Publications by authors named "Yangfei Sun"

In order to specifically deliver drugs into cancer cells with targeted recognition and controlled release, biocompatible hollow mesoporous silica nanocarriers with tumor-targeting and glutathione-responsive release dual properties were developed. These multifunctional nanocarriers were fabricated by anchoring transferrin on the surface of hollow mesoporous silica nanoparticles through disulfide bond conjugation, which could be cleaved in the presence of glutathione. In this case, transferrin acted as the gatekeeper to control the drug release, and as a tumor-targeting agent to improve drug accumulation at the tumor site simultaneously.

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While much effort has been made to prepare magnetic microspheres (MMs) with surface moieties that bind to affinity tags or fusion partners of interest in the recombinant proteins, it remains a challenge to develop a generic platform that is capable of incorporating a variety of capture ligands by a simple chemistry. Herein, we developed core-shell structured magnetic microspheres with a high magnetic susceptibility and a low nonspecific protein adsorption. Surface functionalization of these MMs with azide groups facilitates covalent attachment of alkynylated ligands on their surfaces by "click" chemistry and creates a versatile platform for selective purification and immobilization of recombinant proteins carrying corresponding affinity tags.

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The development of theranostic systems capable of diagnosis, therapy, and target specificity is considerably significant for accomplishing personalized medicine. Here, a multifunctional rattle-type nanoparticle (MRTN) as an effective biological bimodal imaging and tumor-targeting delivery system is fabricated, and an enhanced loading ability of hydrophobic anticancer drug (paclitaxel) is also realized. The rattle structure with hydrophobic Fe3 O4 as the inner core and mesoporous silica as the shell is obtained by one-step templates removal process, and the size of interstitial hollow space can be easily adjusted.

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As a promising non-viral gene vector, cationic polyamidoamine (PAMAM) dendrimer could form complexes with negative charged DNA to mediate efficient gene delivery in vitro and in vivo. However, complicated synthesis technology and potential cytotoxicity limited their application in clinical translational researches. Hyperbranched polyamidoamine (h-PAMAM), which could be synthesized by a simpler one-pot method, has similar properties with PAMAM, and PEGylation modification of h-PAMAM has been used to reduce cytotoxicity.

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In this work, maltodextrin-modified magnetic microspheres Fe3O4@SiO2-Maltodextrin (Fe3O4@SiO2-MD) with uniform size and fine morphology were synthesized through a facile and low-cost method. As the maltodextrins on the surface of microspheres were combined with maltose binding proteins (MBP), the magnetic microspheres could be applied to enriching standard MBP fused proteins. Then, the application of Fe3O4@SiO2-MD in one-step purification and immobilization of MBP fused proteins was demonstrated.

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A controlled drug-delivery system has been developed based on mesoporous silica nanoparticles that deliver anticancer drugs into cancer cells with minimized side effects. The copolymer of two oligo(ethylene glycol) macromonomers cross-linked by the disulfide linker N,N'-bis(acryloyl)cystamine is used to cap hollow mesoporous silica nanoparticles (HMSNs) to form a core/shell structure. The HMSN core is applied as a drug storage unit for its high drug loading capability, whereas the polymer shell is employed as a switch owing to its redox/temperature dual responses.

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In this work, core-shell-shell-structured boronic acid-functionalized magnetic composite microspheres Fe3O4@SiO2@poly (methyl methacrylate-co-4-vinylphenylbornoic acid) (Fe3O4@SiO2@P(MMA-co-VPBA)) with a uniform size and fine morphology were synthesized. Here, Fe3O4 magnetic particles were prepared by a solvothermal reaction, whereas the Fe3O4@SiO2 microspheres with a core-shell structure were obtained by a sol-gel process. 3-(Trimethoxysilyl) propyl methacrylate (MPS)-modified Fe3O4@SiO2 was used as the seed in the emulsion polymerization of MMA and VPBA to form the core-shell-shell-structured magnetic composite microspheres.

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Poly(vinylcaprolactam) (PVCL)-based biodegradable microgels were prepared for the biomedical application as drug delivery system via precipitation polymerization, where N,N-bis(acryloyl) cystamine (BAC) served as cross-linker, methacrylic acid (MAA) and polyethylene glycol (PEG) methyl ether methacrylate acted as comonomers. The microgels with excellent stability had distinct temperature sensitivity as largely observed in the case of PVCL-based particles and their volume phase transition temperature (VPTT) shifted to higher temperature with increasing MAA content and ambient pH. In the presence of reducing agent glutathione (GSH) or dithiothreitol (DTT), the microgels could be degraded into individual linear polymer chains by the cleavage of the disulfide linkages coming from the cross-linker BAC.

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pH-sensitive poly(L-glutamic acid) grafted mesoporous silica nanoparticles (MSN-PLGA) were prepared by the surface-initiated N-carboxyanhydride polymerization method. The resultant MSN-PLGA was well dispersed in aqueous medium and showed high drug loading efficiency, superior stability, and significantly higher drug release rates. The cumulative release of doxorubicin hydrochloride (DOX) from DOX-loaded MSN-PLGA (DOX@MSN-PLGA) was pH-dependent and the release rate was much higher at pH 5.

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Intellectual disability (ID) is a heterogeneous disorder caused by chromosomal abnormalities, monogenic factors and environmental factors. 22q13 deletion syndrome is a genetic disorder characterized by severe ID. Although the frequency of 22q13 deletions in ID is unclear, it is believed to be largely underestimated.

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To date, most genome-wide association studies (GWAS) and studies of fine-scale population structure have been conducted primarily on Europeans. Han Chinese, the largest ethnic group in the world, composing 20% of the entire global human population, is largely underrepresented in such studies. A well-recognized challenge is the fact that population structure can cause spurious associations in GWAS.

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