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Search for "radicals" in Full Text gives 225 result(s) in Beilstein Journal of Nanotechnology. Showing first 200.
Characterization of ZnO nanoparticles synthesized using probiotic Lactiplantibacillus plantarum GP258
Beilstein J. Nanotechnol. 2025, 16, 78–89, doi:10.3762/bjnano.16.8
- MB dye progressed with time and yielded 95% degradation under 120 min. The process involved in dye degradation is exciting electrons and generating holes in the semiconductor. The produced electrons form superoxide radicals (•O2−) by reacting with O2, while holes react with water (H2O) molecules to
- produce hydroxyl radicals (•OH−). These radicals degrade the dye molecules into harmless substances; the degradation is shown in Figure 2d. TEM analysis The size of the ZnO NPs, which was determined from TEM using Image J software, varied from 7 to 98 nm, with an average size of 10 nm. The SAED pattern of
- . ZnO NPs are known to generate reactive oxygen species (ROS), including hydroxyl radicals and superoxide ions, upon interaction with bacterial cells. These ROS disrupt bacterial cell membranes, cause oxidative stress, and damage cellular components, ultimately leading to cell death. Additionally, ZnO
Heterogeneous reactions in a HFCVD reactor: simulation using a 2D model
Beilstein J. Nanotechnol. 2024, 15, 1627–1638, doi:10.3762/bjnano.15.128
- give rise to the surface reactions for the growth of the films. In the reaction mechanisms reported for the growth of SiO2 films, the role of intermediate •H and •OH and •O2 radicals has been pointed out through in situ Fourier-transform infrared spectroscopy. These species react with silane-derived
- convert H to OH. Finally, •H and •OH radicals can attack saturated surface species, removing H to form H2 and H2O, respectively, in the gas phase [21][36]. The presence of dangling bonds in the SiOx films was detected previously. In this study, SiOx films with thermal treatment and without thermal
- exhibited greater photoluminescence compared to those that did not undergo thermal treatment [29]. The SiO species plays an important role in the proposed mechanism; the reaction of SiO with •OH and •H radicals leads to the formation of HSiO and silanes [15]. Silane and silanol species were also found in
Liver-targeting iron oxide nanoparticles and their complexes with plant extracts for biocompatibility
Beilstein J. Nanotechnol. 2024, 15, 1593–1602, doi:10.3762/bjnano.15.125
- , lysosomes, the Golgi apparatus, and the endoplasmic reticulum [44][45]. Wu and colleagues found that Fe3O4 NPs up to 5 nm in size can penetrate cells and initiate the Fenton reaction, resulting in the formation of genotoxic •OH radicals [20]. Moreover, iron overload in cells can lead to ferroptosis [46][47
- the presence of noticeable dystrophic changes only in the group with maximum GPx suppression, it can be assumed that Fe3O4 NPs in combination with certain plant secondary metabolites may lead to excessive formation of free radicals, which cause dystrophic changes. Conclusion The diversity of the
- control, ODsample is the optical density of the sample, and ODremnant is the remnant optical density of DPPH after its complete scavenging. The IC50 value was determined from dose-dependent ARA curves as the concentration of components in the sample necessary for quenching 50% of the DPPH radicals [62
Interaction of graphene oxide with tannic acid: computational modeling and toxicity mitigation in C. elegans
Beilstein J. Nanotechnol. 2024, 15, 1297–1311, doi:10.3762/bjnano.15.105
- , and catalase [61]. Besides that, the metal chelating properties of TA may influence oxidative pathways dependent of these cofactors, such as Fenton’s reaction and copper-mediated formation of free radicals. TA may also act as direct radical scavenger in these reactions [65][66][67][68]. Moreover, TA
Mn-doped ZnO nanopowders prepared by sol–gel and microwave-assisted sol–gel methods and their photocatalytic properties
Beilstein J. Nanotechnol. 2024, 15, 1283–1296, doi:10.3762/bjnano.15.104
- usually involved in the photodegradation of organic compounds in aqueous media as previously reported [54]. The generation of hydroxyl radicals (·OH) by SG and MW catalysts under simulated solar light irradiation (AM1.5) was determined from the PL emission at 451 nm assigned to the presence of a
- fluorescent compound, namely umbelliferone, a coumarin degradation product obtained in the presence of hydroxyl radicals. Figure 11a–c clearly shows that ·OH radicals are photogenerated to a greater extent by the MW catalyst. This could be the result of specific differences in surface chemistry of the two
- oxidation capacity of hydroxyl radicals. The subsequent decrease of the CO2 formation rate could be assigned to a presumed catalyst deactivation due to the strong adsorption of reactant/reaction products on its surface. This observation is in line with the PL measurements in oxalic acid solutions and the
Synthesis, characterization and anticancer effect of doxorubicin-loaded dual stimuli-responsive smart nanopolymers
Beilstein J. Nanotechnol. 2024, 15, 1189–1196, doi:10.3762/bjnano.15.96
- radicals, and a direct effect on cell membranes with the suppression of nucleic acid synthesis. The most hazardous side effect of DOX is dilated cardiomyopathy, which causes congestive heart failure [4]. To prevent side effects of doxorubicin, liposomal formulations were approved, namely “Myocet liposomal
AI-assisted models to predict chemotherapy drugs modified with C60 fullerene derivatives
Beilstein J. Nanotechnol. 2024, 15, 1170–1188, doi:10.3762/bjnano.15.95
- C60 [21]. The unmodified fullerene C60 is known as a “free radical sponge” because its double bonds tend to accept free radicals [22]. Because of its size, surface area, and capacity to extinguish or generate reactive oxygen species, C60 is very promising in medicine and clinical therapy [23][24]. It
Photocatalytic methane oxidation over a TiO2/SiNWs p–n junction catalyst at room temperature
Beilstein J. Nanotechnol. 2024, 15, 1132–1141, doi:10.3762/bjnano.15.92
- that the superior wettability of TiO2/SiNWs (hydrophilic surfaces) compared to TiO2/glass (hydrophobic surfaces) enables partial adsorption of water molecules, which facilitates the generation of radicals necessary for photocatalytic reactions. Furthermore, the TiO2 nanostructure and p-type SiNWs are
Identification of structural features of surface modifiers in engineered nanostructured metal oxides regarding cell uptake through ML-based classification
Beilstein J. Nanotechnol. 2024, 15, 909–924, doi:10.3762/bjnano.15.75
- or passive transport across the cell membrane [12]. Excessive absorption by normal cells enables metal oxide nanoparticles to engage with various subcellular organelles, initiating diverse signaling pathways to generate a stress response within cells. This results in the production of free radicals
Intermixing of MoS2 and WS2 photocatalysts toward methylene blue photodegradation
Beilstein J. Nanotechnol. 2024, 15, 817–829, doi:10.3762/bjnano.15.68
- generation of electron–hole pairs (EHPs) [21]. The generated EHPs react with oxygen and water molecules to produce highly reactive species, such as hydroxyl radicals, which oxidize and degrade MB contaminants. Hence, evaluating the PD processes in the case of MoS2 and WS2 as TMD materials is crucial for
- pollutants is often driven by reactive agents, such as superoxide radicals, hydroxyl radicals, or photo-induced holes produced from either the conduction or valence bands [41][42]. The mechanism of the PD of MB under visible light excitation consists of several steps: Initially, the MB dye molecules are
- electrons (e−), leading to the formation of superoxide anions (O2−) [43]. The adsorbed oxygen has the ability to undergo a reaction with two electrons, resulting in the formation of hydrogen peroxide (H2O2). Hydrogen peroxide subsequently reacts with an electron, forming hydroxyl radicals (•OH), which are
Green synthesis of biomass-derived carbon quantum dots for photocatalytic degradation of methylene blue
Beilstein J. Nanotechnol. 2024, 15, 755–766, doi:10.3762/bjnano.15.63
- structure. Due to its size, the crystal structure effects can be enhanced. The expected mechanism for the photodegradation of MB is related with the formation of electron–hole pairs that, due to their oxidizing properties, promotes the formation of OH− radicals. These species are responsible for the
Laser synthesis of nanoparticles in organic solvents – products, reactions, and perspectives
Beilstein J. Nanotechnol. 2024, 15, 638–663, doi:10.3762/bjnano.15.54
- mechanisms of organic liquid decomposition and carbon shell formation are highlighted and discussed regarding current challenges and future perspectives of LSPC using organic liquids instead of water. Keywords: alloy; photochemistry; pyrolysis; radicals; surface chemistry; Introduction Since the first
- oxygen species (ROS), for example, hydrogen peroxide, hydroxyl radicals, or dissolved oxygen, react with the particles leading to their surface oxidation. During irradiation of water with intense laser pulses, a weakly ionized plasma forms because of optical breakdown, supercontinuum emission, or both
- as water and even aqueous solutes. Thus, this model formed the basis that enabled the derivation of yield functions for a variety of direct electron-mediated DNA damage pathways and indirect damage by •OH radicals resulting from laser and electron interactions with water [85]. In general, LSPC in
Photocatalytic degradation of methylene blue under visible light by cobalt ferrite nanoparticles/graphene quantum dots
Beilstein J. Nanotechnol. 2024, 15, 475–489, doi:10.3762/bjnano.15.43
- iodide (KI), potassium bromate (KBrO3), and p-benzoquinone (BQ) were used as scavengers to capture hydroxyl radicals (•OH), photo-induced holes (h+), photo-induced electrons (e−), and superoxide anions respectively. As can be seen, IPA exhibits a strong interaction with the hydroxyl radical through a
- simple electron transfer process [34]. If the •OH radicals play a crucial role in the MB degradation, the reaction rate is expected to decrease significantly. As depicted in Figure 8a, adding an excess amount of 10 mM IPA to the reaction mixture significantly suppresses the MB degradation (by ca. 28.5
- , available to react with H2O to produce •OH radicals. The electrons in the CB band directly reduce MB to its degradation products or interact with oxygen in the aqueous solution to form peroxy anion radicals (). A part of h+ oxidizes water to form hydroxyl radicals (•OH), or it can oxidize directly MB to its
Classification and application of metal-based nanoantioxidants in medicine and healthcare
Beilstein J. Nanotechnol. 2024, 15, 396–415, doi:10.3762/bjnano.15.36
- , and cancers [1][2]. The human body naturally defends itself against oxidative stress by using antioxidant biomolecules. With the excellent ROS scavenging effect, antioxidants significantly contribute to the balance of ROS and protect the human body from free radicals, which are produced either by
- safely apply these nanomaterials for human healthcare, which strictly require assessment regarding quality control, safety, and efficacy. Many in vitro and in vivo assessments have been reported to prove the potential of metal-based nanomaterials for scavenging free radicals. FeO nanoparticles have 81
- radicals through several pathways such as chelating transition metals, quenching singlet oxygens, decomposing hydrogen peroxides, and deactivating superoxides without generating active radicals [17][18][19]. Transition metals such as Fe2+ and Cu2+ initiate a Fenton reaction in the presence of hydrogen
Exploring the relationships between physiochemical properties of nanoparticles and cell damage to combat cancer growth using simple periodic table-based descriptors
Beilstein J. Nanotechnol. 2024, 15, 297–309, doi:10.3762/bjnano.15.27
- removing electrons from molecules, producing free radicals. Free radicals are unstable and highly reactive. These short-lived radicals are unable to leave the sub-cellular location where they are generated without being reduced, leading to oxidative damage [43]. The presence of high-electronegativity
- hydroxyl radicals, resulting in oxidative damage to proteins. Moreover, they can bind non-specifically to amino acid residues and replace existing metal ions at active sites of enzymes, leading to abnormal protein folding. Protein aggregation diseases are a type of neurodegenerative diseases that occur
- acceleration of damage to the biological membrane. A positive coefficient of Electron Active M indicates more oxidative stress and more damage to the cell due to an increase in free radicals. WO3 has a high descriptor value of 74 resulting in high cell damage (−2.8), while Cr2O3 NP has a low descriptor value
Nanotechnological approaches in the treatment of schistosomiasis: an overview
Beilstein J. Nanotechnol. 2024, 15, 13–25, doi:10.3762/bjnano.15.2
- scavenge free radicals [27]. After that, many authors related a reduction in oxidative stress markers in vivo after metalic nanoparticle administration and/or amelioration in histopathological characteristics after infection, which corroborates the first hypothesis [27][28][29][30][31][32][33][34]. Solid
A combined gas-phase dissociative ionization, dissociative electron attachment and deposition study on the potential FEBID precursor [Au(CH3)2Cl]2
Beilstein J. Nanotechnol. 2023, 14, 1178–1199, doi:10.3762/bjnano.14.98
- formation of two CH3 radicals in this process) it results in threshold values of 13.51 and 14.06 eV at the PBE0-TZVP and DLPNO-CCSD(T)-TZVP levels of theory, respectively. These are ≈4 eV above the AE which is significantly higher than the confidence limits of the experiment. However, considering the
- threshold for this process without new bond formation is found to be 15.01 and 15.04 eV at the respectively levels of theory. Hence, also here new bonds must be formed for this process to be thermochemically possible at its AE. Considering the formation of ethane from two of the methyl radicals, the
- where the threshold values are 13.58 and 13.52 eV at the respective levels of theory. The formation of chloromethane and two methyl radicals, where the respective threshold values are 13.72 and 13.76 eV, are also considered. On the other hand, considering the formation of chloromethane and ethane brings
Prediction of cytotoxicity of heavy metals adsorbed on nano-TiO2 with periodic table descriptors using machine learning approaches
Beilstein J. Nanotechnol. 2023, 14, 939–950, doi:10.3762/bjnano.14.77
- toxicity through an ionic mechanism followed by the generation of reactive oxygen species (ROS). Another, biomarker for ROS is lipid peroxidation [38] as free radicals cause lipid peroxidation inside the cell membrane. The catalytic properties of the metals are also responsible for an increased toxicity of
Green SPIONs as a novel highly selective treatment for leishmaniasis: an in vitro study against Leishmania amazonensis intracellular amastigotes
Beilstein J. Nanotechnol. 2023, 14, 893–903, doi:10.3762/bjnano.14.73
- reaction, catalyzing the formation of highly reactive hydroxyl radicals that lead to oxidative stress [28][29]. Thus, one of the possibilities for the observed antiproliferative effects could be the result of an imbalance in iron homeostasis with the consequent induction of oxidative stress and death of
Carboxylic acids and light interact to affect nanoceria stability and dissolution in acidic aqueous environments
Beilstein J. Nanotechnol. 2023, 14, 762–780, doi:10.3762/bjnano.14.63
- did not occur in the dark in the presence of most carboxylic acids. Light initiates free radicals generated by ceria nanoparticles. Nanoceria completely dissolved in the presence of citric, malic, and isocitric acid when exposed to light, attributed to nanoceria dissolution, release of Ce3+ ions, and
- ]. When exposed to artificial sunlight, ceria nanoparticles produced hydroxy radicals and induced lipid peroxidation of the gills of cardinal tetra, a native species of the Rio Negro region [45]. The citric acid coating can also be altered by UV irradiation. Photolysis of citric acid under a Hg lamp
Titania nanoparticles for photocatalytic degradation of ethanol under simulated solar light
Beilstein J. Nanotechnol. 2023, 14, 616–630, doi:10.3762/bjnano.14.51
- that recombination processes are taking place at that level. This also applies to free holes trapped at acceptor levels [68], which cannot escape as easily as electrons from the donor level. Generation of hydroxyl radicals Reactive oxygen species are usually involved in the photodegradation of organic
- from the interaction with photogenerated hydroxyl radicals. Despite the fact that radical trapping was performed in aqueous solution, it can be indicative for the ability of the catalyst surface to generate hydroxyl radicals in the present investigated system. The main reactions leading to (•OH
- ) formation are the following: or Figure 8 shows a significant ability of TO-250-a, TO-450-a, TO-650-a, TO-850-a, and P 25 catalysts to generate •OH, indicating a presumable activity for CO2 generation. In contrast, the samples of series “b” are almost inactive. Only TO-450-b can produce hydroxyl radicals
Molecular nanoarchitectonics: unification of nanotechnology and molecular/materials science
Beilstein J. Nanotechnol. 2023, 14, 434–453, doi:10.3762/bjnano.14.35
- molecules was also realized. Kawai et al. synthesized three-dimensional graphene nanoribbons by surface chemistry and showed that local probe chemistry can be used to add different molecules by tip manipulation [115]. Specifically, they demonstrated that radicals created by tip-induced debromination can be
- other words, a controlled addition reaction in a single molecule adsorbed on a surface by a local probe at low temperature was demonstrated. Long-lived radicals could be obtained, and C60 molecules could be selectively added to the sites. Such direct addition reactions enable the synthesis of single
Bismuth-based nanostructured photocatalysts for the remediation of antibiotics and organic dyes
Beilstein J. Nanotechnol. 2023, 14, 291–321, doi:10.3762/bjnano.14.26
- by conventional methods [11][12][13][14]. For the oxidation of organic molecules, AOPs rely on the in situ generation of potent oxidants (reactive oxygen species, ROS) such as hydroxyl or sulfate radicals. AOPs have been broadly categorised in terms of how ROS are produced, including non
- hydroxyl radicals, enhancing the photocatalytic reaction. These results unequivocally demonstrate the significance of the pH value in the degradation process and the necessity to fine-tune the photocatalysts to make them functional at all pH values. The removal effectiveness and rate of photocatalytic
- decrease in efficiency was attributed to two causes: First, it is more difficult for photons to reach the photocatalyst at higher concentrations, which resulted in a decrease in the production of oxidant radicals and, as a result, a decrease in the degradation performance. Second, the number of
Recent progress in cancer cell membrane-based nanoparticles for biomedical applications
Beilstein J. Nanotechnol. 2023, 14, 262–279, doi:10.3762/bjnano.14.24
- levels of GSH peroxidases [106]. Based on the conditions in the TME, ferrous/ferric ions can catalyze H2O2 to produce hydroxyl radicals (•OH) through the Fenton reaction [39][107]. Nanoscale agents with ferroptosis function coated by cancer cell membranes can avoid surveillance of the body and travel to
Structural, optical, and bioimaging characterization of carbon quantum dots solvothermally synthesized from o-phenylenediamine
Beilstein J. Nanotechnol. 2023, 14, 165–174, doi:10.3762/bjnano.14.17
- −polyoxypropylene−polyoxyethylene Pluronic 68 generate singlet oxygen through energy transfer to molecular oxygen [21]. But CQDs prepared from o-phenylenediamine do not generate singlet oxygen or OH radicals through energy or electron transfer, because the condensation process of these dots includes NH2 groups in
- their structure whereas the presence of pyrrolic and pyridinic nitrogen is really minor. Thus reaction centers for ROS generation (dominantly pyridinic N) do not exist in o-phenylenediamine CQDs [40]. Hydroxyl radical production To examine the production of hydroxyl radicals, two measurements at
- indicate a low level of PL intensity after all measured time periods (0‒300 min) and (0‒440 min). This fact shows that there is no production of hydroxyl radicals in the CQDs/PU composite samples at the two excitation wavelengths (365 and 405 nm). In the previous section we established that the CQDs do not
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