Strongly fluorescent organogels and self-assembled nanostructures from pyrene coupled coumarin derivatives: application in cell imaging

2015 ◽  
Vol 3 (28) ◽  
pp. 5690-5701 ◽  
Author(s):  
Krishnamoorthy Lalitha ◽  
Subbiah Nagarajan
Keyword(s):  
Fluorescence Imaging ◽  
Self Assembly ◽  
Cell Imaging ◽  
Assembly Process ◽  
Coumarin Derivatives ◽  
Facile Synthesis ◽  
Self Assembled

The present work reports facile synthesis of pyrene coupled coumarin derivatives which could form self-assembled molecular gel and nano-flakes. The nanomaterials obtained via a self-assembly process could be potentially used in fluorescence imaging applications.

Facile synthesis of novel Roe-like TiO2 hollow nanospheres with mesoporous cavity for improved photocatalytic activity

2017 ◽  
Vol 10 (03) ◽  
pp. 1750028 ◽  
Author(s):  
Yan Zhu ◽  
Xiaoxia Yan ◽  
Yuanxin Ge ◽  
Shumin Wang ◽  
Dongmei Deng ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Self Assembly ◽  
Charge Separation ◽  
Synergistic Effects ◽  
Assembly Process ◽  
Hollow Nanospheres ◽  
Facile Synthesis

A facile approach was developed to synthesize novel Roe-like TiO2 hollow nanospheres via a template-assisted self-assembly process. These TiO2 nanospheres possessing mesoporous cavity manifest significantly improved photocatalytic activity owing to the synergistic effects of increased charge separation, more efficient use of the light and specific surface area.

scholarly journals Self-assembled peptide nanostructures for electrical, optical, and magnetic applications

2018 ◽  
Author(s):  
◽  
Soma Khanra
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Nonlinear Optical ◽  
Electronic Devices ◽  
Longitudinal Component ◽  
The Self ◽  
Assembly Process ◽  
Experimental Characterization ◽  
X Ray ◽  
Self Assembled

Bio-nanotechnology has become a widespread exciting field of research as the basic biological structure of bio-inspired materials and nanotechnology share the common length scale. Bio-nanotechnology, which is mainly based on bio-inspired nanostructured materials, has potential applications in nanomedicine, drug delivery, bio-sensors, and bio-degradable electronic devices. The nanostructures obtained from biomolecules are attractive due to their biocompatibility for molecular recognition, ease of chemical modification, and the ability to scaffold other organic and inorganic materials. Peptide nanostructures formed through the self-assembly process of the basic building block of diphenylalanine show promising applications in biodegradable electronic devices, drug delivery, catalysis agent, waveguide, and frequency converter. This research focusses on the self-assembly process in a dipeptide, L, L diphenylalanine (FF) and exploring its electronic, optical, and magnetic properties. The role of solvents in the self-assembly process of FF is explored by combining density functional theory (DFT) along with experimental characterization techniques such as electron microscopy, Raman scattering, and x-ray diffraction (XRD). One of the objectives of this work was to explore the nonlinear optical (NLO) properties of FF nanostructures via second harmonic generation (SHG). The ratio of the nonlinear optical coefficients was obtained from individual FF nanotubes as a function of the tube diameter and thermal annealing conditions. The ratio of the shear to the longitudinal component (d15/d33) of the NLO coefficient increases with the diameter of the tubes. One of the transverse components, d31, of the NLO coefficient is found to be negative, and its magnitude with respect to the longitudinal component (d33) increases with the tube diameter. Thermal treatment of individual FF tubes has a similar effect as increasing the diameter of the tubes in SHG polarimetry. The functionalization of FF micro-nanostructures (FF-MNS) with nanomaterials was studied. FF-MNS with Ag or Au nanoparticles were explored in surface-enhanced Raman scattering (SERS). Such self-assembled nanostructures provide a natural template for tethering Au and Ag nanoparticles (Nps) due to its fractal surface. The FF-MNS undergo an irreversible phase transition from hexagonal packing (hex) to an orthorhombic (ort) structure at [about] 150 [degree]C. The metal Nps form chains on hex FF-MNS as inferred from transmission electron microscopy images and a uniform non-aggregated distribution in the ort phase. The SERS spectra obtained from R6G bound to FF-MNSs with AuNps show a higher enhancement for the ort phase compared with the hex phase. The experimental results agree well with our calculated Raman spectra of model systems using DFT. Our results indicate that FF-MNS both in the hex and ort phase can be used as substrates for SERS analysis with different metal Nps, opening up a novel class of optically active bio-based substrates. The use of magnetic nanoparticles with biomolecules offers a versatile path for tuning the functionality of the composite material for several applications. The functionalization of FF-MNS with cobalt ferrite (CFO) magnetic nanoparticles was achieved. The interaction between CFO nanoparticles and FF-MNS was investigated by optical spectroscopy, x-ray photoelectron spectroscopy (XPS), and magnetization measurements. The changes in the XPS data from pristine FF-MNS and CFO:FF-MNS are indicative of a charge transfer process from CFO to FF-MNS, changing the electronic states of the Fe2+ and Co2+ ions. A comparison of the magnetic characterization from CFO nanoparticles and CFO:FF-MNS shows a higher saturation magnetization from the nanocomposite sample, which is attributed to a change in the cationic distribution in CFO upon binding with the peptide. We were further successful in demonstrating the application of FF-MNS as a bio-degradable active layer in an organic light emitting diode (OLED). FF-MNS were functionalized with two blue-emitting conducting polymers: di-octyl-substituted polyfluorene (PF8) and ethyl-hexyl polyfluorene (PF2/6), and used as an active layer in an OLED architecture. A combination of molecular dynamics and experimental characterization techniques reveals a stronger binding mechanism for PF8 compared to PF2/6 with FF-MNS. Biodegradability tests from FF-MNS:PF8 nanocomposite films show more than 80% weight loss in 2 h by enzymatic action compared to PF8 pristine films, which do not degrade. Self-assembled FF-MNS with organic semiconductors open up a new generation of biocompatible and biodegradable materials in organic electronics.

scholarly journals A simple approach to prepare self-assembled, nacre-inspired clay/polymer nanocomposites

Soft Matter ◽  
2020 ◽  
Vol 16 (23) ◽  
pp. 5497-5505 ◽  
Author(s):  
P. Xu ◽  
T. Erdem ◽  
E. Eiser
Keyword(s):  
Polymer Nanocomposites ◽  
Hierarchical Structure ◽  
Self Assembly ◽  
Simple Approach ◽  
Water Evaporation ◽  
Assembly Process ◽  
Inorganic Nanocomposites ◽  
Self Assembled ◽  
The Relationship

Inspired by the relationship between the ordered architecture of aragonite crystals and biopolymers found in natural nacre, we present a facile strategy to construct organic/inorganic nanocomposites with hierarchical structure via a water-evaporation driven self-assembly process.

scholarly journals STM visualisation of counterions and the effect of charges on self-assembled monolayers of macrocycles

2011 ◽  
Vol 2 ◽  
pp. 674-680 ◽  
Author(s):  
Tibor Kudernac ◽  
Natalia Shabelina ◽  
Wael Mamdouh ◽  
Sigurd Höger ◽  
Steven De Feyter
Keyword(s):  
Self Assembly ◽  
The Self ◽  
Self Assembled Monolayers ◽  
Assembly Process ◽  
Organic Monolayers ◽  
Preferential Adsorption ◽  
Scanning Tunnelling ◽  
Assembled Monolayers ◽  
Tunnelling Microscopy ◽  
Self Assembled

Despite their importance in self-assembly processes, the influence of charged counterions on the geometry of self-assembled organic monolayers and their direct localisation within the monolayers has been given little attention. Recently, various examples of self-assembled monolayers composed of charged molecules on surfaces have been reported, but no effort has been made to prove the presence of counterions within the monolayer. Here we show that visualisation and exact localisation of counterions within self-assembled monolayers can be achieved with scanning tunnelling microscopy (STM). The presence of charges on the studied shape-persistent macrocycles is shown to have a profound effect on the self-assembly process at the liquid–solid interface. Furthermore, preferential adsorption was observed for the uncharged analogue of the macrocycle on a surface.

Facile synthesis of ultralong hydroxyapatite nanowire using wormlike micelles as soft templates

CrystEngComm ◽  
2021 ◽  
Author(s):  
Junhua Zhao ◽  
Qin Hu ◽  
Yinlin Lei ◽  
Chuanhua Gao ◽  
Pinjie Zhang ◽  
...  
Keyword(s):  
Self Assembly ◽  
Soft Template ◽  
Template Method ◽  
Wormlike Micelles ◽  
Assembly Process ◽  
Scientific Interest ◽  
Facile Synthesis ◽  
Micro Scale ◽  
Scale Length ◽  
Soft Templates

As a powerful self-assembly process, the soft-template method has attracted considerable scientific interest, but there is a challenge associated with ultralong hydroxyapatite nanowire (HAPNWs) with several tens of micro-scale length....

scholarly journals 2D Self-assembled molecular networks and on-surface reactivity under nanoscale lateral confinement

2021 ◽  
Author(s):  
Lander Verstraete ◽  
Steven De Feyter
Keyword(s):  
Self Assembly ◽  
Surface Reactivity ◽  
Molecular Networks ◽  
Assembly Process ◽  
Reaction Products ◽  
Kinetics And Thermodynamics ◽  
Lateral Confinement ◽  
Self Assembled ◽  
Network Morphology

Lateral confinement at the nanoscale impacts the kinetics and thermodynamics of on-surface self-assembly, enabling fundamental insights in the assembly process as well as control over network morphology and reaction products.

scholarly journals Deciphering Molecular Self-Assembly through Electron Microscopy and Fluorescence Correlation Spectroscopy

2020 ◽  
Author(s):  
Subhankar Kundu ◽  
Arkaprava Chowdhury, ◽  
Somen Nandi ◽  
Kankan Bhattacharyya ◽  
Abhijit Patra
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Fluorescence Correlation Spectroscopy ◽  
Correlation Spectroscopy ◽  
The Self ◽  
Fine Tuning ◽  
Assembly Process ◽  
Molecular Aggregates ◽  
Fluorescence Correlation ◽  
Self Assembled

Supramolecular self-assembly of small organic molecules has emerged as a powerful tool to construct well-defined micro- and nanoarchitecture through fine-tuning a range of intermolecular interactions. The size, shape, and optical properties of these nanostructures largely depend on the temperature and polarity of the medium, along with the specific self-assembled pattern of molecular building units. The engineering of supramolecular self-assembled nanostructures with morphology-dependent tunable emission is in high demand due to the promising scope in nanodevices and molecular machines. However, challenges are probing the evolution of molecular aggregates from a true solution and directing the self-assembly process in a pre-defined fashion. The structure of molecular aggregates in the solution can be predicted from fluorescence correlation spectroscopy (FCS) and dynamic light scattering (DLS) analysis. On the other hand, the morphology of the aggregates can also be visualized through electron microscopy. Nevertheless, a direct correlation between emission from molecular aggregates in the aqueous dispersion and their morphology obtained through a solid-state characterization is missing. In the present study, we decipher the sequential evolution of molecular nanofibers from solution to spherical and oblong-shaped nanoparticles through the variation of solvent polarity, adjusting the <a>hydrophobic-hydrophilic interactions</a>. The intriguing case of molecular self-assembly is elucidated employing a newly designed π-conjugated thiophene derivative (TPAn) through a combination of steady-state absorption, emission measurements, FCS, and electron microscopy. The FCS analysis and microscopy results infer that small-sized nanofibers in the dispersion are further agglomerated, resulting in a network of nanofibers upon solvent evaporation. <a>The evolution of organic nanofibers and subtle control over the self-assembly process demonstrated in the current investigation provides a general paradigm to correlate the size, shape, and emission properties of diverse fluorescent molecular aggregates in complex heterogeneous media, including a human cell. </a>

A hexaphenylbenzene based AIEE active two photon probe for the detection of hydrogen sulfide with tunable self-assembly in aqueous media and application in live cell imaging

2015 ◽  
Vol 51 (85) ◽  
pp. 15570-15573 ◽  
Author(s):  
Subhamay Pramanik ◽  
Vandana Bhalla ◽  
Hwan Myung Kim ◽  
Hardev Singh ◽  
Hyo Won Lee ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Hela Cells ◽  
Self Assembly ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Aqueous Media ◽  
Live Cell ◽  
Two Photon ◽  
Self Assembled

AIEE active HPB based TPE probe exhibited modulation of self-assembled architecture in presence of H2S and was utilized for TPM imaging for detection of H2S in HeLa cells.

Self-Assembly of Protoporphyrin IX-TEG Derivatives into Tunable Nanoscaled Spherical Structures

2010 ◽  
Vol 63 (9) ◽  
pp. 1326 ◽  
Author(s):  
Sheshanath V. Bhosale ◽  
Sidhanath V. Bhosale ◽  
Mohan B. Kalyankar ◽  
Steven J. Langford ◽  
Ceilica H. Lalander
Keyword(s):  
Self Assembly ◽  
Protoporphyrin Ix ◽  
Triethylene Glycol ◽  
Aprotic Solvents ◽  
Protic Solvent ◽  
Assembly Process ◽  
Micellar Aggregates ◽  
Spherical Structures ◽  
Self Assembled

The results of a solvo-controlled self-assembly process involving a novel non-ionic protoporphyrin IX functionalized with triethylene glycol (Proto-NTEG) chains is discussed. In relatively non-polar aprotic solvents (cyclohexane/CHCl3), the protoporphyrin forms stable, uniformly-sized multilamellar micro-vesicles of approximately 65 nm diameter, while in more polar protic solvent mixes (CHCl3/MeOH), the same protoporphyrin forms micellar aggregates with dimensions of approximately 6 nm. The solvo-control operates based on the differing properties of glycol units in cyclohexane and methanol leading to inverse self-assembled structures.

Self-assembled targeted folate-conjugated eight-arm-polyethylene glycol–betulinic acid nanoparticles for co-delivery of anticancer drugs

2015 ◽  
Vol 3 (18) ◽  
pp. 3754-3766 ◽  
Author(s):  
Lin Dai ◽  
Xin Cao ◽  
Ke-Feng Liu ◽  
Chun-Xiao Li ◽  
Gui-Feng Zhang ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Cancer Cells ◽  
Solid Tumors ◽  
Anticancer Drugs ◽  
Betulinic Acid ◽  
Self Assembly ◽  
Assembly Process ◽  
Epr Effect ◽  
Self Assembled

Folate-8arm-PEG–betulinic acid nanoparticles prepared via a self-assembly process are stable in circulation, resulting in the EPR effect of solid tumors, and are efficiently internalized by cancer cells.

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