Raman spectroscopy, transmission electron microscopy (TEM) and atomic force microscopy (AFM) techniques can perform chemical analyses and acquire high‐resolution images of cell samples. For this ...reason, in this study, semi‐thin sections of a single Penicillium rubens cell were analysed by Raman enhanced surface spectroscopy. The spectra showed peaks corresponding to the macromolecules that make up the cellular components. In addition, the various organelles were analysed by TEM and AFM to observe the cellular nanostructures. With the use of these techniques, it is possible to identify molecules in semi‐thin sections, which provides a wide potential for biomedical applications and for the analysis of cell dynamics.
The observation of the most detailed possible structure of cells is used as a starting point in numerous studies to identify and localise some biochemical processes. Given that the function of eukaryotic cells depends on the location, shape, structure and function of the subcellular organelles (and on the interaction between them), the sum of the data obtained allows a complete analysis of what happens in the cell. This article addresses, from a multidisciplinary point of view, what happens in a single cell of a filamentous fungus (Penicillium rubens) while it is in a physiological moment (secondary metabolism) that allows the biosynthesis of an antibiotic (penicillin). For this purpose, different types of microscopies were used (TEM: transmission electron microscopy, and AFM: atomic force microscopy, which allow visualising small details in the cell) and a spectroscopy method (Raman, which allows detecting certain characteristics of the macromolecules and some stretching bonds). Regarding the results, during the synthesis of penicillin, the antibiotic‐producing Penicillium rubens cells showed significant changes compared to the non‐producing cells: the cell wall is observed to be significantly thickened in the production phase, organelles such as peroxisomes grow in number and size since it is known that the final route of metabolite synthesis takes place in them. When penicillin is released from peroxisomes, they must be degraded to release the load from the cell; this is done by vacuoles, which are active and engulf peroxisomes. The newly synthesised penicillin is found within secretory vesicles that travel towards the cell membrane and both membranes fuse creating ripples. On the other hand, and given that a single cell is being studied, it is essential to increase the signal to detect biomolecules employing the Raman‐SERS technique, using a silver substrate to obtain the increased signal.
This study presents an in vitro analysis of the bactericidal and cytotoxic properties of hybrid films containing nickel oxide (NiO) and nickel ferrite (NiFe2O4) nanoparticles embedded in ...polypropylene (PP). The solvent casting method was used to synthesize films of PP, PP@NiO, and PP@NiFe2O4, which were characterized by different spectroscopic and microscopic techniques. The X-ray diffraction (XRD) patterns confirmed that the small crystallite sizes of NiO and NiFe2O4 NPs were maintained even after they were incorporated into the PP matrix. From the Raman scattering spectroscopy data, it was evident that there was a significant interaction between the NPs and the PP matrix. Additionally, the Scanning Electron Microscopy (SEM) analysis revealed a homogeneous dispersion of NiO and NiFe2O4 NPs throughout the PP matrix. The incorporation of the NPs was observed to alter the surface roughness of the films; this behavior was studied by atomic force microscopy (AFM). The antibacterial properties of all films were evaluated against Pseudomonas aeruginosa (ATCC®: 43636™) and Staphylococcus aureus (ATCC®: 23235™), two opportunistic and nosocomial pathogens. The PP@NiO and PP@ NiFe2O4 films showed over 90% bacterial growth inhibition for both strains. Additionally, the effects of the films on human skin cells, such as epidermal keratinocytes and dermal fibroblasts, were evaluated for cytotoxicity. The PP, PP@NiO, and PP@NiFe2O4 films were nontoxic to human keratinocytes. Furthermore, compared to the PP film, improved biocompatibility of the PP@NiFe2O4 film with human fibroblasts was observed. The methodology utilized in this study allows for the production of hybrid films that can inhibit the growth of Gram-positive bacteria, such as S. aureus, and Gram-negative bacteria, such as P. aeruginosa. These films have potential as coating materials to prevent bacterial proliferation on surfaces.
An easy mechanochemical and eco-friendly method was employed to obtain nanocrystals with an average size of about 9 nm of zinc ferrite (ZnFe
2
O
4
) and copper ferrite (CuFe
2
O
4
). Their ...corresponding X-ray diffraction (XRD) patterns reveal a cubic crystal structure for ZnFe
2
O
4
, whereas in CuFe
2
O
4
the tetragonal and cubic crystal phases coexist, the latter being the majority phase. The transmission electron microscopy (TEM) images of these nano ferrites corroborate the formation of nanocrystals with dimensions consistent with those obtained from the XRD patterns. Furthermore, their corresponding Raman spectra confirm the structure and composition of nano ferrites. In addition, both nano ferrites show an electron paramagnetic resonance (EPR) spectrum with a wide band with g ~ 2.0, characteristic of ferromagnetic oxides. Besides, the antibacterial effect of ZnFe
2
O
4
and CuFe
2
O
4
nanocrystals against two opportunistic pathogens,
Staphylococcus epidermidis
(ATCC 14,990) and
Pseudomonas aeruginosa
(ATCC 43,636), was tested. The minimum bactericidal concentration (MBC) results showed that ZnFe
2
O
4
was more effective against
S. epidermidis
, while CuFe
2
O
4
was for
P. aeruginosa
. On the other hand, when 27 mg/mL of nano ferrites were dispersed in the agar plates, the growth of
S
.
epidermidis
was 100% inhibited, whereas ZnFe
2
O
4
and CuFe
2
O
4
inhibited 67% and 78% of
P. aeruginosa
growth, respectively.
This work focuses on the obtaining and the bactericidal properties study, in vitro, of hybrid films as potential coating materials to inhibit bacteria proliferation. In consequence, hybrid films from ...nickel oxide (NiO) and nickel ferrite (NiFe
2
O
4
) nanoparticles (NPs) embedded in poly-3-hydroxybutyrate (P3HB) were obtained by the solvent casting method. P3HB@NiO and P3HB@NiFe
2
O
4
hybrid films and P3HB film were characterized by X-ray diffraction (XRD), Raman scattering, and scanning electron microscopy (SEM). The XRD of the hybrid films showed that NiO and NiFe
2
O
4
NPs incorporated in the P3HB conserved their nanometric size, and by Energy-dispersive X-ray spectroscopy (EDS) were observed that NPs are homogeneously distributed in the films. The bactericidal effect of the obtained films was evaluated in vitro from the broth surface method against two opportunistic and nosocomial pathogens,
Staphylococcus aureus
and
Pseudomonas aeruginosa
. The results showed that P3HB film, P3HB@NiO, and P3HB@NiFe
2
O
4
hybrid films reduced 90%, 98%, and 97% of the growth of
S. aureus
, respectively. For
P. aeruginosa,
their growth was reduced by 90%, 94%, and 96%, respectively. In addition, the cytotoxic effect of NiO and NiFe
2
O
4
NPs, as well as P3HB film, and P3HB@NiO, and P3HB@NiFe
2
O
4
hybrid films was evaluated using human skin cells; keratinocytes and fibroblast, being the NPs less cytotoxic than films. Although P3HB is known as a biocompatible polymer, here is demonstrated that in our work conditions, their films have bactericidal properties and are cytotoxic to keratinocytes and fibroblasts, the first barrier of the human skin. However, the P3HB@NiO and P3HB@NiFe
2
O
4
hybrid films synergize the bactericidal effect between the P3HB and the NPs. On the other hand, the NPs decrease the P3HB cytotoxicity to keratinocytes. The methodology used in this work is particularly suitable for producing hybrid films with antibacterial activity against Gram-positive and Gram-negative bacterial strains.
Hybrid films for applications in organic electronics from NiFe2O4 nanoparticles (NPs) in poly(3,4 ethylene dioxythiophene), poly(4-styrenesulfonate) (PEDOT:PSS), and poly(methyl methacrylate) (PMMA) ...were fabricated by the spin-coating technique. The films were characterized by infrared spectroscopy, atomic force microscopy, scanning electron microscopy, and energy-dispersive spectroscopy to subsequently determine their optical parameters. The electronic transport of the hybrid films was determined in bulk heterojunction devices. The presence of NiFe2O4 NPs reinforces mechanical properties and increases transmittance in the hybrid films; the PEDOT:PSS-NiFe2O4 NPs film is the one that has a maximum stress of 28 MPa and a Knoop hardness of 0.103, while the PMMA-NiFe2O4 NPs film has the highest transmittance of (87%). The Tauc band gap is in the range of 3.78–3.9 eV, and the Urbach energy is in the range of 0.24–0.33 eV. Regarding electrical behavior, the main effect is exerted by the matrix, although the current carried is of the same order of magnitude for the two devices: glass/ITO/polymer-NiFe2O4 NPs/Ag. NiFe2O4 NPs enhance the mechanical, optical, and electrical behavior of the hybrid films and can be used as semi-transparent anodes and as active layers.
Abstract
In the present study, we investigated the ability of micro-Raman spectroscopy to identify low concentrations of trimethylamine-N-oxide (TMAO) mixed in synthetic urine composed of water, ...sodium chloride, urea, and creatinine using a support vector machine (SVM) as a discrimination tool to differentiate the Raman spectra of the different concentrations of TMAO. TMAO is a novel biomarker associated with cardiovascular diseases, kidney diseases, and complications of type 2 diabetes. We obtained the Raman spectra of four different concentrations of TMAO. The spectra were filtered before being classified using principal component analysis combined with the SVM method. We identify the spectral window that goes from 800 to 870 cm
−1
where TMAO presents Raman activity in the synthetic urine mixture without the intervention of Raman activity of another molecule. We predicted the different concentrations of TMAO in the synthetic urine until 1 ppm (13.21
µ
M) of TMAO, getting an accuracy of classification greater than 70% indicated by the confusion matrix, and the area under the receiver operating characteristic curve of 0.86 for 1 ppm (13.31
µ
M) and 10 ppm (133.13
µ
M) concentration. This study showed that Raman spectroscopy combined with SVM has the potential to detect low concentrations of TMAO in urine.
Antimony sulfide (Sb2S3) is a promising semiconductor material for solar cell applications. In this work, microrods of Sb2S3 were synthesized by microwave heating with different sulfur sources, ...solvents, temperature, heating rate, power, and solution concentration. It was found that 90% of stoichiometric Sb2S3 can be obtained with thiourea (TU) or thioacetamide (TA) as sulfur sources and that their optical band gap values were within the range of 1.59–1.60 eV. The most crystalline Sb2S3 were obtained by using TU. The morphology of the Sb2S3 with TU the individual rods were exhibited, whereas rods bundles appeared in TA-based products. The solvents were ethylene glycol (EG) and dimethylformamide (DMF). EG generates more heat than DMF during the microwave synthesis. As a result, the Sb2S3 obtained with EG contained a larger percentage of oxygen and smaller crystal sizes compared to those from DMF. On the other hand, the length and diameter of Sb2S3 microrods can be increased by applying higher heating power although the crystal size did not change at all. In summary, pure and highly crystalline Sb2S3 microrods of 6–10 μm long and 330–850 nm in diameter can be obtained by the microwave method with a careful selection of chemical and thermodynamic parameters of the synthesis.
•Purity up to 90% of crystalline Sb2S3 nanorods can be obtained by microwave heating.•The combination of solvent and sulfide type affects crystallinity & purity of Sb2S3.•The high pressure generated in microwave heating helps to form Sb2S3nanorods.
This study presents an in vitro analysis of the bactericidal and cytotoxic properties of hybrid films containing nickel oxide (NiO) and nickel ferrite (NiFesub.2Osub.4) nanoparticles embedded in ...polypropylene (PP). The solvent casting method was used to synthesize films of PP, PP@NiO, and PP@NiFesub.2Osub.4, which were characterized by different spectroscopic and microscopic techniques. The X-ray diffraction (XRD) patterns confirmed that the small crystallite sizes of NiO and NiFesub.2Osub.4 NPs were maintained even after they were incorporated into the PP matrix. From the Raman scattering spectroscopy data, it was evident that there was a significant interaction between the NPs and the PP matrix. Additionally, the Scanning Electron Microscopy (SEM) analysis revealed a homogeneous dispersion of NiO and NiFesub.2Osub.4 NPs throughout the PP matrix. The incorporation of the NPs was observed to alter the surface roughness of the films; this behavior was studied by atomic force microscopy (AFM). The antibacterial properties of all films were evaluated against Pseudomonas aeruginosa (ATCCsup.®: 43636™) and Staphylococcus aureus (ATCCsup.®: 23235™), two opportunistic and nosocomial pathogens. The PP@NiO and PP@ NiFesub.2Osub.4 films showed over 90% bacterial growth inhibition for both strains. Additionally, the effects of the films on human skin cells, such as epidermal keratinocytes and dermal fibroblasts, were evaluated for cytotoxicity. The PP, PP@NiO, and PP@NiFesub.2Osub.4 films were nontoxic to human keratinocytes. Furthermore, compared to the PP film, improved biocompatibility of the PP@NiFesub.2Osub.4 film with human fibroblasts was observed. The methodology utilized in this study allows for the production of hybrid films that can inhibit the growth of Gram-positive bacteria, such as S. aureus, and Gram-negative bacteria, such as P. aeruginosa. These films have potential as coating materials to prevent bacterial proliferation on surfaces.
•In2O3 and Mn(III)-doped In2O3 NPs were obtained by a novel synthesis pathway.•This method is suitable for large-scale synthesis of oxides semiconductors NPs.•The PL and the paramagnetic behavior are ...owing to the formation of many defects.
Here we report a novel pathway for the synthesis of Indium oxide and Mn(III)-doped indium oxide nanoparticles (NPs) from mechanochemical activation in absence of basic medium. Nps ∼8nm were obtained after annealing the powder precursor in air at 400°C for 1h. X-ray diffraction (XRD) analysis and high resolution transmission electron microscopy (HR-TEM) reveal that the Nps are single-phase cubic structure of In2O3. Fourier transform infrared spectroscopy (FTIR), Raman, and ultraviolet–visible (UV–vis) spectra suggest the In(III) substitution by Mn(III). Photoluminescence (PL) and electron paramagnetic resonance (EPR) spectra show clear evidence of paramagnetic centers as oxygen and indium defects. This synthesis pathway is particularly suitable for large-scale and high-quality of semiconductor metallic oxide nanoparticles production due to its simple process and low cost.
Adsorption of Pb(II) from aqueous solution using MFe2O4 nanoferrites (M = Co, Ni, and Zn) was studied. Nanoferrite samples were prepared via the mechanochemical method and were characterized by X-ray ...powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), micro-Raman, and vibrating sample magnetometry (VSM). XRD analysis confirms the formation of pure single phases of cubic ferrites with average crystallite sizes of 23.8, 19.4, and 19.2 nm for CoFe2O4, NiFe2O4, and ZnFe2O4, respectively. Only NiFe2O4 and ZnFe2O4 samples show superparamagnetic behavior at room temperature, whereas CoFe2O4 is ferromagnetic. Kinetics and isotherm adsorption studies for adsorption of Pb(II) were carried out. A pseudo-second-order kinetic describes the sorption behavior. The experimental data of the isotherms were well fitted to the Langmuir isotherm model. The maximum adsorption capacity of Pb(II) on the nanoferrites was found to be 20.58, 17.76, and 9.34 mg·g−1 for M = Co, Ni, and Zn, respectively.
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