Table 3.

Nanocomposites/combined nanoparticles and their antimicrobial activity and other key finding (cytotoxic activity and mechanisms)

Nps	Method of synthesis	Shape and size	Bacteria isolates tested	Antibacterial activity (IZD/MIC/MBC) and other key findings	Reference
Biopolymer-Ni, Zn Nps biocomposite	Biosynthesized using Rhodotorula mucilaginosa UANL-00IL exopolysaccharide	Polymorphic arrangement without definite shape 8–26 nm	Resistant strains S. aureus P. aeruginosa	Ni-EPS Showed antimicrobial and antibiofilm activity against the two pathogens at 3 and 2 mg/ml respectively Zn-EPS also showed activity against resistant S. aureus at 1 mg/ml Cytotoxicity: no toxicity, as renal function showed no differences between treatments and control in vivo assays with male rat tests in the study at a concentration of 24 mg/kg of body weight	Garza-Cervantees et al. (2019)
AgNps/ZnONps	Aqueous extract of Ulva fasciata alga	AgNps: spherical, 15 ± 0.55 nm ZnONps: rod-shape, 187 ± 0.5 nm	S. aureus Salmonella enterica sub sp. Bukuru E. coli	Both had increased antibacterial activity with an increase in concentration against E.coli and Salmonella spp. Both demonstrated a good syngergistic effect with antibiotics	Abo-Shama et al. (2020)
Tungsten carbide (Wc), silver (Ag) and copper (Cu) in combination	Commercially obtained	Wc: hexagonal with average diameter of 250 nm AgNps: rod shape, 80–90 nm CuNps:10–20 nm	S. aureus P. aeruginosa	Significant antimicrobial activity	Bankier et al. (2019)
Ag/TiO2	Horizontal vapor phase growth (HVPG) technique	Nanorods geometrical shape 24.8 µm–0.22 nm	S. aureus	Sharp-end nanorods can eradicate bacteria with > 50% efficiency Mechanism: nanorods eliminate bacteria because of their geometrical shape-sharp ends. Sharp-end nanorods with optimal geometrical shape can naturally pierce the cell membrane of bacteria leading to shrinking. This shows that bacteria can be killed not only by the release of ions from Nps but by the ability of utilizing the shape of Nps in killing them	Muflikhun et al. (2019)
Ag-Au/ZnO nanostructure	Justicis adhatoda plant extract	Nano stick shape 20–25 nm	E. coli S. aureus	Good antimicrobial activity	Pandiyan et al. (2019)
α-BiO2-ZnO nanostructure	Chemical synthesis	Monoclinic and hexagonal wurtzite	S. aureus	1.5 cm IZD for 1 mg/l	Chauhan et al. (2019)
T-β-D-glu-ZnONps (Trichoderma-β-D-glucan-zinc oxide nanoparticles	Fungal mycellial water extract derived from T. harzianum (SKCGW009)	Spherical 30.34 nm	S. aureus	Inhibit the growth of S. aureus inside of roundworm and enhanced growth of roundworm Cytotoxicity: not toxic to NIH3T3 cells Exhibited the dose-dependent inhibitory effect to human pulmonary Carcinoma A549 cells IC50 of T-ZnoNps and T-β-D-glu-ZnONps against A549 cells was 158 and 56.25 µg/ml respectively	Saravanakumar et al. (2020)
ZnO/Fe3O4/rGO nanocomposites	Hydrothermal method	Hexagonal wurtzite Inverse spinal structure Rod-shaped morphology Spherical-shaped morphology	E. coli S. aureus	Better cidal effect on E. coli when compared to S. aureus after treatment with 1 mg/ml concentration Addition of rGO intensified antibacterial effect to a great extent	Rajan et al. (2019)
Ag/TiO2	Aqueous extract of Acacia nilotica	Spherical 20–40 nm	E. coli, MRSA, P. aeruginosa	IZD of 24, 20 and 15 mm respectively Maximum IZD was shown at 500 µg/ml concentration. MIC was found to be 64 µg/ml against E. coli and S. aureus while 128 µg/ml against P. aeruginosa Mechanism: Decrease in the level of glutathione, triggered ROS production and lipid peroxidation	Rao et al. (2019)
ZEO-AgNps, ZEO-CuNps and ZEO-ZnNps (silver, copper and zinc zeolite nanocomposites)	–	Spherical 3–15 nm	Vibrio cholera	Each nanocomposite type had a distinctive antimicrobial effect altering each V. cholera lifestyle differently. Exhibit antimicrobial and antibiofilm activity Mechanisms: modification of the relative expression of genes that plays a role in biofilm formation Alteration in the level of outer membrane proteins (OmpT, OmpA, OmpU and OmpW)	Meza-villezcas et al. (2019)
Copper-doped chitosan- gelatin (CSG) nanocomposite coatings (Cu-doped CSG nanocomposite coating)	Green synthesis		E. coli S. aureus	Antibacterial activity was dependent on Cu concentration Cytocompatibility assessment in vitro showed that the activities of bone marrow stromal cells were not impaired on Cu-doped coatings Improved biological performance of Ti-based materials	Huang et al. (2020)