Topical Capsaicin in Poly(lactic-co-glycolic)acid (PLGA) Nanoparticles Decreases Acute Itch and Heat Pain

Background: Capsaicin, the hot pepper agent, produces burning followed by desensitization. To treat localized itch or pain with minimal burning, low capsaicin concentrations can be repeatedly applied. We hypothesized that alternatively controlled release of capsaicin from poly(lactic-co-glycolic acid) (PLGA) nanoparticles desensitizes superficially terminating nociceptors, reducing burning. Methods: Capsaicin-loaded PLGA nanoparticles were prepared (single-emulsion solvent evaporation) and characterized (size, morphology, capsaicin loading, encapsulation efficiency, in vitro release profile). Capsaicin-PLGA nanoparticles were applied to murine skin and evaluated in healthy human participants (n = 21) for 4 days under blinded conditions, and itch and nociceptive sensations evoked by mechanical, heat stimuli and pruritogens cowhage, β-alanine, BAM8-22 and histamine were evaluated. Results: Nanoparticles (loading: 58 µg capsaicin/mg) released in vitro 23% capsaicin within the first hour and had complete release at 72 h. In mice, 24 h post-application Capsaicin-PLGA nanoparticles penetrated the dermis and led to decreased nociceptive behavioral responses to heat and mechanical stimulation (desensitization). Application in humans produced a weak to moderate burning, dissipating after 3 h. A loss of heat pain up to 2 weeks was observed. After capsaicin nanoparticles, itch and nociceptive sensations were reduced in response to pruritogens cowhage, β-alanine or BAM8-22, but were normal to histamine. Conclusions: Capsaicin nanoparticles could be useful in reducing pain and itch associated with pruritic diseases that are histamine-independent.     

新型聚多巴胺纳米颗粒光热蒸发性能评价

聚多巴胺具有与黑色素相似的吸光性能,是一种被广泛关注的高分子近红外吸收材料,在光热转化方面有良好前景。但由于其本身聚合机理多样,内部结构复杂,目前对聚多巴胺功能性设计的研究较少。本文通过设计Fe³⁺和硅烷偶联剂与多巴胺反应,提高了聚多巴胺的吸光特性和亲水性;通过X射线光电子能谱(XPS)、傅里叶变换红外光谱(FTIR)等表征证明,成功合成了高吸光度亲水聚多巴胺纳米颗粒,吸光度达到90%。同时将合成的纳米颗粒真空抽滤,堆叠构建亲水输运通道。实验表明：在太阳光蒸发环境,一个太阳光强下,使用本文设计的光热膜进行纯水蒸发实验,纯水蒸发速率可以达到1.1 kg/(m²·h),光热转化效率为80%,比普通聚多巴胺提高15%,证明该材料有很好的光热转化性能,在海水淡化领域有着良好的应用前景。     

A Novel Nanoparticle‐Based Disposable Electrochemical Immunosensor for Diagnosis of Exposure to Toxic Organophosphorus Agents

A novel disposable electrochemical immunosensor for highly selective and sensitive detection of organophosphorylated butyrylcholinesterase (OP‐BChE), a specific biomarker for exposure to toxic organophosphorus agents, is presented. In this new approach, zirconia nanoparticles (ZrO₂) were employed to selectively capture the OP moiety of OP‐BChE adducts, followed by quantum dot (QD)‐tagged anti‐BChE antibodies for amplified quantification. The captured CdSe‐QD tags can be sensitively detected by stripping voltammetry using an in situ bismuth‐plating method. The OP agent, diisopropylfluorophosphate (DFP), was selected to prepare OP‐BChE adducts in various matrices. The formation of OP‐BChE adducts in plasma sample was confirmed using mass spectroscopy. The developed electrochemical immunosensor demonstrates a highly linear voltammetric response over the range of 0.1 to 30 nM OP‐BChE, with a detection limit of 0.03 nM (based on signal/noise = 3), coupled with a good reproducibility (relative standard deviation 4.5%). Moreover, the immunosensor has been validated with biomonitoring of OP‐BChE adducts in the plasma samples. This novel nanoparticle‐based electrochemical immunosensor thus provides an alternative way for designing a sensitive and cost‐effective sensing platform for on‐site screening/evaluating exposure to a variety of OP agents.     

Epoxy Ring Opening Phase Transfer as a General Route to Water Dispersible Superparamagnetic Fe3O4 Nanoparticles and Their Application as Positive MRI Contrast Agents

A novel and efficient method to produce water dispersible superparamagnetic Fe₃O₄ nanoparticles is described. Nanoparticles prepared by non‐hydrolytic organic phase methods are subsequently functionalized with (3‐glycidyloxypropyl)trimethoxysilane, a linker that prevents aggregation and is available for subsequent coupling reactions with a wide range of polymers and biomolecules. Ring opening coupling reactions were used to coat the epoxy‐functionalized magnetite nanoparticles with aminated polymers (polyetheramines) or small molecules (arginine). The resulting nanoparticles, with hydrodynamic size of 13 nm, are found to be very stable over extended periods in water or PBS due to the presence of a dense stabilizer layer covalently anchored to the surface. Exceptionally high spin‐lattice relaxivity, r₁, values of 17 s^?1 mM^?1, and low r₂/r₁ ratios of 3.3–3.8 were exhibited in the clinical MRI frequency range, irrespective of the molecule selected for nanoparticle stabilization. As a result the dispersions are excellent candidates for incorporation into multi‐functional assemblies or for use as positive contrast agent for MRI.     

Growth factor delivery-based tissue engineering: general approaches and a review of recent developments

The identification and production of recombinant morphogens and growth factors that play key roles in tissue regeneration have generated much enthusiasm and numerous clinical trials, but the results of many of these trials have been largely disappointing. Interestingly, the trials that have shown benefit all contain a common denominator, the presence of a material carrier, suggesting strongly that spatio-temporal control over the location and bioactivity of factors after introduction into the body is crucial to achieve tangible therapeutic effect. Sophisticated materials systems that regulate the biological presentation of growth factors represent an attractive new generation of therapeutic agents for the treatment of a wide variety of diseases. This review provides an overview of growth factor delivery in tissue engineering. Certain fundamental issues and design strategies relevant to the material carriers that are being actively pursued to address specific technical objectives are discussed. Recent progress highlights the importance of materials science and engineering in growth factor delivery approaches to regenerative medicine.     

Study on phenol adsorption from aqueous solutions on exfoliated graphitic nanoplatelets

In this study we report first data on exfoliated graphitic nanoplatelets (xGnPs) as a sorbent for phenol removal and preliminary evaluated the ability of different type of natural organic matter (NOM) to effectively disperse exfoliated graphitic nanoplatelets.     

New optical material europium EDTA complex in polyvinyl pyrrolidone films with fluorescence enhanced by silver plasmons

In our search for efficient Luminescent Solar Concentrators (LSC) we have prepared polyvinyl pyrrolidone (PVP) films incorporated by ethylenediamine tetraacetic acid (EDTA) complex of europium and co-doped with silver nanoparticles (NPs). Steady state fluorescence was studied under weak and strong excitation. Dynamical study was performed by second harmonic of Nd laser. Under weak excitation the fluorescence of europium co-doped with silver plasmons increased by a factor of three and excited by continuous laser by a factor of 50. The lifetimes of films doped by the complex were 755 μs and co-doped with silver nanoparticles 946 μs. This is the first finding that the photon density accumulates the number of plasmons interacting with electronic states of europium increasing its transition probability resulting in the strong intensification of fluorescence. In dynamical measurements of lifetimes a single pulse does not provide enough energy to create such number of plasmons.     

溶胶-凝胶柠檬酸盐自蔓延燃烧法制备的纳米级Mn-Zn软磁铁氧体磁粉

应用溶胶-凝胶柠檬酸盐自蔓延燃烧法制备了软磁Mn-Zn铁氧体磁粉.X射线衍射(XRD)和透射电镜(TEM)分析表明,样品为纳米级单相Mn-Zn铁氧体,其晶粒大小约为25nm.振动样品磁强计(VSM)测得Mn-Zn铁氧体磁粉的饱和磁化强度Ms为60.6m2/kg,矫顽力Hc为15.2kA/m,这表明纳米级Mn-Zn铁氧体磁粉不具有超顺磁特性.由于Mn-Zn铁氧体磁粉还具有很好的活性,可以用来制备高性能的软磁Mn-Zn铁氧体材料.     

Review of Polymer‐Based Nanodielectric Exploration and Film Scale‐Up for Advanced Capacitors

The uprising demands for electrical power and electrification requires advanced dielectric functionalities including high capacitance density, high energy density, high current handling capability, high voltage, high temperature, high thermal conductivity, light weight, and environmental reliability. Nanodielectric engineering emerges and attracts extensive efforts from many countries as a result. Unlike prior reviews focusing on lab scale nanocomposite study, this review focuses on recent innovations in polymer‐based nanodielectric design on a large scale and their film scale‐up efforts for advanced capacitors. The unconventional polymer‐nanofiller engineering and their process in the last two decades are discussed. The nanofunctionalized polymers on a molecular level for high dielectric constants and high dielectric strength are briefly described. The challenge associated with film scale‐up and retention of nanodielectric properties are then pointed out to be crucial toward a transfer of dielectric and capacitor technology. Several important attempts at scaling up dielectric films and capacitors recently supported by the US government and industry are reviewed. An alternative strategic approach to achieving high performance polymer films is introduced by leveraging 2D surface coating on commercially mature large‐scale polymer films. Future pathways for high quality scalable dielectric films exhibiting desirable dielectric properties and feasibility for capacitor manufacturing are suggested.     

Multiscale Nanoparticle Assembly: From Particulate Precise Manufacturing to Colloidal Processing

Nanoparticle assembly and colloidal processing are two techniques with the goal to fabricate materials and devices from preformed particles. While colloidal processing has become an integral part of ceramic processing, nanoparticle assembly is still mainly limited to academic interests. It typically starts with the precise synthesis of building blocks, which are generally not only considerably smaller than those used for colloidal processing, but also better defined in terms of size, shape, and size distribution. Their arrangement into 1D, 2D, and 3D architectures is performed with great accuracy well beyond what is achieved by colloidal processing. At the same time, the final assembly is not sintered such that the intrinsic, nanospecific properties of the initial building blocks are preserved or even lead to collective behavior. However, in contrast to colloidal processing the structures accessible by nanoparticle assembly are often limited to a small length scale. The review presents selected examples of nanoparticle assembly and colloidal processing with the goal to reveal the capabilities of these two techniques to fabricate novel materials from preformed building blocks, and also to demonstrate the immense opportunities that would arise if the two methods could be combined with each other.