Shape engineering boosts antibacterial activity of chitosan coated mesoporous silica nanoparticle doped with silver: a mechanistic investigation

Abstract

In this study mesoporous silica nanoparticles (MSPs) of different size and shape were developed, and their surface coatings altered to study their differential effect in enhancing the antibacterial activity. In brief, MSPs with three different aspect ratios 1, 2 and 4 were prepared, doped with silver ions and finally coated with the polymer chitosan. Both Gram-positive and Gram-negative bacteria were treated with the MSPs. Results indicated that silver ion doped and chitosan coated MSPs with the aspect ratio 4 (Cht/MSP4:Ag + ) has the highest antimicrobial activity among the prepared series. Further studies revealed that Cht/MSP4:Ag + was most effective against Escherichia coli (E.coli) and least effective against Vibrio cholerae (V.cholerae). To investigate the detailed inhibition mechanism of the MSPs, the interaction of the nanoparticles with E.coli membranes and its intracellular DNA was assessed using various spectroscopic and imaging-based techniques. Furthermore to increase the efficiency of the MSP combinatorial antibacterial strategy was also explored -nanoparticles in combination with kanamycin (antibiotic) was treated against Vibrio Cholerae (V. cholerae). Toxicity screening of these MSPs was conducted against Caco-2 cells, and the results show that the dose used for antibacterial screening is below the limit of toxicity threshold. Our findings show that both shape and surface engineering contributes positively towards bacteria killing, and the newly developed silver ion-doped and chitosan-coated MSP has good potential as an antimicrobial nanomaterial.

Synergistic bactericidal activity of chlorhexidine-loaded, silver-decorated mesoporous silica nanoparticles

“…31 In brief, 200 mg of MSNs-NH 2 was dissolved in 90 mL of deionized water under ultrasonic treatment for 1 hour. Then, the silver ammonia complex cation ([Ag(NH 3 ) 2 ] + ) was prepared by mixture of 9.0 mL of 5% AgNO 3 solution and 1 mL of an ammonium hydroxide (28%).…”

“…28,29 Thus, these nanocarriers slowly release silver ions, leading to enhanced efficacy against bacteria. 30,31 In addition, MSNs with entrapped CHX can exhibit sustainable CHX release behavior and inhibit bacterial growth while maintaining their surface integrity. 32,33 However, studies on MSNbased CHX/silver codelivery have not been explored yet.…”

Mesoporous Silica‐Based Materials with Bactericidal Properties

“…MS NPs with different aspect ratios (1 (spherical), 2 (small rods), and 4 (larger rods)) were prepared using well known procedures by Rosenholm and co‐workers . Once the inorganic scaffold was prepared the authors adsorbed, through simple electrostatic interactions, Ag(I) ions onto the external surface.…”

Evolving Technologies and Strategies for Combating Antibacterial Resistance in the Advent of the Postantibiotic Era

“…For instance, the impact of type and degree of surface modification together with the shape of NP on providing multiple bactericidal effects have been evaluated. As presented by Sen Karaman et al55 by tuning the NP aspect ratio, doping with Ag + and coating with a antibacterial polymer surface layer, their results revealed that the NP with the highest aspect ratio and organic surface modification portion also had the greatest impact to attack the targeted bacteria on many fronts, which can be foreseen as a crucial strategy to inhibit the development of resistance 56…”