In vitro DNA binding, antioxidant, antimicrobial and anticancer assessment of amino acid functionalized magnetic nanoparticles

Abstract

Biofunctionalized magnetic nanoparticles (FMNPs) were synthesized through in situ coprecipitations of Fe (II) and Fe (III) salts under air followed by the addition of amino acids (AA): serine (Ser), alanine (Ala), cysteine (Cys), histidine (His), and methionine (Met) via bottom-up approach without following any sophisticated route. However, the effect of amino acid side chain on the formation of γ-Fe2O3 (maghemite) and Fe3O4 (magnetite) was attained through XRD, HR-TEM, SEM, VSM, FTIR, DLS and Mercury Porosimeter (MP). Surprisingly, our study depicts that except His; Ser, Ala, Cys and Met produced more than 50% of magnetite phase and inhibited the oxidation of Fe3O4 in the presence of air. Furthermore, AA@MNPs were used for in vitro biological assessment such as salmon testes DNA (ST-DNA) binding efficiency, DPPH scavenging activity, antimicrobial and anticancer properties using UV–visible spectrophotometry and colorimeter respectively. The ST-DNA binding efficiency was observed at λmax 259 nm and quantitative interaction was determined using 15–125 µM AA@MNPs and 500 µg/ml DNA at physiological temperature, shows stacking interaction. The Cys@MNPs have exhibited highest DPPH scavenging activity with SC50 2.5 µg/mL at λmax 525 nm. Antimicrobial property of AA@MNPs was studied on gram-positive (B. subtilis), gram-negative (E. coli) bacteria and fungi (C. albicans) using disc diffusion assay by measuring zone of inhibition (ZOI) in mm, mentioned as a diameter. Alongside, minimum inhibition concentration (MIC) was estimated by the dilution method for those strains sensitive against AA@MNPs. Although, AA@MNPs showed ∼100% control growth of human lung cancer cell line (A549) with LC50, TGI and GI50 >80 µg/ml shown cells compatibility. These significant results revealed the impact of AA side chain with different surface activities of FMNPs.