Aggregates of fluorescent gels assembled by interfacial dynamic bonds

Life,defined as the specific form of substance,is an integration of aggregates at various scales,ranging from single molecules to tissues.However,these building blocks of common aggregates are usually recognized as confining at the microscopic level,while there are few studies focusing on macroscopic building blocks for aggregates.Fluorescent gels,as the important macroscopic building blocks,are drawing researchers’attention on account of their extraordinary fluorescence as well as soft material properties.Inspired by nature,fluorescent gels can be aggregated through interfacial adhesion.According to the driving forces for interfacial adhesion,a series of aggregates of fluorescent gels(AFGs)was summarized,including H-bond,metal coordinations,host-guest interactions,hydrophobic interactions,electrostatic interactions,dynamic covalent bonds as well as multiple driving forces.These AFGs own dynamic assembled behaviors and rich stimuli responsiveness,which could be applied to information storage,sensing,biomedical systems,and so on.The authors anticipate this review can accelerate the development of aggregate science,especially based on macroscopic building blocks.

Specific protein expression in a rat model of early focal cerebral ischemia:Fluorescent two-dimensional difference gel electrophoresis

BACKGROUND： The use of fluorescent two-dimensional difference gel electrophoresis （2D-DIGE） has been shown to compensate for the shortcomings of conventional two-dimensional gel electrophoresis, such as poor repeatability and large systematic errors. However, little information is presently available regarding the use of 2D-DIGE to investigate mechanisms of ischemic cerebrovascular diseases. Plasma and body fluids have been utilized in proteomic technology to study ischemic cerebrovascular diseases. OBJECTIVE： To perform proteomic analysis of fresh rat brain tissue in peripheral ischemic regions using 2D-DIGE 6 hours after middle cerebral artery occlusion （MCAO）, and to identify specific proteins closely associated with early ischemic cerebrovascular diseases. DESIGN, TIME AND SETTING： Proteomics-based, randomized, controlled, animal experiment was performed at the Laboratories of Neurology and Proteomics, Jilin University between January and April 2006. MATERIALS： 2, 3, 5-triphenyl tetrazolium chloride was purchased from Sigma, USA. Ettan DALTSix system, DeCyder DIA V5.0 differential analysis software, and Ettan matrix-assisted laser desorption/ionization time-of-flight mass spectrometer （MALDI-TOF-MS） were purchased from Amersham Bioscience, Sweden. METHODS： Eight healthy, male, Wistar rats were randomized to experimental and control groups, with four rats in each group. In the experimental group, rat models of focal cerebral ischemia were established by MCAO. In the control group, the internal and external carotid arteries were exposed and then immediately sutured, and the remaining procedures were identical to the experimental group. MAIN OUTCOME MEASURES： At 6 hours after cerebral ischemia, protein expression in the peripheral ischemia region of the experimental group was compared with the control group using 2D-DIGE. Protein spots that exhibited statistical differences between experimental and control groups with 〉 1.4 attributable risk were screened using DeCyder DIA V5.0 differential analysis software. Differential proteins were identified using MALDI-TOF-MS. RESULTS： Triphenyl tetrazolium chloride staining results revealed pink, normal brain tissue and white, ischemic brain tissue, suggesting successful MCAO establishment. The average matching rate of four 2D-DIGE gels was 92.4%. There were （1 758 ± 43） protein spots on each gel, with similar distribution modes. At 6 hours after focal cerebral ischemia, 13 protein spots exhibited marked expression changes, including significantly increased （n = 7） and decreased （n = 6） expression （P 〈 0.05）. MALDI-TOF-MS results revealed two differential protein spots： a-tubulin and heat shock protein 27, which were significantly decreased in the experimental group compared with the control group （P 〈 0.05）. CONCLUSION： Thirteen protein spots with expression changes were revealed by 2D-DIGE proteomics technology. Of them, a-tubulin and heat shock protein 27 expressions were markedly decreased during the early stage of cerebral ischemia. These two proteins were presumed to be proteins associated with early ischemic cerebrovascular diseases.

A Fluorescent Supramolecular Crosslinked Polymer Gel Formed by Crown Ether Based Host-Guest Interactions and Aggregation Induced Emission

Based on the combination of B21C7/dialkylammonium salt host-guest interactions and tetraphenylethylene （TPE）-based aggregation-induced emission （AIE） effect, a fluorescent supramolecular crosslinked polymer gel was successfully prepared. Compared with the solution of TPE-containing small molecules, this gel exhibited remarkable fluorescence enhancement due to the AIE effect of TPE units. The ＂gelation induced fluorescence emission＂ phenomenon can be explained by the hindered intramolecular rotation of phenyl rings of TPE. Because of the reversibility and stimuli-responsiveness of the B21C7/dialkylammonium salt host-guest interactions, the transition between the fluorescent supramolecular crosslinked polymer gel and the disassembled sol with very weak fluorescence can be realized by adding pH and thermal stimuli. This novel material contributes to the development of supramolecular chemistry, polymer science and fluorescent materials and offers a new method to construct functional supramolecular materials.

Research progress on the luminescence of biomacromolecules

Luminescent materials show great potential in various applications.Traditional aggregation-induced emission(AIE)luminogens are mostly produced by complex organic synthesis and have poor hydrophilicity and biocompatibility,which limit their practical applications.Therefore,it is of great significance to develop fluorescent materials with good hydrophilicity and biocompatibility,and biomacromolecules with these properties have attracted our attention.Partial biomacromolecules can generate unique new fluorophores during the gelation process to obtain hydrogels with good fluorescence properties.In addition,biomacromolecules can be modified with fluorescent groups to obtain fluorescent materials with excellent performance,thus improving the hydrophilicity and biocompatibility of fluorophore.In particular,grafting aggregation-caused quenching(ACQ)luminogens onto biomacromolecules can even effectively inhibit the aggregation and self-quenching of luminogens.It is well known that aromatic biological macromolecules such as green fluorescent protein have intrinsic fluorescence.Intrinsic fluorescence is also observed in nonaromatic biological macromolecules without traditional chromophores such as chitosan,cellulose and sodium alginate.The luminescence of nonaromatic biomacromolecule can be rationalized by the clustering-triggered emission(CTE)mechanism,namely,clustering of nonconventional chromophores and subsequent electron overlap and conformation rigidification are accountable for the emssion.In this review,fluorescence gels obtained from biomacromolecules,biomacromolecules modified with fluorophores,and the intrinsic luminescence of biomacromolecular luminogens are assessed.This review will help to develop low-cost,biocompatible luminescent materials and has great significance for comprehending the luminescence of nonconventional luminophores and expanding the application of luminescent compounds.