Diffuse Reflectance Spectroscopy Research Articles

Rational construction of bromine doped rose-like Bi2O2CO3 microspheres for enhanced visible-light-driven degradation

Optimizing the charge distribution of photocatalysts through halide ion doping has been recognized as an effective approach to enhance photocatalytic activity. Herein, the bromine doped rose-like Bi2O2CO3 microspheres were prepared through a one-step hydrothermal process. The visible diffuse reflectance spectroscopy (DRS) revealed that the bromine doping led to a narrowed band gap of Bi2O2CO3 and optimized band structure. In addition, bromine doping can achieve efficient separation of photogenerated electron-hole pairs. Thus, the photodegradation efficiency of the antibiotic oxytetracycline (OTC) and the dye rhodamine B (RhB) were significantly improved over bromine doped rose-like Bi2O2CO3 microspheres, which is 63.5% for OTC and 97.5% for RhB under visible light irradiation. The kinetic constants of the Br-Bi2O2CO3-2 material are 27.3 times for OTC and 156.2 times for RhB compared with those of pristine Bi2O2CO3. The enhanced photocatalytic performance can be attributed to the optimized carrier separation ability and broadened range of light response. The possible intermediates were identified by mass spectrometry (MS), and the degradation pathways were determined. A gradual decrease in toxicity during degradation was found by the Toxicity Estimation Software Tool (T.E.S.T). This work provides a new idea to construct high-performance photocatalysts for organic pollutants degradation.

Characterization of Ce3+ and Eu3+ doped and co-doped ZnO nanoparticles for luminescence applications

This paper investigates the synthesis of Ce3+ and Eu3+ doped, as well as co-doped ZnO nanoparticles using the solution combustion route. The nanoparticles exhibit a hexagonal wurtzite structure of ZnO with crystallite sizes ranging from 19 to 22 nm. Structural parameters, including lattice constants, bond lengths, and bond angles, are evaluated. Morphological diversity is observed in field-emission scanning electron microscopy images. The diffuse reflectance spectroscopy results reveal an energy band gap of 3.20 eV for undoped ZnO nanoparticles. The energy band gap value slightly decreases for Eu-doped ZnO and certain (Ce, Eu) co-doped ZnO nanoparticles. Photoluminescence (PL) excitation peaks are attributed to energy levels of native defects in the ZnO band gap, along with f–d and f–f transitions of rare-earth ions (Ce3+, Eu3+). The PL emission spectra under different excitation wavelengths (350 nm, 394 nm, and 465 nm) display varied peak positions. ZnO co-doped with 0.96 mol% of Ce3+ and 0.92 mol% of Eu3+ emerges as a promising material for luminescence applications, exhibiting a significant increase in green emission intensity. Consequently, this study represents a novel contribution to the field of ZnO-based luminescent materials.

Diffuse photon remission associated with the center-illuminated-area-detection geometry. III.Perspectives on the patterns of saturation.

Understanding scattering insensitiveness in diffuse reflectance spectroscopy (DRS) will be useful to enhancing the spectral specificity to absorption. In DRS based on center-illuminated-area-detection (CIAD), the scattering response can saturate as the relative strength of scattering with respect to the collection size, represented by a dimensionless reduced scattering, increases over a threshold. However, the formation of saturation versus the same range of dimensionless reduced scattering may differ between a fixed reduced scattering over an increasing collection size (case 1) and an increasing reduced scattering over a fixed collection size (case 2), due to the absorption. Part III demonstrates the differences of the scattering saturation as well as the effect of absorption on it in the CIAD geometry between the two cases while assessed over the same range of the dimensionless reduced scattering. A model allows predicting the absorption-dependent levels of saturation and the corner parameters of saturation transition. When assessed for the absorption coefficient to vary over [0.001,0.01,0.1,1]m m -1, the model-predicted levels of saturation agree with MC results with ≤2.2% error in both cases. In comparison, the model-predicted corner parameters of saturation show much different agreement with MC results in the two cases, suggesting that the saturation pattern is much better formed in one than in the other. Experiments conforming to the CIAD geometry support the discrepancy of the saturating patterns between the two cases.

Construction of novel Ru-embedded bulk g-C3N4 photocatalysts toward efficient and sustainable photocatalytic hydrogen production

Novel Ru-embedded bulk graphitic carbon nitride (g-C3N4) photocatalysts containing different wt% of Ru (0.5–2 % wt) were synthesized by a simple mixing method of ruthenium complex with g-C3N4. The photocatalytic activity of the synthesized photocatalysts was assessed for hydrogen production in an aqueous solution containing methanol with and without Pt. The optimal hydrogen production rate of the most active photocatalyst (0.8 % Ru/CN) was 246 μmol/h without Pt and 1021 μmol/h with Pt, which was more than two times higher than pure g-C3N4. Various physiochemical techniques such as X-ray diffraction (XRD), N2 adsorption-desorption isotherms, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (UV–vis DRS), photoluminescence spectroscopy (PL) and transition photocurrent response (PC) were applied to investigate the origin of activity of the Rux/CN photocatalysts. Results indicated that the loading of g-C3N4 with Ru nanoparticles enlarged its surface area and enhanced visible light absorption. Importantly, Ru nanoparticles promoted the charge carrier separation and transfer efficiency of g-C3N4 revealed by the PL and PC measurements, enhancing the photocatalytic activity of the embedded photocatalyst. Furthermore, XPS proved the existence of Ru (II) of RuO2 and metallic Ru0. The Ru-embedded g-C3N4 showed high photocatalytic activity, which makes them attractive materials for further applications in photocatalysis.

UV-Transparent SHG Material Explored in an Alkali Metal Sulfate Selenite System.

The first examples of alkali metal selenite sulfates, namely, Na8(SeO3)(SO4)3 (1), Na2(H2SeO3)(SO4) (2), and K4(H2SeO3)(HSO4)2(SO4) (3), were successfully synthesized by hydrothermal reactions. Their structures display three different zero-dimensional configurations composed of isolated sulfate tetrahedra and selenite groups separated by alkali metals. Na8(SeO3)(SO4)3 (1) features a noncentrosymmetric structure, while Na2(H2SeO3)(SO4) (2) and K4(H2SeO3)(HSO4)2(SO4) (3) are centrosymmetric. Powder second-harmonic-generation measurements revealed that Na8(SeO3)(SO4)3 (1) shows a phase-matchable SHG intensity about 1.2 times that of KDP. UV-vis-NIR diffuse reflectance spectroscopic analysis indicated that Na8(SeO3)(SO4)3 (1) has a short UV cutoff edge and a large optical band gap, which makes it a possible UV nonlinear optical material. Theoretical calculations revealed that the birefringence of Na8(SeO3)(SO4)3 (1) is 0.041 at 532 nm, which is suitable for phase-matching condition. This work provides a good experimental foundation for the exploration of new UV nonlinear crystals in an alkali metal selenite sulfate system.

Enhanced photocatalytic activity of FeSO4 in a ZnO photocatalyst with H2O2 for dye degradation

In this study, the photocatalytic degradation efficiency of ZnO synthesized by a hydrothermal method and iron-supported ZnO catalysts by an impregnation method, dried (D) and calcined (C), was evaluated, through the degradation of methylene blue (MB) and methyl orange (MO) molecules under UV irradiation. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), N2 adsorption-desorption, and UVvisible diffuse reflectance spectroscopy (DRS). XRD showed that FeSO4 is supported on ZnO, and the XPS study revealed higher concentrations of hydroxyl groups and Fe3+ for the dried catalyst. The bandgap energies were 3.24, 3.23, and 3.19 eV for ZnO, Fe/ZnO D and Fe/ZnO C, respectively. The results revealed that Fe/ZnO D with H2O2 exhibited a higher photocatalytic degradation efficiency than ZnO, achieving 97% and 99% degradation for MB and MO at 10 min, which implies that the integrated iron in ZnO serves as an electron-hole separator. In addition, the catalyst has a larger BET specific area, the presence of hydroxyl groups and sulfate ions on the surface of the catalyst with holes forms hydroxyl radicals (•OH), and the presence of Fe3+ on the surface catalyst with H2O2 produces more •OH radicals. •OH radicals are the major oxidation species in this process, which promotes the degradation of dyes. The photocatalytic dye degradation efficiency was also evaluated for various catalyst doses, dye concentrations and solution pH values. Moreover, the stability of the catalyst over repeated cycles of dye treatment was demonstrated.

Reversibly Cross-Linked Isoporous Membranes Fabricated by the Recyclable Block Copolymer with Pendent Dithiolane Groups.

The reversible formation and cleavage of disulfide bonds under physical/chemical stimuli make it a valuable motif in constructing dynamically cross-linked materials. In the present work, the block copolymer bearing pendent dithiolanes was synthesized and fabricated into isoporous membranes by the combination of self-assembly and nonsolvent-induced phase separation strategy. The cross-linking within the membrane was realized by the thiol-initiated ring-opening cascades of cyclic disulfides. Successful formation of disulfide bond networks within the isoporous membranes was proved by the Raman spectra, UV-vis diffuse reflectance spectroscopy, differential scanning calorimetry, and rheological analysis. The cross-linking in membranes was further demonstrated by the notably improved toughness and obviously enhanced swelling resistance to acid/alkaline solution as well as organic solvents. Importantly, the cross-linked isoporous membranes were fully dissolvable in solution containing dithiothreitol, which enabled the complete cleavage of disulfide bonds and successful recovery of the block copolymer that was able to be repeatedly fabricated into isoporous membranes with pore sizes identical to membranes prepared from the freshly synthesized copolymer. Our results indicate that dynamically cross-linked isoporous membranes with improved durability and good recyclability can be custom-made by simply incorporating active dithiolane moieties into self-assembling block copolymers.

Eu3+ doped SrMoO4: A promising nanophosphor for enhanced fingerprint detection and cheiloscopy

Developing a single material with diverse applications like fingerprint detection, cheiloscopy, and anti-counterfeiting is truly innovative and has the potential to revolutionize various fields. Here, we synthesized nano phosphors powders of SrMoO4 nanoparticles, doped with spherical-shaped Eu3+ ions via co-precipitation method. X-ray diffraction (XRD) analysis confirmed the formation of the SrMoO4 phase with Eu3+ successfully incorporated into the lattice. Field emission scanning electron microscopy (FESEM) images revealed the nanoparticles to be spherical and monodispersed with a narrow size distribution. Energy dispersive X-ray spectroscopy (EDS) confirmed the presence of Sr, Mo, Eu3+, and O elements, indicating a homogeneous elemental composition. Fourier transform infrared (FTIR) spectroscopy showed characteristic bands for MoO bonds and hydroxyl groups. Diffuse reflectance spectroscopy (DRS) analysis revealed a decrease in band gap with increasing Eu3+ concentration, suggesting that Eu3+ doping potentially modifying the optical properties of SrMoO4, and introducing new functionalities. Their red photoluminescence property, making them suitable for various optical applications. The nanoparticles showed potential applications in fingerprint detection, cheiloscopy (lip print analysis), and anti-counterfeiting due to their red luminescence, small size, and biocompatibility. The developed fingerprints showed excellent contrast, high sensitivity and selectivity on various substrates. In vitro cytotoxicity studies indicated that the nanoparticles were non-toxic to normal kidney epithelial cells at the tested concentrations. Thess versatilities demonstrate the potential of engineered materials for criminal identification in forensic applications. Therefore, they play a crucial role in solving crimes and bringing justice to victims.

Synthesis of Au‐decorated WO3 nanoplates for simultaneous oxidation of RhB and reduction of Cr(VI) under visible light irradiation

AbstractTungsten oxide (WO3) nanoplates were synthesized by a simple chemical precipitation technique. These nanoplates were decorated by Au nanoparticles via photoreduction route. The obtained samples were characterized by field emission scanning electron microscopy, X‐ray diffractometry and UV–vis diffuse reflectance spectroscopy to investigate their morphological, structural and optical properties. The SEM images show the plate morphology with the size in the range of 50–150 nm, their thickness ≈10 nm; spherical‐like Au nanoparticles ≈20 nm were attached to the surface of the WO3 plates. These materials were applied for the simultaneous photocatalytic degradation of Rhodamine B (RhB) and Cr(VI) under visible light. Due to the efficient separation of photoinduced charge carriers and the enhanced visible light absorption ability, the photocatalytic performance of Au‐decorated WO3 nanoplates was higher. The main active species responsible for the photodegradation reactions were identified by different scavengers and a photocatalytic mechanism was proposed. This work represents that WO3 nanoplates are a promising candidate for the degradation of organic and inorganic pollutants from the industrial wastewater under sun light exposure.

Synthesis, some Physicochemical and Biomedical Properties of colored Apatite‐Structured Compounds with Mn5+ and Cr5+

AbstractDevelopment of new non‐toxic pigments of a wide range of applications (from coloring of bone cements to aesthetic cosmetology, including tattooing) of blue and green shades is an urgent task. In the present work, colored compounds with apatite structure were synthesized by solid‐phase method. The obtained products were crystallized in hexagonal syngony of P63/m space group. The alloying elements – chromophores Mn5+ and Cr5+ in tetrahedrally coordinated positions – were responsible for sky‐blue and turquoise colors of the compounds, respectively. The conducted complex study (crystal structure, IR spectroscopy, color measurements, diffuse reflectance spectroscopy, electron paramagnetic resonance, cytotoxicity, surface morphology) of the colored compounds opens new opportunities for the development of alternative pigments of similar color range and expansion of the field of application of pigments based on compounds of apatite structural type. The results of in vitro study of cytotoxicity demonstrated the potential suitability of sky‐blue color compound (Mn‐containing apatite) for further creation of cold pigments on its basis for tattoo ink and bone cement coloring.

Synergistic augmentation of dielectric and photocatalytic properties of ZnO via Ag nanoparticle integration

This study investigates the effect of Ag incorporation on dielectric and photocatalytic properties of the ZnO matrix. The synthesized samples were characterized using X-ray diffraction (XRD), diffused reflectance spectroscopy (DRS), scanning electron microscopy (SEM), elemental dispersive X-ray spectroscopy (EDX), impedance spectroscopy, and UV–visible infrared spectroscopy. XRD confirmed the successful synthesis of Ag/ZnO nanocomposites without any secondary phase. SEM micrographs showed discs and rods-like morphology of ZnO and Ag NPs, respectively. Furthermore, an increased agglomeration was also observed in the nanocomposite as the concentration of Ag NPs was increased in Ag/ZnO Nanocomposite. The dielectric study revealed that the incorporation of Ag nanoparticles (Nps) increased the dielectric constant of ZnO by 100 times (102 Hz), with minimal tangent loss in Ag/ZnO (20 %). Complex plane plots disclosed the presence of two relaxation processes with different relaxation times in the synthesized samples. The metallic nature of Ag NPs contributed to the reduction of the charge transfer resistance of the nanocomposite. Furthermore, the enhanced dielectric behavior was ascribed to the formation of micro/nano capacitors due to the interaction of conductive Ag NPs with relatively less conducting ZnO grains. The photocatalytic performance of the synthesized nanocomposites was also evaluated for the degradation of methylene blue. The presence of Ag NPs increased the photocatalytic activity due to its enhanced conductivity and sluggish electron-hole recombination. Ag/ZnO (20 %) nanocomposite showed the best photocatalytic activity with a reaction rate of 0.239 min−1. The exceptional dielectric properties demonstrate the potential of Ag/ZnO nanocomposites for low-frequency applications. Furthermore, the enhanced photocatalytic activity of ZnO upon Ag inclusion discloses the potential of the synthesized nanocomposite for water remediation applications.

Can diffuse reflectance spectroscopy identify shuntodynia in pediatric hydrocephalus patients?

Shuntodynia is patient reported pain at the site of the implanted ventriculoperitoneal (VP) shunt. Pediatric hydrocephalus requiring shunt placement is a chronic and prevalent standard of care treatment and requires lifetime management. Shuntodynia is a subjective measure of shunt dysfunction. Quantitative, white-light tissue spectroscopy could be used to objectively identify this condition in the clinic. Pediatric subjects were recruited for optical sensing during routine clinical follow-up visits, post-VP shunt implantations. Acquired optical signals were translated into skin-hemodynamic signatures and were compared between subjects that reported shuntodynia versus those that did not. Diffuse reflectance spectroscopy (DRS) measurements were collected between 450 and 700nm using a single-channel fiber-optical probe from () patients. Multiple reflectance spectra were obtained by the attending physician from regions both proximal and distal to the VP shunt sites and from a matched contralateral site for each subject. Acquired reflectance spectra were processed quantitatively into functional tissue optical endpoints. A two-way, repeated measures analysis of variance was used to assess whether and which of the optical variables were statistically separable, across subjects with shuntodynia versus those without. Analyses indicated that intrapatient differences in vascular oxygen saturation measured between shunt sites relative to that obtained at the scar or contralateral sites was significantly lower in the pain group. We also find that the total hemoglobin concentrations at the shunt site were lowest relative to the other sites for subjects reporting pain. These findings suggest that shuntodynia pain arises in the scalp tissue around the implanted shunts and may be caused due to hypoxia and inflammation. Optically derived hemodynamic variables were statistically significantly different in subjects presenting with shuntodynia relative to those without. DRS could provide a viable mode in routine bedside monitoring of subjects with VP shunts for clinical management and assessment of shuntodynia.

Enhanced upconversion emission in Nd, Yb, Er and Ho tetra-doped Y2O3 phosphor

Yb3+, Nd3+, Er3+ and Ho3+ tetra ions doped Y2O3 upconversion phosphors have been prepared by the combustion route. Crystalline phase purity and cubic phase of prepared samples have been confirmed from powder X-ray diffraction study. Absorbance of samples over spectral range 200–1100 nm has been measured by diffuse reflectance spectroscopy. All samples exhibit large band gaps. Scanning electron micrograph analysis reveals spherical morphology of particles and sizes around 200 nm. Upconversion emission has been studied under a 980 nm diode laser excitation with 166 mW laser power. The Ho3+, Nd3+ and Yb3+ co-doped Y2O3 phosphor show very high emission intensity of a green band centred at around 550 nm and another moderate intensity red band centred on 667 nm, while reverse is the case for Er3+, Nd3+ and Yb3+ co-doped Y2O3 phosphor. Er3+, Ho3+, Nd3+ and Yb3+ co-doped Y2O3 phosphor show enhanced high emission intensity in both green and red bands. These two bands are not visible in Nd3+ and Yb3+ co-doped Y2O3 phosphor but show weak upconversion emission at 549, 568 and 799 nm. Owing to the high emission intensity of green band, Ho3+, Nd3+ and Yb3+ co-doped Y2O3 phosphor may find potential applications in medical and security, while Er3+, Ho3+, Nd3+ and Yb3+ co-doped phosphor showing enhanced upconversion in green and red bands may find applications in white light generation.

Green-synthesized flattened rice-shaped CuO and metal doped CuO nanoparticles using Bauhinia racemosa Lam. leaves extract and their photocatalytic and biological applications

In the present investigation, a sustainable approach to the biogenic fabrication of CuO nanoparticles (NPs) and transition metals (Co, Mn, and Zn) doped CuO NPs (TMDC NPs) was proposed by employing the Bauhinia racemosa (BR) Lam. leaves extract as a stabilizing and capping agent. The fabrication of CuONPs was immediately verified by a change in the color of the Cu solution from blue to dark grey. Characterizations of the bare CuO and TMDC NPs were done to attribute the physical and chemical characteristics of the NPs employing Fourier Transform Infrared (FT-IR), X-ray Diffraction (XRD), UV–Vis Diffuse Reflectance Spectroscopy (UV–Vis DRS), Photoluminescence (PL), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDX), Transmission Electron Microscopy (TEM), and Brunauer − Emmet − Teller (BET) studies. The acquired Co-CuO NPs demonstrated a substantial crystallinity, smaller crystallite size of ∼10.87 nm, lower bandgap, and reduced recombination rate and were implemented as an effective photocatalyst for the degradation of the amoxicillin (AMX) and tetracycline (TC) antibiotics, as examined by UV − vis spectrophotometric study and confirmed by a hypochromic shift. Based on UV − vis analysis, Co-CuO NPs demonstrated a potent and rapid photocatalytic degradation performance of ∼99 and ∼93 % for the AMX and TC antibiotics within 150 and 210 min respectively. Co-CuO NPs also demonstrated strong antimicrobial performance against Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Aspergillusflavus, Aspergillusniger, and Bacillus subtilis. Further investigation of in-vitro cytotoxic potential against the A549 cell line, utilizing MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay and the free radical scavenging performance of the Co-CuO NPs was estimated by DPPH (2,2-diphenyl-1-picrylhydrazyl) assay utilizing L-ascorbic acid as reference were also performed.

Refractive index measurement of pharmaceutical powders in the short-wave infrared range using index matching assisted with phase imaging

Refractive index is a fundamental optical property of powder that is used as an important input in light scattering measurements of the size distribution and diffuse reflectance spectroscopy measurements of the absorption and scattering coefficients. In this work, we demonstrate a method that combines index matching with phase imaging to determine the refractive index of complex powder particles at high accuracy without relying on any assumptions. Index matching is robust, but the accuracy is not high by relying on ocular observation of the interface. Phase imaging using interferometry improves the accuracy of determining the match by an order of magnitude. Using the proposed method, we determine the refractive index of four types of pharmaceutical powder in the short-wave infrared range of 1100–1650 nm.

Zeolitic Imidazole Framework/Silica Nanocomposite for Targeted Cancer Therapeutics: Comparative Study of Chemo-Drug Cisplatin (CPt) and Green Platinum (GPt) Efficacy.

A chemo-drug such as cisplatin is effective for cancer treatment but remains non-specific, is susceptible to drug resistance, and induces several side effects on organ systems. Zeolitic imidazolate framework-8, a type of MOF, has gained attention, including as a drug delivery method for targeted cancer therapeutics. In this study, ZIF-8/Silica nanocomposite was synthesized using a one-pot hydrothermal technique using the Stober technique. We studied the effect of phyto-synthesized GPt and chemo-drug cisplatin CPt on ZIF-8/Silica for targeted efficacy of cancer therapy. The texture, morphology, and chemical environment of Pt on ZIF-8/Silica were analyzed using different characterization techniques such as XRD, FT-IR, BET, diffuse reflectance spectroscopy, SEM-EDX, TEM, zeta potential, and TGA analysis. The isothermal behavior of CPt and GPt adsorption was investigated using isotherm models like Langmuir, Freundlich, and Temkin isotherm. The adsorption kinetics indicating the adsorption efficiency of GPt and CPt are influenced by the concentration of Pt complex and the adsorption sites of ZIF-8/Silica. A high entrapment efficiency and loading capacity of GPt (86% and 4.3%) and CPt (91% and 4.5%) were evident on ZIF-8/Silica. The nanocomposite showed a pH-sensitive Pt release using a dialysis membrane technique. For instance, a high release of GPt (93%) was observed under pH = 6.6 in 72 h, while the release reduced to 50% at pH 7.4 in 72 h. The anti-cancer activity of nanoformulations was studied in vitro using MCF7 (breast cancer cells) and HFF-1 (human foreskin fibroblast) cells. The findings demonstrated that GPt is as effective as CPt; the EC50 value for MCF7 cells treated with ZIF-8/Silica/Cp/PEG was 94.86 µg/mL, whereas for ZIF-8/Silica/GPt/PEG it was 60.19 µg/mL.

Monitoring of Caffeine Consumption Effect on Skin Blood Properties by Diffuse Reflectance Spectroscopy.

Caffeine is the most widely consumed psychoactive substance worldwide, affecting numerous tissues and organs, with notable impacts on the central nervous system, heart, and blood vessels. The effect of caffeine on vascular smooth muscle cells is an initial transient contraction followed by significant vasodilatation. In this study we investigate the use of diffuse reflectance spectroscopy (DRS) for monitoring of vascular changes in human skin induced by caffeine consumption. DRS spectra were recorded on volar sides of the forearms of eight healthy volunteers at time intervals of 0, 30, 60, 120, and 180 min after consumption of caffeine, while one subject served as a negative control. Analytical diffusion approximation solutions for diffuse reflectance from three-layer structures were used to assess skin composition (e.g. dermal blood volume fraction and oxygen saturation) by fitting these solutions to experimental data. The results demonstrate that cutaneous vasodynamics induced by caffeine consumption can be monitored by DRS, while changes in the control subject not consuming caffeine were insignificant.

Vanadocene-functionalized mesoporous silica nanoparticles: platforms for the development of theranostic materials against breast cancer

Nanoscale materials have demonstrated a very high potential in anticancer therapy by properly adjusting their functionalization and physicochemical properties. Herein, we report the synthesis of some novel vanadocene-loaded silica-based nanomaterials incorporating four different S-containing amino acids (penicillamine, methionine, captopril, and cysteine) and different fluorophores (rhodamine B, coumarin 343 or Alexa Fluor™ 647), which have been characterized by diverse solid-state spectroscopic techniques viz; FTIR, diffuse reflectance spectroscopies, 13C and 51V solid-state NMR spectroscopy, thermogravimetry and TEM. The analysis of the biological activity of the novel vanadocene-based nanostructured silicas showed that the materials containing cysteine and captopril aminoacids demonstrated high cytotoxicity and selectivity against triple negative breast cancer cells, making them very promising antineoplastic drug candidates. According to the biological results it seems that vanadium activity is connected to its incorporation through the amino acid, resulting in synergy that increases the cytotoxic activity against cancer cells of the studied materials presumably by increasing cell internalization. The results presented herein hold significant potential for future developments in mesoporous silica-supported metallodrugs, which exhibit strong cytotoxicity while maintaining low metal loading. They also show potential for theranostic applications highlighted by the analysis of the optical properties of the studied systems after incorporating rhodamine B, coumarin 343 (possible) in vitro anticancer analysis, or Alexa Fluor™ 647 (in vivo studies of cancer models).

Skin perfusion and oxygen saturation after mastectomy and radiation therapy in breast cancer patients

The pathophysiological mechanism behind complications associated with postmastectomy radiotherapy (PMRT) and subsequent implant-based breast reconstruction are not completely understood. The aim of this study was to examine if there is a relationship between PMRT and microvascular perfusion and saturation in the skin after mastectomy and assess if there is impaired responsiveness to a topically applied vasodilator (Methyl nicotinate – MN).Skin microvascular perfusion and oxygenation >2 years after PMRT were measured using white light diffuse reflectance spectroscopy (DRS) and laser Doppler flowmetry (LDF) in the irradiated chest wall of 31 women with the contralateral breast as a control. In the non-irradiated breast, the perfusion after application of MN (median 0.84, 25th–75th centile 0.59–1.02 % RBC × mm/s) was higher compared to the irradiated chest wall (median 0.51, 25th–75th centile 0.21–0.68 % RBC × mm/s, p < 0.001). The same phenomenon was noted for saturation (median 91 %, 25th–75th centile 89–94 % compared to 89 % 25th–75th centile 77–93 %, p = 0.001). Eight of the women (26%) had a ≥10 % difference in skin oxygenation between the non-irradiated breast and the irradiated chest wall.These results indicate that late microvascular changes caused by radiotherapy of the chest wall significantly affect skin perfusion and oxygenation.

Highly efficient (V2O5)0.91Zn0.09 powdered catalyst for water organic pollutant elimination

(V2O5)1-x Znx powdered samples with different light doping levels (x = 0.03–0.09) were prepared by a solid-state thermal reaction and studied by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), energy dispersive analysis (EDAX), and optical diffuse reflectance spectroscopies. The prepared samples has been revealed that the increments in Zn-doping levels accompanied by vacuum heat treatment lead to the appearance of an additional V12O26 phase beside the pure V2O5 oxide, resulting not only in more donor vanadium atom liberation but also in multi-heterojunction component formation. Besides, Eg values decrease from 2.38 to 2.2 eV as Zn doping increases from x = 0 to x = 0.09. All previous observations improve the process of purifying water from pollutants by increasing the number of free carriers of V2O5 powder by adding Zn atoms and making vacuum heat treatments. The photocatalytic examination has been carried out using constants of 0.5 g and 0.01 g/L (10 ppm) of the catalyst quantity and MB-dye concentration, respectively, under Vis – irradiations. The acidic solution medium with a pH of 2 strongly motivated the degradation activity. The highest catalytic efficiency of 99.78% was attained by the (V2O5)0.91 Zn 0.09 compound within a time of 70 min and continued invariably for 5 hours in the dark. These catalytic results have proved the possibility of their reusability.