Preparation, Cellular Internalization, and Biocompatibility of Highly Fluorescent PMMA Nanoparticles

Synthesis and Characterization of Diketopyrrolopyrrole-Based Aggregation-Induced Emission Nanoparticles for Bioimaging

Conventional fluorescent dyes have the property of decreasing fluorescence due to aggregation-caused quenching effects at high concentrations, whereas aggregation-induced emission dyes have the property of increasing fluorescence as they aggregate with each other. In this study, diketopyrrolopyrrole-based long-wavelength aggregation-induced emission dyes were used to prepare biocompatible nanoparticles suitable for bioimaging. Aggregation-induced emission nanoparticles with the best morphology and photoluminescence intensity were obtained through a fast, simple preparation method using an ultrasonicator. The optimally prepared nanoparticles from 3,6-bis(4-((E)-4-(bis(40-(1,2,2-triphenylvinyl)-[1,10-biphenyl]-4-yl)amino)styryl)phenyl)-2,5-dihexyl-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (DP-R2) with two functional groups having aggregation-induced emission properties and additional donating groups at the end of the triphenylamine groups were considered to have the greatest potential as a fluorescent probe for bioimaging. Furthermore, it was found that the tendency for aggregation-induced emission, which was apparent for the dye itself, became much more marked after the dyes were incorporated within nanoparticles. While the photoluminescence intensities of the dyes were observed to decrease rapidly over time, the prepared nanoparticles encapsulated within the biocompatible polymers maintained their initial optical properties very well. Lastly, when the cell viability test was conducted, excellent biocompatibility was demonstrated for each of the prepared nanoparticles.

Heterogeneous Bonding of PMMA and Double-Sided Polished Silicon Wafers through H2O Plasma Treatment for Microfluidic Devices

In this work we report on a rapid, easy-to-operate, lossless, room temperature heterogeneous H2O plasma treatment process for the bonding of poly(methyl methacrylate) (PMMA) and double-sided polished (DSP) silicon substrates by for utilization in sandwich structured microfluidic devices. The heterogeneous bonding of the sandwich structure produced by the H2O plasma is analyzed, and the effect of heterogeneous bonding of free radicals and high charge electrons (e−) in the formed plasma which causes a passivation phenomenon during the bonding process investigated. The PMMA and silicon surface treatments were performed at a constant radio frequency (RF) power and H2O flow rate. Changing plasma treatment time and powers for both processes were investigated during the experiments. The gas flow rate was controlled to cause ionization of plasma and the dissociation of water vapor from hydrogen (H) atoms and hydroxyl (OH) bonds, as confirmed by optical emission spectroscopy (OES). The OES results show the relative intensity peaks emitted by the OH radicals, H and oxygen (O). The free energy is proportional to the plasma treatment power and gas flow rate with H bonds forming between the adsorbed H2O and OH groups. The gas density generated saturated bonds at the interface, and the discharge energy that strengthened the OH-e− bonds. This method provides an ideal heterogeneous bonding technique which can be used to manufacture new types of microfluidic devices.

Self-Healable Porous Polyampholyte Hydrogels with Higher Water Content as Cell Culture Scaffolds for Tissue Engineering Applications

In this paper, we first demonstrate the control of the film pore size using neutral hydrophilic 2-hydroxyethyl methacrylate (HEMA) content. To improve the mechanical properties of a polyampholyte (PA), both HEMA and the cross-linker N,N'-methylenebisacrylamide (Bis-Am) were introduced into the PA chain. The predesigned copolymers showed great mechanical properties and optical behavior. The introduction of HEMA significantly increased the water content of the polymer, leading to the formation of porous structures in xerogels. The dynamic interaction between the positive and negative termini of the PA endowed the hydrogels with self-healing ability. The synthesized chemically cross-linked PA gels showed high stability in saline solution. The biocompatibility of the PA gels was confirmed using a cytotoxicity test of cells attached to the synthesized PA-X-2 and PA/HEMA-90/10-X-0.5. The results of this investigation indicate that the synthesized PA gels are applicable as a polymeric scaffold for cell culture.

Incorporation of Coumarin-Based Fluorescent Monomers into Co-Oligomeric Molecules

With the purpose of modifying organic fluorescent dyes based on the coumarin scaffold, and developing and evaluating a route to its incorporation into a polymeric backbone, a study was conducted on the co-polymerization of 3-vinylcoumarins with styrene and methyl acrylate using 2,2-azobis(isobutyronitrile) (AIBN) as the radical initiator. The structural and photophysical characterization proved the incorporation of the coumarin monomers into the polymeric chain and further showed a decrease in the fluorescence quantum yields in the co-oligomers.

Uptake and Intracellular Fate of Engineered Nanoparticles in Mammalian Cells: Capabilities and Limitations of Transmission Electron Microscopy-Polymer-Based Nanoparticles

In order to elucidate mechanisms of nanoparticle (NP)-cell interactions, a detailed knowledge about membrane-particle interactions, intracellular distributions, and nucleus penetration capabilities, etc. becomes indispensable. The utilization of NPs as additives in many consumer products, as well as the increasing interest of tailor-made nanoobjects as novel therapeutic and diagnostic platforms, makes it essential to gain deeper insights about their biological effects. Transmission electron microscopy (TEM) represents an outstanding method to study the uptake and intracellular fate of NPs, since this technique provides a resolution far better than the particle size. Additionally, its capability to highlight ultrastructural details of the cellular interior as well as membrane features is unmatched by other approaches. Here, a summary is provided on studies utilizing TEM to investigate the uptake and mode-of-action of tailor-made polymer nanoparticles in mammalian cells. For this purpose, the capabilities as well as limitations of TEM investigations are discussed to provide a detailed overview on uptake studies of common nanoparticle systems supported by TEM investigations. Furthermore, methodologies that can, in particular, address low-contrast materials in electron microscopy, i.e., polymeric and polymer-modified nanoparticles, are highlighted.

Dual pH and ultrasound responsive nanoparticles with pH triggered surface charge-conversional properties

A novel ultrasound responsive nanoparticle system with tunable surface charge-conversional properties is presented.

Surfactin-functionalized poly(methyl methacrylate) as an eco-friendly nano-adsorbent: from size-controlled scalable fabrication to adsorptive removal of inorganic and organic pollutants

Green synthesis of poly(methyl methacrylate) nanoparticles functionalized with the biosurfactant surfactin for adsorptive and reusable removal of toxic metals and organic compounds.

Comparison of the uptake of methacrylate-based nanoparticles in static and dynamic in vitro systems as well as in vivo

Polymer-based nanoparticles are promising drug delivery systems allowing the development of new drug and treatment strategies with reduced side effects. However, it remains a challenge to screen for new and effective nanoparticle-based systems in vitro. Important factors influencing the behavior of nanoparticles in vivo cannot be simulated in screening assays in vitro, which still represent the main tools in academic research and pharmaceutical industry. These systems have serious drawbacks in the development of nanoparticle-based drug delivery systems, since they do not consider the highly complex processes influencing nanoparticle clearance, distribution, and uptake in vivo. In particular, the transfer of in vitro nanoparticle performance to in vivo models often fails, demonstrating the urgent need for novel in vitro tools that can imitate aspects of the in vivo situation more accurate. Dynamic cell culture, where cells are cultured and incubated in the presence of shear stress has the potential to bridge this gap by mimicking key-features of organs and vessels. Our approach implements and compares a chip-based dynamic cell culture model to the common static cell culture and mouse model to assess its capability to predict the in vivo success more accurately, by using a well-defined poly((methyl methacrylate)-co-(methacrylic acid)) and poly((methyl methacrylate)-co-(2-dimethylamino ethylmethacrylate)) based nanoparticle library. After characterization in static and dynamic in vitro cell culture we were able to show that physiological conditions such as cell-cell communication of co-cultured endothelial cells and macrophages as well as mechanotransductive signaling through shear stress significantly alter cellular nanoparticle uptake. In addition, it could be demonstrated by using dynamic cell cultures that the in vivo situation is simulated more accurately and thereby can be applied as a novel system to investigate the performance of nanoparticle systems in vivo more reliable.

Biodistribution of size-selected lyophilisomes in mice

Lyophilisomes are a novel class of proteinaceous biodegradable nano/microparticle capsules developed for tumor drug delivery. The in vivo characteristics of lyophilisomes are unknown and, therefore, the time course of biodistribution of sized albumin-based lyophilisomes in CD1 mice after intravenous administration was studied. Lyophilisomes, prepared from Dylight680-labeled albumin, were sized using a sucrose gradient centrifugation methodology and four fractions with a mean size of approximately 200nm, 400nm, 550nm, and 650nm were pooled for in/ex vivo localization, (immuno)histochemistry and biochemical analysis. Lyophilisomes were rapidly taken out of the circulation by the liver and spleen. Immunohistochemistry revealed that lyophilisomes were taken up in the liver by F4/80 positive macrophages, and in the spleen by Sign-R1 positive macrophages specifically located in the marginal zones. Lyophilisomes were most likely degraded by the liver and spleen and subsequently excreted via the urine, as high levels of degraded Dylight680-labeled albumin were detected in the urine. This was corroborated by electron microscopy of the spleen, which showed intact lyophilisomes in the marginal zone 5 and 30min after injection, but not after 2h. In conclusion, IV injected lyophilisomes are rapidly entrapped by liver and splenic macrophages, biodegraded, and excreted in the urine.

π-Extension of a 4-ethoxy-1,3-thiazole via aryl alkyne cross coupling: synthesis and exploration of the electronic structure

π-Extension of 4-ethoxy-1,3-thiazolesviaaryl coupling resulted in a twofold increase of molar extinction coefficients and larger Stokes’ shifts.

Zwitterionic poly(2-oxazoline)s as promising candidates for blood contacting applications

The hemocompatibility and cytotoxicity of zwitterionic poly(2-oxazoline)s are investigated.

Synthesis of cholic acid-core poly(ε-caprolactone-ran-lactide)-b-poly(ethylene glycol) 1000 random copolymer as a chemotherapeutic nanocarrier for liver cancer treatment

DTX-loaded CA-(PCL-ran-PLA)-b-PEG_1k NPs were prepared and shown great potential as drug delivery nanocarriers for cancer therapy.

Light-harvesting of polymerizable 4-hydroxy-1,3-thiazole monomers by energy transfer toward photoactive Os(ii) metal complexes in linear polymers

A dye-based polymeric antenna system for energy transfer towards a photoactive Os(ii) metal complex is described.