Table 4 Different metallic nanoparticles exhibit antibacterial activity via a variety of ways

1

NO NPs

NO produces RNOS (reactive nitrogen oxide intermediates) when it reacts with superoxide

[140]

(a) RNOS damages DNA, generating strand breaks, abasic sites, and Fe depletion in bacterial cells

[141]

(b) RNOS inhibits microbial respiration by inactivating zinc metalloproteins

[142]

(c) RNOS induces lipid peroxidation

[143]

2

Chitosan-containing NPs

(a) Because of the positive charge it carries, chitosan binds to DNA in fungal and bacterial cells, blocking mRNA transcription and resulting in protein translation

[144]

(b) Chitosan reduces the metalloproteins activities

3

Ag NPs

Silver's antibacterial action is attributed to its Ag + ions

[145, 146]

(a) Ag + disrupts microorganisms' electron transport chains

(b) Ag + binds to DNA and RNA, causing damage

(c) Ag + suppresses cell division by preventing DNA replication

(d) Ag + ions generate ROS, which are harmful to both bacterial and eukaryotic host cells

4

ZnO NPs

(a) ZnO NPs damage both lipids and proteins of the membrane, causing cell death

[54, 147]

(b) ZnO NPs produce Zn2 + ions and ROS, including H₂O₂, which harm the bacterial cell

5

Cu-containing NPs

(a) Cu interacts with amine & carboxyl groups found in bacteria i.e., B. subtilis

[123, 148]

(b) Higher quantities of Cu²⁺ ions may produce ROS

6

TiO2 NPs

(a) TiO2 nanoparticles in the photocatalysis process produce ROS, i.e., OH and H₂O₂, when exposed to UVA and near-UV radiation

[128]

7

Mg-containing NPs

(a) ROS generated by MgX2 NPs induce lipid peroxidation in the microbial cell envelope

[149]

(b) Lipid peroxidation and a decrease in cytoplasmic pH can be induced by MgF2 nanoparticles, resulting in an elevation of membrane potential