How do different surface modification strategies affect the properties of MnO nanoparticles for biomedical applications? Comparison of PEGylated and SiO2-coated MnO nanoparticles

2011 ◽  
Vol 1355 ◽  
Author(s):  
Thomas D. Schladt ◽  
Kerstin Koll ◽  
Heiko Bauer ◽  
Stefan Weber ◽  
Laura M. Schreiber ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Biomedical Applications ◽  
Silica Shell ◽  
Longitudinal Relaxation Time ◽  
Poly Ethylene Glycol ◽  
Cytotoxic Potential ◽  
Long Term Stability ◽  
Novel Approach ◽  
Poly Ethylene

ABSTRACTMnO nanoparticles (NPs) were surface functionalized by two different approaches, (1) using a dopamine-poly(ethylene glycol) (PEG) (DA-PEG) ligand and (2) by encapsulation within a thin silica shell applying a novel approach. Both MnO@DA-PEG and MnO@SiO2 NPs exhibited excellent long-term stability in physiological solutions. In addition, the cytotoxic potential of both materials was comparatively low. Furthermore, owing to the magnetic properties of MnO NPs, both MnO@DA-PEG and MnO@SiO2 lead to a shortening of the longitudinal relaxation time T1 in MRI. In comparison to the PEGylated MnO NPs, the presence of a thin silica shell led to a greater stability of the MnO core itself by preventing excessive Mn ion leaching into aqueous solution.

scholarly journals Poly(ethylene glycol)-b-poly(1,3-trimethylene carbonate) Copolymers for the Formulation of In Situ Forming Depot Long-Acting Injectables

Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 605
Author(s):  
Marie-Emérentienne Cagnon ◽  
Silvio Curia ◽  
Juliette Serindoux ◽  
Jean-Manuel Cros ◽  
Feifei Ng ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Surface Erosion ◽  
Sustained Delivery ◽  
Trimethylene Carbonate ◽  
Poly Ethylene Glycol ◽  
In Situ Forming ◽  
Poly Ethylene ◽  
Long Acting

This article describes the utilization of (methoxy)poly(ethylene glycol)-b-poly(1,3-trimethylene carbonate) ((m)PEG–PTMC) diblock and triblock copolymers for the formulation of in situ forming depot long-acting injectables by solvent exchange. The results shown in this manuscript demonstrate that it is possible to achieve long-term drug deliveries from suspension formulations prepared with these copolymers, with release durations up to several months in vitro. The utilization of copolymers with different PEG and PTMC molecular weights affords to modulate the release profile and duration. A pharmacokinetic study in rats with meloxicam confirmed the feasibility of achieving at least 28 days of sustained delivery by using this technology while showing good local tolerability in the subcutaneous environment. The characterization of the depots at the end of the in vivo study suggests that the rapid phase exchange upon administration and the surface erosion of the resulting depots are driving the delivery kinetics from suspension formulations. Due to the widely accepted utilization of meloxicam as an analgesic drug for animal care, the results shown in this article are of special interest for the development of veterinary products aiming at a very long-term sustained delivery of this therapeutic molecule.

scholarly journals Long-Term Stability of Different Kinds of Gas Nanobubbles in Deionized and Salt Water

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1808
Author(s):  
Yali Zhou ◽  
Zhenyao Han ◽  
Chunlin He ◽  
Qin Feng ◽  
Kaituo Wang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Bubble Size ◽  
Ostwald Ripening ◽  
Salt Water ◽  
Dlvo Theory ◽  
Deionized Water ◽  
Hydrodynamic Cavitation ◽  
Term Stability ◽  
Long Term Stability

Nanobubbles have many potential applications depending on their types. The long-term stability of different gas nanobubbles is necessary to be studied considering their applications. In the present study, five kinds of nanobubbles (N2, O2, Ar + 8%H2, air and CO2) in deionized water and a salt aqueous solution were prepared by the hydrodynamic cavitation method. The mean size and zeta potential of the nanobubbles were measured by a light scattering system, while the pH and Eh of the nanobubble suspensions were measured as a function of time. The nanobubble stability was predicted and discussed by the total potential energies between two bubbles by the extended Derjaguin–Landau–Verwey–Overbeek (DLVO) theory. The nanobubbles, except CO2, in deionized water showed a long-term stability for 60 days, while they were not stable in the 1 mM (milli mol/L) salt aqueous solution. During the 60 days, the bubble size gradually increased and decreased in deionized water. This size change was discussed by the Ostwald ripening effect coupled with the bubble interaction evaluated by the extended DLVO theory. On the other hand, CO2 nanobubbles in deionized water were not stable and disappeared after 5 days, while the CO2 nanobubbles in 1 mM of NaCl and CaCl2 aqueous solution became stable for 2 weeks. The floating and disappearing phenomena of nanobubbles were estimated and discussed by calculating the relationship between the terminal velocity of the floating bubble and bubble size.

Hierarchical Self-Assembly of Microgel-Modified Biomaterials Surfaces

2014 ◽  
Vol 1622 ◽  
pp. 1-6
Author(s):  
Yong Wu ◽  
Jing Liang ◽  
Qichen Wang ◽  
Matthew Libera
Keyword(s):  
Self Assembly ◽  
Scale Effects ◽  
Control Surface ◽  
Poly Ethylene Glycol ◽  
Hydrogel Particles ◽  
Network Properties ◽  
Tissue Cells ◽  
Poly Ethylene ◽  
Non Line Of Sight

ABSTRACTMicrogels are hydrogel particles with micron and sub-micron diameters. They have beendeveloped, studied, and exploited for a broad range of applications because of their uniquecombination of size, soft mechanical properties, and controllable network properties. We havebeen using microgels to modulate the properties of surfaces to differentially control theirinteractions with tissue cells and bacteria. The long-term goal is to create biomaterials thatpromote healing while simultaneously inhibiting infection. Because poly(ethylene glycol) [PEG]is used in a number of FDA-approved products and has well-known antifouling properties, wework primarily with PEG-based microgels. We render these anionic either by copolymerizationwith monomeric acids or by blending with polyacids. Both methods produce pH-dependentnegative charge. Surfaces, both planar 2-D surfaces as well as topographically complex 3-Dsurfaces, can be modified using a hierarchy of non-line-of-sight electrostatic depositionprocesses that create biomaterials surfaces whose cell adhesiveness is modulated by a submonolayerof microgels. Average inter-microgel spacings of 1-2 microns exploit naturaldifferences between staphylococcal bacteria and tissue cells, which open the opportunity todifferentially control surface interactions with them based on length-scale effects. Afterdeposition, the microgels can be loaded with a variety of small-molecule, cationic antimicrobials.The details of loading depend on the relative sizes of the antimicrobials and the microgelnetwork structure as well as on the amount and spatial distribution of electrostatic charge withinboth the microgel and on the antimicrobial. The exposed surface between microgels can befurther modified by the adsorption of adhesion-promoting proteins such as fibronectin viaelectrostatic interaction. This approach combines a rich interplay of microgel structure andchemistry as a key component in a simple and translatable approach to modulate the surfaceproperties of next-generation biomaterials.

Stabilisation of Hg1-xCdxTe:Hg1-yCdyTex ≠ y) Heterointerfaces and Applications in Infra Red Devices

1990 ◽  
Vol 216 ◽  
Author(s):  
Paul A. Clifton ◽  
Paul D. Brown
Keyword(s):  
Barrier Layer ◽  
Epitaxial Layers ◽  
Long Wavelength ◽  
Long Term Stability ◽  
Novel Approach ◽  
Infra Red ◽  
Passivation Layers ◽  
Cdte Buffer ◽  
Initial Results

ABSTRACTThe interface between Hg1-xCdxTe(0 ≦ x ≦ 1) and Hg1-yCdyTe(0 ≦ y ≦ 1) epitaxial layers of different composition (x ≠ y) is unstable with regard to the intermixing of the Hg and Cd cations within the Group II sublattice. This phenomenon may give rise to long-term stability problems in HgTe-(Hg,Cd)Te superlattices and composition grading between (Hg,Cd)Te absorber layers and CdTe buffer or passivation layers in epitaxial infra red detectors. In this paper, a novel approach to the inhibition of interdiffusion in these systems is discussed. This involves the growth of an intervening ZnTe barrier layer at the heterointerface between two (Hg,Cd)Te layers. Initial results are presented which indicate the effectiveness of this technique in reducing interdiffusion in an experimental heterostructure grown by MOVPE. Some possible applications in a variety of HgTe-based long wavelength devices are discussed.

Preparation and characterization of poly (ethylene glycol) grafted Ca-alginate fibers by γ-irradiation for biomedical applications

2013 ◽  
Vol 27 (2) ◽  
pp. 216-226 ◽  
Author(s):  
Md. Kamal Khan ◽  
Mohammed Mizanur Rahman ◽  
Bodrun Nesa ◽  
Romana Nasrin ◽  
Swajal Molla ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Biomedical Applications ◽  
Poly Ethylene Glycol ◽  
Γ Irradiation ◽  
Alginate Fibers ◽  
Poly Ethylene ◽  
Ca Alginate

Poly(ethylene glycol)-Conjugation and Deoxygenation Enable Long-Term Preservation of Hemoglobin-Vesicles as Oxygen Carriers in a Liquid State

2000 ◽  
Vol 11 (3) ◽  
pp. 425-432 ◽  
Author(s):  
Hiromi Sakai ◽  
Ken-ichi Tomiyama ◽  
Keitaro Sou ◽  
Shinji Takeoka ◽  
Eishun Tsuchida
Keyword(s):  
Ethylene Glycol ◽  
Liquid State ◽  
Oxygen Carriers ◽  
Poly Ethylene Glycol ◽  
Poly Ethylene ◽  
Long Term Preservation
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