Browsing by Author "Zhou, Jin"

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    Injectable OPF/graphene oxide hydrogels provide mechanical support and enhance cell electrical signaling after implantation into myocardial infarct
    (Ivyspring, 2018) Zhou, Jin; Yang, Xiaoning; Liu, Wei; Wang, Chunlan; Shen, Yuan; Zhang, Fengzhi; Zhu, Huimin; Sun, Hongji; Chen, Jiayun; Lam, Johnny; Mikos, Antonios G.; Wang, Changyong; Bioengineering
    After myocardial infarction (MI), the scar tissue contributes to ventricular dysfunction by electrically uncoupling viable cardiomyocytes in the infarct region. Injection of a conductive hydrogel could not only provide mechanical support to the infarcted region, but also synchronize contraction and restore ventricular function by electrically connecting isolated cardiomyocytes to intact tissue. Methods: We created a conductive hydrogel by introducing graphene oxide (GO) nanoparticles into oligo(poly(ethylene glycol) fumarate) (OPF) hydrogels. The hydrogels were characterized by AFM and electrochemistry workstation. A rat model of myocardial infarction was used to investigate the ability of OPF/GO to improve cardiac electrical propagation in the injured heart in vivo. Echocardiography (ECHO) was used to evaluate heart function 4 weeks after MI. Ca2+ imaging was used to visualize beating cardiomyocytes (CMs). Immunofluorescence staining was used to visualize the expression of cardiac-specific markers. Results: OPF/GO hydrogels had semiconductive properties that were lacking in pure OPF. In addition, the incorporation of GO into OPF hydrogels could improve cell attachment in vitro. Injection of OPF/GO 4 weeks after myocardial infarction in rats enhanced the Ca2+ signal conduction of cardiomyocytes in the infarcted region in comparison with PBS or OPF alone. Moreover, the injection of OPF/GO hydrogel into the infarct region enhanced the generation of cytoskeletal structure and intercalated disc assembly. Echocardiography analysis showed improvement in load-dependent ejection fraction/fractional shortening of heart function 4 weeks after injection. Conclusions: We prepared a conductive hydrogel (OPF/GO) that provide mechanical support and biological conduction in vitro and in vivo. We found that injected OPF/GO hydrogels can provide mechanical support and electric connection between healthy myocardium and the cardiomyocytes in the scar via activating the canonical Wnt signal pathway, thus upregulating the generation of Cx43 and gap junction associated proteins. Injection of OPF/GO hydrogel maintained better heart function after myocardial infarction than the injection of a nonconductive polymer.
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    Symmetry in Cascade Chirality-Transfer Processes: A Catalytic Atroposelective Direct Arylation Approach to BINOL Derivatives
    (American Chemical Society, 2016) Wang, Jin-Zheng; Zhou, Jin; Xu, Chang; Sun, Hongbin; Kürti, László; Xu, Qing-Long
    Herein we disclose a scalable organocatalytic direct arylation approach for the regio- and atroposelective synthesis of non-C2-symmetric 2,2′-dihydroxy-1,1′-binaphthalenes (BINOLs). In the presence of catalytic amounts of axially chiral phosphoric acids, phenols and naphthols are coupled with iminoquinones via a cascade process that involves sequential aminal formation, sigmatropic rearrangement, and rearomatization to afford enantiomerically enriched BINOL derivatives in good to excellent yields. Our studies suggest that the (local) symmetry of the initially formed aminal intermediate has a dramatic impact on the level of enantioinduction in the final product. Aminals with a plane of symmetry give rise to BINOL derivatives with significantly lower enantiomeric excess than unsymmetrical ones featuring a stereogenic center. Presumably asymmetric induction in the sigmatropic rearrangement step is significantly more challenging than during aminal formation. Sigmatropic rearrangement of the enantiomerically enriched aminal and subsequent rearomatization transfers the central chirality into axial chirality with high fidelity.