scholarly journals Polymersomes and Wormlike Micelles Made Fluorescent by Direct Modifications of Block Copolymer Amphiphiles

2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
Karthikan Rajagopal ◽  
David A. Christian ◽  
Takamasa Harada ◽  
Aiwei Tian ◽  
Dennis E. Discher
Keyword(s):  
Electron Microscopy ◽  
Drug Delivery ◽  
Transmission Electron Microscopy ◽  
Diblock Copolymers ◽  
Physicochemical Characteristics ◽  
Wormlike Micelles ◽  
Deep Tissue ◽  
Near Ir ◽  
Transmission Electron ◽  
Tissue Fluorescence

Wormlike micelles and vesicles prepared from diblock copolymers are attracting great interest for a number of technological applications. Although transmission electron microscopy has remained as the method of choice for assessing the morphologies, fluorescence microscopy has a number of advantages. We show here that when commercially available fluorophores are covalently attached to diblock copolymers, a number of their physicochemical characteristics can be investigated. This method becomes particularly useful for visualizing phase separation within polymer assemblies and assessing the dynamics of wormlike micelles in real time. Near-IR fluorophores can be covalently conjugated to polymers and this opens the possibility for deep-tissue fluorescence imaging of polymer assemblies in drug delivery applications.

Supramolecular chemistry at interfaces: host-guest interactions for attaching PEG and 5-fluorouracil to the surface of porous nanosilica

2016 ◽  
Vol 5 (6) ◽  
Author(s):  
Tuong Vi Tran ◽  
Uyen Vy Vo ◽  
Dong Yen Pham ◽  
Dai Lam Tran ◽  
Thi Hiep Nguyen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Drug Delivery ◽  
Transmission Electron Microscopy ◽  
Cell Proliferation ◽  
Polyethylene Glycol ◽  
Inclusion Complex ◽  
Spherical Shape ◽  
Burst Release ◽  
Anticancer Drug Delivery ◽  
Transmission Electron

AbstractPorous nanosilica (PNS) has been attracting much attention in fabrication of nanocarriers for a drug delivery system (DDS). However, the unmodified PNS-based carriers exhibited a significant initial burst release of drug, which may limit their potential clinical application. In this study, PNS was surface conjugated with cyclodextrin (CD) which was functionalized with adamantylamine-polyethylene glycol (APEG) for 5-fluorouracil (5-FU) delivery, in which case CD was used due to its ability to form a stable inclusion complex with 5-FU and APEG. The conjugated PNS (PNSC@APEG) was successfully prepared with spherical shape and diameter around 50 nm, determined by transmission electron microscopy (TEM). In addition, 5-FU was efficiently trapped in PNSC@APEG particles, which were around 63.4%±3.8% and was slowly released up to 3 days in phosphate buffer saline (PBS). Furthermore, the cell proliferation kit I (MTT) assay data showed that PNSC@APEG was a biocompatible nanocarrier. These results indicated that PNSC@APEG nanoparticles have a great potential as novel carriers for anticancer drug delivery.

scholarly journals Polymeric Self-Assemblies Based on tetra-ortho-Substituted Azobenzene as Visible Light Responsive Nanocarriers

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2060
Author(s):  
Alejandro Roche ◽  
Luis Oriol ◽  
Rosa M. Tejedor ◽  
Milagros Piñol
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Diblock Copolymers ◽  
Uv Light ◽  
Morphological Changes ◽  
Nile Red ◽  
Green Light ◽  
Light Irradiation ◽  
Transmission Electron ◽  
Amphiphilic Diblock Copolymers

Most of reported polymeric light-responsive nanocarriers make use of UV light to trigger morphological changes and the subsequent release of encapsulated cargoes. Moving from UV- to visible-responsive units is interesting for the potential biomedical applications of these materials. Herein we report the synthesis by ring opening polymerization (ROP) of a series of amphiphilic diblock copolymers, into which either UV or visible responsive azobenzenes have been introduced via copper(I) catalyzed azide-alkyne cycloaddition (CuAAC). These copolymers are able to self-assemble into spherical micelles or vesicles when dispersed in water. The study of the response of the self-assemblies upon UV (365 nm) or visible (530 or 625 nm) light irradiation has been studied by Transmission Electron Microscopy (TEM), Cryogenic Transmission Electron Microscopy (Cryo-TEM), and Dynamic Light Scattering (DLS) studies. Encapsulation of Nile Red, in micelles and vesicles, and Rhodamine B, in vesicles, and its light-stimulated release has been studied by fluorescence spectroscopy and confocal microscopy. Appreciable morphological changes have been induced with green light, and the subsequent release of encapsulated cargoes upon green light irradiation has been confirmed.

Transmission Electron Microscopy of Lipid Vesicles for Drug Delivery: Comparison between Positive and Negative Staining

2010 ◽  
Vol 16 (4) ◽  
pp. 456-461 ◽  
Author(s):  
Valentina Bello ◽  
Giovanni Mattei ◽  
Paolo Mazzoldi ◽  
Nicoletta Vivenza ◽  
Paolo Gasco ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Drug Delivery ◽  
Transmission Electron Microscopy ◽  
Iron Oxide ◽  
Osmium Tetroxide ◽  
Lipid Vesicles ◽  
Negative Staining ◽  
Transmission Electron ◽  
Compositional Characterization

AbstractLipid-containing nanostructures, in the form of solid lipid nanoparticles or iron oxide nanoparticles (NPs) coated with a lipid shell, were used as case studies for assessing and optimizing staining for transmission electron microscopy structural and compositional characterization. These systems are of paramount importance as drug delivery systems or as bio-compatible contrast agents. In particular, we have treated the systems with a negative (phospshotungstic acid) or with a positive (osmium tetroxide) staining agent. For iron-oxide NPs coated with the lipid shell, negative staining was more efficient with respect to the positive one. Nevertheless, in particular cases the combination of the two staining procedures provided more complete morphological and compositional characterization of the particles.

Polyethyleneimine Modified Biocompatible Poly(N-isopropylacrylamide)-Based Nanogels for Drug Delivery

2008 ◽  
Vol 8 (5) ◽  
pp. 2377-2384 ◽  
Author(s):  
Chang-Yun Quan ◽  
Hua Wei ◽  
Yun-Xia Sun ◽  
Si-Xue Cheng ◽  
Kun Shen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Drug Delivery ◽  
Transmission Electron Microscopy ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Transmission Electron ◽  
Potential Applications ◽  
Different Temperatures ◽  
The Mean ◽  
Stimuli Sensitive

A series of biocompatible and stimuli-sensitive poly(N-isopropylacrylamide-co-propyl acrylic acid) (P(NIPAAm-co-PAAc)) nanogels were synthesized by emulsion polymerization. In addition, polyethyleneimine (PEI) was further grafted to modify the PNIPAAm-based nanogels. The P(NIPAAm-co-PAAc)-g-PEI nanogels exhibited good thermosensitivity as well as pH sensitivity. Transmission electron microscopy (TEM) showed that the P(NIPAAm-co-PAAc)-g-PEI and P(NIPAAm-co-PAAc) nanogels displayed well dispersed spherical morphology. The mean sizes of the nanogels measured by dynamic light scattering (DLS) were from 100 nm to 500 nm at different temperatures. The cytotoxicity study indicated P(NIPAAm-co-PAAc) nanogels exhibited a better biocompatibility than both PNIPAAm nanogel and P(NIPAAm-co-PAAc)-g-PEI nanogel although all the three kinds of nanogels did not exhibit apparent cytotoxicity. The drug-loaded nanogels, especially the PEI-grafted nanogels, showed temperature-trigged controlled release behaviors, indicating the potential applications as an intelligent drug delivery system.

scholarly journals Fluorescence and electron microscopy to visualize the intracellular fate of nanoparticles for drug delivery

2016 ◽  
Vol 60 (2) ◽  
Author(s):  
M. Costanzo ◽  
F. Carton ◽  
A. Marengo ◽  
G. Berlier ◽  
B. Stella ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Drug Delivery ◽  
Transmission Electron Microscopy ◽  
Cultured Cells ◽  
Cell System ◽  
Functional Relationships ◽  
Cell Internalization ◽  
Transmission Electron ◽  
Intracellular Fate

<p>In order to design valid protocols for drug release <em>via</em> nanocarriers, it is essential to know the mechanisms of cell internalization, the interactions with organelles, and the intracellular permanence and degradation of nanoparticles (NPs) as well as the possible cell alteration or damage induced. In the present study, the intracellular fate of liposomes, polymeric NPs and mesoporous silica NPs (MSN) has been investigated in an <em>in vitro</em> cell system by fluorescence and transmission electron microscopy. The tested nanocarriers proved to be characterized by specific interactions with the cell: liposomes enter the cells probably by fusion with the plasma membrane and undergo rapid cytoplasmic degradation; polymeric NPs are internalized by endocytosis, occur in the cytoplasm both enclosed in endosomes and free in the cytosol, and then undergo massive degradation by lysosome action; MSN are internalized by both endocytosis and phagocytosis, and persist in the cytoplasm enclosed in vacuoles. No one of the tested nanocarriers was found to enter the nucleus. The exposure to the different nanocarriers did not increase cell death; only liposomes induced a reduction of cell population after long incubation times, probably due to cell overloading. No subcellular damage was observed to be induced by polymeric NPs and MSN, whereas transmission electron microscopy revealed cytoplasm alterations in liposome-treated cells. This important information on the structural and functional relationships between nanocarriers designed for drug delivery and cultured cells further proves the crucial role of microscopy techniques in nanotechnology.</p>

Formation of superlattices in blends of 3-miktoarm star terpolymers with diblock copolymers

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Volker Abetz ◽  
Shimei Jiang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Diblock Copolymers ◽  
Shell Structures ◽  
Core Shell ◽  
Transmission Electron ◽  
Miktoarm Star ◽  
Triblock Terpolymers ◽  
Cyclohexyl Methacrylate

Abstract In this contribution we report on the morphological structures formed in blends of microphase-separated 3-miktoarm star terpolymers of polystyrene-armpolybutadiene- arm-poly(2-vinylpyridine) (SBV*) and polystyrene-block-polybutadiene (SB), polystyrene-block-poly(2-vinylpyridine) (SV), poly(2-vinylpyridine)- block-poly(cyclohexyl methacrylate) (VC) diblock copolymers. The morphologies are characterized by transmission electron microscopy. Blends with similar morphologies as known from linear triblock terpolymers are found, like core-shell structures based on cylinders or gyroids. Other blends show very distorted morphologies, or morphologies similar to the ones found for pure 3-miktoarm star terpolymers. While attractive interactions between blocks of the two species enhance the formation of common superlattices, blends with too large diblock copolymers tend to macrophase-separate.

N-Doped CDs–GP nanospheres as a drug delivery nanocarrier system with carbon dots and a fluorescent tracer

2017 ◽  
Vol 41 (19) ◽  
pp. 10880-10889 ◽  
Author(s):  
Ping Yuan ◽  
Ming Zhang ◽  
Ninglin Zhou ◽  
Cheng Chi ◽  
Xiaohong Chu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Drug Delivery ◽  
Transmission Electron Microscopy ◽  
Fourier Transform ◽  
Fluorescence Spectroscopy ◽  
Carbon Dots ◽  
X Ray Diffraction ◽  
Fluorescent Tracer ◽  
X Ray ◽  
Transmission Electron

In this study, a carbon dots-genipin covalent conjugate (CDs–GP) was synthesized, characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and fluorescence spectroscopy (FL).

scholarly journals Linagliptin loaded Solid-SMEEDS for enhanced solubility and dissolution: Formulation development and optimization by D-optimal design

2019 ◽  
Vol 9 (2) ◽  
pp. 47-56
Author(s):  
Madhubhai M Patel ◽  
Rahulkumar J Patel
Keyword(s):  
Electron Microscopy ◽  
Drug Delivery ◽  
Transmission Electron Microscopy ◽  
Optimal Design ◽  
Zeta Potential ◽  
Drug Delivery Systems ◽  
Delivery Systems ◽  
Dissolution Profile ◽  
Transmission Electron

The aim of the present investigation was to formulate and evaluate solid self-micro emulsifying drug-delivery systems (S-SMEDDS) to improve solubility and dissolution profile of Linagliptin. Solubility of Linagliptin in different oils, surfactants and co-surfactants was assessed and optimizations of pseudo-ternary plots were also carried out for preparation of liquid SMEDDS. D-optimal design mixture was used in the optimization of Linagliptin loaded liquid SMEEDS. The optimized SMEEDS were characterized for globule size, zeta potential, dilution stability, transmittance, pH and in-vitro release profile. The morphology of the Linagliptin SMEEDS was observed by Transmission Electron Microscopy (TEM). Among the different silicates, Nusillin US2 was used as the solid carrier/absorbent to formulate S-SMEEDS of Linagliptin. Improved in-vitro dissolution profile of optimized formulation was observed, resulting in multifold improvement in the absorption profile of Linagliptin as compared with pure drug. In a nutshell, this optimized S-SMEDD formulation holds great promise for enhancement of its physiochemical and biological attributes. Keywords: Linagliptin, Solid Self-micro Emulsifying Drug Delivery Systems, D-optimal design, Zeta-potential, Transmission Electron Microscopy

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