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We report a facile approach of using DNA molecules as switches to selectively activate silica coating onto specific facets of upconversion nanoparticles. Being simple and reproducible, this method improves the understanding of the silica coating mechanism and opens up new opportunities for nanomedicine delivery. [ABSTRACT FROM AUTHOR]

Multifunctional 99mTc-labeled dendrimer-entrapped gold nanoparticles (99mTc-Au DENPs) were designed and synthesized. Our results show that the type of surface groups (acetyl or hydroxyl) significantly impact the biodistribution profile of the 99mTc-Au DENPs, thereby allowing for preferential SPECT/CT imaging of different organs. [ABSTRACT FROM AUTHOR]

We report the synthesis and characterization of lactobionic acid-modified multifunctional polyethyleneimine-entrapped gold nanoparticles for targeted dual mode computed tomography/magnetic resonance imaging. The nanodevice displays good X-ray attenuation properties, good r1 relaxivity, and hepatocellular carcinoma targeting specificity, and can be used for targeted CT/MR imaging of hepatocellular carcinoma in vitro and in vivo. [ABSTRACT FROM AUTHOR]

The advancement of biocompatible nanoplatforms with dual functionalities of diagnosis and therapeutics has been strongly demanded in biomedicine in recent years. In this work, we report the synthesis and characterization of polydopamine (pD)-coated gold nanostars (Au NSs) for computed tomography (CT) imaging and enhanced photothermal therapy (PTT) of tumors. Au NSs were firstly formed via a seed-mediated growth method and then stabilized with thiolated polyethyleneimine (PEI-SH), followed by deposition of pD on their surface. The formed pD-coated Au NSs (Au-PEI@pD NSs) were well characterized. We show that the Au-PEI@pD NSs are able to convert the absorbed near-infrared laser light into heat, and have strong X-ray attenuation properties. Due to the co-existence of Au NSs and pD, the light to heat conversion efficiency of the NSs can be significantly enhanced. These very interesting properties allow them to be used as a powerful theranostic nanoplatform for efficient CT imaging and enhanced phtotothermal therapy of cancer cells in vitro and the xenografted tumor model in vivo. Due to their easy functionalization nature enabled by the coated pD shell, the developed pD-coated Au NSs may be used as a versatile nanoplatform for targeted CT imaging and PTT of different types of cancers. [ABSTRACT FROM AUTHOR]

We report here the fabrication, characterization and use of poly(lactic-co-glycolic acid) (PLGA) hollow microcapsules (HMs) loaded with the anticancer drug doxorubicin (DOX) for targeted drug delivery to cancer cells. In this study, PLGA HMs loaded with DOX (PLGA–DOX HMs) were prepared by a double emulsion method, followed by electrostatic assembly of positively charged polyethyleneimine (PEI) pre-modified with polyethylene glycol–folic acid segments (PEI–PEG–FA). The formed multifunctional PLGA–DOX–PEI–PEG–FA HMs were characterized via different techniques. We show that the HMs having a size of 2.5 μm are stable, and are able to release DOX in a sustained manner with a higher release rate under acidic pH conditions than that under the physiological pH conditions. Importantly, the PLGA–DOX–PEI–PEG–FA HMs displayed an effective therapeutic efficacy, comparable to that of free DOX, and were able to target cancer cells overexpressing high-affinity folic acid receptors and effectively inhibit the growth of the cancer cells. The fabricated PLGA–DOX–PEI–PEG–FA HMs may hold great promise to be used as a versatile carrier system for targeted drug delivery to different types of cancer cells. [ABSTRACT FROM AUTHOR]

Removal of hazardous metal ions from industrial wastewater is of paramount importance. Taking advantage of the metal–ligand binding specificity and electrospun nanofibers with a high surface area to volume ratio and a porous structure, we developed thymine (T)-grafted poly(vinyl alcohol) (PVA)–polyethyleneimine (PEI) nanofibers for selective removal of mercury ions (Hg2+) with high efficiency. In this study, thymine-1-acetic acid was first grafted with the primary surface amines of branched PEI via a 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide coupling reaction. The formed PEI–T conjugate was mixed with PVA solution for subsequent formation of T-grafted electrospun PVA–PEI (PVA–PEI-T) nanofibers. The formed PEI–T conjugate and the crosslinked PVA–PEI-T nanofibers were characterized via different techniques. We show that the grafting of the T moieties onto the surface of PEI does not appreciably impact the smooth fibrous morphology of PVA–PEI-T nanofibers when compared with the PVA–PEI nanofibers without T grafting, except that the T-grafted fibers have slightly increased fiber diameter. With the grafting of T moieties, the formed PVA–PEI-T nanofibers enabled selective removal of Hg2+ from aqueous solution and improved removal efficiency was able to be achieved by increase of the T-grafting density on the PEI surface. With the good reusability for repetitive Hg2+ removal, the newly developed T-functionalized PVA–PEI nanofibers may hold a great promise for high-selectivity and high-efficiency removal of Hg2+ from laboratory and industrial wastes. [ABSTRACT FROM AUTHOR]

Multifunctional 99m Tc-labeled dendrimer-entrapped gold nanoparticles ( 99m Tc-Au DENPs) were designed and synthesized. Our results show that the type of surface groups (acetyl or hydroxyl) significantly impact the biodistribution profile of the 99m Tc-Au DENPs, thereby allowing for preferential SPECT/CT imaging of different organs.

We report here an effective approach to modifying laponite (LAP) nanodisks with folic acid (FA) for targeted anticancer drug delivery applications. In this approach, LAP nanodisks were first modified with 3-aminopropyldimethylethoxysilane (APMES) to render them with abundant surface amines, followed by conjugation with FA via 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) chemistry. The formed FA-modified LAP nanodisks (LM-FA) were then used to encapsulate anticancer drug doxorubicin (DOX). The surface modification of LAP nanodisks and the subsequent drug encapsulation within the LAP nanodisks were characterized via different techniques. We show that the LM-FA is able to encapsulate DOX with an efficiency of 92.1 ± 2.2%, and the formed LM-FA/DOX complexes are able to release DOX in a pH-dependent manner with a higher DOX release rate under acidic pH conditions than under physiological pH conditions. The encapsulation of DOX within LM-FA does not compromise its therapeutic activity. Importantly, the formed LM-FA/DOX complexes are able to specifically target cancer cells overexpressing high-affinity FA receptors as confirmed via flow cytometric analysis and confocal microscopic observation, and exert specific therapeutic efficacy to the target cancer cells. The developed FA-modified LAP nanodisks may hold great promise to be used as an efficient nanoplatform for targeted delivery of different anticancer drugs.

We report a new use of dendrimer-entrapped gold nanoparticles (Au DENPs) modified with folic acid (FA) as a non-viral vector for targeted gene delivery applications. In this study, amine-terminated generation 5 poly(amidoamine) dendrimers modified with FA via covalent conjugation were used as templates to synthesize gold nanoparticles with an Au salt/dendrimer molar ratio of 25 : 1. The synthesized FA-modified Au DENPs (Au DENPs-FA) were used as a non-viral vector for the delivery of plasmid DNA (pDNA) into a model cancer cell line (HeLa cells) overexpressing high-affinity FA receptors (FAR). The DNA compaction ability of the formed Au DENPs-FA was systematically characterized using a gel retardation assay, zeta potential, and dynamic light scattering. We show that similar to the Au DENPs vector without FA, the Au DENPs-FA vector was able to compact the pDNA encoding enhanced green fluorescent protein (EGFP) at an N/P ratio of 0.5. Transfection results show that the Au DENPs-FA vector enables much higher luciferase and EGFP gene expression in HeLa cells overexpressing FAR than the Au DENPs without FA, demonstrating the role played by FA-mediated targeting for enhanced gene transfection in target cells. With a lower cytotoxicity than that of the Au DENPs without FA proven by a cell viability assay, the developed FA-modified Au DENPs may be used as a promising non-viral vector for safe and targeted gene therapy applications.

We describe a facile approach to synthesizing acetylated dendrimer-entrapped gold nanoparticles (Au DENPs) with enhanced Au loading in the dendrimer interior. In this study, amine-terminated generation 5 poly(amidoamine) (PAMAM) dendrimers (G5.NH 2 ) were used as templates to form Au DENPs via a stepwise Au salt complexation/reduction approach, followed by acetylation of the dendrimer terminal amines. The formed Au DENPs before and after acetylation were characterized with different techniques. We show that the stepwise complexation/reduction of HAuCl 4 is able to significantly improve the loading amount of Au within the dendrimer interior. UV-Vis spectroscopy reveals that the intensity of the surface plasmon resonance (SPR) band increases with the Au loading, confirming the stepwise loading synthesis of Au DENPs. TEM images show that the synthesized Au DENPs have a quite uniform size distribution with sizes tunable in the range of 2-4 nm depending on the Au loading. The formed acetylated Au DENPs with enhanced Au loading are very stable under different pH and temperature conditions. Importantly, computed tomography (CT) imaging experiments reveal that the formed acetylated Au DENPs have higher attenuation intensity than a clinically used iodinated contrast agent, Omnipaque, at the same molar concentration of active elements (Au or iodine), and enable significantly enhanced CT imaging of rat heart in vivo. The acetylated Au DENPs with enhanced Au loading formed via the facile stepwise approach may be used as contrast agents for highly sensitive CT imaging applications.