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In JoVE (1)
Other Publications (2)
Articles by Shuai Xu in JoVE
JoVE Bioengineering
Hydrophobic Salt-modified Nafion for Enzyme Immobilization and Stabilization
Departments of Chemistry and Materials Science and Engineering, University of Utah
This article will describe the procedure for synthesizing a hydrophobically modified Nafion enzyme immobilization membrane and how to immobilize proteins and/or enzymes within the membrane and test their specific activity.
Other articles by Shuai Xu on PubMed
Mesoporous Biocompatible and Acid-degradable Magnetic Colloidal Nanocrystal Clusters with Sustainable Stability and High Hydrophobic Drug Loading Capacity
Fabrication of magnetic particles (MPs) with high magnetization and large surface area simultaneously is critical for the application of MPs in bioseparation and drug delivery but remains a challenge. In this article, we describe an unprecedented approach to synthesize mesoporous magnetic colloidal nanocrystal clusters (MCNCs) stabilized by poly(γ-glutamic acid) (PGA) with high magnetization, large surface area (136 m(2)/g) and pore volume (0.57 cm(3)/g), excellent colloidal stability, prominent biocompatibility, and acid degradability. This result provides the important step toward the construction of a new family of MCNCs and demonstrates its capacity in a "magnetic motor" drug delivery system. Here, as an example, we explore the applicability of as-prepared mesoporous MCNCs as hydrophobic drug delivery vehicles (paclitaxel as model drug), and the resultant loading capacity is as high as 35.0 wt %. The antitumor efficacy measured by MTT assay is significantly enhanced, compared with free drugs. Thus, combined with their inherent high magnetization, the mesoporous MCNCs pave the way for applying magnetic targeting drug carriers in antitumor therapeutics.
Toward Designer Magnetite/polystyrene Colloidal Composite Microspheres with Controllable Nanostructures and Desirable Surface Functionalities
An effective method was developed for synthesizing magnetite/polymer colloidal composite microspheres with controllable variations in size and shape of the nanostructures and desirable interfacial chemical functionalities, using surfactant-free seeded emulsion polymerization with magnetite (Fe(3)O(4)) colloidal nanocrystal clusters (CNCs) as the seed, styrene (St) as the monomer, and potassium persulfate (KPS) as the initiator. The sub-micrometer-sized citrate-acid-stabilized Fe(3)O(4) CNCs were first obtained via ethylene glycol (EG)-mediated solvothermal synthesis, followed by 3-(trimethoxysilyl)propyl methacrylate (MPS) modification to immobilize the active vinyl groups onto the surfaces, and then the hydrophobic St monomers were polymerized at the interfaces to form the polymer shells by seeded emulsion radical polymerization. The morphology of the composite microspheres could be controlled from raspberry- and flower-like shapes, to eccentric structures by simply adjusting the feeding weight ratio of the seed to the monomer (Fe(3)O(4)/St) and varying the amount of cross-linker divinyl benzene (DVB). The morphological transition was rationalized by considering the viscosity of monomer-swollen polymer matrix and interfacial tension between the seeds and polymer matrix. Functional groups, such as carboxyl, hydroxyl, and epoxy, can be facilely introduced onto the composite microspheres through copolymerization of St with other functional monomers. The resultant microspheres displayed a high saturation magnetization (46 emu/g), well-defined core-shell nanostructures, and surface chemical functionalities, as well as a sustained colloidal stability, promising for further biomedical applications.
