A great deal of effort has demonstrated magnetite nanoparticles (Fe 3 O 4 NPs) are important subject applied in tumor hyperthermia due to their excellent magneto-thermal effect. Our previous study had ultrafast prepared 6nm Fe 3 O 4 NPs via microwave approach and found that these small size NPs are responsible for microwave energy conversion to accelerate NPs formation. Hence, we suppose that investigating the size-dependent behavior of Fe 3 O 4 NPs should be beneficial for developing their electromagnetic energy conversion application for hyperthermia. In this study, Fe 3 O 4 NPs with four sizes (i.e. 4nm, 20nm, 50nm and 200nm) were prepared by a rapid microwave synthetic strategy. The specific absorption rate (SAR) value and reflection loss (RL) value of samples were investigated by measuring the time-dependent temperature curves in alternating magnetic field (AMF, 390 and 780kHz, 12A) and via vector network analyzer (VNA) range from 2 to 18GHz, respectively. Results indicated that using magnetic induction hyperthermia frequency Fe 3 O 4 NPs with single domain size of 20nm possess maximum, whereas the RL value increases with the size at microwave frequency. More importantly, the frequency of maximum RL value was matched with the clinical microwave hyperthermia. We subsequently introduce the micromagnetic (OOMMF) simulation to help understanding the issue due to the fundamental importance of size effect for magnetic NPs in energy conversion. Simulation results suggested that coupling interaction and magnetic dipole-dipole interaction between magnetic NPs and electromagnetic field would be seen as synergistic effect to impact absorption behavior, and we believe that this work can provide a valuable reference for size selection of magnetic nanoparticles in clinical application of hyperthermia.
Pengpeng Guan,Caijie Yuan,Jiali Li,Zhou Wen,Enling Hu,Guangqian Lan,Bowen Cheng,Yinggui Huang,Fei Lu
The inadequacy of current antithrombotic therapies lies in the limited efficacy of pharmacotherapy and the poor targetability of drugs to thrombotic sites. To address these challenges, we developed a multifunctional nanoplatform, Fe 3 O 4 @MC-DEA-PBAP (FMDP), which integrates magnetic responsiveness and erythrocyte targeting for magnetic hyperthermia thrombolysis (MHT). FMDP is constructed using metal–organic frameworks (MOFs) crosslinking CaCO 3 /cyclodextrin as the base carrier, modified with 2-(Diethylamino)ethyl methacrylate (DEA) and 4-hydroxyphenylboronic acid pinacol ester (PBAP), then conjugated with nano-ferric oxide for MHT. DEA and PBAP make FMDP to adhere onto erythrocytes and scavenge reactive oxygen species (ROS), respectively. In vitro experiments proved that FMDP exhibits high photothermal conversion efficiency and robust magnetic responsiveness, enabling the thrombolytic efficiency of FMDP was three times that of uPA group. In addition, FMDP adhere to erythrocytes (83.5 %) and reach the thrombi under the cover of erythrocytes for MHT. In addition, FMDP effectively scavenges ROS, mitigating endothelial damages and promoting vascular regeneration. Overall, FMDP represents a promising therapeutic strategy for the comprehensive management of thrombosis, offering improved efficacy and reduced bleeding risks compared to conventional thrombolytic therapies.
Gang Fu,Lei Ni,Dan Wei,Juncheng Jiang,Zhiquan Chen,Yong Pan
In this study, toluene nitration was scaled up in a meso-scale flow reactor and safety was considered. The exothermic characteristic was demonstrated in a batch calorimeter . Parallel flow was observed in the flow channel and numerical simulation was carried out to show the hydrodynamics . Mass transfer coefficient of the reactor mixer was determined. The effects of flow rates, temperatures and molar ratios on toluene nitration in the flow reactor were analyzed. The conversion of toluene increased from 26% to 86% with the increase of flow rates while the impacts of temperatures and molar ratios were comparatively small. A productivity of 2572 kg/a could be achieved by this meso-scale flow reactor but the highest overtemperature inside the channel was more than 21.3 ∘ C. A comparison between performances of the batch calorimeter and the flow reactor was also presented. The finding of this study can serve as a reference to design inherently safer meso-scale flow reactors for kinetically fast and highly-exothermic reactions.
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