Chiral separation performance of micrometer-sized monodispersed silica spheres with high protein loading

The influence of bovine serum albumin-modified silica on the physicochemical properties of poly(vinyl alcohol) nanocomposites synthesized by ultrasonication technique

In this study, for the first time polymeric nanocomposite (NC) films of poly(vinyl alcohol)/SiO₂@bovine serum albumin (PVA/SiO₂@BSA) were synthesized by solution casting method under facile and fast method of sonication. In this regard, SiO₂ nanoparticles (NPs) were modified by BSA, at room temperature by using phosphate buffer and ultrasonic-assisted method. Then, PVA/SiO₂@BSA NCs were prepared by insertion of variant amount (3, 6 and 9wt%) of SiO₂@BSA into the PVA matrix, under ultrasonic irradiation. The morphological traits of the NCs were surveyed by Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray diffraction and field emission scanning electron microscopy. It was detected that NPs incorporation didn't remarkably affect the crystallinity and morphology of the NCs. TEM images indicated that the inserted NPs have good diffusions in the PVA matrix, and their embedment in the matrix significantly upgraded its thermal, optical and mechanical behaviors. The tensile strength showed more than 2-fold increase and the thermal stability exhibited about 37% enhancement that was higher, in comparison with those of the similar NCs. This showed that the prepared NCs can have potential application in food packaging.∗∗∗.

Precise Synthesis of Well-Defined Inorganic-Organic Hybrid Particles

Synthesis of hybrid particles toward precisely designed hierarchical nanoarchitectures is summarized. In order to satisfy the demands for a variety of materials' performances, the selection of materials, composition and synthesis is carefully done. Flow reactors are one of the useful synthetic means to prepare hybrid materials, especially those with hierarchically and precisely designed multi-components hybrid particles, owing to the efficient mixing and heat exchange in the reactor as well as its connectable (both parallel and sequential) feature. In this review article, after the summary of the preparation of hybrids based on oxides and organics through conventional batch reactors, the application of flow reactors to the preparation of various hybrid particles is introduced to highlight the present status and future possibility of the flow reactor synthesis.

Liquid–liquid microflow reaction engineering

Engineering characteristics of liquid–liquid microflow and its advantages in chemical reactions.

Chromatographic Studies of Protein-Based Chiral Separations

The development of separation methods for the analysis and resolution of chiral drugs and solutes has been an area of ongoing interest in pharmaceutical research. The use of proteins as chiral binding agents in high-performance liquid chromatography (HPLC) has been an approach that has received particular attention in such work. This report provides an overview of proteins that have been used as binding agents to create chiral stationary phases (CSPs) and in the use of chromatographic methods to study these materials and protein-based chiral separations. The supports and methods that have been employed to prepare protein-based CSPs will also be discussed and compared. Specific types of CSPs that are considered include those that employ serum transport proteins (e.g., human serum albumin, bovine serum albumin, and alpha1-acid glycoprotein), enzymes (e.g., penicillin G acylase, cellobiohydrolases, and α-chymotrypsin) or other types of proteins (e.g., ovomucoid, antibodies, and avidin or streptavidin). The properties and applications for each type of protein and CSP will also be discussed in terms of their use in chromatography and chiral separations.

Penetrable silica microspheres for immobilization of bovine serum albumin and their application to the study of the interaction between imatinib mesylate and protein by frontal affinity chromatography

In the current study, novel featured silica, named penetrable silica, simultaneously containing macropores and mesopores, was immobilized with bovine serum albumin (BSA) via Schiff base method. The obtained BSA-SiO2 was employed as the high-performance liquid chromatographic (HPLC) stationary phase. Firstly, D- and L-tryptophan were used as probes to investigate the chiral separation ability of the BSA-SiO2 stationary phase. An excellent enantioseparation factor was obtained up to 4.3 with acceptable stability within at least 1 month. Next, the BSA-SiO2 stationary phase was applied to study the interaction between imatinib mesylate (IM) and BSA by frontal affinity chromatography. A single type of binding site was found for IM with the immobilized BSA, and the hydrogen-bonding and van der Waals interactions were expected to be contributing interactions based on the thermodynamic studies, and this was a spontaneous process. Compared to the traditional silica for HPLC stationary phase, the proposed penetrable silica microsphere possessed a larger capacity to bond more BSA, minimizing column overloading effects and enhancing enantioseparation ability. In addition, the lower running column back pressure and fast mass transfer were meaningful for the column stability and lifetime. It was a good substrate to immobilize biomolecules for fast chiral resolution and screening drug-protein interactions.

Immobilization of penicillin G acylase on macro-mesoporous silica spheres

In this study, macro-mesoporous silica spheres were prepared with a micro-device and used as the support for the immobilization of penicillin G acylase (PGA). To measure the enzymatic activity, the silica spheres with immobilized PGA were placed into a packed-bed reactor, in which the hydrolysis of penicillin G was carried out. The influences of the residence time, the initial concentration of the substrate, the accumulation of the target product 6-aminopenicillanic acid, and the enzyme loading amount on the performance of the immobilized PGA were investigated. The introduction of macropores increased the enzyme loading amount and decreased the internal mass transfer resistance, and the results showed that the enzyme loading amount reached 895 mg/g (dry support), and the apparent enzymatic activity achieved up to 1033 U/g (dry support). In addition, the immobilized PGA was found to have great stability.

Enantiomer self-disproportionation and chiral stationary phase based selective chiral separation of organic compounds

In modern chromatography, chiral stationary phase (CSP) and enantiomer self-disproportionation (ESD) are new inventions of packing material offer a guarantee for a successful enantiomeric separation. All CSPs were synthesized by chemical bonding of the relevant organic moieties onto a porous parent silica material for the separation of various racemic mixtures whereas achiral silica matrix was used for separation of non-racemic mixtures in ESD. Our present study provides to establish an understanding on the entire enantio-selective profile of amino alcohol based CSP as well as ESD and their precise utilization for high success rates for selective enantiomer separation with its appropriateness.