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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: A new class of boramino acids (BAAs) has been developed as the general marker for imaging the expression of amino acid transporters, suggesting that BAAs hold great promise for the development of new imaging probes and smart AAT-targeting drugs.
Abstract: Amino acid transporters (AATs) are a series of integral channels for uphill cellular uptake of nutrients and neurotransmitters. Abnormal expression of AATs is often associated with cancer, addiction, and multiple mental diseases. Although methods to evaluate in vivo expression of AATs would be highly useful, efforts to develop them have been hampered by a lack of appropriate tracers. We describe a new class of AA mimics-boramino acids (BAAs)-that can serve as general imaging probes for AATs. The structure of a BAA is identical to that of the corresponding natural AA, except for an exotic replacement of the carboxylate with -BF3 (-). Cellular studies demonstrate strong AAT-mediated cell uptake, and animal studies show high tumor-specific accumulation, suggesting that BAAs hold great promise for the development of new imaging probes and smart AAT-targeting drugs.

41 citations

Journal ArticleDOI
TL;DR: Xdynamic therapies (X = sono, radio, microwave, chemo, thermo, and electro) have shown good potential to overcome the drawbacks of photodynamic therapy.
Abstract: Reactive oxygen species (ROS)-related therapeutic approaches are developed as a promising modality for cancer treatment because the aberrant increase of intracellular ROS level can cause cell death due to nonspecific oxidation damage to key cellular biomolecules. However, the most widely considered strategy, photodynamic therapy (PDT), suffers from critical limitations such as limited tissue-penetration depth, high oxygen dependence, and phototoxicity. Non-photo-induced ROS generation strategies, which are defined as Xdynamic therapies (X = sono, radio, microwave, chemo, thermo, and electro), show good potential to overcome the drawbacks of PDT. Herein, recent advances in the development of Xdynamic therapies, including the design of systems, the working mechanisms, and examples of cancer therapy application, are introduced. Furthermore, the approaches to enhance treatment efficiency of Xdynamic therapy are highlighted. Finally, the perspectives and challenges of these strategies are also discussed.

41 citations

Journal ArticleDOI
TL;DR: The parameters fitted with compartmental modeling from the dual-tracer dynamic imaging are consistent with those from single- Tracer imaging, substantiating the feasibility of this methodology and the promise of early prediction of therapy response.
Abstract: A single dynamic PET acquisition using multiple tracers administered closely in time could provide valuable complementary information about a tumor’s status under quasiconstant conditions. This study aimed to investigate the utility of dual-tracer dynamic PET imaging with 18F-alfatide II (18F-AlF-NOTA-E[PEG4-c(RGDfk)]2) and 18F-FDG for parametric monitoring of tumor responses to therapy. Methods: We administered doxorubicin to one group of athymic nude mice with U87MG tumors and paclitaxel protein-bound particles to another group of mice with MDA-MB-435 tumors. To monitor therapeutic responses, we performed dual-tracer dynamic imaging, in sessions that lasted 90 min, starting with injection via the tail vein catheters with 18F-alfatide II, followed 40 min later by 18F-FDG. To achieve signal separation of the 2 tracers, we fit a 3-compartment reversible model to the time–activity curve of 18F-alfatide II for the 40 min before 18F-FDG injection and then extrapolated to 90 min. The 18F-FDG tumor time–activity curve was isolated from the 90-min dual-tracer tumor time–activity curve by subtracting the fitted 18F-alfatide II tumor time–activity curve. With separated tumor time–activity curves, the 18F-alfatide II binding potential (Bp = k3/k4) and volume of distribution (VD) and 18F-FDG influx rate ((K1 × k3)/(k2 + k3)) based on the Patlak method were calculated to validate the signal recovery in a comparison with 60-min single-tracer imaging and to monitor therapeutic response. Results: The transport and binding rate parameters K1–k3 of 18F-alfatide II, calculated from the first 40 min of the dual-tracer dynamic scan, as well as Bp and VD correlated well with the parameters from the 60-min single-tracer scan (R2 > 0.95). Compared with the results of single-tracer PET imaging, 18F-FDG tumor uptake and influx were recovered well from dual-tracer imaging. On doxorubicin treatment, whereas no significant changes in static tracer uptake values of 18F-alfatide II or 18F-FDG were observed, both 18F-alfatide II Bp and 18F-FDG influx from kinetic analysis in tumors showed significant decreases. For therapy of MDA-MB-435 tumors with paclitaxel protein-bound particles, a significant decrease was observed only with 18F-alfatide II Bp value from kinetic analysis but not 18F-FDG influx. Conclusion: The parameters fitted with compartmental modeling from the dual-tracer dynamic imaging are consistent with those from single-tracer imaging, substantiating the feasibility of this methodology. Even though no significant differences in tumor size were found until 5 d after doxorubicin treatment started, at day 3 there were already substantial differences in 18F-alfatide II Bp and 18F-FDG influx rate. Dual-tracer imaging can measure 18F-alfatide II Bp value and 18F-FDG influx simultaneously to evaluate tumor angiogenesis and metabolism. Such changes are known to precede anatomic changes, and thus parametric imaging may offer the promise of early prediction of therapy response.

41 citations

Journal ArticleDOI
10 Jun 2013-Small
TL;DR: F multifunctional siRNA delivery nanoparticles are developed that combine imaging capability of nanoparticles with urokinase plasminogen activator receptor-targeted delivery of siRNA expressing DNA nanocassettes to enhance the therapeutic effect of the siRNA-mediated cancer therapy.
Abstract: Molecular therapy using a small interfering RNA (siRNA) has shown promise in the development of novel therapeutics. Various formulations have been used for in vivo delivery of siRNAs. However, the stability of short double-stranded RNA molecules in the blood and efficiency of siRNA delivery into target organs or tissues following systemic administration have been the major issues that limit applications of siRNA in human patients. In this study, multifunctional siRNA delivery nanoparticles are developed that combine imaging capability of nanoparticles with urokinase plasminogen activator receptor-targeted delivery of siRNA expressing DNA nanocassettes. This theranostic nanoparticle platform consists of a nanoparticle conjugated with targeting ligands and double-stranded DNA nanocassettes containing a U6 promoter and a shRNA gene for in vivo siRNA expression. Targeted delivery and gene silencing efficiency of firefly luciferase siRNA nanogenerators are demonstrated in tumor cells and in animal tumor models. Delivery of survivin siRNA expressing nanocassettes into tumor cells induces apoptotic cell death and sensitizes cells to chemotherapy drugs. The ability of expression of siRNAs from multiple nanocassettes conjugated to a single nanoparticle following receptor-mediated internalization should enhance the therapeutic effect of the siRNA-mediated cancer therapy.

41 citations

Journal ArticleDOI
TL;DR: This theme issue provides an overview on the biology and pathology of various integrins as well as in-depth discussion on the use of integrin as targeting molecules for molecular imaging and molecular therapy.
Abstract: This theme issue provides an overview on the biology and pathology of various integrins as well as in-depth discussion on the use of integrin as targeting molecules for molecular imaging and molecular therapy.

41 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