Tuning the Porosity of Dextran Microgels with Supramacromolecular Nanogels as Soft Sacrificial Templates

Abstract

Hydrogels, as well as colloidal hydrogels (microgels), are important materials for a large variety of applications in the biomedical field. Microgels with a controlled pore size (meso‐ and macropores) are required for efficient nutrient support, modulation of cell adhesion, removal of metabolic products in cell cultures, and probiotic loading. Common microgel fabrication techniques do not provide sufficient control over pore sizes and geometry. In this work, the natural polysaccharide dextran modified with methacrylate groups is used to synthesize highly monodisperse meso‐ and macroporous microgels in a size range of 100–150 µm via photo cross‐linking in microfluidic droplets. The size of mesopores is varied by the concentration of dextran methacrylate chains in the droplets (50–200 g L−1) and the size of macropores is regulated by the integration of pH‐degradable supramacromolecular nanogels with diameters of 300 and 700 nm as sacrificial templates. Using permeability assays combined with confocal laser scanning microscopy, it is demonstrated that functional dextran‐based microgels with uniform and defined pores could be obtained.

A Facilely Synthesized NiCo2S4 with Two Mutually Reinforcing Active Sites for High-Performance Lithium–Sulfur Batteries

“…These active sites provide more sites for the adsorption and catalysis of polysulfides, allowing for more efficient redox reactions. − The disordered structures are expected to provide trapping sites for charge carriers and interfere with their rapid recombination to reduce the resistance to charge transfer and improve the electron transfer efficiency. This enhanced charge transfer contributes to the improved redox reaction kinetics of polysulfides. − The element mappings (Figure g) suggest that the distributions of Ni, Co, and S are homogeneously dispersed throughout the structures, which demonstrate that the as-prepared D-NiCo 2 S 4 is beneficial to the absorption and uniform distribution of sulfur.…”

Microgels with Immobilized Glycosyltransferases for Enzymatic Glycan Synthesis

“…Permeability studies were performed according to the previous work of Bulut et al 58 In short, microgels were dispersed in 1 mg mL −1 FITC-dextran solutions of different molecular weights (4, 40, 150, and 500 kDa), followed by fluorescence intensity profile measurements through confocal microscopy. Therefore, the fluorescence intensity along the microgel diameter was measured from 0 to 200 μm.…”

Porous Anisometric PNIPAM Microgels: Tailored Porous Structure and Thermal Response

“…[17][18][19][20][21]25] In the case of PNIPAM microgels, oil droplets [17] and solid particles [25] are used as templates in the reaction solution for droplet polymerization. Also, gas bubbles [19] and porogens [20,21,42,43] are applied as templates in porous particle synthesis. In addition to templates, in microgel synthesis, porosity can also be induced or adapted using the cononsolvency effect for bulk hydrogels, [22,23] hybrid gels, [44] or microspheres.…”