Correction: Structural, magnetic and hyperthermia properties and their correlation in cobalt-doped magnetite nanoparticles

[This corrects the article DOI: 10.1039/D1RA07407E.].

Structural, optical and conductivity properties in tetragonal BaTi1−xCoxO3 (0≤ x ≤0.1)

This work investigates the structure, optical and electrical conductivity properties of BaTi_1−xCo_xO₃ (0≤ x ≤0.1) ceramics prepared by the hydrothermal method. The X-ray diffraction and Raman scattering analysis demonstrates that the prepared samples have a single-phase tetragonal structure with P4mm symmetry. The UV-vis diffuse reflectance spectrum confirms the influence of Co concentration on the direct optical band gap of BaTi_1−xCo_xO₃ ceramics. The optical band gap shifts from 3.14 eV to 3.44 eV as the Co concentration increases from 0 to 0.1. The dielectric constant increases with the depletion of frequency according to the Maxwell–Wagner and Koops model. The AC conductivity versus frequency curve indicates that the conduction mechanism is determined by using the correlated barrier hopping (CBH) model. The Cole–Cole plot of the complex impedance was investigated for the prepared samples. The compounds showed dielectric relaxation of the non-Debye type.

This work investigates the structure, optical and electrical conductivity properties of BaTi_1−xCo_xO₃ (0≤ x ≤0.1) ceramics prepared by the hydrothermal method.

Structural, magnetic and hyperthermia properties and their correlation in cobalt-doped magnetite nanoparticles

Cobalt doped magnetite nanoparticles (Co_xFe_3−xO₄ NPs) are investigated extensively because of their potential hyperthermia application. However, the complex interrelation among chemical compositions and particle size means their correlation with the magnetic and heating properties is not trivial to predict. Here, we prepared Co_xFe_3−xO₄ NPs (0 ≤ x ≤ 1) to investigate the effects of cobalt content and particle size on their magnetic and heating properties. A detailed analysis of the structural features indicated the similarity between the crystallite and particle sizes as well as their non-monotonic change with the increase of Co content. Magnetic measurements for the Co_xFe_3−xO₄ NPs (0 ≤ x ≤ 1) showed that the blocking temperature, the saturation magnetization, the coercivity, and the anisotropy constant followed a similar trend with a maximum at x = 0.7. Moreover, ⁵⁷Fe Mössbauer spectroscopy adequately explained the magnetic behaviour, the anisotropy constant, and saturation magnetization of low Co content samples. Finally, our study shows that the relaxation loss is a primary contributor to the SAR in Co_xFe_3−xO₄ NPs with low Co contents as well as their potential application in magnetic hyperthermia.

The interrelation among chemical compositions, structure, and heating properties of cobalt doped magnetite nanoparticles (Co_xFe_3−xO₄ NPs) for their potential hyperthermia application.

Initial clinical experience of patient-specific QA of treatment delivery in online adaptive radiotherapy using a 1.5 T MR-Linac

Purpose. This study aims to evaluate the performance of a commercial 1.5 T MR-Linac by analyzing its patient-specific quality assurance (QA) data collected during one full year of clinical operation.Methods and Materials. The patient-specific QA system consisted of offline delivery QA (DQA) and online calculation-based QA. Offline DQA was based on ArcCHECK-MR combined with an ionization chamber. Online QA was performed using RadCalc that calculated and compared the point dose calculation with the treatment planning system (TPS). A total of 24 patients with 189 treatment fractions were enrolled in this study. Gamma analysis was performed and the threshold that encompassed 95% of QA results (T95) was reported. The plan complexity metric was calculated for each plan and compared with the dose measurements to determine whether any correlation existed.Results. All point dose measurements were within 5% deviation. The mean gamma passing rates of the group data were found to be 96.8 ± 4.0% and 99.6 ± 0.7% with criteria of 2%/2mm and 3%/3mm, respectively. T95 of 87.4% and 98.2% was reported for the overall group with the two passing criteria, respectively. No statistically significant difference was found between adaptive treatments with adapt-to-position (ATP) and adapt-to-shape (ATS), whilst the category of pelvis data showed a better passing rate than other sites. Online QA gave a mean deviation of 0.2 ± 2.2%. The plan complexity metric was positively correlated with the mean dose difference whilst the complexity of the ATS cohort had larger variations than the ATP cohort.Conclusions. A patient-specific QA system based on ArcCHECK-MR, solid phantom and ionization chamber has been well established and implemented for validation of treatment delivery of a 1.5 T MR-Linac. Our QA data obtained over one year confirms that good agreement between TPS calculation and treatment delivery was achieved.

Sensitive MnFe2O4–Ag hybrid nanoparticles with photothermal and magnetothermal properties for hyperthermia applications

In this study, we present an experiment showing that designing multifunctional MnFe₂O₄–Ag nanoparticles to act as a dual hyperthermia agent is an efficient route for enhancing their heating ability. Interestingly, the specific absorption rate of the heteromeric MnFe₂O₄–Ag nanoparticles increased 2.7 times under simultaneous irradiation of a 100 Oe magnetic field and 0.14 W cm⁻² laser compared to the action by the magnetic field alone, and more interestingly, is 30% higher than the sum of the two individual actions. The synergistic benefit of the magneto- and photo-thermal properties of the heteromeric structure can reduce the strengths of the magnetic field and laser intensities as well as their irradiation time to levels lower than those required in their hyperthermia applications individually. In vitro cytotoxicity analysis performed on HepG2 liver cancer and Hela cervical cancer cell lines showed that IC₅₀ values were 83 ± 5.6 μg mL⁻¹ (for HepG2) and 122.6 ± 19.8 μg mL⁻¹ (for Hela cells) after 48 h of incubation, therefore, the nanoparticles are moderately cytotoxic and nontoxic to HepG2 and Hela cells, respectively; which offers the potential of safe therapy.

In this study, we present an experiment showing that designing multifunctional MnFe₂O₄–Ag nanoparticles to act as a dual hyperthermia agent is an efficient route for enhancing their heating ability.

Correction: Sensitive MnFe2O4–Ag hybrid nanoparticles with photothermal and magnetothermal properties for hyperthermia applications

Correction for ‘Sensitive MnFe₂O₄–Ag hybrid nanoparticles with photothermal and magnetothermal properties for hyperthermia applications’ by T. T. N. Nha et al., RSC Adv., 2021, 11, 30054–30068. DOI: 10.1039/D1RA03216J

Polymer-coated cobalt ferrite nanoparticles: synthesis, characterization, and toxicity for hyperthermia applications

OA and OLA coated CoFe₂O₄ nanoparticles encapsulated with PMAO through hydrophobic interactions were developed for hyperthermia applications.