Hollow Microcapsules Through Layer-by-Layer Self-Assembly of Chitosan/Alginate on E. coli

MRS Advances ◽  
2020 ◽  
Vol 5 (46-47) ◽  
pp. 2401-2407
Author(s):  
Michael Y. Yitayew ◽  
Maryam Tabrizian
Keyword(s):  
Quantum Dots ◽  
Self Assembly ◽  
Layer By Layer ◽  
E Coli ◽  
Fluorescence Measurements ◽  
Transmission Electron ◽  
Imaging Probes ◽  
Delivery Platform ◽  
20 Nm

AbstractHollow microcapsules prepared via layer-by-layer (LbL) self-assembled polyelectrolytes are prevalent biomaterials in the synthesis of biocompatible delivery systems for drugs, imaging probes, and other macromolecules to control biodistribution and lower toxicity in vivo. The use of LbL self-assembly for the synthesis of these capsules provides several benefits including ease of fabrication, abundance in choice of substrates and coating material, as well as application-specific tunability. This study explores the development of hollow microcapsules by LbL assembly of chitosan and alginate onto live E. coli cells, and also provides a proof-of-concept of this capsule as a delivery platform through the encapsulation of quantum dots as a cargo. The study found that robust bilayers of chitosan/alginate can be formed onto the core substrate (E. coli) containing quantum dots as demonstrated with zeta potential analysis. Confocal microscopy was used to verify cell viability and the internalization of quantum dots into the cells as well as confirmation of the coating using fluorescein-labelled chitosan. Furthermore, transmission electron microscopy (TEM) was used to analyse cells coated with four-bilayers and showed a uniform coating morphology with a capsule thickness of 10-20 nm, which increased to 20-50 nm for hollow capsules after cell lysis. Quantum dot retention in the capsules was demonstrated using fluorescence measurements. Overall, the study shows promising results of a novel fabrication method for hollow microcapsules that uses biocompatible polymers and mild core dissolution conditions using cell templates with applications in sustained release of therapeutics and imaging probes.

Synthesis and Characterization of Electrostatical Self-Assembly CdSe/Polymer Nanocomposite Films

2002 ◽  
Vol 733 ◽  
Author(s):  
Liangmin Zhang ◽  
Fajian Zhang ◽  
R. O. Claus
Keyword(s):  
Quantum Dots ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Polymer Nanocomposite ◽  
Nanocomposite Films ◽  
Cdse Quantum Dots ◽  
Layer By Layer ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

AbstractUsing a novel electrostatic self-assembly (ESA) method to incorporate CdSe quantum dots into polymer we have successfully synthesized ultrathin films. This method allows the molecular-level thickness control and layer-by-layer formation of multilayer thin and thick films using alternative anionic and cationic molecular solution dipping. From ellipsometric measurements, we obtained that the thickness of per bilayer is around 3.7 nm. UV-vis absorption spectra versus the number of bilayers have also been obtained using an Hitachi 2001 spectrometer. The size of CdSe quantum dots has been measured using transmission electron microscopy before the CdSe quantum dots are incorporated and confirmed using atomic force microscopy after the formation of the film, respectively. Both measurements indicate that the diameter of the CdSe quantum dots is 2-3 nm. Xray photoelectron spectroscopy indicates that the concentration of the CdSe quantum dots in the film is 2.14%.

scholarly journals Synthesis, Formulation, and Adjuvanticity of Monodesmosidic Saponins with Olenanolic Acid, Hederagenin and Gypsogenin Aglycones, and some C-28 Ester Derivatives

2020 ◽  
Author(s):  
BW Greatrex ◽  
Alison Daines ◽  
S Hook ◽  
DH Lenz ◽  
W McBurney ◽  
...  
Keyword(s):  
Mhc Class Ii ◽  
Self Assembly ◽  
Vaccine Adjuvant ◽  
Choline Ester ◽  
Activation Markers ◽  
Murine Bone Marrow ◽  
Transmission Electron ◽  
High Concentrations ◽  
Sugar Stereochemistry

© 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. In an attempt to discover a new synthetic vaccine adjuvant, the glycosylation of hederagenin, gypsogenin, and oleanolic acid acceptors with di- and trisaccharide donors to generate a range of mimics of natural product QS-21 was carried out. The saponins were formulated with phosphatidylcholine and cholesterol, and the structures analyzed by transmission electron microscopy. 3-O-(Manp(1→3)Glcp)hederagenin was found to produce numerous ring-like micelles when formulated, while C-28 choline ester derivatives preferred self-assembly and did not interact with the liposomes. When alone and in the presence of cholesterol and phospholipid, the choline ester derivatives produced nanocrystalline rods or helical micelles. The effects of modifying sugar stereochemistry and the aglycone on the immunostimulatory effects of the saponins was then evaluated using the activation markers MHC class II and CD86 in murine bone marrow dendritic cells. The most active saponin, 3-O-(Manp(1→3)Glcp)hederagenin, was stimulatory at high concentrations in cell culture, but this did not translate to strong responses in vivo.

GFP Plasmid and Chemoreagent Conjugated with Graphene Quantum Dots as a Novel Gene Delivery Platform for Colon Cancer Inhibition In Vitro and In Vivo

2020 ◽  
Vol 3 (9) ◽  
pp. 5948-5956
Author(s):  
Pei-Ying Lo ◽  
Guang-Yu Lee ◽  
Jia-Huei Zheng ◽  
Jen-Hsien Huang ◽  
Er-Chieh Cho ◽  
...  
Keyword(s):  
Colon Cancer ◽  
Quantum Dots ◽  
Gene Delivery ◽  
Graphene Quantum Dots ◽  
Novel Gene ◽  
Delivery Platform ◽  
Cancer Inhibition

Preparation and Chromatic Properties of Encapsulated Carbon Black Pigment via Layer-by-Layer Self-Assembly Method

2015 ◽  
Vol 1104 ◽  
pp. 15-20 ◽  
Author(s):  
Xiao Jun Zhang ◽  
Ting Chen ◽  
Wei Hui Jiang ◽  
Jian Min Liu ◽  
Tong Qing Zhou
Keyword(s):  
Carbon Black ◽  
Self Assembly ◽  
Black Pigment ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
Assembly Method ◽  
Transmission Electron ◽  
Color System ◽  
Chromatic Properties ◽  
Cie Color System

Encapsulated carbon black pigment was prepared by layer-by-layer self-assembly method. The RX8002 carbon black particles were well coated by a SiO2 layer, which makes it has good connection with ZrSiO4 layer. Meanwhile, dense ZrSiO4 layer was coated on the C@SiO2 particles surface to prevent the corrosive effects of glaze. The structure and morphology of samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The chromatic value of the pigments was measured by the CIE color system. The results show that the carbon black particles can be well coated by SiO2 and ZrSiO4 layer. When the TEOS/H2O ratio is 0.002 and the ZrSiO4/C ratio is 0.71, the chromatic value of the encapsulated carbon black pigment is 42.55, and the pigment has a good stability in glaze.

Electrorheological Properties of Carbon Nanotube/Polyelectrolyte Composite Silica Nanoparticles by Layer-by-Layer Self-Assembly

2008 ◽  
Vol 8 (8) ◽  
pp. 3895-3899
Author(s):  
Byung-Soo Kim ◽  
Bumsu Kim ◽  
Kyung-Do Suh
Keyword(s):  
Electric Fields ◽  
Self Assembly ◽  
Multiwall Carbon Nanotubes ◽  
Chemical Oxidation ◽  
Composite Particles ◽  
Layer By Layer ◽  
Assembly Method ◽  
Transmission Electron ◽  
Zeta Potential Analysis ◽  
Electrorheological Properties

Multiwall carbon nanotubes (MCNTs)/silica (SiO2) composite particles were prepared by layer-by-layer (LbL) self-assembly method using polyelectrolytes and functionalized MCNTs (fMCNTs). The fMCNTs prepared by chemical oxidation method were incorporated on the outermost layer of polyelectrolyte-coated SiO2 particles. The amount of fMCNTs was varied by LbL self assembly. In the process the number of fMCNT layers on SiO2 particles could be controlled. The fMCNT-coated SiO2 particles were characterized by zeta-potential analysis, transmission electron microscopy (TEM), and optical microscopy (OM). In addition, the electrorheological (ER) properties of multilayers containing fMCNTs on silica particles were investigated under controlled electric fields. The ER properties of the composite particles were influenced by the amount of fMCNTs in multilayers.

scholarly journals Evaluation of optically tailored fluorescent silicon quantum dots for bioimaging of the tear film

2020 ◽  
Author(s):  
Sidra Sarwat ◽  
Fiona Jane Stapleton ◽  
Mark Duncan Perry Willcox ◽  
Peter B O’Mara ◽  
Richard D Tilley ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Transient Absorption ◽  
Imaging System ◽  
Tear Film ◽  
Silicon Quantum Dots ◽  
Transmission Electron ◽  
Custom Made ◽  
Average Size

This experimental study aimed to investigate the feasibility of using silicon quantum dots doped with transition metals: scandium, copper and zinc as contrast agents for eventual application for the study of the tear film in eyes. Si-QDs were synthesized and characterized by transmission electron microscopy, photoluminescence, absorbance and transient absorption measurements. The fluorescence of Si-QDs was investigated when combined with TheraTears® (a balanced electrolyte formula for dry eye therapy). An optical imaging system composed of a modified slit lamp biomicroscope combined with a high-resolution Zyla sCMOS camera, SOLIS software, custom-made optical mounts and emission filters (460 nm, 510 nm and 530 nm) were used for in vitro imaging of Si-QDs with TheraTears®. The average size of Si-QDs was 2.65 nm. In vitro imaging of Sc-Si-QDs and Cu-Si-QDs indicated their stable and bright fluorescence with TheraTears®. Sc-Si-QDs were significantly brighter compared to Cu-Si-QDs and Zn-Si-QDs, and the Zn-Si-QDs showed a tendency to clump in TheraTears®. The fluorescence of the Si-QDs was detected down to a concentration of 0.01 µg/mL within a total volume of 5 µL. Cu-Si-QDs and Sc-Si-QDs showed brighter fluorescence than Zn-Si-QDs. However, Zn-Si-QDs and to a lesser extent, Cu-Si-QDs showed some aggregation at specific concentrations. Sc-Si-QDs are proposed as a better option for further development as an in vivo bioimaging agent to study the tear film dynamics.

scholarly journals Construction and Characterizations of Antibacterial Surfaces Based on Self-Assembled Monolayer of Antimicrobial Peptides (Pac-525) Derivatives on Gold

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1014
Author(s):  
Zijiao Zhang ◽  
Ni Kou ◽  
Weilong Ye ◽  
Shuo Wang ◽  
Jiaju Lu ◽  
...  
Keyword(s):  
Antimicrobial Peptides ◽  
Self Assembly ◽  
The Self ◽  
Self Assembled Monolayer ◽  
E Coli ◽  
Antimicrobial Efficiency ◽  
Gold Substrates ◽  
Self Assembled ◽  
Antibacterial Surfaces

Background: Infection that is related to implanted biomaterials is a serious issue in the clinic. Antimicrobial peptides (AMPs) have been considered as an ideal alternative to traditional antibiotic drugs, for the treatment of infections, while some problems, such as aggregation and protein hydrolysis, are still the dominant concerns that compromise their antimicrobial efficiency in vivo. Methods: In this study, antimicrobial peptides underwent self-assembly on gold substrates, forming good antibacterial surfaces, with stable antibacterial behavior. The antimicrobial ability of AMPs grafted on the surfaces, with or without glycine spaces or a primer layer, was evaluated. Results: Specifically, three Pac-525 derivatives, namely, Ac-CGn-KWRRWVRWI-NH2 (n = 0, 2, or 6) were covalently grafted onto gold substrates via the self-assembling process for inhibiting the growth of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Furthermore, the alkanethiols HS(CH)10SH were firstly self-assembled into monolayers, as a primer layer (SAM-SH) for the secondary self-assembly of Pac-525 derivatives, to effectively enhance the bactericidal performance of the grafted AMPs. The -(CH)10-S-S-G6Pac derivative was highly effective against S. aureus and E. coli, and reduced the viable amount of E. coli and S. aureus to 0.4% and 33.2%, respectively, after 24 h of contact. In addition, the immobilized AMPs showed good biocompatibility, promoting bone marrow stem cell proliferation. Conclusion: the self-assembled monolayers of the Pac-525 derivatives have great potential as a novel therapeutic method for the treatment of implanted biomaterial infections.

DYNAMIC BEHAVIOR OF METHYLENE BLUE ON E. coli K30 CAPSULAR POLYSACCHARIDE USING LAYER BY LAYER SELF-ASSEMBLY TECHNIQUE

2020 ◽  
pp. 2050027
Author(s):  
BANDANA DAS ◽  
ALPANA BAIDYA ◽  
SANTANU MAJUMDER ◽  
RANENDU KUMAR NATH
Keyword(s):  
Thin Film ◽  
Methylene Blue ◽  
Dynamic Behavior ◽  
Self Assembly ◽  
Capsular Polysaccharide ◽  
Layer By Layer ◽  
Cationic Dye ◽  
Bacterial Polysaccharide ◽  
E Coli ◽  
Assembly Technique

Layer-by-layer (LbL) self-assembly is one of the unique methods for fabrication of ultra-thin film. This technique has immense application aross many fields in today’s life. In this paper, we have presented the fabrication of the thin film comprising of antifungal and antibacterial cationic dye methylene blue with negatively charged E. coli K30 bacterial polysaccharide sharing with PAH. The multilayers were characterized by UV–Vis absorption spectra and AFM. Various photophysical behaviors were investigated. Such studies provide a new light in the research of layer by layer self-assembly technique.

Sign in / Sign up

Export Citation Format

Share Document