## 9 Silica-Based Nanocarriers  
Silica nanoparticles (SiNPs) are promising drug delivery systems because of their biocompatibility and stability, which allow for controlled drug release [151]. Additionally, their large surface area, due to uniform pores, enables them to carry a high drug payload and be effectively functionalized with various groups for targeted delivery [151]. Even though these nanoparticles lack inherent antimicrobial properties, they hold significant potential for delivering antibiotics to fight multidrug-resistant infections. This is because they can be designed to carry multiple drugs within their structure [152]. One of the primary reasons SiNPs are effective against biofilms is their ability to penetrate and disrupt the biofilm structure. Their nanoscale size allows them to infiltrate the biofilm matrix, reaching the embedded microorganisms. Once inside, SiNPs can be \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Type of Nanocarrier** & **Composition** & **Bacteria** & **Mechanism of Action** & **References** \\ \hline \multirow{4}{*}{AgNPs} & Silver and leaf extract of & \multirow{2}{*}{_S. aureus_ and _P. aeruginosa_} & Enhanced & \multirow{2}{*}{[176]} \\  & _Convolvulus arrensis_ & & chemical stability & \\ \cline{2-5}  & Silk fibroin/nanohydroxyapatite & _S. aureus_, MRSA, _S._ & \multirow{2}{*}{[137]} \\  & hydrogels with & _epidemidis, E. coli_, and & & Intrinsic \\  & silver nanoparticles & _P. aeruginosa_ & & antimicrobial action \\ \hline \multirow{4}{*}{AuNPs} & Silk fibroin/nanohydroxyapatite & _S. aureus_, MRSA, _S._ & \multirow{2}{*}{[137]} \\  & hydrogels with & _epidemidis, E. coli_, and & & Intrinsic \\  & gold nanoparticles & _P. aeruginosa_ & & antimicrobial action \\ \hline \multirow{4}{*}{ZnONPs} & Hydroxypatite porous granules & \multirow{2}{*}{_S. aureus_ and _S. epidermidis_} & \multirow{2}{*}{Non-specified} & \multirow{2}{*}{[177]} \\  & and zinc oxide nanoparticles & & & \\ \cline{1-1} \cline{2-5}  & Nanohydroxypatite with zinc & \multirow{2}{*}{_S. aureus_ and _E. coli_} & Intrinsic & \multirow{2}{*}{[2]} \\  & oxide nanoparticles & & & \\ \hline \multirow{4}{*}{Magnetic nanoparticles} & Iron oxide & _S. epidermidis_ & Non-specified & [136] \\ \cline{1-1} \cline{2-5}  & & & & \\ \cline{1-1} \cline{2-5}  & Iron oxide & _E. coli_ and _S. aureus_ & Enhanced & [178] \\ \cline{1-1} \cline{2-5}  & & & & \\ \cline{1-1} \cline{2-5}  & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Examples of metallic-based nanocarriers developed to eradicate biofilms. engineered to release antimicrobial agents in a controlled manner, ensuring a sustained attack on the biofilm. This targeted approach not only enhances the efficacy of the treatment but also minimizes the potential for developing resistance [154]. The surface of SiNPs can be easily modified to carry a variety of therapeutic agents. This functionalization allows for the attachment of antibiotics, antifungals, or even enzymes that degrade the biofilm matrix. The large surface area provided by the mesoporous structure of SiNPs enables a high payload of these agents, ensuring a potent delivery to the biofilm. Moreover, functional groups can be added to the SiNP surface to target specific components of the biofilm or the microorganisms within it, enhancing specificity and reducing off-target effects [155]. Ongoing research is continually expanding the potential applications of SiNPs in biofilm treatment. Studies have demonstrated the effectiveness of SiNPs in eradicating biofilms formed by various pathogens, including _Staphylococcus aureus_, _Pseudomonas aeruginosa_, and _Candida_ species [150; 153]. Silica-based nanocarriers are valued in drug delivery and biomedical applications for their large surface area, tunable pore size, and ease of functionalization. While generally considered biocompatible, concerns about toxicity arise from factors like particle size, surface properties, and dosage.