Hydrophilic Polymer Matrix Research Articles

Mechanical, free vibration, electrical, and water absorption properties of vinyl ester composites reinforced with Phoenix sp. fibers: Influence of eco‐friendly sodium bicarbonate treatment

AbstractEnvironmentally sustainable and eco‐friendly natural fiber‐reinforced polymer composites have become the materials of interest in replacing synthetic fibers. However, weak interfacial interaction between hydrophilic natural fibers and hydrophobic polymer matrix limits their commercial applicability. Improving the interfacial interaction using environmentally friendly chemical treatments would be beneficial for both industries and the environment. In this study, vinyl ester‐based composites were made by incorporating Phoenix sp. fibers in different content (5, 10, 15, 20, and 25 wt%) and lengths (5, 10, 15, and 20 mm). To improve the interfacial interactions, the fibers were treated with eco‐friendly sodium bicarbonate solution at different durations (24, 120, and 240 h) prior to reinforcing. The fabricated composites were characterized by mechanical, free vibration, electrical resistance, and water uptake properties. The results reveal that both fiber content and fiber length have a significant effect on the above properties. Specifically, the composites incorporated with 20 wt% of 15 mm length fibers offered better properties. Further, the composites added with 120 h treated fibers have the maximum tensile strength (61.35 MPa) and modulus (4.13 GPa), flexural strength (152.63 MPa) and modulus (10.24 GPa), impact strength (24.67 kJ/m2), and natural frequency (56.72 Hz). This improvement is mainly due to the improved interfacial bonding, which was evidenced in morphological analysis. Based on the findings, the eco‐friendly treated sustainable Phoenix sp. fibers could be used as a promising reinforcement material for fabricating light weight polymer composites for various industrial applications.Highlights Various properties of Phoenix sp. fiber/epoxy composites were investigated. Interfacial bonding is enhanced through eco‐friendly chemical treatments. Vibration behavior of composites improved due to high stiffness of treated fibers. Composites with treated fibers have excellent electrical and water resistance.

Solution and gaseous phase sensing of formaldehyde with economical triphenylmethane based sensors: a tool to estimate formaldehyde content in stored fish samples.

The use of formalin to preserve raw food items such as fish, meat, vegetables etc. is very commonly practiced in the present day. Also, formaldehyde (FA), which is the main constituent of formalin solution, is known to cause serious health issues on exposure. Considering the ill effects of formaldehyde, herein we report synthesis of highly sensitive triphenylmethane based formaldehyde (FA) sensors from a single step reaction of inexpensive reagents namely 4-hydroxy benzaldehyde and 2,6-dimethyl phenol. The synthetic method also provides highly pure product in bulk quantity. The analytical activity of the triphenylmethane sensor 1 with a limit of detection (LOD) value of 2.31 × 10-6 M for FA was significantly enhanced through induced deprotonation and thereafter a LOD value of 1.82 × 10-8 M could be achieved. To the best of our knowledge, the LOD value of the deprotonated form (sensor 2) for FA was superior to those of all the FA optical sensors reported so far. The mechanism of sensing was demonstrated by 1H-NMR titration and recording mass spectra before and after addition of FA to a solution of sensor 2. Both sensor 1 and sensor 2 exhibit quenching in emission upon addition of FA. A fluorescence study also demonstrates enhancement in analytical activity of the sensor upon induced deprotonation. Then the sensor was effectively immobilized into a hydrophilic and biocompatible starch-PVA polymer matrix which enabled detection of FA in a 100% aqueous system reversibly. Again, quick and effective sensing of FA in real food samples (stored fish) with the help of a computational application was demonstrated. The sensors have significant practical applicability as they effectively detect FA in real food samples qualitatively and quantitatively.

Effect of hot-melt extruded Morus alba leaves on intestinal microflora and epithelial cells

Although rutin and isoquercitrin have many effects, they are insoluble substances, making it difficult to obtain pure substances. This study was to investigate whether Morus alba leaves containing rutin and isoquercitrin could improve intestinal health by making a sustained-release formulation through a hot-melt extrusion (HME) process with improved stability and solubility and determine whether it could upregulate the balance of intestinal microorganisms and intestinal epithelial cells. A sustained-release formulation was prepared by the HME process using Morus alba leaves and a hydrophilic polymer matrix. Antibacterial activities of pathogenic microorganisms (Escherichia coli, Streptococcus aureus, Enterococcus faecalis) and proliferative effect of probiotics (Lactobacillus rhamnosus, Pediococcus pentosaceus) were tested against intestinal microorganisms. Regarding intestinal epithelial cells, a co-culture model of Caco-2 cells and RAW 264.7 cells was used. It was confirmed that the extrudate exhibited high antibacterial activities against pathogenic microorganisms and affected the proliferation of probiotics. Furthermore, after inducing inflammation through LPS, it recovered transepithelial electrical resistance-increased levels of tight junction proteins and decreased expression levels of pro-inflammatory cytokines. HME of Morus alba leaves containing rutin and isoquercitrin can upregulate intestinal microbial balance and intestinal epithelial cells.

Recent Approaches of Matrix Release Tablet in NDDS System

The purpose of this analysis is to categorize matrix tablets according to the kind of polymer they are made of as well as the rate at which they release their contents. When it came to medicinal applications, the matrix system was the very first oral extended release platform ever developed. The utilization of matrix tablets enables the modification of drug release characteristics. They are highly favored for this kind of treatment because of the benefits they give for the patient in terms of better adherence to the treatment, more stable medication levels, decreased dose and bad effects, and a bigger safety margin for highly potent medications. Because of their versatility in delivering a desired drug release profile, cheap cost, and general regulatory acceptability, hydrophilic polymer matrix systems are frequently used in oral controlled drug delivery dosage forms. Because of the rapid diffusion of the dissolved medication via the hydrophilic gel network, the use of hydrophilic matrix alone for delayed drug release is not possible for medicines that are very water soluble. It is now generally accepted that the formulation of such drugs requires the use of matrix systems that incorporate hydrophobic polymers. It would appear that the most successful strategy would be to create a formulation for oral controlled release by employing matrix tablets.

SPECTRAL AND PHOTOPHYSICAL CHARACTERISTICS OF ASYMMETRIC POLYMETHINE DYES IN POLYURETHANE MATRICES

Here the composite polymer sorbent hydrogels were synthesized by in situ technique via free radical polymerization of acrylamide (AAm), 2-hydroxyethyl methacrylate (2HEMA) and N,N’-methylene-bis(acrylamide) crosslinker mixture in the presence of as-prepared dispersion of nickel-aluminum layered double hydroxide (NiAl-LDH). A content of active NiAl-LDH filler in the polymer matrix was varied in a range of 30 – 70 wt.%. It was found a high filler content suppresses a molecular mobility of copolymer matrix chains and reduces a beginning of glass transition temperature of the polymer constituent. The results of thermal analysis of polymer composites demonstrate a high hydrophilicity level of polymer matrix and high solvation energy of polar functionalities by Н2О molecules that was concluded from slow moisture elimination process while the temperature grows up to 200–210 оС. Additionally, a dehydration process and changes in a structure of thermally labile filler were also observed at the same temperature interval. At higher temperatures a thermal degradation of polymer poly(AAm-co-2HEMA) matrix is carried out. When a temperature overcomes 400 оС the partially changed filler demonstrates a chemical interaction with degraded organic constituents of the composites and defined catalytic activity as well. Studying sorption activity of the composites shown that introducing NiAl-LDH into hydrophilic polymer matrix provides anion-exchange activity to the composite sorbents and, correspondingly, the ability to eliminate the anionic contaminants from aqueous media while the polymer matrix doesn’t absorb these substances at such conditions. The highest sorption capacity of 11,40 μmol/g against model contaminant – methyl orange dye was determined for composite sorbent with filler content of 70 wt. %. At the same time sorption capacity of NiAl-LDH filler in composite sorbents reduces from 25,7 to 16,6 μmol/g while a filler content grows from 30 to 70 wt.% as a result of filler particles aggregation processes during composites formation stage. To evaluate the ability of the composite sorbents to reuse the experiment of materials recycling was performed. It was stated out the using of anion-exchange technique and aqueous Na2CO3 solution as an efficient and non-hazardous eluent provides 80 % recovering efficiency of the active filler in the composites. It can be concluded the composite sorbents demonstrate a high overall efficiency and are valuable materials for practical application for decontamination of waste water.

The role of matrix tablet in controlled release drug delivery system

The purpose of this review article is to characterize all of the parameters regarding the types, polymers used, and release kinetics of matrix tablets. Matrix system was the earliest oral extended-release platform for medicinal use. Matrix tablets are most commonly used methods to modulate the release profile of drugs. They are much desirable and preferred for such therapy because they offer better patient compliance, maintain uniform drug levels, reduce dose and side effects, and increase safety margin for high potency drugs. Hydrophilic polymer matrix systems are widely used for designing oral controlled drug delivery dosage forms because of their flexibility to provide a desirable drug release profile, cost effectiveness, and broad regulatory acceptance. However, the use of hydrophilic matrix alone for extending drug release for highly water-soluble drugs is restricted due to rapid diffusion of the dissolved drug through the hydrophilic gel network. For such drugs it becomes essential to include hydrophobic polymers in the matrix system. This leads to the conclusion that matrix tablets seem to be most promising when developing an oral controlled release formulation.

Hot-Melt Extrusion Enhances Antioxidant Effects of Mulberry on Probiotics and Pathogenic Microorganisms.

Mulberry is a rich source of anthocyanins (ACNs) known to possess biological activities. However, these ACNs are unstable in high pH, heat, and aqueous environments with a low bioavailability. In this study, a colloidal dispersion was prepared by hot melt extrusion with proper excipients. In this process, a hydrophilic polymer matrix was used to confirm the stability of the compound in high pH, high temperature, and aqueous media. It was confirmed that the particle size and the polydispersity index value were reduced, thereby improving the solubility. In vitro release studies revealed that the extrudate had a sustained release compared to a non-extruded product. As a result of measuring changes of intestinal microorganisms (Lacticaseibacillus rhamnosus, Pediococcus pentosaceus, Escherichia coli, Enterococcus faecalis, and Staphylococcus aureus), contents of probiotics were found to be increased whereas contents of pathogenic microorganisms were decreased. Thus, hot-melt extrusion could enhance the stability of ACN with prolonged release. The processed formulation exhibited probiotic properties and antimicrobial activities against pathogenic intestinal microflora.

Ionophore based optical sensors using hydrophilic polymer matrix – Ratiometric, pH independent ion-selective optodes

Classical approach for cation selective optode sensing requires high lipophilicity of receptor matrix and optical transducer dye, its application is restricted to relatively narrow pH range. We propose an alternative approach to ion-selective optodes, benefiting from rather hydrophilic polymer - plasticized polycaprolacton. This results in presence of lipophlic (plasticizer) and hydrophilic (sample/polycaprolactone) domains within the nanoprobes proposed. In consequence, this approach allows benefiting from alternative optical transducer: Nile blue dye and its unique properties and in consequence to benefit from new optical transduction mechanism allowing ratiometric sensing with no restriction for the sample pH. The response mechanism involves ionophore and ion pair composed of cation-exchanger and Nile blue cation dissolved in the plasticizer phase. Analyte incorporation to the phase occurs on expense of dye cation release to the hydrophilic phase. Ultimately a red staining of plasticizer phase is observed due to incorporation of neutral dye molecules formed in course of spontaneous hydrolysis occurring in water phase. Thus herein proposed optodes offer observable emission change at two wavelengths (increase of intensity emission as well as decrease) allowing ratiometric sensing in a broad concentration range. Moreover, herein proposed approach is applicable both in acidic and alkaline media, also in the absence of buffer, thus it mitigates significant constrain of classical optodes. As model system potassium or calcium selective nanospheres were prepared.

Modified Fabrication of Perovskite-Based Composites and Its Exploration in Printable Humidity Sensors.

Organic perovskites are promising optoelectronic semiconductor materials with photoelectric applications. It is known that the luminescence of perovskites is highly sensitive to hydron molecules due to its low moisture resistance of crystal structure, indicating its potential application on humidity-sensing. Herein, a novel perovskite-based compound (PBC) with minimal defects was developed to promote the photoluminescence performance via optimization of the drying method and precursor constitutions. Perovskite materials with good structural integrity and enhanced fluorescence performance up to four times were obtained from supercritical drying. Moreover, the hydrophilic polymer matrix, polyethylene oxide (PEO), was added to obtain a composite of perovskite/PEO (PPC), introducing enhanced humidity sensitivity and solution processibility. These perovskite/PEO composites also exhibited long-term stability and manifold cycles of sensitivity to humidity owing to perovskite encapsulation by PEO. In addition, this precursor solution of perovskite-based composites could be fancily processed by multiple methods, including printing and handwriting, which demonstrates the potential and broaden the applications in architecture decoration, logos, trademarks, and double encryption of anti-fake combined with humidity.

Anticoagulant biomimetic consecutive gas exchange network for advanced artificial lung membrane

Artificial lung membrane as extracorporeal blood-gas barriers could execute similar functions as human alveoli, whereby accomplish blood gas exchange process, providing imperative life support for patients with cardiopulmonary failure. However, the gas exchange performance for current membranous modules is restrained to the dense polymer matrix with low CO2 permeability. Meanwhile, it has long been difficult to balance the contradiction between haemorrhagic risk generated by heparin systemic anticoagulation and thrombogenesis during extracorporeal blood circulation. Here, inspired by the natural mammalian alveoli, a biomimetic consecutive gas exchange network (CGEN) is constructed on porous PES substrate by using aperture-modulated UIO-66-NH2 nanoparticles and hydrophilic CO2-affinitive polymer matrix to simulate the physiological structures and gas exchange features of human alveoli in vitro. The porous MOF particles within CGEN establish the main gas exchange channels, which not only enhance the total gas permeation, but also improve the CO2/O2 permselectivity to 13.17, approaching to the level of natural alveoli. Additionally, the prepared composite membrane with good hemocompatibility could effectively inhibit the formation of thrombus and provide a reliable local self-anticoagulation state during extracorporeal blood circulation. Overall, this biomimetic thin film composite membrane could provide new ideals for the preparation of advanced artificial lung membrane.

Molecular-Level Examination of Amorphous Solid Dispersion Dissolution.

Amorphous solid dispersions (ASDs) are commonly used to orally deliver small-molecule drugs that are poorly water-soluble. ASDs consist of drug molecules in the amorphous form which are dispersed in a hydrophilic polymer matrix. Producing a high-performance ASD is critical for effective drug delivery and depends on many factors such as solubility of the drug in the matrix and the rate of drug release in aqueous medium (dissolution), which is linked to bioperformance. Often, researchers perform a large number of design iterations to achieve this objective. A detailed molecular-level understanding of the mechanisms behind ASD dissolution behavior would aid in the screening, designing, and optimization of ASD formulations and would minimize the need for testing a wide variety of prototype formulations. Molecular dynamics and related types of simulations, which model the collective behavior of molecules in condensed phase systems, can provide unique insights into these mechanisms. To study the effectiveness of these simulation techniques in ASD formulation dissolution, we carried out dissipative particle dynamics simulations, which are particularly an efficient form of molecular dynamics calculations. We studied two stages of the dissolution process: the early-stage of the dissolution process, which focuses on the dissolution at the ASD/water interface, and the late-stage of the dissolution process, where significant drug release would have occurred and there would be a mixture of drug and polymer molecules in a predominantly aqueous environment. Experimentally, we used Fourier transform infrared spectroscopy to study the interactions between drugs, polymers, and water in the dry and wet states and the chromatographic technique to study the rate of drug and polymer release. Both experiments and simulations provided evidence of polymer microstructures and drug-polymer interactions as important factors for the dissolution behavior of the investigated ASDs, consistent with previous work by Pudlas et al. (Eur. J. Pharm. Sci.2015, 67, 21-31). As experimental and simulation results are consistent and complementary, it is clear that there is significant potential for combined experimental and computational research for a detailed understanding of ASD formulations and, hence, formulation optimization.

Glibenclamide Nanocrystal-Loaded Bioactive Polymeric Scaffolds for Skin Regeneration: In Vitro Characterization and Preclinical Evaluation.

Skin restoration following full-thickness injury poses significant clinical challenges including inflammation and scarring. Medicated scaffolds formulated from natural bioactive polymers present an attractive platform for promoting wound healing. Glibenclamide was formulated in collagen/chitosan composite scaffolds to fulfill this aim. Glibenclamide was forged into nanocrystals with optimized colloidal properties (particle size of 352.2 nm, and polydispersity index of 0.29) using Kolliphor as a stabilizer to allow loading into the hydrophilic polymeric matrix. Scaffolds were prepared by the freeze drying method using different total polymer contents (3–6%) and collagen/chitosan ratios (0.25–2). A total polymer content of 3% at a collagen/chitosan ratio of 2:1 (SCGL3-2) was selected based on the results of in vitro characterization including the swelling index (1095.21), porosity (94.08%), mechanical strength, rate of degradation and in vitro drug release. SCGL3-2 was shown to be hemocompatible based on the results of protein binding, blood clotting and percentage hemolysis assays. In vitro cell culture studies on HSF cells demonstrated the biocompatibility of nanocrystals and SCGL3-2. In vivo studies on a rat model of a full-thickness wound presented rapid closure with enhanced histological and immunohistochemical parameters, revealing the success of the scaffold in reducing inflammation and promoting wound healing without scar formation. Hence, SCGL3-2 could be considered a potential dermal substitute for skin regeneration.

Moisture-Wicking and Solar-Heated Coaxial Fibers with a Bark-like Appearance for Fabric Comfort Management.

Maintaining the human body's comfort is a predominant requirement of functional textiles, but there are still considerable drawbacks to design an intelligent textile with proper moisture absorption and evaporation properties. Herein, we develop moisture-wicking and solar-heated coaxial fibers with a bark-like appearance for fabric comfort management. The cortex layer of coaxial fibers can absorb moisture via the synergistic effect of the hierarchical roughness and the hydrophilic polymeric matrix. The core layer containing zirconium carbide nanoparticles can assimilate energy from the body and sunlight, which raises the surface temperature of the material and accelerates moisture evaporation. The resulting coaxial fiber-based membrane exhibits an excellent droplet diffusion radius of 2.73 cm, an excellent wicking height of 6.97 cm, and a high surface temperature of 61.7 °C which is radiated by simulated sunlight. Moreover, the designed fabric also exhibits a significant UV protection factor of 2000. Overall, the successful synthesis of such fascinating fibrous membranes enables the rapid removal of sweat from the human body textile, providing a suitable and comfortable microenvironment for the human body.

POLYMER BIOCOMPOSITES BASED ON AGRO WASTE: PART I. SOURCE, CLASSIFICATION, CHEMICAL COMPOSITION AND TREATMENT METHODS OF LIGNOCELLULOSIC NATURAL FIBERS

At present, the depletion of natural resources and environmental problems have generated great interest in finding a sustainable alternative to create new materials that are environmentally friendly. In recent years, many researchers have focused on investigations related to agricultural waste products to solve environmental problems associated with the disposal of agro waste. Thanks to their annual renewability and biodegradability, over the past two decades, agricultural waste has become an environmentally friendly alternative to synthetic fibers. In this regard, this review gives a general idea of new lignocellulosic polymer composite materials in which various natural fibers are used as fillers and reinforcing additives. The sources, classification and chemical composition of lignocellulosic natural fibers have been also given. Natural fibers include a hydroxyl functional group that makes the fibers hydrophilic. Hydrophilic natural fibers and hydrophobic polymer matrix lead to incompatibility and weak interfacial bonds between them. To resolve the problem of incompatibility of plant fibers with non-polar polymer matrices, various methods of surface treatment of natural fibers, including physical, chemical and biological processing, have been considered. From this perspective, in our opinion, the data presented in this article can be used as a database for further study of agricultural waste as fillers or reinforcing additives in polymer composites in order to accelerate the development and stimulate the commercial production of these new materials.

Mechanical and water absorption properties of nano TiO2 coated flax fibre epoxy composites

The present study aims at evaluating the mechanical properties such as tensile, flexural and interlaminar shear strength of unmodified and nano TiO2 coated flax fibre composites. Nano TiO2 coating on the flax fibres is done by immersing the fibres in a solution containing ethanol and silane coupling agent in volume ratio 10:1 and further adding nano TiO2. Effect of fibre coating on the composites is also evaluated by conducting water absorption tests. The composites are prepared using the compression molding technique. Results indicate an improvement in the tensile, flexural and interlaminar shear strength values by 22%, 24% and 16% respectively. Water diffusion coefficient of fibre modified composites reduced by 42% for 0.6 wt% TiO2 coated samples. Nanoparticle grafting on the fibre surface by silane treatment enhanced the compatibility between the hydrophilic fibre and hydrophobic polymer matrix. Chemical and mechanical bonding is developed between the fibre and matrix on account to the fibre surface grafting with nano TiO2 and silane coupling agent. Mechanical properties and water absorption resistance are thus improved. Nanoparticle coating on the fibre surface is validated from the scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analysis.

In vitro and in vivo evaluation of a sustained-release once-a-day formulation of the novel antihypertensive drug MT-1207

Hypertension is one of the most common chronic cardiovascular disorders. Sustained-release formulations are developed to maintain drug therapeutic levels throughout the treatment of hypertension, to promote patient compliance and improve patient outcomes. We have developed and tested in in vivo trials a once-a-day tablet formulation for the novel antihypertensive drug MT-1207. The tablets based upon a hydrophilic polymer matrix underwent post-compression parameter and physicochemical characterisations, along with in vitro drug release testing. The most promising formulation containing 31% w/w HPMC K15M gave a 24-hour release of MT-1207 with an almost constant release rate up to 20 hours. Follow in in vivo studies were carried out in Beagle dogs for the optimised sustained-release tablets in comparison to immediate-release tablets. The results showed that a sustained release of MT-1207 from the new formulation was achieved with a drug t1/2 2–2.5 times longer than the immediate-release tablets. Moreover, the AUC0-24h values of both sustained- and immediate-release tablets were identical at the same dose of 30 mg, indicating that the same amount of drug was absorbed in each case. For treatments based upon MT-1207, this development is significant for future commercial exploitation via scale-up and further trials, and for improved patient outcomes.

Inkjet-printed O2 gas sensors in intelligent packaging.

An inkjet printed membrane is presented as a colorimetric sensor for oxygen for use in smart packaging, in order to quickly inform the consumer about possible degradation reactions in modified atmosphere products (MAP). The colorimetric sensor is based on the redox dye, toluidine blue (TB), a sacrificial electron donor, glycerol, and, hydroxypropyl methylcellulose, as the hydrophilic polymeric matrix. The UVC-wavelength activated TB is photoreduced by SnO2 nanoparticle ink. This colorimetric oxygen indicator stays colourless upon exposure in nitrogen atmosphere to 7 min UVC light (6 W·cm-2). The photoreduced TB to leuco TB recovers its original colour upon exposure to oxygen for 55 min under ambient conditions (∼21 °C, ∼55%RH, 21% O2). The characteristics of the sensor have been evaluated, including its functionality through the colorimetric response to different oxygen concentrations as well as the influence of experimental variables such as humidity and temperature using a digital camera as the detector. The results obtained show that: (1) the colorimetric sensor remains stable in the absence of oxygen; (2) relative humidity greater than 60% significantly affects the reoxidation process; and (3) the temperature has a significant influence on the colour recovery, although the stability increases considerably when the sensor is kept refrigerated at 4 °C. A real application to packaged ham was performed, demonstrating that the printed colorimetric sensor is stable for at least 48 hours once activated and when the container deteriorates upon the entrance of oxygen, the sensor returns to its original blue colour, demonstrating its utility as a UVC-activated colorimetric oxygen sensor.

Graphene-Incorporated Natural Fiber Polymer Composites: A First Overview.

A novel class of graphene-based materials incorporated into natural lignocellulosic fiber (NLF) polymer composites is surging since 2011. The present overview is the first attempt to compile achievements regarding this novel class of composites both in terms of technical and scientific researches as well as development of innovative products. A brief description of the graphene nature and its recent isolation from graphite is initially presented together with the processing of its main derivatives. In particular, graphene-based materials, such as nanographene (NG), exfoliated graphene/graphite nanoplatelet (GNP), graphene oxide (GO) and reduced graphene oxide (rGO), as well as other carbon-based nanomaterials, such as carbon nanotube (CNT), are effectively being incorporated into NLF composites. Their disclosed superior mechanical, thermal, electrical, and ballistic properties are discussed in specific publications. Interfacial shear strength of 575 MPa and tensile strength of 379 MPa were attained in 1 wt % GO-jute fiber and 0.75 wt % jute fiber, respectively, epoxy composites. Moreover, a Young’s modulus of 44.4 GPa was reported for 0.75 wt % GO-jute fiber composite. An important point of interest concerning this incorporation is the fact that the amphiphilic character of graphene allows a better way to enhance the interfacial adhesion between hydrophilic NLF and hydrophobic polymer matrix. As indicated in this overview, two basic incorporation strategies have so far been adopted. In the first, NG, GNP, GO, rGO and CNT are used as hybrid filler together with NLF to reinforce polymer composites. The second one starts with GO or rGO as a coating to functionalize molecular bonding with NLF, which is then added into a polymeric matrix. Both strategies are contributing to develop innovative products for energy storage, drug release, biosensor, functional electronic clothes, medical implants, and armor for ballistic protection. As such, this first overview intends to provide a critical assessment of a surging class of composite materials and unveil successful development associated with graphene incorporated NLF polymer composites.

Luminescent N-heterocycles based molecular backbone interleaved within LDH host structure and dispersed into polymer

A pyrazino-1,3a,6a-triazapentalene dye-based molecule was intercalated by direct co-precipitation method into the galleries of negatively charged layered double hydroxide (LDH) to form a new luminescent LDH filler. The materials of cation composition Zn/Al = 2 lead to well-defined organic inorganic assemblies. The structure of the hybrid materials was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectra (FTIR) and UV–visible spectra. Optical properties of the materials, at both solid state and slurry state, were also recorded and absolute photoluminescent quantum yields (PLQY) were determined showing that the nanohybrid LDH slurry exhibited higher luminescence properties under UV excitation than the corresponding LDH powder. LDH fillers were used to prepare composite films by dispersion in both hydrophobic or hydrophilic polymer matrix such as poly (dimethyl siloxane) (PDMS) and poly(ethylene oxide) (PEO), respectively. Composite films were characterized by Small Angle X-ray Scattering (SAXS) and PLQY were recorded in order to compare the behaviour of the nanohybrid LDH filler in both polymer matrices. It was found that the aggregation of particles is still observed by SAXS.

Development of Molecular Probes for Live Imaging of Cancer and Infectious Diseases

Positron emission tomography (PET) and single photon emission computed tomography (SPECT) are powerful molecular imaging methods for examining disease-related factors in the whole body using specific imaging probes. Recently, we tried to develop molecular imaging probes that specifically visualize pathological factors associated with cancers and infectious diseases. Although survivin is highly expressed in several cancers, its expression is undetectable in non-dividing tissues. Thus, we developed several small molecular imaging probes that target survivin. These ligands not only showed high affinity for survivin protein, but also showed consistent cellular accumulation with respect to survivin expression levels, thereby indicating the feasibility of their backbones as scaffolds for tumor-specific imaging agents that target survivin. Prion diseases are fatal neurodegenerative diseases characterized by the deposition of amyloid plaques containing abnormal prion protein aggregates (PrPSc). Thus, we developed flavonoids, acridines, and benzofurans as PrPSc-imaging probes. A styrylchromone derivative ([123I]SC-OMe) appears to be a particularly promising SPECT radioligand for monitoring prion deposit levels in living brains. Gallium-68 is a positron emitter in clinical PET applications that can be produced by a 68Ge/68Ga generator without a cyclotron. Notably, we developed new adsorbents for 68Ge by introducing N-methylglucamine groups into the Sephadex series to serve as a hydrophilic polymer matrix. We also demonstrated that generator-eluted 68Ga-citrate could be used for PET imaging of infectious mouse models. Our polysaccharide-based 68Ge/68Ga generators were shown to be prospectively cost-effective production systems for 68Ga radiopharmaceuticals. This Review describes the major findings of these three studies and the future prospect of these fields.