Jin Y.,CAS Changchun Institute of Applied Chemistry
Accounts of Chemical Research | Year: 2014
Gold nanoshells (AuNSs) with tunable localized surface plasmon resonance (LSPR) peaks in the near-infrared (NIR) region possess unique optical properties - particularly that soft tissues are "transparent" at these wavelengths - making them of great interest in cancer diagnosis and treatment. Since 1998 when Halas and co-workers invented the first generation of AuNS, with a silica core and Au shell, researchers have studied and designed AuNSs for theranostic - individualized, combination diagnosis and therapy - nanomedicine. As demand has increased for more powerful and practical theranostic applications, so has demand for the next generation of AuNSs - compact yet complex multifunctional AuNSs with finely integrated plasmonic and nonplasmonic inorganic components.For in vivo biomedical applications, such a hybrid AuNS offers the desirable optical properties of NIR LSPR. Size, however, has proved a more challenging parameter to control in hybrid AuNSs. The ideal size of therapeutic NPs is 10-100 nm. Larger particles have limited diffusion in the extracellular space, while particles less than 5 nm are rapidly cleared from the circulation through extravasation or renal clearance. Conventional methods of preparing AuNS have failed to obtain small-sized hybrid AuNSs with NIR LSPR responses.In this Account, we present a new class of multifunctional hybrid AuNSs with ultrathin AuNSs and varied, functional (nonplasmonic) core components ranging from "hard" semiconductor quantum dots (QDs), to superparamagnetic NPs, to "soft" liposomes made using poly-l-histidine as a template to direct Au deposition. The resultant hybrid AuNSs are uniform and compact (typically 15-60 nm) but also preserve the optical properties and shell-type NIR response necessary for biomedical use. We also demonstrate these particles' innovative plasmonic applications in biosensing, multimodal imaging and controlled release. More importantly, the magnetic-plasmonic Fe3O 4/Au core-shell NP enables a new biological imaging method - magnetomotive photoacoustic (mmPA) imaging, which suppresses the nonmagnetomotive background and therefore offers remarkable contrast enhancement and improved specificity compared with photoacoustic images using conventional NP contrast agents.The advantages of our AuNSs are obvious: they are monodisperse, small (<100 nm), highly integrated, and have tunable visible-NIR plasmonic responses. All of these properties are crucial for in vitro or in vivo biological/biomedical studies and many applications, especially for studies of single cells or molecules which require particle monodispersity and tight size control. The plasmonic fluorescent QD/Au and the magnetic plasmonic Fe3O4/Au core-shell NPs may also reveal new physical phenomena that may lead to useful applications, owing to their well-defined core-shell nanoarchitectures and underlying nanoscale physical interactions. © 2013 American Chemical Society.
Jin Y.,CAS Changchun Institute of Applied Chemistry
Advanced Materials | Year: 2012
The fields of biosensing and nanomedicine have recently witnessed an explosion of interest and progress in the design and study of plasmonic Au nanostructures (p-AuNSs) or metamaterials geared towards a broad range of biological and biomedical applications. Due to their tunable and versatile plasmonic properties, such artificially engineered p-AuNSs and materials have the potential to push biosensor sensitivity towards the single-molecule detection limit, enabling new bioimaging modalities and new analytical techniques and tools capable of single-molecule detection, analysis and manipulation, and to revolutionize the diagnosis and treatment of many diseases, including cancers. This report summarizes and highlights recent major advances in the emerging field of bioapplication-oriented engineering of p-AuNSs and hybrids, focusing on design considerations and ways to carry them out. A brief overview of the optical properties of p-AuNSs is introduced, and then the importance of plasmonic engineering and future promising research directions and challenges in the field are discussed. Nanoengineering of plasmonic nanostructures and metamaterials geared towards biosensing and nanomedicine has recently witnessed an explosion of interest and progress due to their tunable and versatile plasmonic properties. This report summarizes and highlights recent major advances in the emerging field of bioapplication-oriented nanoengineering of plasmonic Au nanostructures, hybrids, and metamaterials. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Zhu C.,CAS Changchun Institute of Applied Chemistry
Nanoscale | Year: 2012
We demonstrated a simple, in situ reduction route to the synthesis of two-dimensional graphene oxide/SiO(2) (GSCN) hybrid nanostructures consisting of Au nanoparticles (Au NPs) supported on the both sides of GSCN. The as-prepared GSCN/Au NPs hybrid nanomaterials exhibited good catalytic activity for the reduction of 4-nitrophenol. This approach provided a useful platform based on GO hybrid nanomaterials for the fabrication of GSCN/Au NPs hybrid nanomaterials, which could be very useful in catalytic applications.
Cheng Y.,CAS Changchun Institute of Applied Chemistry
Biomacromolecules | Year: 2012
Thermosensitive hydrogels based on PEG and poly(l-glutamate)s bearing different hydrophobic side groups were separately synthesized by the ring-opening polymerization (ROP) of l-glutamate N-carboxyanhydrides containing different alkyl protected groups, that is, methyl, ethyl, n-propyl, and n-butyl, using mPEG(45)-NH(2) as macroinitiator. The resulting copolymers underwent sol-gel transitions in response to temperature change. Interestingly, the polypeptides containing methyl and ethyl showed significantly lower critical gelation temperatures (CGTs) than those bearing n-propyl and butyl side groups. Based on the analysis of (13)C NMR spectra, DLS, circular dichroism spectra, and ATR-FTIR spectra, the sol-gel transition mechanism was attributed to the dehydration of poly(ethylene glycol) and the increase of β-sheet conformation content in the polypeptides. The in vivo gelation test indicated that the copolymer solution (6.0 wt %) immediately changed to a gel after subcutaneous injection into rats. The mass loss of the hydrogel in vitro was accelerated in the presence of proteinase K, and the MTT assay revealed that the block copolymers exhibited no detectable cytotoxicity. The present work revealed that subtle variation in the length of a hydrophobic side group displayed the decisive effect on the gelation behavior of the polypeptides. In addition, the thermosensitive hydrogels could be promising materials for biomedical applications due to their good biocompatibility, biodegradability, and the fast in situ gelation behavior.
Han F.-S.,CAS Changchun Institute of Applied Chemistry |
Han F.-S.,Dalian University of Technology
Chemical Society Reviews | Year: 2013
In the transition-metal-catalyzed cross-coupling reactions, the use of the first row transition metals as catalysts is much more appealing than the precious metals owing to the apparent advantages such as cheapness and earth abundance. Within the last two decades, particularly the last five years, explosive interests have been focused on the nickel-catalyzed Suzuki-Miyaura reactions. This has greatly advanced the chemistry of transition-metal-catalyzed cross-coupling reactions. Most notably, a broad range of aryl electrophiles such as phenols, aryl ethers, esters, carbonates, carbamates, sulfamates, phosphates, phosphoramides, phosphonium salts, and fluorides, as well as various alkyl electrophiles, which are conventionally challenging, by applying palladium catalysts can now be coupled efficiently with boron reagents in the presence of nickel catalysts. In this review, we would like to summarize the progress in this reaction. © 2013 The Royal Society of Chemistry.