Differentially Degradable Janus Particles for Controlled Release Applications

Janus particles with differentially degradable compartments were prepared by electrohydrodynamic (EHD) co‐jetting and subsequent controlled crosslinking. These bicompartmental particles are composed of an interpenetrating polymer network of poly(ethylene oxide) and poly(acrylamide‐co‐acrylic acid) in one hemisphere and a crosslinked copolymer of dextran and poly(acrylamide‐co‐acrylic acid) segments in the second compartment. The compositional anisotropy caused differential hydrolytic susceptibility: Although both compartments were stable at pH 3.0, selective degradation of the PEO‐containing compartment pH 7.4 was observed wtihin 5 days. Janus particles with differentially degradable polymer compartments may be of interest for a range of oral drug delivery applications because of their propensity for decoupled release profiles.     

双面粒子的制备及应用研究进展

双面粒子是指粒子的两个半球表面具有不同组成或性质的微粒.这种各向异性或不对称的结构使其有很广泛的应用,但也使其制备变得困难.近年来已发展了很多制备方法,本文总结了最近几年双面粒子在制备及应用方面的研究进展.     

Five New Terpenes with Cytotoxic Activity from Pestalotiopsis sp.

Five new compounds called Pestalotis A–E (1–5), comprising three monoterpene-lactone compounds (1–3), one tetrahydrobenzofuran derivative (4), and one sesquiterpene (5), were isolated from the EtOAc extract of Pestalotiopsis sp. The structures of the new compounds were elucidated by analysis of their NMR, HRMS, and ECD spectra, and the absolute configurations were established through the comparison of experimental and calculated ECD spectra. All compounds were tested for antitumor activity against SW-480, LoVo, HuH-7, and MCF-7. The results showed that compounds 2 and 4 exhibited potent antitumor activity against SW-480, LoVo, and HuH-7 cell lines. Furthermore, compound 4 was assessed against HuH-7, and the results indicated that the rate of apoptosis was dose-dependent.     

磁性粒子在蛋白质分离纯化中的应用

磁性粒子与磁性分离技术结合用于生物分子和生物微粒的分离近年来受到了广泛关注。磁性粒子经过适当的表面修饰,可高度选择性地结合目标蛋白,在解决蛋白质的快速分离及高特异性的选择性分离方面具有优势。随着蛋白质组学研究的发展,磁性粒子用于蛋白质分离纯化的研究日渐增多。本文介绍了磁性粒子和磁性分离的基本特点,综述了近5年国内外有关磁性粒子在蛋白质分离纯化中的应用和发展现状。     

Synthesis of Latex Particles with Surface Functional Groups and Their Applications for the Fabrication of Porous Materials

In this study, monodisperse latex particles with specific surface functional groups were synthesized by emulsifier-free emulsion polymerization. Amidine or carboxylated polystyrene nanospheres with narrow size distribution were prepared by emulsion polymerization using AIBA (α,α′-zodiisobutyramidine dihydrochloride) as amine-containing initiator or acrylic acid as carboxyl-containing comonomer, respectively. Factors affecting the particle size and distribution were systemically studied by changing the amount of initiator or monomer, the polymerization temperature, and the stirring speed of emulsion polymerization reactor. Monodisperse polymethylmethacrylate beads were also synthesized by soapless emulsion polymerization using methacrylic acid or aminoethylmethacrylate hydrogen hydrochloride as comonomer for the surface functionalization of the particles. As applications of the latex beads, the polymeric particles were adopted as templating materials for the fabrication of macroporous titania film and meso-macroporous silica particles by colloidal templating method.     

Development of Gas-Chromatographic Method for Simultaneous Determination of Cannabinoids and Terpenes in Hemp

An original gas chromatographic method has been developed for simultaneous determination of major terpenes and cannabinoids in plant samples and their extracts. The main issues to be addressed were the large differences in polarity and volatility between both groups of analytes, but also the need for an exhaustive decarboxylation of cannabinoid acidic forms. Sample preparation was minimised, also by avoiding any analyte derivatisation. Acetone was found to be the most appropriate extraction solvent. Successful chromatographic separation was achieved by using a medium polarity column. Limits of detection ranged from 120 to 260 ng/mL for terpenes and from 660 to 860 ng/mL for cannabinoids. Parallel testing proved the results for cannabinoids are comparable to those obtained from established HPLC methods. Despite very large differences in concentrations between both analyte groups, a linear range between 1 and 100 µg/mL for terpenes and between 10 and 1500 µg/mL for cannabinoids was determined.     

Fabrication of Porous Titania Particles from Water-in-Oil Emulsions for the Applications of Photocatalyst

In this study, polystyrene nanospheres were synthesized by dispersion polymerization using batch-type reactor for the self-organization with precursor materials inside emulsion droplets. Mechanical homogenization was applied for the emulsification of the polymeric nanospheres and titanium diisopropoxide bis (acetylacetonate) to produce the macroporous titania particles by evaporation-driven self-assembly. Similarly, spherical titania crystallites could be synthesized via self-organization using triblock copolymer instead of polymeric latex beads after successive calcination. The morphologies of the porous particles were observed using electron microscope, and the crystallinity of the porous titania particles was analyzed by powder x-ray diffraction. As a demonstrative application, the macroporous titania microparticles with anatase phase were adopted as photocatalyst for the decomposition of Rhodamine B, and excellent catalytic performance was observed with higher rate constant compared to the result from commercial titania nanocolloid. Collectively, our macroporous titania microparticles were found to be safe catalytic materials for human body minimizing the skin toxicity since the size of the catalysts is in the micron-range.     

A Simple,Efficient Device for Determining Terpenes Present as Traces in the Atmosphere

Abstract

Up to the present it has been established that natural hydrocarbons, such as isoprene and the monoterpenes, play an important role in the physical chemistry of the atmosphere because of their high reactivity.

However, their true contribution to the natural chemical system has not yet been clearly defined as the seasonal variations in their concentrations are not sufficiently accurately known due to their low content in the atmosphere (a few hundredths of a ppb to a few ppb). We have developed an analysis procedure which enables quantitative trapping to be carried out together with excellent chromatographic separation. It consists of enrichment on adsorbents followed by very rapid thermal desorption and instantaneous chromatographic injection without further cryogenic trapping.

Our adsorption-desorption cycle does not reduce the efficiency of the chromatographic separation at all and does not bring about any decomposition of these highly reactive plant oils.     

Self-Crosslinked Ellipsoidal Poly(Tannic Acid) Particles for Bio-Medical Applications

Self-crosslinking of Tannic acid (TA) was accomplished to obtain poly(tannic acid) (p(TA)) particles in single step, surfactant free media using sodium periodate (NaIO₄) as an oxidizing agent. Almost monodisperse p(TA) particles with 981 ± 76 nm sizes and −22 ± 4 mV zeta potential value with ellipsoidal shape was obtained. Only slight degradation of p(TA) particles with 6.8 ± 0.2% was observed at pH 7.4 in PBS up to 15 days because of the irreversible covalent formation between TA units, suggesting that hydrolytic degradation is independent from the used amounts of oxidation agents. p(TA) particles were found to be non-hemolytic up to 0.5 mg/mL concentration and found not to affect blood clotting mechanism up to 2 mg/mL concentration. Antioxidant activity of p(TA) particles was investigated by total phenol content (TPC), ferric reducing antioxidant potential (FRAP), trolox equivalent antioxidant capacity (TEAC), total flavanoid content (TFC), and Fe (II) chelating activity. p(TA) particles showed strong antioxidant capability in comparison to TA molecules, except FRAP assay. The antibacterial activity of p(TA) particles was investigated by micro-dilution technique on E. coli as Gram‑negative and S. aureus as Gram-positive bacteria and found that p(TA) particles are more effective on S. aureus with over 50% inhibition at 20 mg/mL concentration attained.     

Inkjetting Plus Peroxidase‐Mediated Hydrogelation Produces Cell‐Laden,Cell‐Sized Particles with Suitable Characters for Individual Applications

The authors report a method to prepare cell‐laden, cell‐sized microparticles from various materials suitable for individual applications. The method includes a piezoelectric inkjetting technology and a horseradish peroxidase (HRP)‐catalyzed crosslinking reaction. The piezoelectric inkjetting technology enables production of cell‐laden, cell‐sized (20–60 μm) droplets from a polymer aqueous solution. The HRP‐catalyzed crosslinking of the polymer in the ejected solution enables production of spherical microparticles from various materials. Superior cytocompatibility of the microencapsulation method is confirmed from the viability and growth profiles of normal murine mammary gland epithelial cells.

     

应用于热控的壳厚可控核壳结构SiO2@TiO2颗粒制备

利用St觟ber方法合成了平均粒径在800 nm,球形度、单分散性良好的SiO2微球,再将其作为制备核壳结构SiO2@TiO2颗粒的内核。利用钛酸四丁酯水解反应,在SiO2内核上包覆制备了壳厚在30～100 nm的TiO2壳层,TiO2壳层厚度可根据水解反应中钛酸四丁酯的量调控。将制得的SiO2@TiO2核壳结构颗粒在550℃煅烧1 h,氧化钛壳层的晶型转变为锐钛矿相,晶型转变为锐钛矿相的TiO2更适合作为填料应用于近红外反射涂层。本文合成厚度可控SiO2@TiO2微球的方法是一种改进的溶胶凝胶方法,即在溶胶凝胶方法的基础上增加水热合成工艺。另外,本合成方法工艺简单,无表面活性剂或者耦合剂的引入。     

Magnetic Latex Particles in Nanobiotechnologies for Biomedical Diagnostic Applications: State of the Art

Summary: The main objective of this short state-of-the art is to report on the preparation of reactive magnetic latexes for biomedical applications. The main advantage of colloidal magnetic particles is their separation upon applying an external permanent magnetic field. Then magnetic particles bearing reactive groups or specific receptors are used in biomedical diagnosis such as immunoassay, molecular diagnosis for specific capture and detection of nucleic acids, viruses extraction and detection, cell sorting and more recently in numerous biotechnological applications. The preparation of magnetic latexes requires the use of well-defined iron oxide nanoparticles in appropriate medium. In this direction, aqueous ferrofluids were largely used to prepare functional magnetic latexes, whereas few approaches have been devoted to the use of organic ferrofluids.     

In situ Localization of Molecules in Crosslinked Particles during Electrohydrodynamic Process: Simple Route to Produce Microcapsules and Fibers with Controlled Release

This study reports a spontaneous selective localization of molecules in crosslinked particles during electrospraying and electrospinning polymer solutions containing the particles. It provides a facile way of preparing microcapsules and fibers with controlled release. The dye molecules were phase separated from the crystalline polymer matrix during the electrohydrodynamic process and moved to the solvent‐rich crosslinked particles. The position of the particles in the microcapsules and fibers could be controlled by adjusting compatibility of the particles with the matrix polymer. The microcapsules and fibers did not show the initial burst release of the molecules and gave considerably prolonged release behavior.

     

A Polymeric Bowl for Multi‐Agent Delivery

This paper describes a simple system for multi‐agent delivery. The system consists of a biodegradable polymer particle with a hollow interior, together with a hole on its surface that can be completely or partially sealed via thermal annealing. A hydrophobic dye, Nile‐red, entrapped within the shell of hollow particles presents a sustained release behavior while methylene blue, a hydrophilic model agent, encapsulated in the hollow interior shows a fast release manner. The release profiles of the probes can be further independently controlled by encapsulating methylene blue‐loaded polymer nanoparticles, instead of free dye, in the hollow particle with a small hole on its surface.

     

Engineered bacterially expressed polypeptides: assembly into polymer particles with tailored degradation profiles

In nature, the sequence of amino acids in a protein is determined by the genetic code. Biosynthesis of polypeptides by bacteria can be used to exploit this natural process to afford exact control over properties such as molecular weight, chemical functionality, and structure. It is demonstrated how control over the positioning of functional groups can be used to tune the degradation of assembled polypeptide particles (see scheme).     

Alginate Bioconjugate and Graphene Oxide in Multifunctional Hydrogels for Versatile Biomedical Applications

In this work, we combined electrically-conductive graphene oxide and a sodium alginate-caffeic acid conjugate, acting as a functional element, in an acrylate hydrogel network to obtain multifunctional materials designed to perform multiple tasks in biomedical research. The hybrid material was found to be well tolerated by human fibroblast lung cells (MRC-5) (viability higher than 94%) and able to modify its swelling properties upon application of an external electric field. Release experiments performed using lysozyme as the model drug, showed a pH and electro-responsive behavior, with higher release amounts and rated in physiological vs. acidic pH. Finally, the retainment of the antioxidant properties of caffeic acid upon conjugation and polymerization processes (Trolox equivalent antioxidant capacity values of 1.77 and 1.48, respectively) was used to quench the effect of hydrogen peroxide in a hydrogel-assisted lysozyme crystallization procedure.     

Smart multifunctional hollow microspheres for the quick release of drugs in intracellular lysosomal compartments

Prepared to self-destruct: When poly(d,l-lactic-co-glycolic acid) (PLGA) hollow microspheres containing NaHCO(3) entered the endocytic organelles of a live cell, the NaHCO(3) in the aqueous core reacted with protons that infiltrated from the compartment to generate CO(2) gas. The evolution of CO(2) bubbles led to the formation of small holes in the PLGA shell and thus rapid release of the encapsulated drug doxorubicin (DOX; see picture).