图 1 用于全水球丝水凝胶微丝制备的微流控系统示意图

Fig. 1 Schematic diagrams of the microfluidic system for generating all-aqueous droplet-filled hydrogel microfibers a. configuration of the microfluidic chip: the injection unit, the droplet generation unit, fiber generation unit, the collection unit and the procedure of the pneumatic valve for the generation of droplet. Dextran (DEX), poly(ethylene glycol) (PEG) with alginate (NaA), and PEG with calcium chloride (CaCl2) were introduced to the system through inner-phase, middle-phase, and outer-phase inlets, respectively. b. procedures for droplet and fiber generation. c. schematic illustration of the reaction of NaA and CaCl2 within the microfibers.

图 2 全水球丝制备以及形貌表征

Fig. 2 Generation and morphological characterization of the all-aqueous droplet-filled hydrogel microfibers a. bright-field image of the flows in the droplet generation unit and fiber generation unit; b. macroscopic (i), microscopic (ii), and schematic (iii) images of the all-aqueous droplet-filled hydrogel microfibers; c. fluorescence and bright-field images of fluorescein isothiocyanate-labeled sodium alginate (FITC-labeled NaA) collected in the all-aqueous droplet-filled hydrogel microfibers; d. SEM images of the (i and ii) side and (iii) cross-sectional views of the freeze-dried microfibers. The valve cycle was fixed to 0.4 s, and the inner-phase, middle-phase, and outer-phase flow rates were set to 0.6, 5.5, and 300 μL/min, respectively, for all collected fibers shown in the figure.

图 3 海藻酸盐微丝中不同形状的液滴包封分布图及表征图

Fig. 3 Characterization and distribution maps of different-shaped droplets encapsulated in the alginate microfibers a. morphology of different types of droplet-filled and hollow fibers; b. distribution of fiber morphologies formed at different inner-phase and middle-phase flow rates.

图 4 不同(a)内相、(b)中间相和(c)外相流速下球丝异质载体的明场图和对液滴直径、液滴间距和微丝宽度的统计图

Fig. 4 Bright-field images of droplet-filled hydrogel microfibers and statistical diagrams of the droplet diameter, droplet distance, and microfiber width under the different (a) inner-phase, (b) middle-phase, (c) outer-phase flow rates **p<0.01; ***p<0.001. Quantitative analyses of the droplet diameter, droplet distance, and microfiber width were performed on at least 20 samples.

图 5 全水球丝中负载和形成3D细胞球

Fig. 5 Encapsulation and formation of 3D cell spheroids in the all-aqueous droplet-filled hydrogel microfibers a. schematic diagram of the encapsulation of tumor cells in the all-aqueous droplet-filled hydrogel microfibers and formation of 3D cell spheroids; b. bright-field image of continuous fibers loaded with multiple tumor spheroids; c. bright-field images of tumor spheroids in the droplets 1, 3, 5, and 7 d after loading and the corresponding statistical analysis of the tumor spheroid diameter (n=3); d. fluorescence images of the live/dead staining experiment and fluorescence quantitative analysis to assess the viability of cells within the tumor spheroids 1, 3, 5, and 7 d after loading (n=3).

图 6 A549细胞球药物测试表征

Fig. 6 Characterization of the drug response of A549 cells in the spheroids a. bright-field and fluorescence images of the live/dead staining of A549 cells in 2D cultures treated with different concentrations of cisplatin (0.1-1000 μmol/L) for 24 h; b. the corresponding dose-response curve and IC50 value of cisplatin in A549 cells cultured in 2D plate (n=3); c. bright-field and fluorescence images of the live/dead staining of A549 tumor spheroids in all-aqueous droplet-filled hydrogel microfibers treated with different concentrations of cisplatin (0.1-1000 μmol/L) for 24 h; d. the corresponding dose-response curve and IC50 value of cisplatin in A549 cells cultured in the all-aqueous droplet-filled hydrogel microfibers (n=3).