Moharramzadeh Fereshteh, Seyyed Ebrahimi Seyyed Ali, Zarghami Vahid, Lalegani Zahra, Hamawandi Bejan
Advanced Magnetic Materials Research Center, School of Metallurgy and Materials, University of Tehran, Tehran 11155 4563, Iran.
Department of Materials and Metallurgy, Faculty of Mechanical and Energy Engineering, Shahid Beheshti University, Tehran 16589 53571, Iran.
Gels. 2023 Jun 19;9(6):501. doi: 10.3390/gels9060501.
Magnetic hybrid hydrogels have exhibited remarkable efficacy in various areas, particularly in the biomedical sciences, where these inventive substances exhibit intriguing prospects for controlled drug delivery, tissue engineering, magnetic separation, MRI contrast agents, hyperthermia, and thermal ablation. Additionally, droplet-based microfluidic technology enables the fabrication of microgels possessing monodisperse characteristics and controlled morphological shapes. Here, alginate microgels containing citrated magnetic nanoparticles (MNPs) were produced by a microfluidic flow-focusing system. Superparamagnetic magnetite nanoparticles with an average size of 29.1 ± 2.5 nm and saturation magnetization of 66.92 emu/g were synthesized via the co-precipitation method. The hydrodynamic size of MNPs was changed from 142 nm to 826.7 nm after the citrate group's attachment led to an increase in dispersion and the stability of the aqueous phase. A microfluidic flow-focusing chip was designed, and the mold was 3D printed by stereo lithographic technology. Depending on inlet fluid rates, monodisperse and polydisperse microgels in the range of 20-120 μm were produced. Different conditions of droplet generation in the microfluidic device (break-up) were discussed considering the model of rate-of-flow-controlled-breakup (squeezing). Practically, this study indicates guidelines for generating droplets with a predetermined size and polydispersity from liquids with well-defined macroscopic properties, utilizing a microfluidic flow-focusing device (MFFD). Fourier transform infrared spectrometer (FT-IR) results indicated a chemical attachment of citrate groups on MNPs and the existence of MNPs in the hydrogels. Magnetic hydrogel proliferation assay after 72 h showed a better rate of cell growth in comparison to the control group ( = 0.042).
磁性混合水凝胶在各个领域都展现出了显著的功效，尤其是在生物医学科学领域，这些创新材料在药物控释、组织工程、磁分离、磁共振成像造影剂、热疗和热消融等方面展现出了诱人的前景。此外，基于微滴的微流控技术能够制造出具有单分散特性和可控形态形状的微凝胶。在此，通过微流控流动聚焦系统制备了含有柠檬酸化磁性纳米颗粒（MNPs）的藻酸盐微凝胶。采用共沉淀法合成了平均粒径为29.1±2.5 nm、饱和磁化强度为66.92 emu/g的超顺磁性磁铁矿纳米颗粒。柠檬酸基团附着后，MNPs的流体动力学尺寸从142 nm变为826.7 nm，导致水相的分散性和稳定性增加。设计了一种微流控流动聚焦芯片，并通过立体光刻技术3D打印了模具。根据入口流体速率，制备了20-120μm范围内的单分散和多分散微凝胶。考虑到流量控制破裂模型（挤压），讨论了微流控装置中不同的液滴生成条件（破裂）。实际上，本研究为利用微流控流动聚焦装置（MFFD）从具有明确宏观性质的液体中生成具有预定尺寸和多分散性的液滴提供了指导方针。傅里叶变换红外光谱仪（FT-IR）结果表明柠檬酸基团在MNPs上发生了化学附着，并且水凝胶中存在MNPs。72小时后的磁性水凝胶增殖试验表明，与对照组相比，细胞生长速率更好（P = 0.042）。
