When nanoparticles (NPs) enter a physiological environment, medium components compete for binding to the NP surface leading to formation of a rich protein shell known as the “protein corona”. Unfortunately, opsonins are also adsorbed. These proteins are immediately recognized by the phagocyte system with rapid clearance of the NPs from the bloodstream. Polyethyleneglycol (PEG) coating of NPs (PEGylation) is the most efficient anti-opsonization strategy. Linear chains of PEG, grafted onto the NP surface, are able to create steric hindrance, resulting in a significant inhibition of protein adsorption and less recognition by macrophages. However, excessive PEGylation can lead to a strong inhibition of cellular uptake and less efficient binding with protein targets, reducing the potential of the delivery system. To reach a compromise in this regard we employed a multi-component (MC) lipid system with uncommon properties of cell uptake and endosomal escape and increasing length of PEG chains. Nano liquid chromatography coupled with tandem mass spectrometry (nanoLC-MS/MS) analysis allowed us to accurately determine the corona composition showing that apolipoproteins are the most abundant class in the corona and that increasing the PEG length reduced the protein adsorption and the liposomal surface affinity for apolipoproteins. Due to the abundance of apolipoproteins, we exploited the “protein corona effect” to deliver cationic liposome–human plasma complexes to human prostate cancer PC3 cells that express a high level of scavenger receptor class B type 1 in order to evaluate the cellular uptake efficiency of the systems used. Combining laser scanning confocal microscopy with flow cytometry analysis in PC3 cells we demonstrated that MC-PEG2k is the best compromise between an anti-opsonization strategy and active targeting and could be a promising candidate to treat prostate cancer in vivo.

Effect of polyethyleneglycol (PEG) chain length on the bio–nano-interactions between PEGylated lipid nanoparticles and biological fluids: from nanostructure to uptake in cancer cells

Optically transparent, mechanically durable, and self-cleaning superhydrophobic coatings are greatly awaited for applications in daily life. An attempt has been made to develop sol–gel processed semi-transparent, durable and self-cleaning superhydrophobic coatings on glass using a silica–PMMA composite. A water drop acquires a near spherical shape on the coating exhibiting a water contact angle of ∼159° and immediately rolled off under small disturbance. A 10 μl water drop could individually collect around 10 mg of dirt particles along the way whilst rolling off the coating surface. The superhydrophobicity of the coatings remained intact under the impact of a water jet. A water jet hits the superhydrophobic coating and was repelled straightaway off the surface, without leaving any trace of water. These coatings showed both strong superhydrophobicity and superoleophilicity. We observed an improvement in mechanical stability, as well as optical transparency of the coatings in the visible range after low loadings of PMMA polymer (2 vol%) in silica. The prepared coatings maintained excellent superhydrophobicity even after 6 months storage under normal conditions in air.

Development of sol–gel processed semi-transparent and self-cleaning superhydrophobic coatings

Polycaprolactone/Polymethylmethacrylate (PCL/PMMA) biopolymer blend can be prepared by casting technique. Structural, optical and thermal properties of the blend have been studied using X-ray diffr...

Spectroscopic studies and thermal properties of PCL/PMMA biopolymer blend

Polymer blends yield carbon materials with superior performances for supercapacitor applications since blending can lead to controlled and fine pore architectures. In this study, a supercapacitor electrode material derived from an immiscible polymer blend comprising polyacrylonitrile (PAN) and polymethyl methacrylate (PMMA) was investigated. PAN was used as the carbonizing polymer while PMMA was used as the sacrificial polymer. The polymer blend solutions in DMF were electrospun to obtain freestanding nanofiber mats. The resulting mat was carbonized and activated by CO2 at 1000 °C to obtain porous carbon nanofibers (CNFs), as PAN converts to carbon and the sacrificial polymer decomposes creating pores. We demonstrated that the pore sizes can be tuned by varying the amount of PMMA loading in the blend compositions. PAN : PMMA (95 : 5), was found to be the optimum blend composition, affording the highest surface area of 2419 m2 g−1, higher degree of graphitization, higher carbon yield and lower charge transfer resistance among the blend compositions studied. Furthermore, the PAN : PMMA (95 : 5) CNFs showed the highest capacitance of 140 F g−1 and energy densities of 67 W h kg−1 at 3.5 V and 101 W h kg−1 at 4 V in an ionic electrolyte (EMITFSI) and also showed good cycling stability with 85% capacitance retention after 1000 cycles.

Supercapacitor performance of carbon nanofiber electrodes derived from immiscible PAN/PMMA polymer blends

We present a facile, low-cost and cleanroom-free technique for the fabrication of microneedles using molds created by laser ablation. Microneedle mold with high aspect ratios is achieved on acrylic sheet by engraving a specific pattern of crossover lines (COL) using CO2 laser cutter. Ablating COL pattern on the acrylic sheet creates a sharp conical shape in the center of the design. We have shown that a variety of microneedle shapes with different heights and tip angles can be easily achieved by changing the number and the length of the COL. Polydimethylsiloxane (PDMS) microneedles were fabricated by casting the PDMS on the mold. The resulted PDMS microneedles are oxygen plasma treated and then silanized. Another PDMS layer is casted on PDMS microneedles and detached after curing. The silanization prevents those two layers of PDMS from bonding to each other and makes them easily detachable. After detachment of the PDMS mold of microneedles, the mold is used to fabricate degradable polyvinyl alcohol microneedle patch suitable for transdermal drug delivery. The release kinetics of the needles are also shown and discussed in order to prove the applicability of the needles. A low-cost method to make microneedles for non-invasive drug delivery across the skin has been devised by a team in the United States. By forming microchannels in the skin, microneedles allow drugs such as insulin to be administered without a painful injection and with improved efficacy. However, conventional methods for fabricating microneedles are expensive, requiring cleanroom facilities. Sameer Sonkusale and co-workers at Tufts University have developed a method that does not require a cleanroom. They use a laser cutter to fabricate molds for microneedles in an acrylic sheet. The cone-shaped molds are created by passing the laser beam through the same point but by different paths, resulting in the greatest amount of material being removed from the central point. The researchers demonstrate their mold by making degradable microneedle patch from various polymers.

/pdf/low-cost-and-cleanroom-free-fabrication-of-microneedles-3lhrxfkl4h.pdf

Low-cost and cleanroom-free fabrication of microneedles

Superfine powders of poly (methyl methacrylate) (PMMA) have been prepared by means of an emulsion polymerization method. These have been used as templates in the synthesis of tetragonal phase mesoporous zirconia by the sol–gel method, using zirconium oxychloride and oxalic acid as raw materials. The products have been characterized by infrared spectroscopy, X-ray diffraction analysis, transmission electron microscopy, N2adsorption-desorption isotherms, and pore size distribution. The results indicate that the average pore size was found to be 3.7 nm.

/pdf/preparation-and-characterization-of-mesoporous-zirconia-made-18n5o2qxiq.pdf

Preparation and Characterization of Mesoporous Zirconia Made by Using a Poly (methyl methacrylate) Template

A study of supermolecular polarization of comb-like polycarboxylate admixtures synthesized with polyoxyethylene macromolecules

Polyetheramine carboxylate high-efficiency water-reducing agent

Soft-template synthesis of ZrOC2O4 nanocapsule with mesoporous core and microporous shell structure

The utility model relates to an agitated reactor liquid sampler comprising a storage tank, wherein the storage tank is provided with a sampling port, a feeding tube, a return tube, a vacuum tube and an emptying tube; the sampling port is provided with a sampling valve; the feeding tube and the return tube are respectively connected with the agitated reactor and respectively provided with a feeding valve and a return valve; the vacuum tube is connected with a vacuum system and provided with a vacuum control valve; and the emptying tube is provided with an emptying valve. The sampler can lead the system to be replaced by the feed liquid through repeated feeding and returning, then regular feeding and sampling are conducted, after sampling, the left feed liquid in the storage tank is pressed back to the agitated reactor through an air compressing system at atmospheric pressure or above the atmospheric pressure. The utility model has simple structure and reliable operation, after sampling, the excess material in the storage tank can return to the agitated reactor, thus having no pollution to the environment and especially being capable of solving the sampling problem of high-temperature corrosive materials.

Aimei Li

Papers

Preparation and Characterization of Mesoporous Zirconia Made by Using a Poly (methyl methacrylate) Template

A study of supermolecular polarization of comb-like polycarboxylate admixtures synthesized with polyoxyethylene macromolecules

Polyetheramine carboxylate high-efficiency water-reducing agent

Soft-template synthesis of ZrOC2O4 nanocapsule with mesoporous core and microporous shell structure

Agitated reactor liquid sampler