Tailored Silica–Antibiotic Nanoparticles: Overcoming Bacterial Resistance with Low Cytotoxicity

Abstract

New and more aggressive antibiotic resistant bacteria arise at an alarming rate and represent an ever-growing challenge to global health care systems. Consequently, the development of new antimicrobial agents is required to overcome the inefficiency of conventional antibiotics and bypass treatment limitations related to these pathologies. In this study, we present a synthesis protocol, which was able to entrap tetracycline antibiotic into silica nanospheres. Bactericidal efficacy of these structures was tested against bacteria that were susceptible and resistant to antibiotics. For nonresistant bacteria, our composite had bactericidal efficiency comparable to that of free-tetracycline. On the other hand, the synthesized composites were able to avoid bacterial growth of resistant bacteria while free-tetracycline has shown no significant bactericidal effect. Finally, we have investigated the cytotoxicity of these nanoparticles against mammalian cells to check any possible poisoning effect. It was found that these nanospheres are not apoptosis-inducers and only a reduction on the cell replication rate was seen when compared to the control without nanoparticles.

Controlling release kinetics of gentamicin from silica nano-carriers

“…Moreover, as gentamicin partitions predominately in the aqueous phase, the nanocarriers prepared through this protocol had the highest load of antibiotic. Similar loading results were reported for the encapsulation of vancomycin in mesoporous silica nanoparticles [15]. The functionalisation of the nanoparticles, the adsorption or conjugation of the antibiotic or the LbL deposition are processes affecting only the outer surface of the nanoparticles thus they did not impact the overall size and shape of the carriers.…”

“…The adsorptiondesorption curves of N2 (Figure 3) depict a typical Type II profile confirming the lack of mesopores in the nanocarriers. Furthermore, the lower amount of N2-adsorbed/desorbed by the nanocarriers with entrapped gentamicin compared to the other carriers, along with the lower values of total pore volume, suggests that the antibiotic is entangled inside the network of silane-oxygen bonds as suggested by Capeletti et al [15] and Hakeem et al [49]. Moreover, as gentamicin partitions predominately in the aqueous phase, the nanocarriers prepared through this protocol had the highest load of antibiotic.…”

Tailored Silica Nanoparticles Surface to Increase Drug Load and Enhance Bactericidal Response

“…In our previous works, [46][47][48][49][50][51][52][53][54] we investigated the correlation between the nanoparticles physical properties and their behavior in biological systems.These properties, that include size, surface charge and hydrophobicity, play an important role for the interaction between nanomaterials and biological systems. In the present study, we go further and show for the first time the bactericidal properties of amino-functionalized curcumin-loaded silica nanoparticles obtained from PSG method.…”

“…More recently, a plethora of works [39][40][41][42][43][44][45] demonstrating that surface-modified curcumin-loaded silica nanoparticles can be successfully and selectively used against different types of cancer cells were reported. However, to the best of our knowledge, nothing has been done in order to use nanostructured silica and curcumin (CCM) complexes as bactericidal agents.In our previous works, [46][47][48][49][50][51][52][53][54] we investigated the correlation between the nanoparticles physical properties and their behavior in biological systems.These properties, that include size, surface charge and hydrophobicity, play an important role for the interaction between nanomaterials and biological systems. In the present study, we go further and show for the first time the bactericidal properties of amino-functionalized curcumin-loaded silica nanoparticles obtained from PSG method.…”

Antibacterial Drug Releasing Materials by Post-Polymerization Surface Modification

“…Of interest, however, was whether the surface loading density which could be achieved using this approach, which was generally in the range 0.01-0.2 mmol/g, [2][3][4] was su±cient to permit the reversible binding of small molecules at a level which was both detectable and had the capacity for a therapeutic e®ect; that this might be possible which was suggested from earlier work in which the binding of hydrogen peroxide was shown to lead to bactericidal properties, a result which was considered likely to be a best case scenario, since the existence of an extensive hydrogen binding network appeared to support multiple hydrogen peroxide units per unit of introduced surface urea groups giving high overall surface loading. 8 The development of drug delivery systems, and in particular the surface delivery of bioactive agents, especially from nanoparticles, [16][17][18][19][20][21] is currently of interest for its obvious medical and hygiene applications [22][23][24] especially in the area of antibacterials 25 ; recent work is noteworthy in that regard. 26,27 Inspiration for the work reported herein came from a report in which small anions were found to bind reversibly with spiropyrans, 28,29 and of interest was whether a similar phenomenon might also bind carboxylates, and therefore penicillin, which would in turn impart bactericidal properties to a supporting polymer; the delivery of penicillin from polymers has been reported.…”