Browsing by Author "Kotov, Nicholas A."

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    Chiral plasmonics of self-assembled nanorod dimers
    (Nature Publishing Group, 2013) Ma, Wei; Kuang, Hua; Wang, Libing; Xu, Liguang; Chang, Wei-Shun; Zhang, Huanan; Sun, Maozhong; Zhu, Yinyue; Zhao, Yuan; Liu, Liqiang; Xu, Chuanlai; Link, Stephan; Kotov, Nicholas A.
    Chiral nanoscale photonic systems typically follow either tetrahedral or helical geometries that require four or more different constituent nanoparticles. Smaller number of particles and different chiral geometries taking advantage of the self-organization capabilities of nanomaterials will advance understanding of chiral plasmonic effects, facilitate development of their theory, and stimulate practical applications of chiroplasmonics. Here we show that gold nanorods self-assemble into side-by-side orientated pairs and ‘‘ladders’’ in which chiral properties originate from the small dihedral angle between them. Spontaneous twisting of one nanorod versus the other one breaks the centrosymmetric nature of the parallel assemblies. Two possible enantiomeric conformations with positive and negative dihedral angles were obtained with different assembly triggers. The chiral nature of the angled nanorod pairs was confirmed by 4p full space simulations and the first example of single-particle CD spectroscopy. Self-assembled nanorod pairs and ‘‘ladders’’ enable the development of chiral metamaterials, (bio)sensors, and new catalytic processes.
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    Chiral templating of self-assembling nanostructures by circularly polarized light
    (Nature Publishing Group, 2015) Yeom, Jihyeon; Yeom, Bongjun; Chan, Henry; Smith, Kyle W.; Dominguez-Medina, Sergio; Bahng, Joong Hwan; Zhao, Gongpu; Chang, Wei-Shun; Chang, Sung Jin; Chuvilin, Andrey; Melnikau, Dzmitry; Rogach, Andrey L.; Zhang, Peijun; Link, Stephan; Král, Petr; Kotov, Nicholas A.
    The high optical and chemical activity of nanoparticles (NPs) signifies the possibility of converting the spin angular momenta of photons into structural changes in matter. Here, we demonstrate that illumination of dispersions of racemic CdTe NPs with right- (left-)handed circularly polarized light (CPL) induces the formation of right- (left-)handed twisted nanoribbons with an enantiomeric excess exceeding 30%, which is ∼10 times higher than that of typical CPL-induced reactions. Linearly polarized light or dark conditions led instead to straight nanoribbons. CPL 'templating' of NP assemblies is based on the enantio-selective photoactivation of chiral NPs and clusters, followed by their photooxidation and self-assembly into nanoribbons with specific helicity as a result of chirality-sensitive interactions between the NPs. The ability of NPs to retain the polarization information of incident photons should open pathways for the synthesis of chiral photonic materials and allow a better understanding of the origins of biomolecular homochirality.
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    Diverse Applications of Nanomedicine
    (American Chemical Society, 2017) Pelaz, Beatriz; Alexiou, Christoph; Alvarez-Puebla, Ramon A.; Alves, Frauke; Andrews, Anne M.; Ashraf, Sumaira; Balogh, Lajos P.; Ballerini, Laura; Bestetti, Alessandra; Brendel, Cornelia; Bosi, Susanna; Carril, Monica; Chan, Warren C.W.; Chen, Chunying; Chen, Xiaodong; Chen, Xiaoyuan; Cheng, Zhen; Cui, Daxiang; Du, Jianzhong; Dullin, Christian; Escudero, Alberto; Feliu, Neus; Gao, Mingyuan; George, Michael; Gogotsi, Yury; Grünweller, Arnold; Gu, Zhongwei; Halas, Naomi J.; Hampp, Norbert; Hartmann, Roland K.; Hersam, Mark C.; Hunziker, Patrick; Jian, Ji; Jiang, Xingyu; Jungebluth, Philipp; Kadhiresan, Pranav; Kataoka, Kazunori; Khademhosseini, Ali; Kopeček, Jindřich; Kotov, Nicholas A.; Krug, Harald F.; Lee, Dong Soo; Lehr, Claus-Michael; Leong, Kam W.; Liang, Xing-Jie; Lim, Mei Ling; Liz-Marzán, Luis M.; Ma, Xiaowei; Macchiarini, Paolo; Meng, Huan; Möhwald, Helmuth; Mulvaney, Paul; Nel, Andre E.; Nie, Shuming; Nordlander, Peter; Okano, Teruo; Oliveira, Jose; Park, Tai Hyun; Penner, Reginald M.; Prato, Maurizio; Puntes, Victor; Rotello, Vincent M.; Samarakoon, Amila; Schaak, Raymond E.; Shen, Youqing; Sjöqvist, Sebastian; Skirtach, Andre G.; Soliman, Mahmoud G.; Stevens, Molly M.; Sung, Hsing-Wen; Tang, Ben Zhong; Tietze, Rainer; Udugama, Buddhisha N.; VanEpps, J. Scott; Weil, Tanja; Weiss, Paul S.; Willner, Itamar; Wu, Yuzhou; Yang, Lily; Yue, Zhao; Zhang, Qian; Zhang, Qiang; Zhang, Xian-En; Zhao, Yuliang; Zhou, Xin; Parak, Wolfgang J.
    The design and use of materials in the nanoscale size range for addressing medical and health-related issues continues to receive increasing interest. Research in nanomedicine spans a multitude of areas, including drug delivery, vaccine development, antibacterial, diagnosis and imaging tools, wearable devices, implants, high-throughput screening platforms, etc. using biological, nonbiological, biomimetic, or hybrid materials. Many of these developments are starting to be translated into viable clinical products. Here, we provide an overview of recent developments in nanomedicine and highlight the current challenges and upcoming opportunities for the field and translation to the clinic.