Facile Synthesis of Antimicrobial Aloe Vera-“Smart” Triiodide-PVP Biomaterials

Abstract

Antibiotic resistance is an eminent threat for the survival of mankind. Nosocomial infections caused by multidrug resistant microorganisms are a reason for morbidity and mortality worldwide. Plant-based antimicrobial agents are based on synergistic mechanisms which prevent resistance and have been used for centuries against ailments. We suggest the use of cost-effective, eco-friendly Aloe Vera Barbadensis Miller (AV)-iodine biomaterials as a new generation of antimicrobial agents. In a facile, one-pot synthesis, we encapsulated fresh AV gel with polyvinylpyrrolidone (PVP) as a stabilizing agent and incorporated iodine moieties in the form of iodine (I2) and sodium iodide (NaI) into the polymer matrix. Ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), x-ray diffraction (XRD), microstructural analysis by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) verified the composition of AV-PVP-I2, AV-PVP-I2-NaI. AV, AV-PVP, AV-PVP-I2, AV-PVP-I2-NaI, and AV-PVP-NaI were tested in-vitro by disc diffusion assay and dip-coated on polyglycolic acid (PGA) sutures against ten microbial reference strains. All the tested pathogens were more susceptible towards AV-PVP-I2 due to the inclusion of “smart” triiodides with halogen bonding in vitro and on dip-coated sutures. The biocomplexes AV-PVP-I2, AV-PVP-I2-NaI showed remarkable antimicrobial properties. “Smart” biohybrids with triiodide inclusions have excellent antifungal and promising antimicrobial activities, with potential use against surgical site infections (SSI) and as disinfecting agents.

Antimicrobial Hexaaquacopper(II) Complexes with Novel Polyiodide Chains

“…These are the absorption bands of C-H, CH 2 , C-C, C-O, and CH-CH [ 28 , 30 , 32 ]. The spectrum of [Cu(H 2 O) 6 (12-crown-4) 5 ]I 6 · 2I 2 contains absorption signals indicating the presence of hydroxyl groups ( Table 2 , Supplement 5 ) [ 11 , 28 , 30 , 32 ]. The signal at 3746 and the broad band around 3418 cm −1 are due to symmetric (ν 1s ) and asymmetric (ν 2a ) stretching vibrations of hydroxyl groups, respectively ( Table 2 , Supplement 3 ) [ 11 , 45 ].…”

“…The spectrum of [Cu(H 2 O) 6 (12-crown-4) 5 ]I 6 · 2I 2 contains absorption signals indicating the presence of hydroxyl groups ( Table 2 , Supplement 5 ) [ 11 , 28 , 30 , 32 ]. The signal at 3746 and the broad band around 3418 cm −1 are due to symmetric (ν 1s ) and asymmetric (ν 2a ) stretching vibrations of hydroxyl groups, respectively ( Table 2 , Supplement 3 ) [ 11 , 45 ]. These two bands show a blue shift in comparison to corresponding pure water vibrational stretching modes at 3418 and 3200 cm −1 [ 45 ].…”

“…Antimicrobial polymeric coatings can reduce the burden of infections through contaminated fomites in all indoor and outdoor settings [ 8 , 9 , 10 , 11 , 12 , 13 ]. Inclusion of known antimicrobial agents like iodine and copper into polymeric coating materials can mitigate antimicrobial resistance [ 13 , 14 , 15 , 16 ].…”

“…Polyiodides are formed from basic [I 2k+n ] n− units (k = integer, n = 1–4), that can be controlled through synthesis [ 17 , 18 ]. Extended polyiodide networks result through attachment of triiodide I 3 − anions (I 3 − ) to iodine (I 2 ) molecules by halogen and hydrogen bonding [ 11 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. 1,4,7,10-tetraoxacyclododecane (12-crown-4), a crown-ether, forms stable tri- and pentaiodides [ 27 , 28 , 29 , 30 , 31 ].…”

Facile Synthesis of Bio-Antimicrobials with “Smart” Triiodides

“…Aloe Vera Barbadensis Miller (AV) has been used for centuries against ailments due to its antimicrobial and anti-inflammatory properties [29,30]. AV consists of a plethora of different phytochemicals, which act by synergistic mechanisms against microbial pathogens [29][30][31][32][33][34][35][36][37][38][39][40][41]. AV has shown antiviral activities against different flu strains [32,33].…”