Stretch Vibration Research Articles

Accelerated Vibrational Energy Relaxation of Water in Alkaline Environments.

We observe that hydrated hydroxide ions introduce an additional relaxation channel for the vibrational relaxation of the OD vibrations of HDO molecules in aqueous NaOH solutions. This additional relaxation path involves resonant (Förster) vibrational energy transfer from the excited OD vibration to OH stretch vibrations of hydrated OH– complexes. This energy transfer constitutes an efficient mechanism for dissipation of the OD vibrational energy, as the accepting OH stretch vibrations show an extremely rapid subsequent relaxation with a time constant of <200 fs. We find that the Förster energy transfer is characterized by a Förster radius of 2.8 ± 0.2 Å.

Machine Learning Approach for Describing Water OH Stretch Vibrations.

A machine learning approach employing neural networks is developed to calculate the vibrational frequency shifts and transition dipole moments of the symmetric and antisymmetric OH stretch vibrations of a water molecule surrounded by water molecules. We employed the atom-centered symmetry functions (ACSFs), polynomial functions, and Gaussian-type orbital-based density vectors as descriptor functions and compared their performances in predicting vibrational frequency shifts using the trained neural networks. The ACSFs perform best in modeling the frequency shifts of the OH stretch vibration of water among the types of descriptor functions considered in this paper. However, the differences in performance among these three descriptors are not significant. We also tried a feature selection method called CUR matrix decomposition to assess the importance and leverage of the individual functions in the set of selected descriptor functions. We found that a significant number of those functions included in the set of descriptor functions give redundant information in describing the configuration of the water system. We here show that the predicted vibrational frequency shifts by trained neural networks successfully describe the solvent-solute interaction-induced fluctuations of OH stretch frequencies.

Isomers of the Allyl Carbocation C3H5 + in Solid Salts: Infrared Spectra and Structures.

Three isomers of the allyl cation C3H5+ were obtained in salts with the carborane anion CHB11Cl11–. Two of them, angular CH3–CH=CH+ (I) and linear CH3–C+=CH2 (II), were characterized by X-ray crystallography, and the third one, (CH2CHCH2)+ (III), is formed in an amorphous salt. The stretch vibration of the charged double bond C=C+ of I and II is decreased by 162 cm–1 (I) or 76 cm–1 (II) as compared to that of neutral propene. This result contradicts the prediction of DFT and MP2 calculations with the 6-311G++(d,p) basis set that the appearance of the positive charge on the C=C bond should increase its stretch vibration by 200 cm–1 (I) or 210 cm–1 (II). According to infrared spectra, the CC bonds in isomer III have one-and-a-half bond status. Isomers I and II in the crystal lattice are stabilized due to uniform ionic interactions with neighboring anions with partial transfer of a positive charge to them. Additional stabilization of II is provided by a weak hyperconjugation effect. Isomer III is stabilized in the amorphous phase due to ion paring with a counterion and a strong intramolecular hyperconjugation effect.

Green synthesis, characterization, antioxidant, antibacterial, and photocatalytic activity of Suaeda maritima (L.) Dumort aqueous extract-mediated copper oxide nanoparticles

BackgroundThe aim of this work was to synthesize copper oxide nanoparticles (CuO NPs) utilizing heartwood aqueous extract of Suaeda maritima (L.) Dumort. The synthesis of CuO NPs using green methodology with small size and high stability paved the way to protect the environment by not involving toxic chemicals and environment-friendly methodology for pharmacological and photocatalytic applications. The aqueous areal parts extract of S. maritima (L.) Dumort was used for synthesis, characterization of CuO NPs was studied, and further its antioxidant, antibacterial, and photocatalytic activity for the removal of methylene blue was studied. ResultsThe synthesized CuO NPs shows characteristic UV-visible absorption maximum at 282 nm. The FT-IR spectra shows peak at 3640 cm−1 attributed to hydrogen bonded O-H group of poly phenols, alcohols, and N-H of amide. Strong peak at 1122 cm−1 corresponds to C-OH stretch in phenols and alcohols. Peaks at 1467 cm−1 and 1585 cm−1 corresponds to C=C in aromatic compounds. Strong peak at 1749 cm−1 represents the C=O in aldehydes or in keto compounds. Several strong bonds identified in the range of 1088 to 1225 cm−1 representing C-O-C stretch vibrations. The synthesized particles were circular in shape with rough surface morphology and dispersed as clusters with size of 37 nm with metallic content of 73.8%. The synthesized CuO NPs were proved as potent antibacterial and antioxidant activities. The photocatalytic for the removal of methylene blue in aqueous solution was studied and results proved that the CuO NPs were effectively remove the dye up to 86.91% within less time of 75 min. Hence, the CuO NPs synthesized are high efficiency with less particle size and can be used as antioxidant, antibacterial agent, and also applicable for the removal of hazardous methylene blue dye from effluents and can contribute indirectly to clean up the environment. ConclusionsThe investigation reports the eco-friendly, cost-effective method for synthesizing copper oxide nanoparticles from S. maritima extract with biomedical applications.

Photodissociation and Infrared Spectroscopy of Uranium-Nitrogen Cation Complexes.

Laser vaporization of uranium in a pulsed supersonic expansion of nitrogen is used to produce complexes of the form U+(N2)n (n = 1-8). These ions are mass selected in a reflectron time-of-flight spectrometer and studied with visible and UV laser fixed-frequency photodissociation and with tunable infrared laser photodissociation spectroscopy. The dissociation patterns and spectroscopy of U+(N2)n indicate that N2 ligands are intact molecules and that there is no insertion chemistry resulting in UN+ or NUN+. Fixed frequency photodissociation at 532 and 355 nm indicate that the U+-N2 bond dissociation energy varies little with changing coordination. The photon energy and the number of ligands eliminated allow an estimate of the average U+-N2 dissociation energy of 12 kcal/mol. Infrared bands are observed for these complexes near the N-N stretch vibration via elimination of N2 molecules. These resonances are observed to be shifted about 130 cm-1 to the red from the free-N2 frequency for complexes with n = 3-8. Density functional theory indicates that U+ is most stable in the sextet state in these complexes and that N2 molecules bind in end-on configurations. The fully coordinated complex is predicted to be U+(N2)8, which has a cubic structure. The vibrational frequencies predicted by theory are consistently lower than those in the experiment, independent of the isomeric structure or spin state of the complexes. Despite its failure to reproduce the infrared spectra, theory provides an average U+-N2 dissociation energy of 11.8 ± 0.5 kcal/mol, in good agreement with the value from the experiments.

The Hydrates of TEMPO: Water Vibrations Reveal Radical Microsolvation.

An organic radical monohydrate complex is detected in vacuum isolation at low temperature by FTIR supersonic jet spectroscopy for the first time. It is shown to exhibit a rich conformational and vibrational coupling dynamics, which can be drastically reduced by appropriate isotope substitution. Its detection with a new gas recycling infrared spectrometer demonstrates the thermal metastability of the gaseous TEMPO radical even under humid gas conditions. Compared to its almost isoelectronic and isostructural, closed shell ketone analogue, the hydrogen bond of the solvating water is found to be less directional, but stronger and more strongly downshifting the bonded water OH stretch vibration. A second solvent water directs the first one into a metastable hydrogen bond position to solvate the nitrogen center and the first water at the same time.

The Hydrates of TEMPO: Water Vibrations Reveal Radical Microsolvation

AbstractAn organic radical monohydrate complex is detected in vacuum isolation at low temperature by FTIR supersonic jet spectroscopy for the first time. It is shown to exhibit a rich conformational and vibrational coupling dynamics, which can be drastically reduced by appropriate isotope substitution. Its detection with a new gas recycling infrared spectrometer demonstrates the thermal metastability of the gaseous TEMPO radical even under humid gas conditions. Compared to its almost isoelectronic and isostructural, closed shell ketone analogue, the hydrogen bond of the solvating water is found to be less directional, but stronger and more strongly downshifting the bonded water OH stretch vibration. A second solvent water directs the first one into a metastable hydrogen bond position to solvate the nitrogen center and the first water at the same time.

Comparison of chemical compositions in wood and bark of Persian silk tree (Albizia julibrissin Durazz.)

ABSTRACT This research was conducted to identify and compare the chemical compositions in Persian silk tree (Albizia julibrissin Durazz.) from different parts of wood and bark, using Fourier Transform Infrared (FTIR) Spectroscopy, gas and liquid chromatography coupled to mass spectrometry (GC-MS, LC-MS), and elemental analysis. FTIR analysis showed significant differences in the chemical structure of bark and wood at peaks that belong to the cellulose and hemicelluloses. According to the results, the C-O-C asymmetric stretch vibration in cellulose and hemicelluloses peak of Persian silk tree was lower in the bark and ѵC=O in quinone or p-quinone peak was higher in the bark. The results of GC-MS showed 12 chemical constituents in the bark and 43 in the wood, respectively. Among these, hexadecanoic acid and inositol were in common. According to the LC-MS analyses, bark samples were rich in lignan compositions and triterpenoid saponins, whereas wood was poor in these compositions. Altogether 61 compositions have been tentatively identified and described from bark and wood tissues; many of them were identified for the first time. Energy-dispersive X-ray (EDX) spectrometry illustrated that the bark contained iron and aluminium, sodium, phosphorus, sulphur and chlorine, while these elements did not exist in wood.

Improved photocatalytic activity for degradation of textile dyeing waste water and thiazine dyes using PbWO4 nanoparticles synthesized by co-precipitation method

The coloured dyes released from the textile industrial effluents into water resources cause non-aesthetic pollution and aquatic life toxicity. Thus textile waste water treatment has been studied globally for many years. Photocatalytic properties of lead tungstate (PbWO4) nanoparticles (NPs) were analyzed for thiazine dyes and textile waste water under ultraviolet light conditions. XRD result showed the tetragonal scheelite structure of PbWO4 NPs. The crystallinity of the sample was confirmed from the SAED and XRD pattern. The existence of stretch vibration of Pb–O and O–W–O confirmed from FTIR results. EDAX displays optical absorption signals of Pb, W and O, and confirm the formation of PbWO4. Optical studies reveal that the band gap of the obtained nanoparticles increases with respect to their bulk counterparts that may be attributed to reduction in particle size. TEM images of PbWO4 powder consists of hexagonal particles and relatively uniform and smooth surface rod shaped prism-like structures. The photocatalytic activity of the prepared nanoparticles was analyzed through the degradation of textile waste water under UV light irradiation. The photocatalytic reaction rate constant was found to be 0.014/min. The small sized PbWO4 particles can adsorb more OH groups and oxidatively degrade the pollutants in the textile waste water.

Molecular Dynamics Simulations of Energy Dissipation on Amorphous Solid Water: Testing the Validity of Equipartition.

Many different molecular species have been observed in the interstellar medium. These range from simple diatomic species to saturated organic molecules with several carbon atoms. The latter molecules are assumed to be formed predominantely on the surface of interstellar dust grains. All surface reactions that can proceed under the low interstellar temperatures are exothermic. Their exothermicity can be as high as a few electron volts, which is considerable compared to the thermal energy of the molecules at 10 K. It is postulated that this exothermicity can be used for the desorption of reaction products from the grain. In previous studies, we have shown that translational excitation can lead to desorption, whereas vibrational and rotational excitations are much less efficient in the desorption of surface products. Vibrational excitation is however much more likely upon bond formation than translational excitation. The present study follows energy dissipation upon translational, vibrational, or rotational excitation of admolecules on a surface and its conversion, or lack thereof, to different energy contributions. To this end, thousands of molecular dynamics simulations were performed with an admolecule on top of a surface that received a fixed amount of energy, vibrational, rotational, or translational. Three different surface species have been considered, CO2, H2O, and CH4, spanning a range in binding energies, the number of internal degrees of freedom, and molecular weights. A fast exchange of energy between vibrational stretches is observed, but only very limited exchange to rotational or translation excitation has been found. For the dissipation of energy to the surface, excitation of the surface–admolecule bond is critical. Astrochemical models often assume instantaneous equipartition of energy after a reaction process to estimate the amount of available energy for chemical desorption. Based on the present study, we conclude that this assumption is not justified.

Schmidt decomposition analysis of normal- to local-mode transition in highly excited molecular vibration

The stretch vibrations SO2 are studied by the Schmidt decomposition focusing on the normal- to local-mode transition that takes place in the highly excited vibrational states. The von Neumann entropy is calculated from the eigenvalues of the reduced density matrices for the level sequences having excitations into the symmetric-stretch mode. The entropy shows significant increase as the typical trend, while those sequences with an even number of nonzero quanta in the antisymmetric-stretch mode show temporal decrease prior to the appearance of the local-mode bifurcation. The observed trends are rationalized on the basis of complexity or non-separability of the wave functions.

Quantification of the nonlinear susceptibility of the hydrogen and deuterium stretch vibration for biomolecules in coherent Raman micro-spectroscopy.

Deuterium labelling is increasingly used in coherent Raman imaging of complex systems, such as biological cells and tissues, to improve chemical specificity. Nevertheless, quantitative coherent Raman susceptibility spectra for deuterated compounds have not been previously reported. Interestingly, it is expected theoretically that -D stretch vibrations have a Raman susceptibility lower than -H stretch vibrations, with the area of their imaginary part scaling with their wavenumber, which is shifted from around 2900 cm-1 for C-H into the silent region around 2100 cm-1 for C-D. Here, we report quantitative measurements of the nonlinear susceptibility of water, succinic acid, oleic acid, linoleic acid and deuterated isoforms. We show that the -D stretch vibration has indeed a lower area, consistent with the frequency reduction due to the doubling of atomic mass from hydrogen to deuterium. This finding elucidates an important trade-off between chemical specificity and signal strength in the adoption of deuterium labelling as an imaging strategy for coherent Raman microscopy.

Dynamics of Ionic Liquid through Intrinsic Vibrational Probes Using the Dispersion-Corrected DFT Functionals.

First principles molecular dynamics simulations have been utilized to study the spectral properties of the protic ionic liquid, methylammonium formate (MAF). All simulations were performed using density functional theory (DFT) and various van der Waals-corrected exchange-correlation functionals. We calculated the vibrational stretch frequency distributions, determined the time-frequency correlations of the intrinsic vibrational probes, the N-H and C-O modes in MAF, and the frequency-structure correlations. We also estimated the average hydrogen-bond lifetimes and orientation dynamics to capture the ultrafast spectral response. The spectroscopic signature of the N-H stretching vibrations using the Becke-Lee-Yang-Parr (BLYP) and Perdew-Burke-Ernzerhof (PBE) functionals displays a spectral shift in the lower frequency side, suggesting stronger hydrogen-bonding interactions represented by the gradient approximation functionals than the van der Waals (vdW)-corrected simulations. The carboxylate frequency profiles with the dispersion-corrected representations are almost similar without a significant difference in the normalized distributions. Besides, the COO stretching frequencies at the peak maxima positions of the PBE functionals exhibit a lesser deviation from the experimental data. Spectral diffusion dynamics of the intrinsic vibrational probes on the cationic and anionic sites of the ionic liquid proceed through a short time relaxation of the intact hydrogen bonds followed by an intermediate time constant and a longer time decay indicating the switchover of hydrogen bonds. Dispersion-corrected atom-centered one-electron potential (DCACP) correction added to the BLYP system slows down the picosecond time scales of frequency correlation and the time constants of rotational motion, lengthening the overall system dynamics. The observed trends in the time-dependent decays of frequency fluctuations and the orientation autocorrelation functions correlate with the structural interactions in liquid MAF and hydrogen-bond dynamics. In this study, we examine the predictions made by different density functional treatments comparing the results of the uncorrected BLYP and PBE representations with the semiempirical vdW methods of Grimme and matching our calculated data with the experimental observations.

Can tendon reflexes be elicited by both stretch and vibration in man?

Aim of studyWhen the biceps tendon is tapped, a contraction is elicited in the biceps muscle. This also occurs with tapping of the radial bone, and it has been suggested that vibration is a stimulus for deep tendon reflexes. We investigated whether the normal stimulus for the deep tendon reflex is a sudden stretch, a phasic vibration, or both. Furthermore, we investigated the importance of forearm position for the reflex response in controls and stroke patients.MethodsWe investigated 50 neurological outpatients without clinical signs of neurological disorders in the arms. The biceps tendon and distal radius were tapped with the forearm in the midway (90°), supinated, and pronated positions. In 10 of these patients, the two reflexes were also investigated with quantitative electromyography (EMG) measurements in the 3 positions. Another 10 patients were investigated clinically when stretch of elbow was eliminated and 17 patients were examined when prestretching of the biceps tendon was avoided. Finally, we examined 32 patients that had experienced stroke.ResultsIn 94% (47/50) of patients, after a radial tap, the biceps contraction disappeared in the supinated forearm, and the median peak‐to‐peak amplitude of the surface EMG response (n = 10) decreased from 1.1 to 0.2 mV (p < .01). Elimination of elbow stretch as well as pressure on the biceps tendon did not change the reflex response. In 84% (27/32) of stroke patients, after a radial tap, the biceps contraction persisted in supination in the arm with hyperreflexia.ConclusionThe combined clinical and EMG results are consistent with the concept that the deep tendon reflexes in man can be elicited by both stretch and phasic vibration. Clinicians should be aware that the brachioradial reflex depends on the forearm position.

Ion spectroscopy in methane activation.

This review is devoted to ion spectroscopy studies of complexes relevant for the understanding of methane activation with metal ions and clusters. Methane activation starts with the formation of a complex with a metal ion. The degree of the interaction between an intact methane molecule and the ion can be monitored by the perturbations of C–H stretch vibrations in the methane molecule. Binding mediated by the electrostatic interaction results in a η3 type coordination of methane. In contrast, binding governed by orbital interactions results in a η2 type coordination of methane. We further review the spectroscopic characterization of activation products of metal–methane reactions, such as the metal–carbene and carbyne products resulting from the interaction of selected 5d metals with methane. The focus of recent research in the field has shifted towards the investigation of interactions between methane and metal clusters. We show examples highlighting that metal clusters can be more reactive in methane activation reactions.

Adsorption of Cd(II) Ion Using α-Cellulose Immobilized Humic Acid with Crosslinker Agent Epichlorohydrin

An environment is said to be polluted if there have been changes in the environmental order so that it is no longer the same as its original form, as a result of the entry and inclusion of a foreign substance or object in the environmental order. Various cases of heavy metal pollution have been reported in both developed and developing countries, as well as adverse effects on the population living in the vicinity. This heavy metal pollution including cadmium metal. Generally, the contamination of cadmium in waters originates from the waste of the metal ore processing industry. Cadmium which accumulates in the body of living things has a long half-life and generally accumulates in the liver and kidneys. This study focuses on reducing levels of heavy metals in the environment with an adsorbent from natural products, namely palm oil empty fruit bunches and humic acid from peat soils. This research combines two adsorbents of natural products, namely by immobilizing cellulose and humic acid with the epichlorohydrin crosslinker agent. The purpose of this study was to determine the effect of the optimum dose of epichlorohydrin on cellulose and humic acid immobilization, determine the optimum pH, adsorption isotherm, cadmium metal adsorption kinetics and determine the type of interaction between adsorbent and adsorbate. The results showed a link between cellulose and humic acid which was connected via epichlorohydrin from FT-IR results in certain wavenumbers, including OH vibration (3415cm–1), stretching CH vibration (2903 cm–1), NH bending vibration (1625 cm–1), COO stretch vibration (1373 cm–1) and CO stretch vibration (1058 cm–1). For the optimum dose of epichlorohydrin obtained at 15 mL (1 recipe) with an adsorption capacity of 7.4705 mg/g. While the optimum pH was obtained at pH 6, the adsorption isotherm obtained the largest capacity at 200 ppm by following the Freundlich isotherm (R2 = 0.9512).

Vesicle‐Released Glutamate Maintains Muscle Spindle Afferent Excitability in Adult Mice

The molecular mechanisms by which Group Ia and II muscle spindle (MS) afferents transduce muscle movement into action potentials is not fully understood, although the rapidly adapting PIEZO2 mechanically sensitive cation channel is essential. Mechanosensation in many types of sensory neurons relies on PIEZO2, suggesting that unique response properties are mediated by the complement of molecular mediators found in the different sensory neurons. Synaptic-like vesicles containing glutamate are released from the MS afferent receptor ending in a stretch and calcium dependent manner, suggesting a way to couple depolarization and increased intracellular calcium via PIEZO2 with additional depolarizing current via glutamate. Here we test the hypothesis that vesicle-released glutamate is necessary for maintaining MS afferent excitability especially during the static phase of stretch. We isolated the extensor digitorum longus muscle and the sciatic nerve from adult mice (8-12 wks old) and compared identified MS afferent firing rates during ramp-and-hold stretch and vibration before and after the addition of glutamate and an inhibitor of glutamate packaging into vesicles (xanthurenic acid; XA). Glutamate addition led to a significant increase in MS afferent firing rate during the end of stretch (1mM; n=12 in control and glutamate groups), while blocking glutamate release with XA significantly decreased firing (3mM; n=17), with 5 afferents exhibiting a complete absence of firing. Firing rates during the dynamic phase of stretch and sinusoidal vibrations were not as affected by drug treatment. However, we noticed heterogeneity in MS afferent responses, with some afferents not responding to the drug treatments. To confirm our pharmacological findings, we used a transgenic mouse line with 1 or 2 copies of the vesicular glutamate 1 transporter gene (VGLUT1; B6.129X1-Sic17a7tm1Edw/MmcD; Fremeau, 2004). VGLUT1+/- afferents (n=14) had significantly lower firing rates during the end of stretch than afferents from wildtype littermates (WT; n=14), however firing rates during vibration were not significantly different. Importantly, 3 of 14 VGLUT1+/- afferents could not maintain firing throughout the entire 4 s stretch, something never seen in WT afferents. These results support our hypothesis that glutamate is critical to maintaining MS afferent firing during maintained stretch. Future studies will explore which glutamate receptor subtype and signaling pathway mediates this effect. A better understanding of MS afferent mechanotransduction could define targets for therapeutic intervention during diseases with abnormal afferent excitability.

Angle-independent plasmonic substrates for multi-mode vibrational strong coupling with molecular thin films

Vibrational strong coupling of molecules to optical cavities based on plasmonic resonances has been explored recently because plasmonic near-fields can provide strong coupling in sub-diffraction limited volumes. Such field localization maximizes coupling strength, which is crucial for modifying the vibrational response of molecules and, thereby, manipulating chemical reactions. Here, we demonstrate an angle-independent plasmonic nanodisk substrate that overcomes limitations of traditional Fabry-Pérot optical cavities because the design can strongly couple with all molecules on the surface of the substrate regardless of molecular orientation. We demonstrate that the plasmonic substrate provides strong coupling with the C=O vibrational stretch of deposited films of PMMA. We also show that the large linewidths of the plasmon resonance allow for simultaneous strong coupling to two, orthogonal water symmetric and asymmetric vibrational modes in a thin film of copper sulfate monohydrate deposited on the substrate surface. A three-coupled-oscillator model is developed to analyze the coupling strength of the plasmon resonance with these two water modes. With precise control over the nanodisk diameter, the plasmon resonance is tuned systematically through the modes, with the Rabi splitting from both modes varying as a function of the plasmon frequency and with strong coupling to both modes achieved simultaneously for a range of diameters. This work may aid further studies into manipulation of the ground-state chemical landscape of molecules by perturbing multiple vibrational modes simultaneously and increasing the coupling strength in sub-diffraction limited volumes.

Transient CO desorption from thin Pt films induced by mid-IR pumping.

Resonant and off-resonant mid-infrared pump-probe spectroscopy is used to measure the vibrational dynamics of CO adsorbed to thin (0.2 nm, 2 nm, and 10 nm) heterogeneous Pt layers in an aqueous solution. The transient signals observed with resonant pumping are dominated by vibrational relaxation of the CO internal stretch vibration with a lifetime of T1 ∼ 3 ps in all cases. Off-resonant pumping suppresses that contribution to the signal and singles out a signal, which is attributed to heating of the metal layer as well as transient desorption of the CO molecules. Due to the small photon energy (0.2 eV) used as pump pulses, the mechanism of desorption must be thermal, in which case the desorption yield depends exclusively on the fluence of absorbed light and not its wavelength. The thin Pt layers facilitate CO desorption, despite a relatively low pump pulse fluence, as they concentrate the absorbed energy in a small volume.

Moringa oleifera gum based silver and zinc oxide nanoparticles: green synthesis, characterization and their antibacterial potential against MRSA

BackgroundHerein, we first time used the gum Moringa oleifera as reducing and capping agent for successful synthesis of silver nitrate and zinc oxide nanoparticles(NPs) through green synthesis approach. This study was aimed to check antibacterial activities of synthesized NPs against multidrug resistant bacteria methicillin-resistant Staphylococcus aureus (MRSA).MethodsAqueous solutions of AgNO3 and purified gum powder were mixed with 1:1 ratio, autoclaved at 120oC for 2 min. NPs pellet collected after centrifugation at 10,000 g for 20 min. ZnO NPs were prepared by mixing purified gum powder and metal salt with1:1 ratio, heated (70oC) and stirred at 100 rpm for 4 h followed by centrifugation at 10,000 g for 20 min. Pellet was washed and calcinated at 400oC for 4 h. Antibacterial potential against E. coli, S. aureus and methicillin-resistant Staphylococcus aureus (MRSA) was assessed by widely used Kirby-Bauer antibiotic susceptibility test.ResultsOptical observation of colour change from transparent to dark and UV-Visible analysis confirmed the synthesis of NPs. Fourier transform infrared spectroscopy (FTIR) of prepared nonmaterial revealed the characteristic AgNPs and ZnO stretch vibrations at wave number of 523 cm− 1 and 471 cm− 1resectively. Crystalline nature of AgNPs and ZnO NPs was confirmed by x-ray diffraction pattern with clear sharp Peaks. Scanning electron microscopy (SEM) revealed good surface morphology of AgNPs and ZnO NPs with 50nm and 60nm size respectively. AgNPs and ZnO NPs exhibited excellent antibacterial activity against E. coli (with zone of inhibition of 21 ± 02mm and 22 ± 03mm) and S.aureus ( with zone of inhibition of 20 ± 03mm and 21 ± 02mm) while good activity was observed against “super bug” methicillin-resistant Staphylococcus aureus (MRSA) with 16 ± 03mm ad 17 ± 02mm zone if inhibitions respectively.ConclusionsThis novel addition of Moringa Gum based nanoparticles will open new dimensions in the field of nanomedicine and pharmaceutics especially against MDR bacterial strains.