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Xiaoyuan Chen

Bio: Xiaoyuan Chen is an academic researcher from National University of Singapore. The author has contributed to research in topics: Physics & Photothermal therapy. The author has an hindex of 149, co-authored 994 publications receiving 89870 citations. Previous affiliations of Xiaoyuan Chen include Brown University & University of Southern California.


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TL;DR: In this paper, a new kind of colortunable Gd-Zn-Cu-In-S/ZnS quantum dots with stable crystal structure has been successfully synthesized and utilized for magnetic resonance (MR) and fluorescence dual modality imaging.
Abstract: Inorganic nanoparticles have been introduced into biological systems as useful probes for in vitro diagnosis and in vivo imaging, due to their relatively small size and exceptional physical and chemical properties. A new kind of colortunable Gd-Zn-Cu-In-S/ZnS (GZCIS/ZnS) quantum dots (QDs) with stable crystal structure has been successfully synthesized and utilized for magnetic resonance (MR) and fluorescence dual modality imaging. This strategy allows successful fabrication of GZCIS/ZnS QDs by incorporating Gd into ZCIS/ZnS QDs to achieve great MR enhancement without compromising the fluorescence properties of the initial ZCIS/ZnS QDs. The as-prepared GZCIS/ZnS QDs show high T 1 MR contrast as well as “color-tunable” photoluminescence (PL) in the range of 550–725 nm by adjusting the Zn/Cu feeding ratio with high PL quantum yield (QY). The GZCIS/ZnS QDs were transferred into water via a bovine serum albumin (BSA) coating strategy. The resulting Cd-free GZCIS/ZnS QDs reveal negligible cytotoxicity on both HeLa and A549 cells. Both fluorescence and MR imaging studies were successfully performed in vitro and in vivo. The results demonstrated that GZCIS/ZnS QDs could be a dual-modal contrast agent to simultaneously produce strong MR contrast enhancement as well as fluorescence emission for in vivo imaging.

63 citations

Journal ArticleDOI
TL;DR: This first-in-human study demonstrated that 177Lu-EB-PSMA-617 had higher accumulation in mCRPC and that low imaging dose appears to be effective in treating tumors with high 68Ga-PSma-617 uptakes.
Abstract: This translational study is designed to assess the safety, dosimetry and therapeutic response to a single, low-dose of 177Lu-EB-PSMA-617 in comparison to 177Lu-PSMA-617 in patients with mCRPC. Following institutional review board approval and informed consent, nine patients with mCRPC were recruited. Four patients accepted intravenous injection of 0.80–1.1 GBq (21.5–30 mCi) of 177Lu-EB-PSMA-617, then underwent serial whole-body planar and SPECT/CT imaging at 2, 24, 72, 120 and 168 h. The other five patients accepted intravenous injection of 1.30–1.42 GBq (35–38.4 mCi) 177Lu-PSMA-617, then underwent the same imaging procedures at 0.5, 2, 24, 48, and 72 h. All patients were evaluated by 68Ga-PSMA-617 PET/CT before and one month after the treatment. Dosimetry evaluation was compared in both patient groups. When the bone metastasis tumors with comparable baseline SUVmax in the range of 10.0–15.0 were selected from the two groups for comparison, the accumulated radioactivity of 177Lu-EB-PSMA-617 was about 3.02-fold higher than that of 177Lu-PSMA-617. Imaging dose of 177Lu-EB-PSMA-617 treatment showed significant decrease of 68Ga-PSMA-617 uptake within a month, which was not observed in patients imaged with 177Lu-PSMA-617 (SUV change: −32.43 ± 0.14% vs. 0.21 ± 0.37%; P = 0.002). 177Lu-EB-PSMA-617 also had higher absorbed doses in the red bone marrow and kidneys than 177Lu-PSMA-617 (0.0547 ± 0.0062 vs. 0.0084 ± 0.0057 mSv/MBq for red bone marrow, P < 0.01; 2.39 ± 0.69 vs. 0.39 ± 0.06 mSv/MBq for kidneys, P < 0.01). This first-in-human study demonstrated that 177Lu-EB-PSMA-617 had higher accumulation in mCRPC and that low imaging dose appears to be effective in treating tumors with high 68Ga-PSMA-617 uptakes. Elevated uptakes of 177Lu-EB-PSMA-617 in kidneys and red bone marrow were well tolerated at the administered low dose. Further investigations with increased dose and frequency of administration are warranted.

63 citations

Journal ArticleDOI
TL;DR: Zhang et al. as mentioned in this paper proposed a method to use the Key Basic Research Project (973 Program) and National Natural Science Foundation of China (NNGF) for key basic research project (CB933901).
Abstract: National Program on Key Basic Research Project (973 Program) [2010CB933901]; National Natural Science Foundation of China [51102258, 20803040, 81028009, 31170961]; Chinese Academy of Sciences [2011T2J06]; New Century Excellent Talents of the Ministry of Education of China [NCET-08-0350]; Zhejiang Provincial Natural Science Foundation [LY12H11011]

63 citations

Journal ArticleDOI
TL;DR: Ostwald ripening-mediated grafting of MOF on a single multidentate inorganic colloidal nanocrystal via heterogeneous nucleation provides insight into the design of MXF nanoparticles for a wide range of applications involving advanced functional materials.
Abstract: MXF, a metal-organic framework (MOF) that contains more than two components, such as heterogeneous inorganic nanoparticle@MOF (NP@MOF) with precisely defined structures, is important in applications such as catalysis, energy, and biochemistry. However, the ambiguous growth mechanism of MXF has hindered the exploration of controllable design of nanoparticle level MXF complexes. Here, we report an Ostwald ripening-mediated grafting of MOF on a single multidentate inorganic colloidal nanocrystal via heterogeneous nucleation. The grafting relies on the carboxylic acid groups anchored on the surface of the colloidal nanocrystal. Ostwald ripening-mediated grafting enabled us to obtain uniform MXF with a wide range of sizes of nanoparticles and a controlled thickness of the MOF layer on the surface of colloidal nanocrystal. A dual FRET-induced singlet oxygen generation with near-infrared light was achieved from an UCNP@ZrMOF hybrid. This generalizable grafting strategy provides insight into the design of MXF nanoparticles for a wide range of applications involving advanced functional materials.

63 citations

Journal Article
TL;DR: The results of this study suggest that RGD-PEG conjugation is an effective way to modify Ad vector tropism for improved systemic gene delivery.
Abstract: Recombinant adenovirus (rAd) has been widely used as an attractive gene delivery vehicle to mammalian cells because of its unparalleled efficacy in accomplishing gene transfer in vivo (1,2). There are, however, some limitations associated with Ad for gene delivery. One such disadvantage is related to the wide native tropism of Ad, which often results in high accumulation in nontargeting tissues (3–9). Another major disadvantage for using Ad vector in vivo is that administration of Ad to a host leads to the host immune response against Ad (10–12). Vector targeting to a specific tissue of cell type would enhance gene therapy efficacy and permit the delivery of lower doses, which would consequently result in reduced toxicity. Cell-specific gene delivery via Ad vectors has been achieved by both genetic (13–15) and chemical (16–22) approaches. Chemical modification is a nongenetic strategy to modify the surface of a viron by covalently attaching a polymer containing the targeting ligand with the lysine residues on the surface of Ad. Modification of Ad vectors with poly(ethylene glycol) (PEG) prolongs persistence in the blood and circumvents inflammatory and humoral immune responses (16–22). However, the PEGylation of Ad vectors also leads to loss of infectivity due to the steric hindrance induced by PEG chains. To overcome the decreased efficiency of infection of PEGylated Ad, vectors containing functional molecules on the tip of PEG restore target-specific infectivity. Lanciotti et al. reported targeted Ad vectors using heterofunctional PEG and FGF-2 (22). Ogawara et al. (17) reported PEGylated Ad vectors containing E-selectin–specific antibody or αv integrin–specific RGD peptide for targeting activated endothelial cells. Ad vectors coated with polymers other than PEG have also been developed. Fisher et al. used a multivalent hydrophilic polymer based on poly[N-(2-hydroxypropyl) methacrylamide] to modify Ad vectors (23). Although improved pharmacokinetic properties of polymer-coated Ad vectors without ligands have been reported, those of polymer-coated Ad vectors with ligands have not been reported in detail. Most studies performed in animal models to optimize vector targeting and functional gene delivery use protocols that require the animals to be sacrificed to monitor reporter gene expression. Recently, however, several noninvasive technologies for monitoring reporter gene expression in vivo have been described (24). The most commonly used PET reporter gene is herpes simplex virus 1 thymidine kinase (HSV1-tk). Many of the enzyme substrates have been labeled with 18F or 124I to image HSV1-tk gene expression. Two major substrates for HSV1-tk enzyme/PET include 9-[4-18F-fluoro-3-(hydroxymethyl)butyl]guanine (18F-FHBG) and 124I- or 18F-labeled 2′-fluoro-2′-deoxy-5′-iodo-1-β-D-arabinofuranosyluracil (124I-FIAU or 18F-FIAU) (25–27). It has also been reported that the mutant HSV1-sr39tk is more effective than the wild-type HSV1-tk at using acycloguanosines as substrates. We have demonstrated that the utility of HSV1-sr39tk and 18F-FHBG is able to monitor the reporter gene expression over a 3-mo period after somatic gene transfer (26,28). In this study, a replication-deficient Ad was modified with bifunctional PEG and then conjugated with cyclic RGD peptide (Fig. 1). We hypothesized that surface modification of Ad fiber knobs with PEGylated-RGD peptide will ablate the normal tropism and reduce transduction of nontarget tissues in vivo; incorporation of integrin αvβ3–specific RGD peptides will enhance the gene delivery to tumor neovasculature and integrin-positive tumor cells. To monitor the localization and expression of the chemically modified virus we packed the HSV1-sr39tk mutant as a reporter gene under the control of cytomegalovirus (CMV) promoter. The homing selectivity and transgene expression after intravenous administration of integrin-directed adenovirus were studied by microPET using 18F-FHBG as a reporter probe. FIGURE 1 Schematic representation of Ad vector modified with RGD-PEG. Synthesis of RGD-PEG-NHS (where NHS = N-hydroxysuccinimide) is shown on the top and coupling is shown on the bottom. Where Adtk is the first-generation Ad vector encoding the HSV1-sr39tk gene; ...

63 citations


Cited by
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[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1(PfPMP1)与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员,通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

18,940 citations

Journal ArticleDOI
TL;DR: The interest in nanoscale materials stems from the fact that new properties are acquired at this length scale and, equally important, that these properties are equally important.
Abstract: The interest in nanoscale materials stems from the fact that new properties are acquired at this length scale and, equally important, that these properties * To whom correspondence should be addressed. Phone, 404-8940292; fax, 404-894-0294; e-mail, mostafa.el-sayed@ chemistry.gatech.edu. † Case Western Reserve UniversitysMillis 2258. ‡ Phone, 216-368-5918; fax, 216-368-3006; e-mail, burda@case.edu. § Georgia Institute of Technology. 1025 Chem. Rev. 2005, 105, 1025−1102

6,852 citations