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. Author manuscript; available in PMC: 2023 Mar 1.
Published in final edited form as: Mater Today Chem. 2021 Dec 9;23:100673. doi: 10.1016/j.mtchem.2021.100673

Table 2.

Processing and antibacterial activity of SFBs combined with inorganic nanoparticles for different biomedical applications

Antimicrobial additive (Inorganic nanoparticles) Other additive(s) Synthesis method Content Antimicrobial capability Application Refs
AgNPs ----- Reduction of Ag ions by SF solution using a microfluidic device 125 μg/mL AgNO3 Live/dead assay:
Maximum bacterial death at 3 h
RE (2 h):
E. coli (>75%) in an infected mouse model		 Surgical site infections [65]
AgNPs Polylactic acid (PLA)
Nano hydroxyapatite (nHA)
Polydopamine (PDA)		 Reduction of Ag ions by SF and fabrication of SF/Ag/nHA/PLA composites 50 mM AgNO3 solution Turbidity test against E. coli and S. aureus (24 h):
Lower absorbance of the medium containing the scaffolds		 Bone TE [67]
Ag NPs ----- SF as the reducing and stabilizing agent for preparation of SF-AgNPs solutions under light 0–153.6 mg/L MRSA:
MIC (19.2 mg/L)
MBC (76.8 mg/L)
CLSM and SEM (10 h):
No biofilm formation at concentrations higher than MIC		 General biomedical applications [66]
AgNPs ----- Dip-coating Tasar SF nanofibrous mats in AgNPs solution 1 mM AgNO3 solution ZOI (12 h):
S. aureus (10 mm)
E. coli (14mm)
P. aeruginosa (8 mm)
S. epidermidis (10 mm)		 Skin TE [78]
AgNPs ----- Dip-coating and microwave irradiation of SF fibers in AgNO3 solution 0.5, 1 and 1.5 mmol L−1 of AgNO3 solutions Diffusion assay (24 h):
S. aureus, M. tuberculosis, and E. coli (dose-dependent antibacterial activity)		 Wound healing [90]
Ag doped hydroxy appetite (HA) NPs Chitosan (CS) Strontium (Sr) Freeze-dried AgSrHA/CS/SF cryogels ----- Turbidity test (24 h):
Growth inhibition of E. coli and S. epidermidis 		Bone TE [91]
AgNPs Strontium nanotubes (SNT)
Titanium (Ti)
Polydopamine (PDA)		 SF/Ag coating on PDA modified SNTs (created by anodizing Ti) Turbidity test and ZOI (24 h):
Antibacterial activity against S. aureus and E. coli
RE (1–5 d):
S. aureus and E. coli (100–70%)		 Bone TE [92]
AgNPs ------ The SF solution containing AgNO3 was exposed to light to form SF/AgNPs films 0.1–2 % AgNO3 ZOI (2 d):
Antibacterial activity at 0.5–1% against S. aureus and kanamycin resistant E. coli (quantitative data N/A) 		Bone TE [93]
AgNPs ----- In situ reduction of Ag ions and fabrication of AgNPs loaded SF gels 26.5±1.24 ppm MIC (6±1.32 ppm) and
ZOI (11±2.12mm) against S. aureus after 2 d		 Wound healing [94]
AgNPs Carboxymethyl chitosan (CMC) In situ synthesis of AgNPs in SF solution, and fabrication of freeze-dried AgNPs-SF-CMC sponges AgNO3 solution (0.05 wt%) Turbidity test and ZOI (24 h): Significantly lower OD values and larger inhibition zones against S. aureus and P. aeruginosa compared to control without Ag NPs and compared to AQUACEL® Ag Wound healing [95]
AgNPs ----- In situ reduction reaction between SF and silver nitrate under light 153.6 and 384 mg/L of SF-AgNPs solution SEM (7 d):
Significant reduction of S aureus biofilm at 384 mg/L of SF-NS solution compared with saline.		 Sinusitis treatment [96]
AgNPs ----- Impregnation of silk fibers with AgNPs using in situ (AgNO3 solution) and ex situ (colloidal AgNPs solution) approaches AgNO3 solution (4 mM) Higher antibacterial activity of in situ prepared fibers after 24 h
P. aeruginosa:
ZOI (3.3±0.5 mm), RE (99.9%)
S. aureus:
ZOI (2.4±0.4 mm), RE (95%)		 Wound healing [77]
AgNPs ----- Electrospinning SF/AgNO3 solution and irradiation with UV to obtain SF/AgNPs nanofibers 0.1%, 0.5%, and 1% wt/v No antibacterial activity at 0.1% and 0.5% against S. aureus and S. epidermidis
ZOI (24 h) at 1%:
S. aureus (6.5 mm)
S. epidermidis (5.6 mm)
P. aeruginosa (9.3 mm)		 Wound healing [97]
AgNPs ----- Dip-coating and in situ photoreduction of Ag ions on SF sutures 0.5 wt/v % AgNO3 solution Inhibition zone against S. aureus and E. coli
after 24 h (Diameter N/A)
RE (24 h-bacteria in solution):
E. coli (78%), S. aureus (81%)
RE (24 h-adhered bacteria):
E. coli (34%), S. aureus (35%)		 Suture [98]
Ag@AgCl NPs Cellulose acetate (CA) Photocatalytic reduction and in situ formation of Ag@AgCl NPs on SF/CA composite membranes 0.1 M AgNO3 aqueous solution ZOI (24 h):
E. coli (13.99 mm)
S. aureus (12.59 mm)		 Antibacterial applications [99]
AuNPs ----- Reduction of AuNPs by SF solution 0.5 mM SF-AuNPs colloidal solution RE (24 h):
E. fecalis (85.19 ± 3.24 %)
S. aureus (32.34 ± 1.70 %)
E. coli (77.95 ± 9.59 %)
P. aeruginosa (63.38 ± 4.26 %)		 Nanoparticles with antibacterial and anticancer properties [69]
AuNPs
AgNPs		 Nano-hydroxyapatite (nHA) In situ reduction of AgNPs and AuNPs by SF/nHA solution and fabrication of hydrogels 0, 0.1, 0.5 and 1% HAuCl4·3H2O and AgNO3 Turbidity test and resazurin assay (24 h):
SF/AgNPs (0.1–1 %):
Antibacterial activity against
MSSA, MRSA, S. epidermidis, E. coli, and P. aeruginosa
SF/AuNPs (≥0.5%):
Antibacterial activity against
MSSA, MRSA, S. epidermidis, E. coli, and P. aeruginosa
No antibacterial activity against S. epidermidis 		Bone regeneration [68]
Diamino-2-pyrimidinethiol-functionalized Au NPs (DAPT-Au NPs) ----- Aqueous SF/Au-DAPT membranes 27 μg/cm2 MIC and ZOI (20 h):
E. coli and MDR E. coli (4 μg/mL, ~14 mm)
Inhibition of growth after 20 h.		 Wound healing [100]
Ca2+ Polyethylene glycol diglycidyl ether (PEG-DE) Freeze-dired Ca2+ loaded SF-PEG-DE porous material 1.8, 3.6, 5.4, and 7.2%, (w/w) CFU and turbidity test (6 h):
Inhibitory effect on the bacterial growth and propagation of E. coli and S. aureus 		Hemostatic material [86]
Calcium peroxide (CPO) Gelatin (GL) Human keratin (HK) Physical blending to make composite film scaffolds 20% CPO ZOI (24 h):
E. coli (3.55 ± 0.24 mm)
S. aureus (2.89 ± 0.20 mm)		 Urethral TE [87]
CuBTC MOF particles ----- Formation of CuBTC MOF on silk yarns by immersing in Cu(OAc)2.2H2O, and H3BTC solution 2–8 dipping cycles ZOI (24 h- IV-cycle 4):
E. coli (7.7 mm)
S. aureus (6.5 mm)
ZOI (24 h- IV-cycle 10):
E. coli (8.0 mm)
S. aureus (7.5 mm)		 Wound healing and medical applications [70]
Graphene oxide (GO) ----- Electrospinning 5 wt% GO Survival rate after 18 h:
E. coli (35.7 ± 3.6 %)
S. aureus (41.6 ± 0.3%)
SEM:
Shrunken morphology of E. coli on the SF/GO nanofibers		 Wound dressing [80]
Graphene oxide (GO)
Reduced GO (RGO)
Graphene (Gr)		 ----- Electrospinning 1 wt% RE (24 h):
Antibacterial activity of SF/GO, SF/RGO, and SF/Gr against S. aureus (92.8%, 98.6%,80.6%) and E. coli (70.3%, 84.9%, 69.5%)		 TE [101]
Reduced Graphene oxide (GO)
TiO2 		----- Electrospinning 0.01 wt% RE against S. aureus:
SF/RGO: 94.8%
SF/TiO2: 83.6%
SF/GO/TiO2: 84.9%		 TE [102]
MgOH2 nanorods Polyvinyl alcohol Sodium Alginate Freeze-dried Hydrogels 0.3 wt% Crystal violet assay (24 h):
Inhibition of P. aeruginosa biofilm formation		 TE and general biomedical applications [103]
MoSe2 nanosheets ----- Exfoliation of MoSe2 nanosheets by carboxyl-modified SF (CMSF) solution MoSe2–CMSF nanosheets (50 μg mL−1) Live/dead assay, SEM, turbidity test, and CFU (6 h):
Antibacterial activity against E. coli and B. subtilis 		Wound dressing [76]
TiO2 ----- TiO2 /SF blend membranes TiO2/SF weight ratios: 1/1000, 3/1000, 5/1000, and 10/1000 1/1000 samples showed the highest antibacterial activity
ZOI (24 h):
S. aureus (19.0±0.2)
E. coli (17.0±0.1)
P. aeruginosa (13.0±0.2)		 Skin TE and wound dressing [85]
TiO2 Chitin (Ch) Glycerol (Gly) Freeze-dried SF/Ch/TiO2 wound dressings 0.5, 1.5, 3.0 % (w/w) TiO2 ZOI (24 h):
S. aureus (19 mm)
E. coli (20–22 mm)
CFU (3% TiO2):
5-fold decrease in number of colonies		 Wound dressing [84]
ZnO NPs Sodium alginate (SA) Dip-coating SF fibers functionalized with SA in ZnO NPs solution 0.5% suspension of ZnO NPs ZOI (2–6 d):
S. aureus (1.9–0.5 mm)		 Suture [83]
ZnO NPs Hyaluronic acid (HA) Co-axial electrospinning 1, 3, and 5% w/v ZnO NPs ZOI (24 h) (5% ZnO fibers):
E. coli (2.93±0.12 mm)
S. aureus (3.37±0.12 mm)
CFU (24 h):
E. coli (28±2 colonies)
S. aureus (6±1 colonies)		 Burn wound healing [82]
Porous ZnO NPs (PZ) ----- Dip-coating silk thread in PZ solution 50 mM Zn(NO3)2·6H2 O initial solution RE (6–8 h):
S. aureus and E. coli (~80%)
Suppressing bacterial infection in a mouse model (2 w)		 Suture [81]

MDR, multi drug resistanat; MSSA, methicillin-susceptible Staphylococcus aureus; S. epidermidis, Staphylococcus epidermidis; MBC, minimum bactericidal concentration; SEM, scanning electron microscopy; CLSM, confocal laser scanning microscopy