scholarly journals pH-Responsive Hollow Polymeric Microspheres from Irradiated Cyclic Ether Aqueous Solution

2021 ◽  
Vol 11 (18) ◽  
pp. 8652
Author(s):  
Chuhong Yu ◽  
Jing Peng ◽  
Jiuqiang Li ◽  
Maolin Zhai
Keyword(s):  
Aqueous Solution ◽  
Laser Scanning ◽  
Average Diameter ◽  
Cyclic Ether ◽  
Oil Field ◽  
Hollow Microspheres ◽  
Confocal Laser ◽  
Ph Responsive ◽  
Polymeric Microspheres ◽  
Wide Range

Smart hollow polymeric microspheres have been widely applied in various fields such as controlled release, drug delivery, catalysis, and so on. Herein, a facile, green and one-step template-free method is introduced for preparing pH-responsive hollow polymeric microspheres via gamma irradiation of cyclic ether aqueous solution. The hollow polymeric microspheres are synthesized by radiation-induced polymerization and following the self-assembly and self-organization of amphiphilic polymer with cyclic ethers as monomers in water. SEM, TEM, micro-FTIR, and NMR confirmed the morphology and structures of the resultant microspheres. The confocal laser scanning microscope was used to investigate the stimuli-responsiveness and release behavior of hollow microspheres using 1-pyrene carboxaldehyde as a hydrophobic molecule model. The well-defined hollow polymeric microspheres with an average diameter of ca. 2.6 μm or 1.6 μm were prepared directly from dicyclohexal-18-crown-6 or tetraphydropyrane aqueous solution, respectively. The prepared hollow microspheres exhibit obvious pH stimuli-responsiveness and can release the encapsulated hydrophobic molecules when pH is higher than 5.0. Moreover, the reversible morphology transition between hollow microspheres and micelles makes the prepared hollow polymeric microspheres potentially suitable for a wide range of applications, including removal of dyes, oil field engineering, and biomedical fields.

scholarly journals Intracellular Macromolecular Mobility Measured by Fluorescence Recovery after Photobleaching with Confocal Laser Scanning Microscopes

2004 ◽  
Vol 15 (10) ◽  
pp. 4749-4760 ◽  
Author(s):  
José Braga ◽  
Joana M.P. Desterro ◽  
Maria Carmo-Fonseca
Keyword(s):  
Aqueous Solution ◽  
Diffusion Coefficients ◽  
Laser Scanning ◽  
Fluorescence Recovery After Photobleaching ◽  
Fluorescent Protein ◽  
Confocal Laser Scanning ◽  
Fluorescence Recovery ◽  
Confocal Laser ◽  
Wide Range ◽  
Green Fluorescent

Fluorescence recovery after photobleaching (FRAP) is a widely used tool for estimating mobility parameters of fluorescently tagged molecules in cells. Despite the widespread use of confocal laser scanning microscopes (CLSMs) to perform photobleaching experiments, quantitative data analysis has been limited by lack of appropriate practical models. Here, we present a new approximate FRAP model for use on any standard CLSM. The main novelty of the method is that it takes into account diffusion of highly mobile molecules during the bleach phase. In fact, we show that by the time the first postbleach image is acquired in a CLSM a significant fluorescence recovery of fast-moving molecules has already taken place. The model was tested by generating simulated FRAP recovery curves for a wide range of diffusion coefficients and immobile fractions. The method was further validated by an experimental determination of the diffusion coefficient of fluorescent dextrans and green fluorescent protein. The new FRAP method was used to compare the mobility rates of fluorescent dextrans of 20, 40, 70, and 500 kDa in aqueous solution and in the nucleus of living HeLa cells. Diffusion coefficients were lower in the nucleoplasm, particularly for higher molecular weight dextrans. This is most likely caused by a sterical hindrance effect imposed by nuclear components. Decreasing the temperature from 37 to 22°C reduces the dextran diffusion rates by ∼30% in aqueous solution but has little effect on mobility in the nucleoplasm. This suggests that spatial constraints to diffusion of dextrans inside the nucleus are insensitive to temperature.

scholarly journals One-step preparation of antimicrobial silicone materials based on PDMS and salicylic acid: insights from spatially and temporally resolved techniques

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Luca Barbieri ◽  
Ioritz Sorzabal Bellido ◽  
Alison J. Beckett ◽  
Ian A. Prior ◽  
Jo Fothergill ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Laser Scanning ◽  
Pathogenic Bacteria ◽  
Pharmaceutical Products ◽  
Laser Scanning Microscopy ◽  
Wound Dressings ◽  
Confocal Laser ◽  
Vis Spectroscopy ◽  
Wide Range ◽  
One Step

AbstractIn this work, we introduce a one-step strategy that is suitable for continuous flow manufacturing of antimicrobial PDMS materials. The process is based on the intrinsic capacity of PDMS to react to certain organic solvents, which enables the incorporation of antimicrobial actives such as salicylic acid (SA), which has been approved for use in humans within pharmaceutical products. By combining different spectroscopic and imaging techniques, we show that the surface properties of PDMS remain unaffected while high doses of the SA are loaded inside the PDMS matrix. The SA can be subsequently released under physiological conditions, delivering a strong antibacterial activity. Furthermore, encapsulation of SA inside the PDMS matrix ensured a diffusion-controlled release that was tracked by spatially resolved Raman spectroscopy, Attenuated Total Reflectance IR (ATR-IR), and UV-Vis spectroscopy. The biological activity of the new material was evaluated directly at the surface and in the planktonic state against model pathogenic bacteria, combining confocal laser scanning microscopy, electron microscopy, and cell viability assays. The results showed complete planktonic inhibition for clinically relevant strains of Staphylococcus aureus and Escherichia coli, and a reduction of up to 4 orders of magnitude for viable sessile cells, demonstrating the efficacy of these surfaces in preventing the initial stages of biofilm formation. Our approach adds a new option to existing strategies for the antimicrobial functionalisation of a wide range of products such as catheters, wound dressings and in-dwelling medical devices based on PDMS.

scholarly journals Astrogliosis in an Experimental Model of Hypovitaminosis B12: A Cellular Basis of Neurological Disorders due to Cobalamin Deficiency

Cells ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 2261
Author(s):  
Zuzanna Rzepka ◽  
Jakub Rok ◽  
Justyna Kowalska ◽  
Klaudia Banach ◽  
Justyna Magdalena Hermanowicz ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Cobalamin Deficiency ◽  
Confocal Laser ◽  
In Vivo Model ◽  
Cellular Expression ◽  
Wide Range ◽  
Vitro Model

Cobalamin deficiency affects human physiology with sequelae ranging from mild fatigue to severe neuropsychiatric abnormalities. The cellular and molecular aspects of the nervous system disorders associated with hypovitaminosis B12 remain largely unknown. Growing evidence indicates that astrogliosis is an underlying component of a wide range of neuropathologies. Previously, we developed an in vitro model of cobalamin deficiency in normal human astrocytes (NHA) by culturing the cells with c-lactam of hydroxycobalamin (c-lactam OH-Cbl). We revealed a non-apoptotic activation of caspases (3/7, 8, 9) in cobalamin-deficient NHA, which may suggest astrogliosis. The aim of the current study was to experimentally verify this hypothesis. We indicated an increase in the cellular expression of two astrogliosis markers: glial fibrillary acidic protein and vimentin in cobalamin-deficient NHA using Western blot analysis and immunocytochemistry with confocal laser scanning microscopy. In the next step of the study, we revealed c-lactam OH-Cbl as a potential non-toxic vitamin B12 antagonist in an in vivo model using zebrafish embryos. We believe that the presented results will contribute to a better understanding of the cellular mechanism underlying neurologic pathology due to cobalamin deficiency and will serve as a foundation for further studies.

Preparation, Characterization and Properties Evaluation of Buprofezin Nanocomposites Obtained by Polyelectrolytes Assembly

2011 ◽  
Vol 183-185 ◽  
pp. 1677-1681 ◽  
Author(s):  
Zhe Zhang ◽  
De Fu Chi ◽  
Jia Yu
Keyword(s):  
Laser Scanning ◽  
Orthogonal Experiment ◽  
Drug Loading ◽  
In Vitro Release ◽  
Average Diameter ◽  
Laser Scanning Microscopy ◽  
Release Time ◽  
Confocal Laser ◽  
Layer By Layer

Buprofezin (BPF) microcrystals were directly encapsulated with nature polysaccharides chitosan (CHI) and sodium alginate (ALG) through layer-by-layer (LbL) self-assembly. The coated colloids were characterized using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The surface of the coated microcrystal was smoothened and the coating was uniform. Different concentrations of the ALG, CHI, BPF and CaCl2 were selected as the influencing factors, and then, the microcapsules were optimized by orthogonal experiment. The size distribution of microcapsules was determined by Laser Diffraction Size Analyzer. It showed statistically normal distribution. The average diameter of BPF was 1.5m. The encapsulation efficiency of the BPF loaded microparticles was about 67.2±0.73%. The drug loading content was about 66.7±0.31% after encapsulated. The in vitro release experiments revealed that the polyelectrolytes prolonged the release time of the encapsulated BPF microcrystals.

scholarly journals Magnetic poly(ε-caprolactone)/iron-doped hydroxyapatite nanocomposite substrates for advanced bone tissue engineering

2013 ◽  
Vol 10 (80) ◽  
pp. 20120833 ◽  
Author(s):  
A. Gloria ◽  
T. Russo ◽  
U. D'Amora ◽  
S. Zeppetelli ◽  
T. D'Alessandro ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Laser Scanning ◽  
Magnetic Measurements ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Hyperthermia Treatment ◽  
Wide Range ◽  
Iron Doped

In biomedicine, magnetic nanoparticles provide some attractive possibilities because they possess peculiar physical properties that permit their use in a wide range of applications. The concept of magnetic guidance basically spans from drug delivery and hyperthermia treatment of tumours, to tissue engineering, such as magneto-mechanical stimulation/activation of cell constructs and mechanosensitive ion channels, magnetic cell-seeding procedures, and controlled cell proliferation and differentiation. Accordingly, the aim of this study was to develop fully biodegradable and magnetic nanocomposite substrates for bone tissue engineering by embedding iron-doped hydroxyapatite (FeHA) nanoparticles in a poly(ε-caprolactone) (PCL) matrix. X-ray diffraction analyses enabled the demonstration that the phase composition and crystallinity of the magnetic FeHA were not affected by the process used to develop the nanocomposite substrates. The mechanical characterization performed through small punch tests has evidenced that inclusion of 10 per cent by weight of FeHA would represent an effective reinforcement. The inclusion of nanoparticles also improves the hydrophilicity of the substrates as evidenced by the lower values of water contact angle in comparison with those of neat PCL. The results from magnetic measurements confirmed the superparamagnetic character of the nanocomposite substrates, indicated by a very low coercive field, a saturation magnetization strictly proportional to the FeHA content and a strong history dependence in temperature sweeps. Regarding the biological performances, confocal laser scanning microscopy and AlamarBlue assay have provided qualitative and quantitative information on human mesenchymal stem cell adhesion and viability/proliferation, respectively, whereas the obtained ALP/DNA values have shown the ability of the nanocomposite substrates to support osteogenic differentiation.

Interspecies Uptake of Polymeric Microspheres

1998 ◽  
Vol 550 ◽  
Author(s):  
Chris Thanos ◽  
Maryellen Sandor ◽  
Yong Jong ◽  
Jules Jacob ◽  
Kay-Pong Yip ◽  
...  
Keyword(s):  
Light Microscopy ◽  
Laser Scanning ◽  
Polarized Light ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Optical Sectioning ◽  
Intestinal Tissue ◽  
Polymeric Microspheres ◽  
Particle Uptake

AbstractParticle uptake into intestinal tissue has seen increasing attention due to its implications in drug delivery. We attempted to observe a delivery system in vivo and examine uptake in different species. Microspheres were fabricated from polymers including polyanhydrides and delivered to an isolated loop of intestine in several species. The microspheres contained a dye either conjugated to a protein or incorporated freely and were used to qualitatively detect and locate the spheres in the villi of the length of the small intestine. Microspheres were dispersed, sized by a Coulter particle size analyzer, and characterized by confocal and cross-polarized light microscopy, FTIR and SEM. Coulter analysis revealed microspheres to be generally less than 5 microns in diameter. SEM typically showed homogeneous morphology among groups of microspheres. In vivo uptake experiments were performed in rodents, pigs, and ruminants using various microsphere formulations. Microspheres were delivered into the proximal end of the jejunum of anesthetized animals and allowed adequate transit time to be taken up. Animals were euthanized at various time points for explantation of tissue and sampling of blood. Excised samples were embedded inq polyvinyl alcohol, frozen, and cut into sections ranging between 7 and 14 μm in thickness. Our method of incorporating dyes allowed for simultaneous visualization by visible light microscopy and confocal laser scanning microscopy. Two-fluorochrome fluorescence of the microspheres and optical sectioning confirmed the presence of microspheres within intestinal tissue. The amount of uptake depended on the animal model, the duration of the experiment, and the composition of the microsphere. An assay for either the fluorescent dye, the protein attached to it, or the polymer encapsulating it may enable us to determine intracellular concentrations of mierospheres for the quantification of uptake.

scholarly journals Self-Assembly System Based on Cyclodextrin for Targeted Delivery of Cannabidiol

2021 ◽  
Vol 9 ◽  
Author(s):  
Panyong Zhu ◽  
Pin Lv ◽  
Yazhou Zhang ◽  
Rongqiang Liao ◽  
Jing Liu ◽  
...  
Keyword(s):  
Inclusion Complex ◽  
Anticancer Activity ◽  
Targeted Delivery ◽  
Laser Scanning ◽  
Water Solubility ◽  
Cannabis Sativa ◽  
Human Cancer ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Wide Range

Cannabidiol (CBD) is one specific kind of the cannabinoid in Cannabis sativa L with a wide range of pharmacological activities. However, the poor water solubility and specificity of CBD limits its application in pharmaceutical field. For solving these problems, in this work, we successfully prepared a targeted carrier by grafting biotin (BIO) onto ethylenediamine-β-Cyclodextrin (EN-CD) in a single step to generate a functionalized supramolecule, named BIO-CD. Subsequently, an amantadine-conjugated cannabinoids (AD-CBD) was prepared and self-assembled with the BIO-CD. A series of methods were used to characterize the inclusion behavior and physicochemical properties of AD-CBD and BIO-CD. The results showed that AD-CBD entered the cavity of BIO-CD and formed a 1:1 host-guest inclusion complex. MTT assay and confocal laser scanning microscopy (CLSM) revealed that the targeting effect and anticancer activity of AD-CBD/BIO-CD inclusion complex against three human cancer cell lines were higher than BIO-CD, AD-CBD and free CBD. Moreover, the inclusion complex could release drugs under weakly acidic conditions. These results demonstrated that AD-CBD/BIO-CD inclusion complex possess excellent targeted and anticancer activity, which is hopeful to be applied in clinic as a new therapeutic approach.

scholarly journals Cell-to-Cell Signaling in Xylella fastidiosa Suppresses Movement and Xylem Vessel Colonization in Grape

2008 ◽  
Vol 21 (10) ◽  
pp. 1309-1315 ◽  
Author(s):  
Subhadeep Chatterjee ◽  
Karyn L. Newman ◽  
Steven E. Lindow
Keyword(s):  
Cell Signaling ◽  
Type Strain ◽  
Laser Scanning ◽  
Wild Type Strain ◽  
Xylella Fastidiosa ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Deficient Mutant ◽  
Wild Type ◽  
Wide Range

Cell-to-cell signaling mediated by a fatty acid diffusible signaling factor (DSF) is central to the regulation of the virulence of Xylella fastidiosa. DSF production by X. fastidiosa is dependent on rpfF and, although required for insect colonization, appears to reduce its virulence to grape. To understand what aspects of colonization of grape are controlled by DSF in X. fastidiosa and, thus, those factors that contribute to virulence, we assessed the colonization of grape by a green fluorescent protein–marked rpfF-deficient mutant. The rpfF-deficient mutant was detected at a greater distance from the point of inoculation than the wild-type strain at a given sampling time, and also attained a population size that was up to 100-fold larger than that of the wild-type strain at a given distance from the point of inoculation. Confocal laser-scanning microscopy revealed that approximately 10-fold more vessels in petioles of symptomatic leaves harbored at least some cells of either the wild type or rpfF mutant when compared with asymptomatic leaves and, thus, that disease symptoms were associated with the extent of vessel colonization. Importantly, the rpfF mutant colonized approximately threefold more vessels than the wild-type strain. Although a wide range of colony sizes were observed in vessels colonized by both the wild type and rpfF mutant, the proportion of colonized vessels harboring large numbers of cells was significantly higher in plants inoculated with the rpfF mutant than with the wild-type strain. These studies indicated that the hypervirulence phenotype of the rpfF mutant is due to both a more extensive spread of the pathogen to xylem vessels and unrestrained multiplication within vessels leading to blockage. These results suggest that movement and multiplication of X. fastidiosa in plants are linked, perhaps because cell wall degradation products are a major source of nutrients. Thus, DSF-mediated cell-to-cell signaling, which restricts movement and colonization of X. fastidiosa, may be an adaptation to endophytic growth of the pathogen that prevents the excessive growth of cells in vessels.

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