Institute of Chemistry
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Nitrogen and sulfur co-doped carbon dots for highly selective and sensitive detection of Hg (II) ions
No full textNitrogen and sulfur co-doped carbon dots (N,S/C-dots) with high fluorescence quantum yields (FLQY, 25%) was successfully synthesized by a one-step microwave-assisted method. In comparison with nitrogen doped C-dots (N/C-dots) prepared using the same method, the resulting N,S/C-dots featured small particle size, uniform surface state, insensitive FL properties to excitation wavelengths and environmental conditions, negligible cytotoxicity and excellent biocompatibility. Simultaneous doping of N and S effectively promoted electron-transfer and coordination interaction between N,S/C-dots and Hg2+. Thus, when used as fluorescence probe for Hg2+ label-free detection, the resulting N,S/C-dots showed good detection sensitivity and ion selectivity. The limit of detection was 2 mu M; among 15 metal ions investigated, only Fe3+ showed interference to the Hg2+ detection. Fortunately, this interference could be effectively shielded using a chelating agent sodium hexametaphoshpate. The applicability of N,S/C-dots as fluorescence probe for Hg2+ detection in lake water and tap water was demonstrated. Finally, based on its favorable features of negligible cytotoxicity and excellent biocompatibility, the N,S/C-dots were successfully applied to probe Hg2+ in living cells, which broaden its application in biological system. (C) 2015 Elsevier B.V. All rights reserved
Colloidal pseudocapacitor: Nanoscale aggregation of Mn colloids from MnCl2 under alkaline condition
No full textNovel colloidal pseudocapacitors are designed using commercially available MnCl2 salts as starting materials and KOH as electrolyte, where the colloids synthesis and subsequently integrating into practical electrode structures occur at the same spatial and temporal scale. Highly electroactive Mn7O13.5H(2)0 colloids are formed in-situ by electric field assisted chemical coprecipitation in KOH solution. The highly efficient Faradaic redox reactions involving Mn3+ <-> Mn4+ and Mn2+ <-> Mn3+ are confirmed in electroactive Mn7O13.5H(2)O pseudocapacitors, which can deliver high specific capacitance of 2518 F/g based on active Mn cations at current density of 5 A/g. The present results show that instead of one-electron Faradaic reaction, Mn cations in our designed system can lead to two-electron Faradaic reactions. The colloidal pseudocapacitor system involving Mn-based colloids is a novel route to engineer electrochemical performances of inorganic pseudocapacitors. (C) 2015 Elsevier B.V. All rights reserved
Recent advances in bioapplications of C-dots
No full textLuminescent nanomaterials have been explored intensively to serve as biosensors and bioimaging agents and for other biomedical bioapplications. Among them, carbon dots (C-dots) as a new type of biocompatible carbon-based nanomaterials have attracted tremendous attention because of their low toxicity, excellent water solubility, ease of synthesis and functionalization, and outstanding photostability. In this review, we introduce the fundamental properties of C-dots and focus on their recent bioapplications in biosensing and bioimaging. In addition, we also summarize the most recent progress in drug and gene delivery, biomimic catalysis, and interactions with biomolecules, such as C-dots induced DNA B-Z transition. (C) 2014 Elsevier Ltd. All rights reserved
Electrospun PLA/MWCNTs composite nanofibers for combined chemo- and photothermal therapy
No full textCarbon nanotubes are effective thermal generators by absorbing near-infrared radiation (NIR). In this study, multiwalled carbon nanotubes (MWCNTs) and doxorubicin (DOX) were successfully electrospun into the poly-I.-lactic acid (PLLA) nanofibers. It is confirmed that NIR radiation could not only initiate burst release of DOX from the fibers due to the relatively low glass transition temperature (T-g) of PLLA, but also significantly increase the temperature of fibers-covering tumor site. The multifunctional fibers showed increased cytotoxicity both in vitro and in vivo by the combination of photothermal induced hyperthermia and chemotherapy with DOX. This drug delivery system could be very useful and convenient in future clinical applications for localized cancer therapy
Nanostructure-Dependent Interfacial Interactions between Poly(3-hexylthiophene) and Graphene Oxide
No full textPoly(3-hexylthiophene) (P3HT) nanofibers with different nanostructures and intrachain order were prepared, and the interactions between different P3HT nanofibers and GO were investigated by UV-vis, Raman, and atomic force microscopy (AFM) measurements, etc. We found that at the liquid-GO interface the conjugated length of nanofibers with lower intrachain order increased since polymer chains fractions were more likely to be involved in the formation of the nanofibers. We also demonstrated that GO can be differently doped when interacting with different P3HT nanofibers, which were confirmed by Raman spectroscopy and AFM. Kelvin probe force microscopy (KPFM) was also used to monitor the surface potential (SP) change of P3HT nanofibers after they interacted with GO and further confirmed the varied interactions between different P3HT nanofibers and GO
Facile Preparation of Doxorubicin-Loaded Upconversion@Polydopamine Nanoplatforms for Simultaneous In Vivo Multimodality Imaging and Chemophotothermal Synergistic Therapy
No full textThe development of biosafe nanoplatforms with diagnostic and therapeutic multifunction is extremely demanded for designing cancer theranostic medicines. Here, a facile methodology is developed to construct a multifunctional nanotheranostic that gathers five functions, upconversion luminescence (UCL) imaging, T-1-weighted magnetic resonance imaging (MRI), X-ray computed tomography (CT) imaging, photothermal therapy (PTT), and chemotherapy, into one single nanoprobe (named as UCNP@PDA(5)-PEG-DOX). For generating the UCNP@PDA(5)-PEG-DOX, a near-infrared light (NIR)-absorbing polydopamine (PDA) shell is directly coated on oleic-acid-capped -NaGdF4:Yb3+,Er3+@-NaGdF4 upconverting nanoparticle (UCNP) core for the first time to form monodisperse, ultrastable, and noncytotoxic core-shell-structured nanosphere via water-in-oil microemulsion approach. When combined with 808 nm NIR laser irradiation, the UCNP@PDA(5)-PEG-DOX shows great synergistic interaction between PTT and the enhanced chemotherapy, resulting in completely eradicated mouse-bearing SW620 tumor without regrowth. In addition, leakage study, hemolysis assay, histology analysis, and blood biochemistry assay unambiguously reveal that the UCNP@PDA(5)-PEG has inappreciable cytotoxicity and negligible organ toxicity. The results provide explicit strategy for fabricating multifunctional nanoplatforms from the integration of UCNP with NIR-absorbing polymers, important for developing multi-mode nanoprobes for biomedical applications
Chemiluminescence Detection of a Protein through the Aptamer-Controlled Catalysis of a Porphyrin Probe
No full textSensitive and selective protein detection based on the aptamer-controlled noncovalent porphyrin probe self-assembly is reported for the first time. Vascular endothelial growth factor (VEGF) is a predominant biomarker in cancer angiogenesis. In this work, a positively charged porphyrin probe, manganese(III) meso-tetrakis(N-methylpyridinum-4-yl)porphyrin (Mn-PyP), was prepared. Using it as a catalyst, a label-free chemiluminescence (CL) turn-on approach for sensitive VEGF detection is developed. Mn-PyP could catalyze the luminol CL reaction. The VEGF aptamer could induce aggregation of Mn-PyP. As a result, the Mn-PyP-catalyzed CL reaction is efficiently suppressed. Upon the addition of VEGF, the specific binding of VEGF to the aptamer weakens the interactions between the aptarner and Mn-PyP. The Mn-PyP monomers are released, and a turn-on CL signal is thus detected. Our method is quite sensitive; SO pM of VEGF could be easily detected. It is also very selective against other proteins. Our assay provides an aptamer-based efficient way for protein quantification
epsilon-Methacryloyl-L-lysine based polypeptides and their thiol-ene click functionalization
No full textFacile synthesis of biopolymers that facilitate versatile post-polymerization modification is of great interest for biotechnological and biomedical applications. In this study, a methacryloyl-substituted L-lysine N-carboxyanhydride (LysMA-NCA) monomer was designed and synthesized, and methacryloyl-functionalized polypeptides were prepared through the ring opening polymerization (ROP) of the L-lysine-based monomer. The post-polymerization functionalization of the methacryloyl-containing polypeptides with various thiol-containing molecules was achieved with high efficiency through facile radical-mediated thiol-ene chemistry. Moreover, a block copolypeptide bearing both methacryloyl and alkynyl pendants was developed through successive ROP of LysMA-NCA and gamma-propargyl-L-glutamate (PPLG-NCA). The sequential modification of the block copolypeptide with hydrophilic and hydrophobic molecules, respectively, was achieved by the successive alkyne-azido and thiol-ene "click" reactions. Overall, the facile synthesis of polypeptides bearing functional substituents and their versatile post-polymerization modification may serve as a useful platform for the development of various functional polymers
聚合物诱导苝探针自组装在生物分析中的应用
No full text荧光分析方法，因其灵敏度高，操作简单，已经受到了人们广泛关注，在生物、环保、医药、石油勘探等诸多领域都有广泛的应用。这些年，人们发展了许多基于先进功能材料如共轭聚电解质，量子点，金纳米粒子，纳米簇，碳纳米点等等的荧光传感战略。相比于这些材料，小分子探针具有相对简单的化学结构，易于合成和修饰等优点。本论文中，我们着重研究了聚合物（聚电解质）诱导的苝衍生物探针分子的可控自组装性质，并且将此性质应用于生物分析检测，发展了简单灵敏，免标记的荧光检测新方法。其主要内容如下： 第一部分工作：基于聚电解质诱导的苝衍生物探针的非共价自组装，以及λ核酸外切酶的特异性切割作用，我们发展了一种检测碱性磷酸酶活性的新方法。首先，我们合成了一种带有负电荷的苝酰亚胺衍生物分子作为荧光探针，带有正电荷的聚电解质能够通过非共价静电相互作用力诱导探针分子集聚，探针的单体荧光被有效的猝灭，此时，如果向溶液中加入带负电荷的单链...Fluorescent methods have received considerable attention during the past several decades owing to its easy operation and high detection sensitivity. They have been widely used for biological technology, environmental protection, medicine, and oil exploration. In recent years, many fluorescent sensors have been developed, such as conjugated polyelectrolytes, quantum dots, gold nanoclasters and carbon nanodots based methods. Compared with these advanced fluorescent materials, small molecular probes have relatively simple chemical structure, which can be synthesized and functionalized more easily. Perylene derivatives have been used as excellence fluorescent probes. In this work, we foucs on polyeletrolyte-induced perylene probe controlled self-assembly and its applications for bioanlysis. Th..
稀土及过渡金属-芳香多元羧酸配位聚合物的合成、结构与性质研究
No full text配位聚合物作为一类新兴的固体孔材料，凭借着其独特的优势（结构可剪裁设计性）受到了科研工作者越来越多的关注，成为了化学、材料学研究领域的热点。目前，配位聚合物在气体的存储和分离，催化，荧光传感，磁性，药物缓释，质子传导等领域表现出广泛的应用前景。然而，定向设计合成出具有既定目标结构的功能性配位聚合物一直是人们期望实现的目标。影响配位聚合物结构的因素有很多，如有机配体、辅助配体、金属离子、pH值和反应的溶剂等。本论文从晶体工程学原理出发，通过选用不同的芳香多羧酸配体和改变金属离子中心，主要取得以下成果： 1. 我们以刚性的苯四酸（H4betc）作为配体，三氮唑（trz）作为辅配体，在溶剂热的条件下得到了一个3D的柱层状框架[Zn(trz)(H2betc)0.5]?DMF (DMF = dimethylformamide) (1)。这个框架中包含有未配位的羧基基团，并且展现了卓越的稳定性。它能有...Coordination polymers have attracted more and more attention and become focal point of research in chemistry and material science field, due to their highly designable nature and the structures tenability. At present, coordination polymers have promising applications in gas storage and separation, catalysis, magnetism, fluorescent sensing, drug delivery, proton conduction and other areas. However, it is still a chanllenge to synthesis of goal structure of functional coordination polymers with the predesigned structure and expected property. The structure of coordination polymers are influenced by many factors, such as organic ligand, auxiliary ligand, metal ion, pH value and reaction solvent etc. In this dissertation, based on the principle of crystal engineering, through selecting differe..