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1.
ACS Appl Mater Interfaces ; 11(34): 31270-31282, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31348641

RESUMO

Typical aggregation-induced emission (AIE) luminogens tetraphenylethylene (TPE) and triphenylamine have been used to construct an AIE-active conjugated polymer, namely, poly(N,N-diphenyl-4-(4-(1,2,2-triphenylvinyl)styryl)aniline) (PTPA), which consist of D-π-A architecture by Wittig polymerization. We fabricated mesoporous silica hollow nanospheres (MSHNs) which were encapsulated with the AIE-active polymer for applications in cellular imaging. It exhibits a positive solvatochromism effect by increasing solvent polarity, supported by theoretical calculation using density functional theory. The structure of the monomers and polymer was confirmed by Fourier transform infrared, nuclear magnetic resonance, and high-resolution mass spectrometry techniques. Considering the advantage of high brightness in the fluorescence of PTPA, it was encapsulated into MSHNs by a noncovalent approach, and the surface was functionalized with an anti-EpCAM (antiepithelial cell adhesion molecule) aptamer through conjugation with γ-glycidoxypropyltrimethoxysilane for targeting cancer cells specifically. The aptamer-functionalized Apt-MSHNs exhibited excellent biocompatibility with the liver cancer-Huh-7 cells used for this study and was efficiently internalized by these cells. Because EpCAM are overexpressed in multiple carcinomas, including liver cancer, these aptamer-conjugated AIE MSHNs are therefore good candidates for targeted cellular imaging applications.


Assuntos
Meios de Contraste , Imagem por Ressonância Magnética , Nanosferas/química , Neoplasias , Dióxido de Silício , Meios de Contraste/química , Meios de Contraste/farmacologia , Humanos , Células MCF-7 , Neoplasias/diagnóstico por imagem , Neoplasias/metabolismo , Neoplasias/patologia , Dióxido de Silício/química , Dióxido de Silício/farmacologia , Espectrometria de Fluorescência
2.
Analyst ; 143(15): 3741-3748, 2018 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-29995040

RESUMO

In this article, we tried to redefine the unexplored potential of a benzothiazole type of Schiff-base (OM), which was identified as an AIE-active molecule that exhibits excited-state intramolecular proton transfer (ESIPT). Interestingly, this compound shows ultra-sensitivity and selectivity in the detection of Al(iii) (12 pM; 456 ppt). The OM was capable of pH sensing and was also tested for internalization in cancerous cells for intracellular imaging. Computational modeling was performed and the results were in good agreement with the experimental UV-Vis spectrum and the energy gap obtained in basic and acidic media.

3.
Dalton Trans ; 47(13): 4613-4624, 2018 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-29517794

RESUMO

Advanced biomedical research has established that cancer is a multifactorial disorder which is highly heterogeneous in nature and responds differently to different treatment modalities, due to which constant monitoring of therapy response is becoming extremely important. To accomplish this, different theranostic formulations have been evaluated. However, most of them are found to suffer from several limitations extending from poor resolution, radiation damage, to high costs. In order to develop a better theranostic modality, we have designed and synthesized a novel platinum(ii)-based 'aggregation induced emission' (AIE) molecule (named BMPP-Pt) which showed strong intra-cellular fluorescence and also simultaneously exhibited potent cytotoxic activity. Due to this dual functionality, we wanted to explore the possibility of using this compound as a single molecule based theranostic modality. This compound was characterized using elemental analysis, NMR and IR spectroscopy, mass spectrometry and single crystal X-ray structure determination. BMPP-Pt was found to exhibit a high AIE property with emission maxima at 497 nm. For more efficient cancer cell targeting, BMPP-Pt was encapsulated into mesoporous silica nanoparticles (Pt-MSNPs) and the MSNPs were further surface modified with an anti-EpCAM aptamer (Pt-MSNP-E). Pt-MSNPs exhibited higher intracellular fluorescence compared to free BMPP-Pt, though both of them induced a similar degree of cell death via the apoptosis pathway, possibly via cell cycle arrest in the G1 phase. Anti-EpCAM aptamer modification was found to increase both cytotoxicity and intracellular fluorescence compared to unmodified MSNPs. Our study showed that EpCAM functionalized BMPP-Pt loaded MSNPs can efficiently internalize and induce apoptosis of cancer cells as well as show strong intracellular fluorescence. This study provides clues towards the development of a potential single compound based theranostic modality in future.


Assuntos
Antineoplásicos/farmacologia , Portadores de Fármacos/farmacologia , Nanopartículas/química , Platina/química , Dióxido de Silício/química , Nanomedicina Teranóstica/métodos , Antineoplásicos/síntese química , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Aptâmeros de Nucleotídeos/química , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Portadores de Fármacos/síntese química , Portadores de Fármacos/química , Corantes Fluorescentes/química , Humanos , Porosidade
4.
Small ; 13(15)2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28134490

RESUMO

Aggregation-induced emission (AIE) is commonly observed in irregular bulk form. Herein, unique aggregation properties of an AIE-active complex into branched supramolecular wires are reported for the first time. Mono-cyclometalated Ir(III) complex shows in-plane J-aggregation at the air-water interface owing to the restriction of intramolecular vibration of bidentate phenylpyridinato and intramolecular rotations of monodentate triphenylphosphine ligands at air-water interface. As a consequence, a large enhancement of luminescence comparable to the solid state is obtained from the monolayers of supramolecular wires. This unique feature is utilized for the fabrication of light-emitting diodes with low threshold voltage using supramolecular wires as active layer. This study opens up the need of ordered assembly of AIE complexes to achieve optimal luminescence characteristics.

5.
ACS Omega ; 2(4): 1489-1504, 2017 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-30023637

RESUMO

In recent years, the use of silver nanoparticles (AgNPs) in biomedical applications has shown an unprecedented boost along with simultaneous expansion of rapid, high-yielding, and sustainable AgNP synthesis methods that can deliver particles with well-defined characteristics. The present study demonstrates the potential of metal-tolerant soil fungal isolate Penicillium shearii AJP05 for the synthesis of protein-capped AgNPs. The particles were characterized using standard techniques, namely, UV-visible spectroscopy, transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The anticancer activity of the biosynthesized AgNPs was analyzed in two different cell types with varied origin, for example, epithelial (hepatoma) and mesenchymal (osteosarcoma). The biological NPs (bAgNPs) with fungal-derived outer protein coat were found to be more cytotoxic than bare bAgNPs or chemically synthesized AgNPs (cAgNPs). Elucidation of the molecular mechanism revealed that bAgNPs induce cytotoxicity through elevation of reactive oxygen species (ROS) levels and induction of apoptosis. Upregulation of autophagy and activation of JNK signaling were found to act as a prosurvival strategy upon bAgNP treatment, whereas ERK signaling served as a prodeath signal. Interestingly, inhibition of autophagy increased the production of ROS, resulting in enhanced cell death. Finally, bAgNPs were also found to sensitize cells with acquired resistance to cisplatin, providing valuable insights into the therapeutic potential of bAgNPs. To the best of our knowledge, this is the first study that provides a holistic idea about the molecular mechanisms behind the cytotoxic activity of protein-capped AgNPs synthesized using a metal-tolerant soil fungus.

6.
Dalton Trans ; 44(14): 6581-92, 2015 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-25757518

RESUMO

On reaction of 2,2'-bipyridine with iridium(iii), an "aggregation induced phosphorescence (AIP)" active "rollover" complex, [Ir(PPh3)2(bipy-H)(Cl)(H)] (bipy-H = κ(2)-N,C-2,2'-bipyridine) or [Ir(bipy-H)], is obtained. The emission colour changes from bluish-green to yellowish-orange and vice versa after repeated protonation and deprotonation of [Ir(bipy-H)], respectively, which unequivocally supports its reversible nature. [Ir(bipy-H)] is sensitive to acids with different pKa values. Tuning of the emission properties can be achieved in the presence of acids with different pKas. This behaviour allows the complex, [Ir(bipy-H)], to function as a phosphorescent acid sensor in both solution and the solid state, as well as a chemosensor for detecting acidic and basic organic vapours. The protonated form, [Ir(bipy-H)H(+)], which is generated after protonation of [Ir(bipy-H)] can be used as a solvatochromic probe for oxygen containing solvents, and also shows vapochromic properties. The emission, absorption and (1)H NMR spectra of [Ir(bipy-H)] under acidic and basic conditions demonstrate its reversible nature. DFT based calculations suggest that changes in the electron affinity of the pyridinyl rings are responsible for all these processes.

7.
Dalton Trans ; 43(43): 16431-40, 2014 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-25249482

RESUMO

Design and syntheses of 'aggregation induced emission (AIE)' active blue-emitting bis-cyclometalated iridium(III) complexes with appended diphosphine ligands [Ir(F2ppy)2(L1/L2)2(Cl)] (F2ppy = 2-(2',4'-difluoro) phenylpyridine; L1 = 1,2-bis(diphenylphosphino)ethane; L2 = bis(diphenylphosphino)propane) have been realized on a suitable route. The free phosphorous donor atom present on the appended diphosphine is shown to provide selective binding to the mercuric ion (Hg(2+)). The selective binding ability of the probe molecule towards mercuric ions results in a detectable signal due to complete quenching of their AIE properties. The quenching effect of the probe molecule has been explored and found to be the result of the degradation of the probe iridium(III) complex triggered by the presence of mercuric ions due to an interplay of a soft-soft interaction between the free phosphorous atom of the probe molecule and mercuric ions. These complexes were modelled to obtain deeper understanding of excited state properties and the results were tentatively correlated with the experimental data.

8.
Dalton Trans ; 41(31): 9276-9, 2012 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-22763705

RESUMO

Strong solid-state greenish-blue emitting, mono-cyclometalated iridium complexes, [Ir(ppy)(PPh(3))(2)(H)(Cl)], 2a and [Ir(F(2)ppy)(PPh(3))(2)(H)(Cl)], 2b [ppyH = 2-phenylpyridine; F(2)ppyH = 2-(2',4'-difluoro)phenylpyridine], have been synthesized by a convenient route. The 'aggregation induced enhanced phosphorescence (AIEP)' activity exhibited by these complexes has been rationalized.

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