Enzyme‐Triggered Disassembly of Perylene Monoimide‐based Nanoclusters for Activatable and Deep Photodynamic Therapy

Photodynamic therapy (PDT) exhibits great potential for cancer therapy, but still suffers from nonspecific photosensitivity and poor penetration of photosensitizer. Herein, a smart perylene monoimide‐based nanocluster capable of enzyme‐triggered disassembly is reported as an activatable and deeply penetrable photosensitizer. A novel carboxylesterase (CE)‐responsive tetrachloroperylene monoimide (P1) was synthesized and assembled with folate‐decorated albumins into a nanocluster ( FHP ) with a diameter of circa 100 nm. Once P1 is hydrolyzed by the tumor‐specific CE, FHP disassembles into ultrasmall nanoparticles (ca. 10 nm), facilitating the deep tumor penetration of FHP . Furthermore, such enzyme‐triggered disassembly of FHP leads to enhanced fluorescence intensity (ca. 8‐fold) and elevated singlet oxygen generation ability (ca. 4‐fold), enabling in situ near‐infrared fluorescence imaging and promoted PDT. FHP permits remarkable tumor inhibition in vivo with minimal side effects through imaging‐guided, activatable, and deep PDT. This work confirms that this cascaded multifunctional control through enzyme‐triggered molecular disassembly is an effective strategy for precise cancer theranostics.     

Crosslink-Enhanced Emission Effect on Luminescence in Polymers: Advances and Perspectives

The crosslink-enhanced emission effect was first proposed to explore the strong luminescence of nonconjugated polymer dots possessing only either non-emissive or weakly emissive sub-luminophores. Interesting phenomena in recent research indicate such enhancement caused by extensive crosslinking appears in diverse luminescent polymers with sub-luminophores (electron-rich heteroatomic moieties) or luminophores (conjugated π domains). This enhancement can promote the emission from nonluminous to luminous, from weakly luminous to strongly luminous, and even convert the pathway of radiative transitions. The concept of the crosslink-enhanced emission effect should be updated and extended to an in-depth spatial effect, such as electron overlap and energy splitting in confined domains by effective crosslinking, more than initial immobilization. This Minireview outlines the development of the crosslink-enhanced emission effect from the perspective of the detailed classification, inherent mechanism and applicable systems. An outlook on the further exploration and application of this theory are also proposed.     

Enzyme-Triggered Disassembly of Perylene Monoimide-based Nanoclusters for Activatable and Deep Photodynamic Therapy

Photodynamic therapy (PDT) exhibits great potential for cancer therapy, but still suffers from nonspecific photosensitivity and poor penetration of photosensitizer. Herein, a smart perylene monoimide-based nanocluster capable of enzyme-triggered disassembly is reported as an activatable and deeply penetrable photosensitizer. A novel carboxylesterase (CE)-responsive tetrachloroperylene monoimide (P1) was synthesized and assembled with folate-decorated albumins into a nanocluster ( FHP ) with a diameter of circa 100 nm. Once P1 is hydrolyzed by the tumor-specific CE, FHP disassembles into ultrasmall nanoparticles (ca. 10 nm), facilitating the deep tumor penetration of FHP . Furthermore, such enzyme-triggered disassembly of FHP leads to enhanced fluorescence intensity (ca. 8-fold) and elevated singlet oxygen generation ability (ca. 4-fold), enabling in situ near-infrared fluorescence imaging and promoted PDT. FHP permits remarkable tumor inhibition in vivo with minimal side effects through imaging-guided, activatable, and deep PDT. This work confirms that this cascaded multifunctional control through enzyme-triggered molecular disassembly is an effective strategy for precise cancer theranostics.     

FT-Raman,FT-infrared and NIR spectroscopic characterization of oxygen-delignified kraft pulp treated with hydrogen peroxide under acidic and alkaline conditions

The effects of bleaching treatment of oxygen-delignified softwood kraft pulp with hydrogen peroxide under acidic and alkaline conditions were studied using standard technological techniques and spectroscopic analytical methods: near-infrared (NIR), Fourier-transform infrared (FTIR) and Fourier-transform (FT) Raman spectroscopies. Among the three tested spectroscopic techniques, NIR analysis appeared to be the most appropriate in terms of possible technological applications. The use of NIR spectroscopy combined with multivariate data analysis allowed to create models for pulp bleaching monitoring based on CIE L*a*b* measurements. Near-infrared and FTIR spectroscopic studies allowed differentiating between the effects of the acidic and alkaline peroxide bleaching stages, but failed in relation to the delignification process. The most representative bands in the FTIR and FT-Raman spectra in terms of delignification and chromophore removal exhibited no correlation with standard technological measurement results.     

Crystal Structure and Luminescent Properties of a Zn(Ⅱ) Coordination Polymer Assembled by Mixed-ligand

A Zn(Ⅱ) coordination polymer [Zn(NIP)(3,3'-bpt)]·H2O(1, NIP = 5-nitroisophthalate, 3,3'-bpt = 1H-3,5-bis(3-pyridyl)-1,2,4-triazolate) has been synthesized by the hydrothermal reaction at 140 ℃ and structurally characterized by IR spectroscopy, X-ray diffraction, thermal analysis, single-crystal X-ray diffraction and luminescent properties. In complex 1, the zinc atom is five-coordinated with three carboxylate oxygen atoms from three H2 NIP and two nitrogen atoms from two 3,3'-bpt, respectively, forming a distorted trigonal bipyramidal geometry and showing a 1D chain structure, which is further bridged by NIP to form a 3D supramolecular network via self-assembly of hydrogen bonds.     

A Two-dimensional Anthracene-9,10-dicarboxylate Zinc(Ⅱ) Coordination Polymer Based on Binuclear [Zn_2Cl_2] Nodes: Synthesis,Characterization and Luminescent Properties

A two-dimensional(2D) 44 topological ZnⅡ coordination polymer {[Zn2Cl2(L)(4bpy)2]}∞(H2L = anthracene-9,10-dicarboxylic acid, 4bpy = 4,4ˊ-bipyridine) based on binuclear [Zn2Cl2] nodes has been synthesized and characterized by IR, elemental analysis, X-ray powder diffraction and single-crystal X-ray diffraction analysis. Moreover, the luminescent properties of the correspon- ding compound have been briefly investigated.     

Synthesis, Crystal Structure and Luminescence Property of a Cd(Ⅱ) Complex Assembled by 4-Carboxymethoxy Phenylacetic Acid

A new structure with the molecular formula [CdL]n was formed by CdSO4 with 4-carboxymethoxy phenylacetic acid (H2L) through the hydrothermal method. The complex was characterized by elemental analysis and infrared spectroscopy. The structure of the complex was determined by single-crystal X-ray diffraction, which is of monoclinic system, space group P21/c with a = 10.3887(2), b = 7.10710(10), c = 14.7212(2) , β = 120.6940(10)°, V = 934.65(3) 3, Dc = 2.278 g·cm-3, Z = 4, F(000) = 624, S = 1.022, the final R = 0.0187 and wR = 0.0487 for 2000 observer reflections (Ⅰ > 2σ(Ⅰ)). The center metal ion Cd(Ⅱ) in the complex is six-coordinated in a distorted octahedral geometry, and is connected with L ligands to form a 3D fishing net structure, which is a novel (3,6) network topology. The luminescence of the complex has been investigated, and the result reveals that it displays luminescent property in the voilet region.     

以3,5-二溴苯甲酸及吡啶构筑的一维镉(Ⅱ)和锰(Ⅱ)配位聚合物的合成、晶体结构、荧光及磁性质

通过水热方法,以3,5-二溴苯甲酸(3,5-HBr2BC)和吡啶(py)分别与Cd(NO3)2·4H2O和Mn SO4·2H2O反应,合成了2个具有同质异心结构的一维链状配位聚合物[M3(3,5-Br2BC)6(py)2]n(M=Cd,1;Mn,2),并对其结构、荧光和磁性质进行了研究。结构分析结果表明2个化合物属于三斜晶系,P1空间群。这些配合物具有一维链状结构,而且这些一维链状结构通过Br…Br卤键和C-H…Br氢键作用进一步形成了三维超分子框架。配合物1在室温下能分别发出很强的绿色荧光,配合物2中相邻锰离子间存在反铁磁相互作用。     

白光LED用Sr_(0.955)Al_2Si_(2-x)Ti_xO_8∶Eu~(2+)荧光粉的晶体结构和光谱特性

由高温固相反应制得Sr0.955Al2Si2-xTixO8∶Eu2+(x=0~1.0)系列试样,研究了Ti4+置换Si4+对其晶体结构和光谱特性的影响。Ti4+以类质同相替代Si4+进入基质晶格中,形成了连续固溶体,其晶胞参数a,b,c,β和晶胞体积V随Ti4+置换量呈线性递增。Ti4+置换Si4+对晶胞参数c的影响显著,b其次,a最小。荧光激发谱为宽带,位于230~400nm,由267nm、305nm、350nm和375nm4个峰拟合成,表观峰值位于351nm;随着Ti4+置换量的增加,半高宽(FWHM)从105nm减小到93nm。发射光谱位于380~600nm,表观峰值位于407nm,可由406nm和441nm两峰拟合而成并且随Ti4+置换量增加线性红移,Ti4+进入晶格对长波长发射中心影响较少;Ti4+置换量为1.0时,表观发射峰位从407nm红移至417nm;利用试样荧光光谱和VanUitert经验公式,得出SrAl2Si2O8∶Eu2+中Sr2+的配位数为9。随着Ti4+置换量Si4+进入基质晶格,造成Eu-O距离变小,使得Eu2+所处的晶体场强度增强,发光中心Eu2+的5d能级分裂增大,造成Eu2+最低发射能级重心下移,两拟合谱峰峰位均呈线性红移。