CAS Institute of Process Engineering

Beijing, China

CAS Institute of Process Engineering

Beijing, China
Time filter
Source Type

Ma G.,CAS Institute of Process Engineering
Journal of Controlled Release | Year: 2014

Bio-degradable poly(lactide) (PLA)/poly(lactide-glycolide) (PLGA) and chitosan microspheres (or microcapsules) have important applications in Drug Delivery Systems (DDS) of protein/peptide drugs. By encapsulating protein/peptide drugs in the microspheres, the serum drug concentration can be maintained at a higher constant value for a prolonged time, or injection formulation can be changed to orally or mucosally administered formulation. PLA/PLGA and chitosan are most often used in injection formulation and oral formulation. However, in the preparation and applications of PLA/PLGA and chitosan microspheres containing protein/peptide drugs, the problems of broad size distribution and poor reproducibility of microspheres, and deactivation of protein during the preparation, storage and release, are still big challenges. In this article, the techniques for control of the diameter of microspheres and microcapsules will be introduced at first, then the strategies about how to maintain the bioactivity of protein drugs during preparation and drug release will be reviewed and developed in our research group. The membrane emulsification techniques including direct membrane emulsification and rapid membrane emulsification processes were developed to prepare uniform-sized microspheres, the diameter of microspheres can be controlled from submicron to 100 μm by these two processes, and the reproducibility of products can be guaranteed. Furthermore, compared with conventional stirring method, the big advantages of membrane emulsification process were that the uniform microspheres with much higher encapsulation efficiency can be obtained, and the release behavior can be adjusted by selecting microsphere size. Mild membrane emulsification condition also can prevent the deactivation of proteins, which frequently occurred under high shear force in mechanical stirring, sonification, and homogenization methods. The strategies for maintaining the bioactivity of protein drug were developed, such as adding additives into protein solution, using solid drug powder instead of protein solution, and employing hydrophilic poly(lactide)-poly(ethylene glycol) (PELA) as a wall material for encapsulation in PLA/PLGA microspheres/microcapsules; developing step-wise crosslinking process, self-solidification process, and adsorbing protein drug into preformed chitosan microsphere with hollow-porous morphology for encapsulation in chitosan microsphere. As a result, animal test demonstrated that PELA microcapsules with uniform size and containing recombinant human growth hormone (rhGH) can maintain higher blood drug concentration for 2 months, and increased animal weight more apparently only by single dose, compared with PLA and PLGA microcapsules; hollow-porous chitosan microsphere loading insulin decreased blood glucose level largely when it was used as a carrier for oral administration. © 2014 Elsevier B.V.

Ge J.,Tsinghua University | Ge J.,CAS Institute of Process Engineering | Lei J.,Stanford University | Lei J.,CAS Institute of Process Engineering | Zare R.N.,CAS Institute of Process Engineering
Nature Nanotechnology | Year: 2012

Flower-shaped inorganic nanocrystals have been used for applications in catalysis and analytical science, but so far there have been no reports of ĝ€ nanoflowersĝ€™ made of organic components. Here, we report a method for creating hybrid organic-inorganic nanoflowers using copper (II) ions as the inorganic component and various proteins as the organic component. The protein molecules form complexes with the copper ions, and these complexes become nucleation sites for primary crystals of copper phosphate. Interaction between the protein and copper ions then leads to the growth of micrometre-sized particles that have nanoscale features and that are shaped like flower petals. When an enzyme is used as the protein component of the hybrid nanoflower, it exhibits enhanced enzymatic activity and stability compared with the free enzyme. This is attributed to the high surface area and confinement of the enzymes in the nanoflowers. © 2012 Macmillan Publishers Limited.

Lai X.,CAS Institute of Process Engineering | Halpert J.E.,CAS Institute of Process Engineering | Wang D.,CAS Institute of Process Engineering | Wang D.,Harbin Institute of Technology
Energy and Environmental Science | Year: 2012

Hollow micro-/nano-structured materials are now playing an important role in cutting edge innovations for energy conversion and storage technologies such as solar cells, fuel cells, lithium ion batteries and super capacitors. These materials show great promise in addressing growing environmental concerns for cleaner power sources at a time of increasing global demand for energy. In this perspective, we show that complex multi-shelled micro-/nano-materials show significant material advantages in many applications over conventional simple hollow structures. We also summarize the vast array of synthetic strategies used to create multi-shelled hollow structures, and discuss the possible application of these novel materials for power generation and storage. Finally, the emergent challenges and future developments of multi-shelled hollow structures are further discussed. © The Royal Society of Chemistry 2012.

Shi J.,CAS Shanghai Institute of Ceramics | Shi J.,East China University of Science and Technology | Shi J.,CAS Institute of Process Engineering
Chemical Reviews | Year: 2013

The heterogeneous catalytic performance is largely dependent on the catalyst nanostructures or, in another word, processing technologies, in addition to the intrinsic physical and chemical properties of the constitutive components. Compared to the amorphous framework of mesoporous silica, mesoporous metal oxides synthesized by a hard templatereplicating method usually have a crystallized structure and exhibit excellent catalytic activities, as reported in many documents. The loading or dispersion of catalytically active guest species into the host mesopore network results in mesostructured composites of a crystallized framework and highly dispersed catalytic species in its mesopore network. Mesoporous inorganic oxide materials, in the form of either powder or thin film, with high surface areas, ordered pore structures, finely tunable pore sizes, and flexible wallcompositions have been investigated widely of their chemical synthesis and potential applications in catalysis, adsorption, chemical sensing, electrochemistry, biomedical areas, and so on.

Friedrich Loeffler Institute and CAS Institute of Process Engineering | Date: 2013-11-06

The invention provides a process for generating an avian cell line of duck origin by a process comprising:- cultivating embryonic avian cells in cell culture medium, preferably comprising fetal calf serum (FBS) for more than 40 passages while reducing the concentration of FBS to 1 - 2% vol/vol FBS,- transferring passaged cells into cell culture medium having 0% FBS,- resulting in the generation of a non-embryonic avian cell line suitable for non-adherent growth, i.e. for growth in suspended culture.

Yang J.,Institute Of Bioengineering And Nanotechnology, Singapore | Yang J.,CAS Institute of Process Engineering | Ying J.Y.,Institute Of Bioengineering And Nanotechnology, Singapore
Angewandte Chemie - International Edition | Year: 2011

With a little help from my friends: Successive deposition of different noble metals on Ag2S nanocrystals yields binary, ternary, and quaternary hybrid nanocomposites (see picture). In particular, the platinum-containing systems were found to exhibit superior catalytic activity toward methanol oxidation. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Yang J.,Institute Of Bioengineering And Nanotechnology, Singapore | Yang J.,CAS Institute of Process Engineering | Ying J.Y.,Institute Of Bioengineering And Nanotechnology, Singapore
ACS Nano | Year: 2012

Controlling the morphology of Pt-based nanomaterials can be an effective way to improve the catalytic activity on a mass basis. Herein we demonstrate for the first time the synthesis of monodispersed core-shell AgPd@Pt nanoparticles with multiply twinned structures. These multiply twinned particles (MTPs), which possess the icosahedra structure, exhibit superior catalytic activity toward oxygen reduction reaction (ORR) in fuel cells. The Ag component of the alloy AgPd inner core is crucial for the construction of the multiply twinned structure of the core-shell nanoparticles, while the Pd component is used to reduce the tensile strain effect of the Ag on the deposited Pt layers, rendering the Pt binding energy in core-shell AgPd@Pt MTPs to be close to that of commercial Pt nanoparticles. The enhanced ORR activity of AgPd@Pt/C can be explained in terms of a much higher surface fraction of atoms on the (111) facets for icosahedral MTPs. This core-shell structure offers an interesting example to investigate the morphology and lateral strain effect of the substrate on the deposited layers, and their influence on the catalytic activity of metal catalysts. © 2012 American Chemical Society.

Dong K.,CAS Institute of Process Engineering | Zhang S.,CAS Institute of Process Engineering
Chemistry - A European Journal | Year: 2012

Ionic liquids (ILs) have attracted intensive attention in academia and industry due to their unique properties and potential applications. Nowadays, much interest is focused on finding out what is the main force that determines the properties of ionic liquids. Intuitively like NaCl, in high-temperature molten salt (HTMS) the electrostatic Coulomb force is regarded as the dominant factor that determines the behaviors of ILs. However, a large amount of evidence indicates that such a molten-salt-based simplified explanation is not consistent with the corresponding experimental results. Besides the Coulomb force, the hydrogen bond is another important noncovalent interaction in the IL and is closely related to some important properties and applications, as suggested in some new research results. Therefore in this review, we present results concerning the hydrogen bond in ILs, from the perspective of experiment and calculation, to shed light on its effects and roles. The deep insights into structure, in particular the hydrogen bonds, can provide us with a rational design for the new ILs to fulfill the demands in some complicated chemical processes. To hydrogen bond or not? Hydrogen bonds exist in many different ionic liquids (ILs) and become a key factor to elucidate the ILs. Many properties and applications of ILs are closely related to hydrogen bonds. The integrated review on hydrogen bonds in ILs will be helpful to design task-specific ILs. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Du J.,CAS Institute of Process Engineering | Qi J.,CAS National Center for Nanoscience and Technology | Wang D.,CAS Institute of Process Engineering | Tang Z.,CAS National Center for Nanoscience and Technology
Energy and Environmental Science | Year: 2012

Au@TiO2 hollow submicrospheres with controllable sizes and shell thicknesses are easily synthesized by the hydrothermal method. When Au@TiO 2 hollow submicrospheres are used as the photoanodes of DSSCs, a power conversion efficiency of 8.13% is achieved, which exhibits a 30% increase compared with the conventional DSSCs fabricated with P25 TiO2 photoanodes. © 2012 The Royal Society of Chemistry.

Chen H.,CAS Institute of Process Engineering | Qiu W.,CAS Institute of Process Engineering
Biotechnology Advances | Year: 2010

Controversies on bioethanol produced from straw mainly revolve around the unfitted economical feasibility and environmental concerns of the process, which attribute mainly to unilateral researches from own specialties of each scholar without regard to the characteristics of the straws themselves. To achieve an economical and environmentally-friendly system of bioethanol production from straw, a number of breakthroughs are needed, not only in individual process steps, but also in the balance and combination of these processes. This article gives an overview of the new technologies required and the advances achieved in recent years, especial progresses achieved in our group, based on the concept of fractional conversions. An eco-industrial multi-production pattern is established, by which the maximum efficacy and benefit of process can be achieved due to the production of many high-value co-products simultaneously with ethanol. We believed that, in the future, the bioethanol production from straw will be competitive economically and environmentally. © 2010.

Loading CAS Institute of Process Engineering collaborators
Loading CAS Institute of Process Engineering collaborators