Constructing Three-Dimensional Macroporous TiO2 Microspheres with Enhanced Pseudocapacitive Lithium Storage under Deep Discharging/Charging Conditions.

TiO2 has been intensively investigated as an anode material for lithium-ion batteries (LIBs) in 1.0-3.0 V (vs Li+/Li). However, it is a challenge to realize its theoretical capacity (336 mAh g-1) in this limited potential range. Extending the potential range below 1.0 V would increase its capacity but usually at the expense of its cyclic stability owing to the sluggish ionic diffusion and unsatisfactory structural stability. Here, three-dimensional (3D) macroporous TiO2 microspheres with interconnected pores and nanocrystalline thin walls have been constructed through a scalable template-assisted spray drying method to overcome these obstacles. When applied to LIBs, high and stable discharge capacity (300 mAh g-1 at 0.1 A g-1) as well as superior cyclic stability (242 mAh g-1 after 1000 cycles at 1.0 A g-1) can be achieved under deep discharging/charging conditions (0.01-3.0 V vs Li+/Li). Furthermore, the 3D macroporous structure is well preserved under deep discharging/charging and the in situ X-ray diffraction (XRD) patterns and Raman spectra reveal the dominant pseudocapacitive contribution at low potentials (0.01-1.0 V). This work not only develops a facile method to synthesize macroporous metal oxides but also provides insight into the lithium storage mechanism of TiO2 under deep discharging/charging conditions.

Rapid and high-capacity loading of IgG monoclonal antibodies by polymer brush and peptides functionalized microspheres.

Fast-throughput and cost reduction of current purification platforms are becoming increasing requests during antibody manufacture. The macroporous-matrix absorbents have presented extensive potentiality in improving operational throughput during purification of macromolecule. And meanwhile the peptide ligand has become a promising alternative to recombinant protein ligands for cost reduction of chromatographic purification. Therefore, here we designed a functionalized microspheres resin with both macroporous matrix of polymerized glycidyl methacrylate and ethylene glycol dimethacrylate (PGMA-EDMA) and peptide ligand of hexapeptide (FYEILH). In order to circumvent the steric effect of peptides and amplify the binding sites on macroporous matrix, the peptide ligand was coupled on a liner PGMA polymer brushes grafted on microspheres. Comparing to the conventional agarose-matrix resin and the general peptide-grafted microspheres, the functionalized microspheres presented excellent permeability and high capacity to rapid loading hIgG by maintaining a stable level of dynamic binding capacity at fast flow rate above 110 column volume per hour (cv/h) and very short residence time below 0.5 min. Such functionalized microspheres provide a facile and broadly applicable strategy to develop the attractive candidate for rapid and cost-reduced purification of antibody.

Fabrication of poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) macroporous microspheres through activators regenerated by electron transfer atom transfer radical polymerization for rapid separation of proteins.

Activators regenerated by electron transfer atom transfer radical polymerization (AGET ATRP) were firstly used in suspension polymerization to prepare macroporous microspheres based on a copolymer of glycidyl methacrylate and ethylene glycol dimethacrylate. Compared to conventional radical polymerization (CRP), the microspheres by AGET ATRP showed more homogeneous structure, larger pores, and higher protein binding capacity. The body of microspheres are formed by the large clusters resulted from the aggregated little particles. The size of the particles in microspheres by AGET ATRP was 10-300 nm which was smaller than that (400-800 nm) of the microspheres by CRP. AGET ATRP gave larger pore size (275 ±â€¯5 nm) and surface area (59.3 ±â€¯1 m2/g) than CRP (234 ±â€¯5 nm, 37.5 ±â€¯1 m2/g). The microspheres were modified with polyethylene imine for anion resins that were evaluated in term of its protein binding capacity. The results indicated that the static (69 ±â€¯0.5 mg/mL) and dynamic binding capacity (61 ±â€¯0.5 mg/mL) of proteins on modified microspheres by AGET ATRP were higher than that (34 ±â€¯0.5 mg/mL and 19 ±â€¯0.5 mg/mL) by CRP. Meanwhile, the proteins binding capacity on the microspheres by AGET ATRP decreased only less than 10% when the flow rate increased 10 times. These macroporous media show a large potential in rapid separation of proteins.

Effect of Porogen Solubility Parameter on Structure of Chromatographic Supports with Large Pores / 分析化学

The macroporous microspheres were prepared through suspension polymerization and based on a copolymer of glycidyl methacrylate and ethylene glycol dimethacrylate.The effect of porogen on the microspheres structure was evaluated in terms of pore size and surface area.Porogen contained dichloromethane (δ=9.7 (cal/cm3)1/2) and N-octanol (δ=10.3 (cal/cm3)1/2) which corresponded to a good and poor solvent,respectively.The solubility parameter of porogen was controlled in the range of 9.89-10.09 (cal/cm3)1/2.The pore size of microspheres increased with the difference value of solubility parameter between the polymer and the porogen.On the contrary,the surface area of microspheres decreased in this study.The anion exchange media was prepared through coupling poly(ethylene imine) in the microspheres,and the proteins transport was determined by frontal analysis method.The macroporous microspheres with 257 nm pore size could still afford a high proteins capacity (45.1 mg/mL).These macroporous supports showed a large potential in a rapid separation of proteins.