Facile Fabrication of Biomimetic Chitosan Membrane with Honeycomb-Like Structure for Enrichment of Glycosylated Peptides

In the study of glycoproteomics with mass spectrometry, certain pretreatments of samples are required for eliminating the interference of nonglycopeptides and improving the efficiency of glycopeptides detection. Although hydrophilic interaction chromatography (HILIC) has been developed for enrichment of glycosylated peptides, a plethora of hydrophilic materials always suffered from large steric hindrance, great cost, and difficulty with modifications of high-density hydrophilic groups. In this work, a 1 mm thick biomimetic honeycomb chitosan membrane (BHCM) with honeycomb-like accessible macropores was directly prepared by the freeze-casting method as an adsorbent for HILIC. The N-glycopeptides from trypsin digests of immunoglobulin G (IgG), mixture of IgG and bovine serum albumin (BSA), and serum proteins were enriched using this material and compared with a commercial material ZIC-HILIC. The biomimetic membrane could identify as many as 32 N-glycopeptides from the IgG digest, exhibiting high sensitivity (about 50 fmol) and a wide scope for glycopeptide enrichment. A molar ratio of IgG trypsin digest to bovine serum albumin trypsin digest as low as 1/500 verified the outstanding specificity and efficiency for glycopeptide enrichment. In addition, 270 unique N-glycosylation sites of 400 unique glycopeptides from 146 glycosylated proteins were identified from the triplicate analysis of 2 μL human serum. Furthermore, 48 unique O-glycosylation sites of 278 unique O-glycopeptides were identified from the triplicate analysis of 30 μg deglycosylated fetuin digest. These results indicated that the chitosan-based membrane prepared in this work had great potential for pretreatment of samples in glycoproteomics.

Electrophoretic fabrication of an active and selective wrinkle surface on hydrogels

We developed a novel method for the fabrication of a wrinkle structure on the hydrogel surface in aqueous conditions by the electrophoretic formation of a polyion complex.

In situ synthesis of CuO nanoparticles over functionalized mesoporous silica and their application in catalytic syntheses of symmetrical diselenides

A versatile and novel mesoporous silica supported CuO nanoparticle catalyst (nCuO-FMS) and its application in the syntheses of symmetrical diselenides.

Cost-Effective, Highly Selective and Environmentally Friendly Superhydrophobic Absorbent from Cigarette Filters for Oil Spillage Clean up

Ecological and environmental damage caused by oil spillage has attracted great attention. Used cigarette filters (CF) have also caused negative environmental consequences. Converting CF to economical materials is a feasible way to address these problems. In this study, we demonstrate a simple method for production of a highly hydrophobic absorbent from CF. CF was modified by using different volume ratios of octadecyltrichlorosilane and methyltrimethoxysilane. When the volume ratio was 3:2, the modified CF had the high water contact angle of 155°. It could selectively and completely absorb silicone oil from an oil-water mixture and showed a good absorption capacity of 38.3 g/g. The absorbed oil was readily and rapidly recovered by simple mechanical squeezing, and it could be reused immediately without any additional treatments. The as-obtained superhydrophobic modified CF retained an absorption capacity of 80% for pump oil and 82% for silicone oil after 10 cycles. The modified CF showed good elasticity in the test of repeated use. The present study provides novel design of a functional material for development of hydrophobic absorbents from used CF via a facile method toward oil spillage cleanup, as well as a new recycling method of CF to alleviate environmental impacts.

Activated carbon monoliths derived from bacterial cellulose/polyacrylonitrile composite as new generation electrode materials in EDLC

Bacterial cellulose (BC) gel is synthesized by static culture process at the interface between air and medium. The solvent-exchanged BC gel is incorporated into polyacrylonitrile (PAN) copolymer solution under heating at 90 °C and subsequent cooling gives bacterial cellulose-polyacrylonitrile composite (BC-PAN) monolith. The BC-PAN monolith is carbonized at 1000 °C with physical activation in the presence of CO₂ to obtain the activated carbon monolith, BC-PAN-AC, with large surface area and high microporosity. Unique morphologies are observed for BC gel which is propagated to the BC-PAN monolith and restored in BC-PAN-AC. The BC nanofibers remain entwined throughout the porous skeleton of the PAN backbone and the entangled structure helps in retaining the continuity of the matrix of BC-PAN-AC and reduce the grain boundary impedance for electrical conduction. Cyclic voltammetry shows that these activated carbons are good electrode materials in electric double layer capacitors (EDLC) with capability of high-speed charging and discharging.

An ideal enzyme immobilization carrier: a hierarchically porous cellulose monolith fabricated by phase separation method

Cellulose monolith with a hierarchically porous morphology was utilized as a novel solid support for enzyme immobilization. After a series of modifications, succinimidyl carbonate (SC)-activated cellulose monolith (SCCL monolith) was obtained and it was employed to immobilize a model enzyme (horseradish peroxidase, HRP) through covalent bonding. The HRP immobilization capacity on SCCL monolith was calculated as 21.0 mg/g. The thermal stability measurement illustrated that the immobilized HRP exhibited a largely improved thermal resistance compared to its free counterpart. The reusability of the immobilized HRP was investigated, and it could be reused at least 10 cycles without significant activity loss. Therefore, cellulose monolith is found to be an ideal solid support for enzyme immobilization.

Unique Ivy-Like Morphology Composed of Poly(lactic acid) and Bacterial Cellulose Cryogel

This study examines the unique morphology and properties of enhanced poly(l-lactic acid) (PLLA) monoliths having a bacterial cellulose (BC) framework. Open-porous BC/PLLA monoliths were successfully prepared using thermally induced phase separation (TIPS) and a freeze-drying technique. The BC/PLLA monoliths exhibited a unique ivy-like structure composed of leaf-like PLLA units and a BC fiber network. We demonstrated for the first time that the interpenetrating BC fiber gives PLLA monoliths four times higher compressive strength than the pristine PLLA. Scanning electron microscopy observation and the N₂ adsorption test revealed that the size of PLLA units and the surface area of the monoliths can be manipulated by varying the starting PLLA concentration during the TIPS process. Moreover, the hydrophilicity of the PLLA monoliths was easily controlled by incorporating BC; the neat PLLA monoliths showed a high static water contact angle of as high as 128.8 ± 1.1°, whereas the BC/PLLA monoliths exhibited a much lower contact angle (102.1 ± 1.7°) and greater absorbability to water.

Sea cucumber mimicking bacterial cellulose composite hydrogel with ionic strength-sensitive mechanical adaptivity

A novel sea cucumber-mimicking bacterial cellulose composite hydrogel shows stiffness changes in response to ionic strength without significant volume changes.

Rapid uniaxial actuation of layered bacterial cellulose/poly(N-isopropylacrylamide) composite hydrogel with high mechanical strength

This study deals with the unique morphology and properties of methylene diphenyl diisocyanate (MDI)-modified bacterial cellulose/poly(N-isopropylacrylamide) (BC/PNIPAAm) composite hydrogel prepared by in situ polymerization method. The influence of the molar ratio of MDI/glucose unit of BC on the properties of the resulting hydrogel was investigated. Scanning electron microscopic analysis revealed that after the MDI modification the BC/PNIPAAm hydrogel could preserve the unique layered (known as anisotropic) structure. The mechanical property evaluated by stress–strain test was significantly enhanced when compared to that of neat PNIPAAm hydrogel, due to the presence of the BC matrix as well as the MDI modification. Based on the deswelling behaviors, the BC/PNIPAAm hydrogel exhibited improved and controlled responsive rate when compared with neat PNIPAAm hydrogel. Furthermore, the anisotropic thermo-sensitive property was proved by temperature-responsive test with the fact that the composite hydrogel could only deswell and swell in the axial perpendicular to the layers. Along with desired recyclability, the present composite hydrogel may have an application as artificial muscles.

Anisotropic thermo-sensitive composite hydrogel based on bacterial cellulose was prepared by in situ polymerization, which could swell and deswell uniaxially.

Pronounced effect of pore dimension of silica support on Pd-catalyzed Suzuki coupling reaction under ambient conditions

The pore size of the mesoporous silica support affects the reactivity of heterogeneous palladium catalysts in the Suzuki reaction under ambient conditions, which is leveled at higher temperature.

A cellulose acetate/Amygdalus pedunculata shell-derived activated carbon composite monolith for phenol adsorption

Amygdalus pedunculata is expected to be a good candidate plant for desert reclamation (“greening”) since it has notable tolerance to cold and drought and can grow in a wide range of areas with different soil types and moisture contents. In this study, we have developed a single-step method to fabricate a cellulose acetate (CA)/A. pedunculata shell (APS)-derived activated carbon (AC) composite monolith by thermally induced phase separation (TIPS) for removal of toxic phenol from aqueous solution. The composite monolith was easily fabricated by TIPS of a CA solution in the presence of the dispersed AC, in which AC was well loaded onto the monolithic skeleton of CA. The as-obtained monolith showed a maximum adsorption capacity of 45 mg g⁻¹ at the initial phenol concentration of 0.8 mg mL⁻¹. The present composite can be prepared with an arbitrary shape by a facile method from cheap materials, and is more convenient to recycle than powder adsorbents. Therefore, the present CA/APS-derived AC composite monolith has great potential as a promising adsorbent of low cost with convenient separation for toxic phenol-containing wastewater.

In this study, we have developed a single-step method to fabricate a cellulose acetate (CA)/APS-derived activated carbon (AC) composite monolith by thermally induced phase separation (TIPS) for removal of toxic phenol from aqueous solution.

Effect of hydrogel elasticity and ephrinB2-immobilized manner on Runx2 expression of human mesenchymal stem cells

The objective of this study is to design the manner of ephrinB2 immobilized onto polyacrylamide (PAAm) hydrogels with varied elasticity and evaluate the effect of hydrogels elasticity and the immobilized manner of ephrinB2 on the Runx2 expression of human mesenchymal stem cells (hMSC). The PAAm hydrogels were prepared by the radical polymerization of acrylamide (AAm), and N,N'-methylenebisacrylamide (BIS). By changing the BIS concentration, the elasticity of PAAm hydrogels changed from 1 to 70kPa. For the bio-specific immobilization of ephrinB2, a chimeric protein of ephrinB2 and Fc domain was immobilized onto protein A-conjugated PAAm hydrogels by making use of the bio-specific interaction between the Fc domain and protein A. When hMSC were cultured on the ephrinB2-immobilized PAAm hydrogels with varied elasticity, the morphology of hMSC was of cuboidal shape on the PAAm hydrogels immobilized with ephrinB2 compared with non-conjugated ones, irrespective of the hydrogels elasticity. The bio-specific immobilization of ephrinB2 enhanced the level of Runx2 expression. The expression level was significantly high for the hydrogels of 3.6 and 5.9kPa elasticity with bio-specific immobilization of ephrinB2 compared with other hydrogels with the same elasticity. The hydrogels showed a significantly down-regulated RhoA activity. It is concluded that the Runx2 expression of hMSC is synergistically influenced by the hydrogels elasticity and their immobilized manner of ephrinB2 immobilized.

STATEMENT OF SIGNIFICANCE

Differentiation fate of mesenchymal stem cells (MSC) is modified by biochemical and biophysical factors, such as elasticity and signal proteins. However, there are few experiments about combinations of them. In this study, to evaluate the synergistic effect of them on cell properties of MSC, we established to design the manner of Eph signal ligand, ephrinB2, immobilized onto polyacrylamide hydrogels with varied elasticity. The gene expression level of an osteogenic maker, Runx2, was enhanced by the immobilized manner, and significantly enhanced for the hydrogels of around 4kPa elasticity with bio-specific immobilization of ephrinB2. This is the novel report describing to demonstrate that the Runx2 expression of MSC is synergistically influenced by the hydrogels elasticity and their manner of ephrinB2 immobilized.