Sustainable γ-cyclodextrin frameworks containing ultra-fine silver nanoparticles with enhanced antimicrobial efficacy

Cyclodextrin metal-organic frameworks (CD-MOF) are a class of biocompatible MOF with a great potential in drug delivery applications. Original CD-MOF crystals are fragile and large (0.2-1 mm), which are less useful in pharmaceutical applications. Cetyltrimethylammonium bromide and long chain poly(ethylene) glycol, used in size modulation to produce nanosized CD-MOF can compromise the biocompatibility, and physiochemical properties of CD-MOF as their complete removal from frameworks is difficult. To avoid the use of above-mentioned modulators, herein, we demonstrate the synthesis of nanosized CD-MOF using triethylamine (TEA) as a modulator to reduce their size to ~254 nm. The MOF characteristics such as crystal and chemical structure remain unaffected and the surface area of CD-MOF synthesised with TEA is measured 1075.5 m2/g, almost 50 % higher than those of synthesised using bulky modulators. The improved CD-MOF architecture utilized for the in-situ synthesis of silver nanoparticles resulted in enhanced antimicrobial efficacy tested against Staphylococcus aureus and Escherichia coli bacteria and Candida albicans fungus. And minimum inhibitory concentration (MIC) is recorded in the range of 31-15 μg/mL. Overall, the structural improvement in CD-MOF supported with thorough comparative investigations and enhanced antimicrobial efficacy could be very helpful in further establishing them in biomedicine field.