Table 1.

Studies demonstrating the efficacy of antimicrobial coatings based on non-functionalized and functionalized chitosans

Coating	Material	Medical application	Species	Major conclusions	Reference
Chitosan	Polyethylene cathetersa,b	Central venous catheters and other medical devices	C. albicansf C. parapsilosisf	In vivostudies: The fungal burden on CS-treated catheters reduced by 2.5-fold compared with untreated catheters. SEM images demonstrated that biofilms formed on untreated catheters were more extensive than on CS catheters. In vitrostudies: The viability of Candida sp. biofilms reduced 95% after 30 min.	(Martinez et al., 2010b) d
	Polystyrene microtiter platesb	Indwelling medical devices	C. neoformansg	C. neoformans biofilms formed in the presence of 0.312 mg/mL CS reduced their metabolic activity by 80%. Mature biofilms also significantly decreased their metabolic activity and viability (p< 0.001) after 30 min.	(Martinez et al., 2010a) e
	Siliconeb	Implantable devices or biosensors	S. aureush	Results demonstrated that S. aureus biofilm formation was suppressed on CS-coated silicone films. In addition, biofilm metabolic activity on CS films reduced 60% compared to the uncoated films.	(Bulwan et al., 2012) d
	NDb	Indwelling medical devices	K. pneumoniaei	Chitosan (0.0625 mg/mL) induced a biofilm reduction of 86.5%.	(Magesh et al., 2013) e
	Glassb	Indwelling medical devices	C. albicansf	Results demonstrated that 0.0313% CS killed more than 50% of cells in the early and intermediate phases of biofilm development.	(Pu et al., 2014) e
	Polyurethane filmsb	Indwelling medical devices	P. aeruginosaj S. aureush	Chitosan (0.5%)-coated films reduced P. aeruginosa and S. aureus biofilm viability to 24.0% and 51.7%, respectively.	(Kara et al., 2014) d
	Polystyrene filmsb	Indwelling medical devices	A. baumanniik	A. baumannii adhered to CS-coated films showed a reduction of biomass and metabolic activity of 93% and 43%, respectively; biofilm biomass and metabolic activity were also inhibited by 80% and 39%, respectively.	(Costa et al., 2017) e
	Foley urinary catheter segmentsb	Urinary catheters	E. colil K. pneumoniaei	High and low molecular weight CS reduced bacterial adhesion by 70% and 58%, respectively. A low percentage of viable K. pneumoniae and E. coli cells (about 20%) were recovered from catheters after CS treatments.	(Campana et al., 2017) e
	Foley urinary catheter segmentsb	Urinary catheters	E. colil K. pneumoniaei	After 48 h, CS-coated catheters were able to reduce K. pneumoniae and E. coli biofilm formation up to 6.3 Log.	(Campana et al., 2018) e
	Silicone catheters segmentsb	Urinary catheters	C. albicansf S. epidermidish	CS-coated catheters inhibited C. albicans, S. Epidermis, and mixed biofilms by 68%, 65%, and 60%, depending on their development stage.	(Rubini et al., 2021) d
Low molecular weight CS	Polyurethane-like catheters segmentsb	Central venous catheters	A. baumanniik C. albicansf S. epidermidish S. aureush	Chitosan (78 mg/mL) reduced the biofilm metabolic activity of S. epidermidis by 80.5%, CS (5.0×103 mg/mL) reduced the C. albicans biofilm metabolic activity by 87.5% and 90.0% after 24 and 48 h, respectively.	(Cobrado et al., 2012) e
	Polyurethane catheter segmentsa	Central venous catheters	A. baumanniik C. albicansf S. epidermidish S. aureush	The metabolic activity and total biomass of S. epidermidis biofilms decreased by 57.6% and 41.3%, respectively, in CS catheters (80 mg/mL CS). In turn, C. albicans biofilms reduced their metabolic activity and biomass by 43.5% and 23.2%, respectively, in treated catheters (2.5x103 mg/mL).	(Cobrado et al., 2013) d
Functionalized-CS
Carboxymethyl chitosan	Silicone pre-treated with polydopamineb,c	Medical devices	E. colil P. mirabilism	Carboxymethyl CS coating reduced E. coli and P. mirabilis adhesion by more than 90% after 4 h. Biofilm formation was also inhibited on CS coating under static and flow conditions.	(Wang et al., 2012b) d
	Silicone filmsb	Indwelling medical devices	C. tropicalisf C. parapsilosisf C. kruseif C. glabrataf	Candida spp. biofilm formation was inhibited by 70% for single-species and 73.4% for multi-species biofilms.	(Tan et al., 2016c) e
	Medical-grade siliconeb,c	Voice prosthesis	C. albicansf C. tropicalisf L. gasserin R. dentocariosao S. epidermidish S. salivariusp	Carboxymethyl chitosan-coated films displayed a surface coverage of 4% less than untreated films.	(Tan et al., 2016b) e
	Medical-grade siliconeb	Voice prosthesis	C. albicansf C. tropicalisf L. gasserin R. dentocariosao S. epidermidish S. salivariusp	Carboxymethyl CS inhibited the adhesion of fungi and bacteria with an efficiency greater than 90%. CS coatings inhibited mixed biofilm formation by 73% and decreased their metabolic activity by more than 60%.	(Tan et al., 2016a) e
	Medical-grade siliconeb,c	Indwelling medical devices	C. tropicalisf S. epidermidish	After 90 min, more than 90% of cells were unable to adhere to carboxymethyl CS (2.5 mg/mL)-coated surfaces. Coated silicone films also inhibited S. epidermidis, C.tropicalis, and mixed biofilm formation by 64.1%, 66.6%, and 54.7% respectively.	(Tan et al., 2018) e
Quaternised chitosan derivative	Polymethylmethacrylate (PMMA)-based cementb,c	Orthopedic implants	MRSAh S. epidermidish	The viability of biofilms formed on functionalized-CS-PMMA surfaces was significantly lower than on PMMA surfaces (p< 0.01).	(Tan et al., 2012)n.d.
Fatty acid derivatives	Poly(ethylene terephthalate) and butylene dilinoleate (50:50) polymerb	Catheters	E. colil	E. coli colonization on CS/fatty acid derivates coatings was reduced by more than 80%.	(Niemczyk et al., 2019) d
Cathechol	Polyurethane filmsb,c	Urethral catheter	E. colil	During the initial adhesion, the number of live E. coli cells significantly decreased in the CS-catechol hydrogel-coated films compared to the bare substrate (85.23% vs. 48.32%).	(Yang et al., 2019) d

MRSA, methicillin-resistant Staphylococcus aureus.

n.d., not described.

^ain vivo study.

^bin vitro study.

^cstudy performed under hydrodynamic conditions.

^ddip coating.

^enon-immobilized CS.

^fCandida sp.

^gCryptococcus sp.

^hStaphylococcus sp.

ⁱKlebsiella sp.

^jPseudomonas sp.

^kAcinetobacter sp.

^lEscherichia sp.

^mProteus sp.

ⁿLactobacillus sp.

^oRothia sp.

^pStreptococcus sp.