa followed by S. aureus, and E.coli.	[129]
CSNPa	H. pineodora	27.56%	158.70 nm†	+24.10 mV	S. aureus, MRSA, P. aeruginosa, E. coli, B. subtilis, B. cereus, P. mirabilis, S. typhimurium, Yersinia sp., K. pneumoniae, S. boydii, A. anitratus, C. albicans, C. utilis	• H. pineodora encapsulated in CSNPs had significantly larger ZOI than H. pineodora essential oil, CSNPs and chloramphenicol across all microorganisms tested except for C. albicans. • H. pineodora encapsulated in CSNPs showed 90.0% – 99.9% synergism between the H. pineodora and CSNP. • Up to 83.03% and 80.71% reduction in colony counts were observed in an in vitro collagen wound model and simulated wound fluid, respectively.	[119]
CSNPa	Insulin	77%	294.50 ± 21.92 nm†	+17.89 ± 0.74 mV	–	• Samples treated with wound dressings containing insulin-loaded CSNPs had lower microbial penetration across the wound dressing. • Optical density of the Brain heart infusion broth of the positive control (absorbance≈30) was significantly higher than dressings containing insulin-loaded CSNPs (absorbance<5), by Day 7.	[130]
CMCSNPs
CMCSNPd	OH30	82.46 ± 1.11%	258.70 ± 13.30 nm†	+30.20 ± 5.10 mV	E. coli	• OH30-loaded CMCSNPs sustained 100% antibacterial activity while the unloaded CMCSNPs peaked at less than 50%.	[120]
CMCSNPe	OH30	92.14 ± 1.05%	164.60 ± 5.00 nm†	−37.60 ± 1.50 mV	S. aureus, E. coli	• Dressings containing OH30-loaded CMCSNP produced >80% antibacterial activity against both S. aureus and E. coli. • Unloaded dressings produced around 40% and 20% antibacterial activity against S. aureus and E. coli, respectively.	[121]
CS-modified metal NPs
CS-ZnONP ||	ZnO	–	∼180 nm¶	–	S. aureus, E. coli, M. luteus	• Nanocomposites loaded with CS-ZnONPs had higher antimicrobial activity on Gram-positive bacteria than Gram-negative bacteria. • At 7.5 wt% concentration, CS-ZnONPs had ≈1.6, ≈3.0, and ≈3.0 antibacterial activity against E. coli, S. aureus and M. luteus, respectively.	[131]
CS-AgNP#	Ag	–	5 – 50 nm§	–	S. aureus, P. aeruginosa, E. coli	• CS-AgNPs cross-linked with genipin showed significant antimicrobial activities and inhibition of bacterial growth. • The highest antimicrobial activity was observed in P. aeruginosa (ZOI≈4 mm), followed by E. coli (ZOI≈3 mm) and S. aureus (ZOI≈2 mm).	[132]
CS-SeNP#	Se	–	55 – 500 nm*	–	S. aureus, MRSA, E. coli	• No significant antimicrobial activity against E. coli. • CS-SeNPs achieved up to 52% growth inhibition in S. aureus and 54% growth inhibition in MRSA.	[133]
PVA/CS-AgNP#	Ag	–	190 – 200 nm†,§	–	S. aureus, P. aeruginosa, E. coli, M. luteus S. enterica, S. typhimurium, B. cereus, E. faecalis	• Higher AgNO3 concentrations in PVA/CS-AgNPs led to higher antibacterial activity. • PVA/CS-AgNPs showed highest inhibitory activity against S. aureus (ZOI=21 ± 1 mm) and M. luteus (ZOI=20 ± 0.5 mm). • PVA/CS-AgNPs showed the lowest inhibitory activity against E. coli (ZOI=13 ± 0.5) and S. typhimurium (ZOI=10 ± 0.1)	[134]
COS-AgNP#	Ag	–	15.70 ± 4.73 nm§	–	S. aureus, E. coli	• A significantly larger ZOI was observed in plates treated with COS-AgNPs than AgNPs. • Inhibition ratio of S. aureus treated with COS-AgNPs and AgNPs were ≈100% and ≈90%, respectively, after about 5 h. • Inhibition ratio of E. coli treated with COS-AgNPs and AgNPs were ≈80% and ≈60%, respectively, after about 5 h.	[123]
2-mercapto-1-methylimidazole (MMT)-CS-AuNp#	Au	–	10.07 ± 2.34 nm†	-	S. aureus, MRSA, E. coli	• MMT-CS-AuNPs had similar inhibition ratios (between 90% - 100%) as ampicillin for S. aureus and E. coli. • MMT-CS-AuNPs (>90%) had a significantly higher inhibition ratio than ampicillin for MRSA (10% – 20%).	[135]
CS-AgNP#	Ag	–	22.80 nm†	−45.90 mV	E. coli	• CS- AgNP-loaded CS films (62.22% ± 0.91%) produced the highest E. coli inhibition as compared to CS-AgNP solution (58.52% ± 0.52%), blank CS film (16.67% ± 0.91%), and CS solution (29.63% ± 1.05%).	[124]
CS-AgNP#	Ag	–	225.30 nm†	−21.40 mV	S. aureus, P. aeruginosa	• The MIC of CS-AgNPs (2.98 µg/ml) were significantly lower than unmodified AgNPs (4.68 µg/ml) and CS alone (3.10 µg/ml) against S. aureus. • The MIC of CS-AgNPs (1.92 µg/ml) were significantly lower than unmodified AgNPs (3.5 6 µg/ml) and CS alone (2.84 µg/ml) against P. aeruginosa.	[136]
CS-AgNP#	Ag	–	10 – 30 nm§	–	MRSA	• There was no significant difference in bactericidal activity against MRSA between CS-AgNPs, PVP-AgNPs, and AgNPs with all of them achieving 100% bactericidal activity at 8 µg/ml and having an IC50 of about 4 µg/ml.	[137]
CS-SER-AgNP#	Ag	–	96.93 ± 0.50 nm†	−0.42 ± 0.12 mV	S. aureus, MRSA, P. aeruginosa, S. epidermis, A. baumannii	• CS-SER-AgNPs (31.24 ± 0.43 mm & 29.17 ± 0.41 mm) had larger ZOIs than CS-AgNPs (15.33 ± 0.25 mm & 23.33 ± 0.58 mm) when tested against MRSA and P. aeruginosa, respectively. • CS-SER-AgNPs (11.25 ± 0.43 mm & 13.75 ± 0.43 mm) had smaller ZOIs than CS-AgNPs (27.00 ± 0.78 mm & 16.75 ± 0.50 mm) when tested against S. aureus and A. baumannii, respectively. • CS-SER-AgNPs (22.50 ± 0.53 mm) had similar ZOIs as CS-AgNPs (22.00 ± 0.76 mm) when tested against S. epidermis.	[138]
CS-SER-AgNP#	Ag	–	239.90 ± 1.56 nm†	+37 ± 3.6 mV	S. aureus, E. coli	• The ZOI of CS-SER-AgNPs (21.00 ± 1.50 mm) was larger than AgNPs (8.00 ± 1.50 mm) when tested against E. coli. • The ZOI of CS-SER-AgNPs (17.00 ± 1.45 mm) was larger than AgNPs (7.00 ± 1.00 mm) when tested against S. aureus.	[139]
CS-AgNP#	Ag	–	10 – 50 nm§	–	MRSA, P. aeruginosa	• MIC of CS-AgNPs (1.84 ± 0.17 µg/ml & 3.78 ± 1.70 µg/ml) were significantly lower than unmodified AgNPs (2.65 ± 1.40 µg/ml & 4.89 ± 1.80 µg/ml) and CS alone (3.84 ± 1.80 µg/ml & 5.10 ± 2.20 µg/ml) against P. aeruginosa and MRSA, respectively. • ZOI of CS-AgNPs (20 ± 0.2 mm & 18 ± 0.6 mm) were significantly higher than unmodified AgNPs (10 ± 0.9 mm & 9 ± 1.1 mm) and CS alone (12 ± 0.4 mm & 10 ± 1.8 mm) against P. aeruginosa and MRSA, respectively.	[140]
TMC-immobilised AgNP ‡	Ag	–	–	–	S. aureus, P. aeruginosa, E. coli	• Sponges loaded with TMC-immobilised AgNPs displayed antibacterial effects against S. aureus (ZOI≈7 mm), P. aeruginosa (ZOI≈8 mm), and E. coli (ZOI≈7 mm). • TMC and CS sponges did not show any antibacterial activity.	[110]

^aPrepared using ionic gelation method with TPP as a cross-linker;.

^bPrepared using ionic gelation method with carboxymethyl-β-cyclodextrin (CM-β-CD);.

^cPrepared by gelation of CS and gelatin mixture;.

^dPrepared using ionic gelation method with a mixture of CMCS and OH30;.

^ePrepared using electrostatic droplet method;.

^||Prepared using precipitation method;.

^#Prepared using chemical reduction method;.

^‡Prepared using template method;.

^†Size measured using dynamic light scattering (DLS);.

^¶Size measured using scanning electron microscopy (SEM);.

^§Size measured using transmission electron microscopy (TEM);.

^⁎Method used unspecified.