Mucoadhesive Nanoparticles for Drug Delivery to the Anterior Eye

While the use of topical drops for the delivery of drugs to the anterior of the eye is well accepted, it is far from efficient with as little as 5% of the drug instilled on the eye actually reaching the target tissue. The ability to prolong the residence time on the eye is desirable. Based on the acceptability of 2-hydroxyethyl methacrylate based polymers in contact lens applications, the current work focuses on the development of a poly(2-hydroxyethyl methacrylate (HEMA)) nanoparticle system. The particles were modified to allow for degradation and to permit mucoadhesion. Size and morphological analysis of the final polymer products showed that nano-sized, spherical particles were produced. FTIR spectra demonstrated that the nanoparticles comprised poly(HEMA) and that 3-(acrylamido)phenylboronic acid (3AAPBA), as a mucoadhesive, was successfully incorporated. Degradation of nanoparticles containing N,N′-bis(acryloyl)cystamine (BAC) after incubation with DL-dithiothreitol (DTT) was confirmed by a decrease in turbidity and through transmission electron microscopy (TEM). Nanoparticle mucoadhesion was shown through an in-vitro zeta potential analysis.

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Campylobacter jejuni 81-176 forms distinct microcolonies on in vitro-infected human small intestinal tissue prior to biofilm formation

Microbiology ◽

10.1099/mic.0.039867-0 ◽

2010 ◽

Vol 156 (10) ◽

pp. 3079-3084 ◽

Cited By ~ 24

Author(s):

Graham Haddock ◽

Margaret Mullin ◽

Amanda MacCallum ◽

Aileen Sherry ◽

Laurence Tetley ◽

...

Keyword(s):

Campylobacter Jejuni ◽

Biofilm Formation ◽

Target Tissue ◽

Apical Surface ◽

Intestinal Tissue ◽

Time Points ◽

Transmission Electron ◽

Large Numbers ◽

Ileal Tissue

Human small and large intestinal tissue was used to study the interaction of Campylobacter jejuni with its target tissue. The strain used for the study was 81-176 (+pVir). Tissue was processed for scanning and transmission electron microscopy, and by immunohistochemistry for light microscopy. Organisms adhered to the apical surface of ileal tissues at all time points in large numbers, in areas where mucus was present and in distinct groups. Microcolony formation was evident at 1–2 h, with bacteria adhering to mucus on the tissue surface and to each other by flagellar interaction. At later time points (3–4 h), biofilm formation on ileal tissue was evident. Flagellar mutants did not form microcolonies or biofilms in tissue. Few organisms were observed in colonic tissue, with organisms present but not as abundant as in the ileal tissue. This study shows that C. jejuni 81-176 can form microcolonies and biofilms on human intestinal tissue and that this may be an essential step in its ability to cause diarrhoea in man.

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In Vitro Synthesis of Calcium Nanoparticles Using the Protein Cage of Apoferritin

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.361-363.183 ◽

2007 ◽

Vol 361-363 ◽

pp. 183-186 ◽

Cited By ~ 1

Author(s):

Hiroko Fukano ◽

Mamoru Aizawa ◽

Hideyuki Yoshimura

Keyword(s):

Lattice Structure ◽

Spherical Particles ◽

Bulk Solution ◽

Mixed Solution ◽

In Vitro Synthesis ◽

Protein Cage ◽

Transmission Electron ◽

High Resolution Tem ◽

Calcium Compounds

Recently the creation of calcium compounds with a highly controlled ultrastructure is noted as next generation materials for biomedical applications. Here we propose the novel method for synthsizing calcium nanoparticles using iron strange protein, apoferritin. Apoferritin was incubated in saturated Ca(HCO3)2 solution at 18 °C. Temperature of the reaction solution was then increased to 37 °C and left for 2 hours to make CaCO3 sedimentated. After removing the sediments in the bulk solution by centrifugation, the supernatant was concentrated. Saturated Ca(HCO3)2 was added to it and the mixed solution was incubated at 37 °C for 30 min. This process was repeated four times. With a Transmission Electron Microscope (TEM), nearly spherical particles with a diameter of about 6 nm were observed to form in the cavity of apoferritin. The nanoparticles were observed to have a lattice structure of spacing about 0.22 nm with high resolution TEM. With Energy Dispersive X-ray spectroscopy (EDS) analysis, the peak of Ca (Kα; 3.7 keV) was detected from a synthesized nanoparticle. According to the solvent condition, nanoparticles formed in the apoferritin cavity would be CaCO3.

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Biosynthesis of Silver Nanoparticles and Their Biocontrol Potentials Against Aspergillus Niger and Fusarium Udum

10.21203/rs.3.rs-152979/v1 ◽

2021 ◽

Author(s):

Aneesh Sikka ◽

Triveni Sodimalla ◽

NAGARAJU YALAVARTHI

Keyword(s):

Silver Nanoparticles ◽

Aspergillus Niger ◽

Environmentally Benign ◽

Fusarium Udum ◽

Spherical Mean ◽

Transmission Electron ◽

Mean Size ◽

The Media ◽

Zeta Potential Analysis

Abstract Silver nanoparticles can be biosynthesized from bacteria, fungi, and plant extracts but due to their ability to synthesize nanoparticles in varying sizes and shapes at ease, bacterial has drawn interest. Bacterial based biosynthesis is effective, inexpensive, and simple thus, Pseudomonas fluorescence cell filtrates were used to synthesize silver nanoparticles in the present study. The chromatic shifts (yellow to brown) in the media after overnight incubation and the absorption of UV-Vis spectra at 420 nm confirmed the biosynthesis of AgNP’s. Besides that, the SPR analysis of AgNP’s showed a 400–500 nm band width, supporting the formation of silver nanoparticles and their small size with a uniform shape. AgNP’s transmission electron microscopy (TEM) images confirmed their shape as quasi spherical, mean size as 30 nm and anisotropy. From the Zeta potential analysis (-42.7 mV at pH = 7 with a single peak), highly repulsive nature of nanoparticles was confirmed. On the other hand, bio-fabricated silver nanoparticles were tested for antifungal activity against Fusarium udum and Aspergillus niger under in vitro conditions. At 150 ppm concentration of AgNP’s, Fusarium udum and Aspergillus niger were inhibited up to 100 and 80.50 %, respectively. In conclusion, synthesis of nanoparticle with aqueous Pseudomonas fluorescence extract is simple and environmentally benign.

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In Vitro Cytotoxicity of Mesoporous SiO2@Eu(OH)3Core-Shell Nanospheres in MCF-7

Journal of Nanomaterials ◽

10.1155/2016/7691861 ◽

2016 ◽

Vol 2016 ◽

pp. 1-6 ◽

Cited By ~ 6

Author(s):

M. Atif ◽

Muhammad Fakhar-e-Alam ◽

Najeeb Abbas ◽

Maqsood A. Siddiqui ◽

Anees A. Ansari ◽

...

Keyword(s):

Morphological Analysis ◽

Morphological Changes ◽

Sol Gel ◽

Average Diameter ◽

In Vitro Cytotoxicity ◽

Core Shell ◽

Clinical Approach ◽

Transmission Electron ◽

Mcf 7

Initially, the sample was synthesized by a modified sol-gel process. Morphological analysis of growth SiO2@Eu(OH)3was confirmed by applying field emission transmission electron microscopy (high and low resolution FETEM). The images confirmed the average diameter of mesoporous SiO2@Eu(OH)3core-shell nanospheres (~392–400 nm) with a silica core of ~230 nm in diameter and a shell composed of europium hydroxide ~162 nm (thickness). Moreover, an absorption band at 280 nm was confirmed which initiates from the europium hydroxide. The photoluminescence spectrum of the nanosphere was also recorded at ambient temperature under the excitation of 3.82 eV. Cytotoxic studies in vitro were performed by applying MTT, NR assays, and morphological analysis. Morphological changes and % loss in cellular viability was assessed in human breast cancer cells (MCF-7) labeled with mesoporous SiO2@Eu(OH)3core-shell nanospheres at different concentrations ranging from 10 µg/mL to 200 µg/mL. Current study demonstrates the quite rational strategy which might be useful in future clinical approach/applications.

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Maytansine-Induced Mitotic Arrest in Human Lymphoblasts

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100079747 ◽

1977 ◽

Vol 35 ◽

pp. 460-461

Author(s):

Tai-Te Chao ◽

John Sullivan ◽

Awtar Krishan

Keyword(s):

Electron Microscopy ◽

Cell Cycle ◽

Transmission Electron Microscopy ◽

Tubulin Polymerization ◽

Vinca Alkaloids ◽

Antimitotic Activity ◽

Transmission Electron ◽

Flow Microfluorometry ◽

Brain Tubulin

Maytansine, a novel ansa macrolide (1), has potent anti-tumor and antimitotic activity (2, 3). It blocks cell cycle traverse in mitosis with resultant accumulation of metaphase cells (4). Inhibition of brain tubulin polymerization in vitro by maytansine has also been reported (3). The C-mitotic effect of this drug is similar to that of the well known Vinca- alkaloids, vinblastine and vincristine. This study was carried out to examine the effects of maytansine on the cell cycle traverse and the fine struc- I ture of human lymphoblasts.Log-phase cultures of CCRF-CEM human lymphoblasts were exposed to maytansine concentrations from 10-6 M to 10-10 M for 18 hrs. Aliquots of cells were removed for cell cycle analysis by flow microfluorometry (FMF) (5) and also processed for transmission electron microscopy (TEM). FMF analysis of cells treated with 10-8 M maytansine showed a reduction in the number of G1 cells and a corresponding build-up of cells with G2/M DNA content.

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Correlation Between Cellular Functions and Morphological Changes of Human Trophoblast in Vitro

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100116620 ◽

1975 ◽

Vol 33 ◽

pp. 600-601

Author(s):

John C. Garancis ◽

Robert O. Hussa ◽

Michael T. Story ◽

Donald Yorde ◽

Roland A. Pattillo

Keyword(s):

Electron Microscopy ◽

Cellular Proliferation ◽

Morphological Changes ◽

Culture Fluid ◽

Cellular Functions ◽

Human Trophoblast ◽

Transmission Electron ◽

Marked Activity ◽

Malignant Trophoblast

Human malignant trophoblast cells in continuous culture were incubated for 3 days in medium containing 1 mM N6-O2'-dibutyryl cyclic adenosine 3':5'-monophosphate (dibutyryl cyclic AMP) and 1 mM theophylline. The culture fluid was replenished daily. Stimulated cultures secreted many times more chorionic gonadotropin and estrogens than did control cultures in the absence of increased cellular proliferation. Scanning electron microscopy revealed remarkable surface changes of stimulated cells. Control cells (not stimulated) were smooth or provided with varying numbers of microvilli (Fig. 1). The latter, usually, were short and thin. The surface features of stimulated cells were considerably different. There was marked increase of microvilli which appeared elongated and thick. Many cells were covered with confluent polypoid projections (Fig. 2). Transmission electron microscopy demonstrated marked activity of cytoplasmic organelles. Mitochondria were increased in number and size; some giant forms with numerous cristae were observed.

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Hemolysis of erythrocytes by the hemolytic system from the blood-feeding stable fly, Stomoxys calcitrans

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100123854 ◽

1992 ◽

Vol 50 (1) ◽

pp. 690-691

Author(s):

H. J. Kirch ◽

G. Spates ◽

R. Droleskey ◽

W.J. Kloft ◽

J.R. DeLoach

Keyword(s):

Blood Feeding ◽

Stomoxys Calcitrans ◽

Stable Fly ◽

Digestive Physiology ◽

Transmission Electron ◽

Erythrocyte Lysis ◽

Mammalian Blood ◽

Bovine Erythrocytes ◽

Potential Tool

Blood feeding insects have to rely on the protein content of mammalian blood to insure reproduction. A substantial quantity of protein is provided by hemoglobin present in erythrocytes. Access to hemoglobin is accomplished only via erythrocyte lysis. It has been shown that midgut homogenates from the blood feeding stable fly, Stomoxys calcitrans, contain free fatty acids and it was proposed that these detergent-like compounds play a major role as hemolysins in the digestive physiology of this species. More recently sphingomyelinase activity was detected in midgut preparations of this fly, which would provide a potential tool for the enzymatic cleavage of the erythrocyte's membrane sphingomyelin. The action of specific hemolytic factors should affect the erythrocyte's morphology. The shape of bovine erythrocytes undergoing in vitro hemolysis by crude midgut homogenates from the stable fly was examined by scanning and transmission electron microscopy.

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Application of Transmission Electron Microscope and Scanning Electron Microscope in experimental tumor studies

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100159084 ◽

1990 ◽

Vol 48 (3) ◽

pp. 306-307

Author(s):

Gao Fengming

Keyword(s):

Electron Microscope ◽

Scanning Electron Microscope ◽

Malignant Transformation ◽

Transmission Electron Microscope ◽

Experimental Tumor ◽

Transmission Electron ◽

Embryo Cells ◽

Tumor Studies ◽

Scanning Electron

Transmission electron microscope(TEM) and scanning electron microscope(SEM) were widely used in experimental tumor studies. They are useful for evaluation of cellular transformation in vitro, classification of histological types of tumors and treating effect of tumors. We have obtained some results as follows:1. Studies on the malignant transformation of mammalian cells in vitro. Syrian golden hamster embryo cells(SGHEC) were transformed in vitro by ThO2 and/or ore dust. In a few days after dust added into medium, some dust crystals were phagocytized. Two weeks later, malignant transformation took place. These cells were of different size, nuclear pleomorphism, numerous ribosomes, increasing of microvilli on cell surface with various length and thickness, and blebs and ruffles(Figs. 1,2). Myelomonocytic leukemic transformation of mouse embryo cells(MEC) was induced in vitro by 3H-TdR. Transformed cells were become round from fusiform. The number of mitochondria and endoplasmic reticulum was reduced, ribosomes and nucleoli increased, shape of nuclei irregular, microvilli increased, and blebs and ruffles appeared(Fig. 3).

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STEROID HORMONE METABOLISM IN RESPONSIVE TISSUES IN VITRO

Acta Endocrinologica ◽

10.1530/acta.0.068s279 ◽

1971 ◽

Vol 68 (1_Suppl) ◽

pp. S279-S294 ◽

Cited By ~ 12

Author(s):

Paul Robel

Keyword(s):

Steroid Hormone ◽

Physiological Activity ◽

Physiological State ◽

Target Cells ◽

Target Tissue ◽

Hormone Metabolism ◽

Metabolizing Enzymes ◽

Relationship Of

ABSTRACT Of the information available on steroid hormone metabolism in responsive tissues, only that relating hormone metabolism to physiological activity is reviewed, i. e. metabolite activity in isolated in vitro systems, binding of metabolites to target tissue receptors, specific steroid hormone metabolizing enzymes and relationship of hormone metabolism to target organ physiological state. Further, evidence is presented in the androgen field, demonstrating 5α-reduced metabolites, formed inside the target cells, as active compounds. This has led to a consideration of testosterone as a »prehormone«. The possibility that similar events take place in tissues responding to progesterone is discussed. Finally, the role of hormone metabolism in the regulation of hormone availability and/or renewal in target cells is discussed. In this context, reference is made to the potential role of plasma binding proteins and cytosol receptors.

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EVALUATION OF TISSUE STEROID BINDING IN VITRO

Acta Endocrinologica ◽

10.1530/acta.0.068s223 ◽

1971 ◽

Vol 68 (1_Suppl) ◽

pp. S223-S246 ◽

Cited By ~ 2

Author(s):

C. R. Wira ◽

H. Rochefort ◽

E. E. Baulieu

Keyword(s):

Protein Binding ◽

Binding Sites ◽

Experimental System ◽

Specific Protein ◽

Coupling Mechanism ◽

Target Tissue ◽

Protein Binding Sites ◽

Definition Of ◽

Hormone Specificity

ABSTRACT The definition of a RECEPTOR* in terms of a receptive site, an executive site and a coupling mechanism, is followed by a general consideration of four binding criteria, which include hormone specificity, tissue specificity, high affinity and saturation, essential for distinguishing between specific and nonspecific binding. Experimental approaches are proposed for choosing an experimental system (either organized or soluble) and detecting the presence of protein binding sites. Techniques are then presented for evaluating the specific protein binding sites (receptors) in terms of the four criteria. This is followed by a brief consideration of how receptors may be located in cells and characterized when extracted. Finally various examples of oestrogen, androgen, progestagen, glucocorticoid and mineralocorticoid binding to their respective target tissues are presented, to illustrate how researchers have identified specific corticoid and mineralocorticoid binding in their respective target tissue receptors.

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