Photocatalytic, Bactericidal and Molecular Docking Analysis of Annealed Tin Oxide Nanostructures

Abstract

Nanosized tin oxide was fabricated with a simple and cost-effective precipitation technique and was analyzed by performing x-ray powder diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, high-resolution transmission electron (HR-TEM) microscopy, energy-dispersive x-ray (EDX) and UV–Vis spectroscopy. The XRD results revealed that tin oxide particles possessed typical orthorhombic structure and exhibited improved crystallinity with annealing. Calcination at 250 °C produced predominantly orthorhombic SnO which transformed to SnO2 at higher temperatures of 500 and 750 °C. HRTEM and FESEM images showed existence of agglomeration within the particles of tin oxide. The absorption was found to increase up to a certain annealing temperature followed by a decrease, which was recorded via UV–Vis spectroscopy. The effect of annealing temperature on dye decomposition behavior of synthesized photocatalysts was studied. It was noted that annealing temperature affects the size of synthesized particles, band gap width and photoactivity of tin oxide. The sample prepared at 500 °C followed first-order kinetics and exhibited maximum photocatalytic reactivity toward methylene blue. The experimental results obtained from the present study indicate that SnO2 is a promising and beneficial catalyst to remove contaminants from wastewater and environment. The antimicrobial evaluation of SnO annealed at 500 °C against selected targets such as E. coli and S. aureus depicted significant inhibition zones in comparison with 250 and 750 °C samples. Furthermore, molecular docking predictions of SnO2 nanoparticles (NPs) were performed against active pocket of β-lactamase and DNA gyrase enzyme belonging to cell wall and nucleic acid biosynthetic pathway, respectively. The fabricated NPs showed good binding score against β-lactamase of both E. coli (− 5.71 kcal/mol) and S. aureus (− 11.83 kcal/mol) alongside DNA gyrase (− 9.57 kcal/mol; E. coli and − 8.61 kcal/mol; S. aureus). These in silico predictions suggested SnO2 NPs as potential inhibitors for selected protein targets and will facilitate to have a clear understanding of their mechanism of action that may contribute toward new antibiotics discovery.

Flower-like SnO2 Nanoparticle Biofabrication Using Pometia pinnata Leaf Extract and Study on Its Photocatalytic and Antibacterial Activities

“…The extrapolation of (α h ν) 2 versus hν to zero gives the band gap energy of 3.5 eV. This value lies within the range of 3.1-3.9 eV, as mentioned in the literatures, and is comparable to the band gap energy of SnO 2 NPs synthesized using the hydrothermal method [17,40,41]. The photoluminescence (PL) spectrum was recorded with varying excitation wavelengths (l = 360~380 nm), and the spectrum of SnO 2 NPs showed an excitation wavelength of 396 and 550 nm, of which the peak at 550 nm is attributed to 6A1→4T1(4G) ligand field transition of Sn 4+ .…”

“…Among many photoactive metal oxide nanoparticles, SnO 2 nanoparticles (SnO 2 NPs) have been widely studied for such purposes, and have exhibited highly photocatalytic activity with a band gap energy of about 3.2-3.6 eV. SnO 2 also offers and gives higher electron mobility (100-200 cm 2 V −1 s −1 ) compared to other semiconductors such as TiO 2 , leading to faster photo generated electron transport during the photocatalysis mechanism [17]. From several studies on the use of plant extracts in the SnO 2 NP synthesis, it can be concluded that different plant species gave the specific character and morphology of the nanoparticles, and influence the physicochemical character and activity [18].…”

“…Matoa or Pometia pinnata is an endemic plant in Southeast Asia, including Indonesia, especially in Papua Island. The leaf of Pometia pinnata has been utilized in traditional medical applications, and further analysis has revealed that the activities in medical applications are in correlation with the high content of flavonoids, tannins, triterpenoids, glycosides and saponins [17,19,20]. These compounds have been proven to be effective as bioreductors for the plant extract-mediated synthesis of silver NPs and in the synthesis of reduced graphene oxide [21,22], but, to our knowledge, utilization for SnO 2 NP synthesis has not been reported yet.…”

MoS2/cellulose-doped ZnO nanorods for catalytic, antibacterial and molecular docking studies

“… 29 The selected enzyme structures were prepared for docking predictions using the method reported in our previous studies. 30,31 Docking predictions were performed using ICM Molsoft software, 32 where basic steps involved the removal of the native ligand and water of crystallization followed by the addition of polar H atoms and energy minimization. The active pocket was defined within 10 Å of the co-crystalized ligand to specify the docking position of nanocomposites in the current study.…”

“…Crystal structure of enzymes were retrieved from protein data bank with accession code 2ANQ (Resolution: 2.13 Å) [27] for DHFR E.coli , 5U0W (Resolution: 1.97 Å) for DHPS E.coli [28], and 4FGG (Resolution: 2.30 Å) for DHFR S. aureus [29]. The selected enzyme structures were prepared for docking predictions using method reported in our previous studies [30,31].…”