Zhang Cheng, Wang Yong, Chen Yuduo, Ma Xing, Chen Wenjun
Sauvage Laboratory for Smart Materials, School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China.
Nanomaterials (Basel). 2021 Dec 30;12(1):115. doi: 10.3390/nano12010115.
This article introduces a facile droplet-based microfluidic method for the preparation of FeO-incorporated alginate hydrogel magnetic micromotors with variable shapes. By using droplet-based microfluidics and water diffusion, monodisperse (quasi-)spherical microparticles of sodium alginate and FeO (Na-Alg/FeO) are obtained. The diameter varies from 31.9 to 102.7 µm with the initial concentration of Na-Alginate in dispersed fluid ranging from 0.09 to 9 mg/mL. Calcium chloride (CaCl) is used for gelation, immediately transforming Na-Alg/FeO microparticles into Ca-Alginate hydrogel microparticles incorporating FeO nanoparticles, i.e., Ca-Alg/FeO micromotors. Spherical, droplet-like, and worm-like shapes are yielded depending on the concentration of CaCl, which is explained by crosslinking and anisotropic swelling during the gelation. The locomotion of Ca-Alg/FeO micromotors is activated by applying external magnetic fields. Under the rotating magnetic field (5 mT, 1-15 Hz), spherical Ca-Alg/FeO micromotors exhibit an average advancing velocity up to 158.2 ± 8.6 µm/s, whereas worm-like Ca-Alg/FeO micromotors could be rotated for potential advancing. Under the magnetic field gradient (3 T/m), droplet-like Ca-Alg/FeO micromotors are pulled forward with the average velocity of 70.7 ± 2.8 µm/s. This article provides an inspiring and timesaving approach for the preparation of shape-variable hydrogel micromotors without using complex patterns or sophisticated facilities, which holds potential for biomedical applications such as targeted drug delivery.
本文介绍了一种简便的基于液滴的微流控方法，用于制备具有可变形状的掺有FeO的海藻酸盐水凝胶磁性微马达。通过基于液滴的微流控技术和水扩散，获得了单分散的（准）球形海藻酸钠和FeO（Na-Alg/FeO）微粒。其直径在31.9至102.7 µm之间变化，分散液中Na-海藻酸钠的初始浓度范围为0.09至9 mg/mL。氯化钙（CaCl）用于凝胶化，可立即将Na-Alg/FeO微粒转变为掺入FeO纳米颗粒的海藻酸钙水凝胶微粒，即Ca-Alg/FeO微马达。根据CaCl的浓度可产生球形、液滴状和蠕虫状形状，这可以通过凝胶化过程中的交联和各向异性膨胀来解释。Ca-Alg/FeO微马达的运动通过施加外部磁场来激活。在旋转磁场（5 mT，1 - 15 Hz）下，球形Ca-Alg/FeO微马达的平均前进速度高达158.2±8.6 µm/s，而蠕虫状Ca-Alg/FeO微马达可旋转以实现潜在的前进。在磁场梯度（3 T/m）下，液滴状Ca-Alg/FeO微马达以70.7±2.8 µm/s的平均速度向前拉动。本文提供了一种鼓舞人心且节省时间的方法，用于制备形状可变的水凝胶微马达，无需使用复杂的图案或精密的设备，这在靶向药物递送等生物医学应用中具有潜力。
