Preparation of Photoluminescent Nanorings with Controllable Bioreducibility and Stimuli‐Responsiveness

Abstract

Nanoring materials with multiple functionalities have attracted significant attention owing to their potential applications in optical and electronic resonators, biological and chemical sensors, molecular imaging, and gene delivery. [1] Recently, several approaches have been proposed for fabricating nanoring materials, including synthesis of silver nanorings prepared from a one-pot procedure, [2] Au and Ag nanorings fabricated using the outer profile of silica nanoparticles as template, [3] and mesoscopic rings prepared by a method based on capillary force in the colloidal crystal. [4] Also, many interesting and unique properties of nanoring materials have been observed; for example, the toroidal structure of packed DNA is natures most efficient morphology for transporting genetic information, done particularly well by viruses. Some researchers want to mimic this process by condensing DNA into a nanoring morphology to improve the effect of gene therapy. The DNA nanoring packed in viruses is multifunctional, but the nanoring materials fabricated to date are limited by a lack of the multiple functionalities. Thus, the preparation of nanoring materials with multiple functionalities of stimuliresponsiveness, biocompatibility, biodegradability, and photoluminescence will be very attractive.[5] We report herein an easy approach to fabricating multifunctional nanorings by the assembly of DNA with a novel multifunctional hyperbranched macromolecule.It has been reported that multivalent cations can condense DNA into nanorings under suitable conditions. [1a,c,i] To prepare nanorings with multiple functionalities of stimuli-responsiveness, biodegradability, and photoluminescence, multivalent cations having these functionalities are prepared first and then used to condense plasmid DNA. Hyperbranched macromolecules are a special kind of macromolecule with three-dimensional structure. It is very easy to incorporate different functionalities into a single molecule of this type. [6,7] To develop photoluminescent nanorings with multiple functionalities, we prepared a novel disulfide-containing hyperbranched poly(amido amine) (HPAA) by Michael addition polymerization. Note that the syntheses of some linear disulfide-containing poly(amido amine)s have been reported, but these species easily condense plasmid DNA into nanoparticles; therefore, we prepared hyperbranched analogues.The co-polyaddition reaction of 1-(2-aminoethyl)piperazine (AEPZ) with N,N'-cystaminebisacrylamide (CBA) and N,N'-methylenebisacrylamide (MBA; Scheme 1) was employed in the preparation of the HPAA containing a 1:2 molar ratio of the CBA unit to the MBA unit (HPAA12). This synthetic route was chosen for three reasons: 1) The disulfidecontaining HPAA with a 1:0 molar ratio of CBA to MBA (HPAA10) obtained by polyaddition of AEPZ and CBA (at a molar ratio of 1:2) and the disulfide-containing HPAA with a 1:1 molar ratio of CBA to MBA (HPAA11) obtained by polyaddition of AEPZ with CBA and MBA at a 1:2 molar ratio of AEPZ to CBA + MBA are not water-soluble, an...

Long‐Chain Hyperbranched Polymers: Synthesis, Properties, and Applications

“…The conventional HBPs with short subchains have demonstrated to display various morphologies of aggregate in solution and present excellent loading efficiency of guest molecules as unimolecular containers originating from their dendritic topologies . However, LCHBPs with tunable subchains between branching points allow the incorporation of additional amphiphilicity, thus some research work has been devoted to investigating their microphase separation in bulk state and self‐assembly morphologies of different shapes in solution, as it is of great significance to understand the structure–property correlation of this kind of LCHBP.…”

“…Hyperbranched polymers (HBPs) are highly branched macromolecules, resembling dendrimers, with a 3D dendritic globular conformation . Both of HBPs and dendrimers have demonstrated several common characteristics when compared with linear ones, such as a high number of terminal functional groups, lower solution and melt viscosity, better solubility, and lack of chain entanglement.…”

“…Although excellent achievements have been made on HBPs, in contrast with linear polymers, the quite low viscosity and amorphous nature or high brittleness of HBP materials arising from their dendritic topologies with subchain lengths much shorter than the critical molecular weight for entanglement, give rise to poor processability and inferior mechanical properties, that are not possible for structural applications . Nevertheless, long‐chain hyperbranched polymers (LCHBPs), essentially the long‐chain analogs of HBPs with a linear long subchain segment between branching points, may combine the advantageous properties of HBPs and linear polymers, which may allow the formation of entanglements and also crystallinity like their linear segments, making them less brittle materials than their short‐chain analogs .…”

Luminescent Polymers Containing Unconventional Chromophores

“…对比研究发现: [17] . Fluorescence spectra and images of the aqueous solutions of the derived hb-PAMAM excited at different wavelengths [15] 合物结构中 [18] HypET15, HypET20 和 HypET24, 并深入研究了所得聚 合物的发光性能(图 11 Figure 9 An illustration of the β-cyclodextrin-modified hb-PAMAM [19] 超 支 化 聚 醚 酰 胺 [hyperbranched poly(ether amide)s, [20] Figure 10 Reaction scheme for preparing hyperbranched poly(amino ester)s with different terminal groups [20] 2007 年, 香港科技大学唐本忠教授课题组 [29,30] [29] Sijbesma 研究小组 [34] 图 15 聚合物合成路线在左侧, 右侧的截图为反应各个步骤所得产 物对应的荧光照片 [35] Figure 15 Polymer synthesis and the corresponding fluorescence microscope images at each step of the reaction provided on the right (1) O-xylylene dibromide solution in chloroform in a capillary, (2) image of poly(trithiocarbonate) (PTTC) solution in chloroform in a capillary, (3) RAFT polymerization mixture of NIPAM using PTTC as RAFT agent in a capillary [35] 5 总结与展望 …”

Bright Blue Photoluminescence Emitted from the Novel Hyperbranched Polysiloxane‐Containing Unconventional Chromogens

“…More recently, the luminescent polymers constructed through the polymerization of some nonfluorescent monomers carrying unconventional chromogens have been a research focus owing to environmental friendliness, ameliorations concerned with ease of configurational modification, ample flexibility in preparation and topology, and processibility . One of the most extensively studied photoluminescent polymers, synthesized by creative synthetic approaches, are those bearing dendritic or hyperbranched configurations, such as poly(amino ester)s, poly(amidoamine)s (PAMAM), polyureas, and poly(ether amide)s .…”