Post cross-linked ROS-responsive poly(ß-amino ester)-plasmid polyplex NPs for gene therapy of EBV-associated nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is one of the most common tumors in South China and Southeast Asia and is thought to be associated with Epstein-Barr virus (EBV) infection. Downregulation of latent membrane protein 1 (LMP1) encoded by EBV can reduce the expression of NF-κB and PI3K, induce apoptosis, and inhibit the growth of EBV-related NPC. For targeted cleavage of the Lmp1 oncogene via the CRISPR/Cas9 gene editing system, a post cross-linked ROS-responsive poly(ß-amino ester) (PBAE) polymeric vector was developed for the delivery of CRISPR/Cas9 plasmids both in vitro and in vivo. After composition optimization, the resultant polymer-plasmid polyplex nanoparticles (NPs) showed a diameter of ∼230 nm and a zeta potential of 22.3 mV with good stability. Compared with the non-cross-linked system, the cross-linked NPs exhibited efficient and quick cell uptake, higher transfection efficiency in EBV-positive C666-1 cells (53.5% vs. 40.6%), more efficient gene editing ability against the Mucin2 model gene (Muc2) (17.9% vs. 15.4%) and Lmp1 (8.5% vs. 5.6%), and lower intracellular reactive oxygen species (ROS) levels. The NPs achieved good tumor penetration and tumor growth inhibition in the C666-1 xenograft tumor model via Lmp1 cleavage, indicating their potential for gene therapy of EBV-related NPC.

Modified cellulose paper with photoluminescent acrylic copolymer nanoparticles containing fluorescein as pH-sensitive indicator.

Herein, novel fluorescein mono-acrylate (Flu-Ac) was synthesized and copolymerized with methyl methacrylate and glycidyl methacrylate to produce epoxy-functionalized latex nanoparticles. Fluorescent cellulose paper was then obtained by dip-coating and subsequent heat treatment. Synthesis of Flu-Ac, its incorporation efficiency into the epoxy-functionalized nanoparticles (almost 92 %), spherical morphology of the particles and their sizes (89-93 nm), and optical properties were studied comprehensively. SEM micrographs showed effective wetting of the cellulose fibers with uniform diffusion and deposition of the prepared functional nanoparticles through the establishment of physical and chemical interactions. Visual and spectroscopic emission intensity of the impregnated cellulose paper (λmax of 529 nm) were enhanced by increasing pH of the solution (from 2 to14) as a consequence of the transformation of cationic fluorescein to its neutral and anionic form. These observations depicted that such fluorescent cellulose substrates could be exploited in reusable indicators with good ability for sensing pH of solutions with diverse acidity or basicity.

Preparation of Photoswitchable Polyacrylic Nanocomposite Fibers Containing Au Nanorods and Spiropyran: Optical and Plasmonic Properties.

Photoswitchable nanofibers and nanocomposite fibers containing plasmonic nanoparticles have attracted a great deal of interest in optical and plasmonic devices. Herein, photoswitchable poly(methyl methacrylate-co-vinylimidazole-co-spiropyran ethyl acrylate) (MVSP) and its copolymer with butyl acrylate (MBVSP) were prepared via emulsion polymerization, and the corresponding nanofibers (MVSP@NF and MBVSP@NF) and nanocomposite fibers (MVSP/Au@NF and MBVSP/Au@NF) containing AuNRs were fabricated through electrospinning. FTIR and 1H NMR analyses confirmed the progress of the copolymerization reaction. The morphology of the prepared nanofibers containing AuNRs with an aspect ratio of 2.5 was identified by SEM and TEM techniques. The inclusion of vinylimidazole into the copolymer chains resulted in well-dispersed AuNRs. Photoisomerization studies revealed a higher photochromic efficiency for MBVSP@F (reflective intensity of 37.4%) with respect to MVSP@NF (reflective intensity of 62.5%) because of the greater flexibility of the chains. In addition, the presence of AuNRs in the nanocomposite fibers with high absorptivity intensified the photochromic properties for both samples. The polarization-dependent plasmonic band of AuNRs was switched between 650 and 634 nm through the photoisomerization of nonpolar SP to polar MC reversibly for MVSP/Au@NF. This displacement was just 4 nm for MBVSP/Au@NF, owing to the limited coupling between AuNRs and MC isomers. Besides, the capability of both nanocomposite fibers for reversible optical patterning was investigated by fast write-erase cycles. Enhanced photofatigue resistance in those fibers and the photomodulation of the plasmonic band of AuNRs using SP to MC isomerization revealed their promising potential for optical patterning and on-demand real-time plasmonic devices.

Spiropyran-based photoswitchable acrylic nanofibers: A stimuli-responsive substrate for light controlled C6 glioma cells attachment/detachment.

Reversible and remote cell manipulation with high spatiotemporal precision is now a highly attractive subject in various biological applications such as tissue engineering and cell-matrix interaction. Herein, photoresponsive poly(methyl methacrylate-co-hydroxy ethyl methacrylate-co-spiropyran ethyl acrylate) terpolymer (MHSP) was prepared using emulsion polymerization and the corresponding nanofibers (MHSP@NF) and film (MHSP@F) were prepared using electrospinning and drop-casting techniques, respectively. Structure of MHSP@NF with cylindrical cross-section and uniform diameter size of 169 nm were characterized by 1H-NMR and SEM analyses. Time-dependent UV-vis spectra of the prepared acrylic nanofibers and films demonstrated maximum forward photoisomerization after 3- and 8-min UV irradiation at 365 nm together with a 96° and 5° decrement in their surface water contact angles, respectively. High photoresponsivity of the nanofibers was attributed to their extensive surface area which exposes more spiropyran groups to UV light. MHSP@F and MHSP@NF with chemically-attached spiropyran groups demonstrated significant biocompatibility with negligible toxicity toward C6 glioma cancer cells up to 5 days. However, MH/SP@NF with doped SPOH exhibited a sudden decrease in cell viability relating to the migration and leakage of SPOH molecules. Photoreversible cell adhesion results showed a dramatic and switchable C6 cells attachment/detachment upon alternating UV and visible lights irradiations for MHSP@NF sample, while this was not observed for the similar film. These indicate potentiality of MHSP@NF as a promising substrate for dynamic switching of biomolecules and cell sheet engineering.

MTX-Loaded Dual Thermoresponsive and pH-Responsive Magnetic Hydrogel Nanocomposite Particles for Combined Controlled Drug Delivery and Hyperthermia Therapy of Cancer.

In recent years, the exploitation of magnetic nanoparticles in smart polymeric matrices have received increased attention in several fields as site-specific drug delivery systems. Here, ultrasonic-assisted emulsion copolymerization of N-isopropylacrylamide (NIPAM) and 2-(N,N-diethylaminoethyl) methacrylate (DEAEMA) in the presence of Fe3O4 nanoparticles was employed to prepare pH- and temperature-responsive magnetite nanocomposite particles (MNCPs). The obtained MNCPs were fully characterized by TEM, DSC, FT-IR, VSM, and XRD techniques. They had an average particle size of 70 nm with a lower critical solution temperature of 42 °C and superparamagnetic properties. In addition, MNCPs were loaded with methotrexate (MTX) as an anticancer drug, and their in vitro drug release was studied in different pH values and temperatures and in the presence of an alternating magnetic field. Noteworthy that the highest rate of MTX release was observed at pH 5.5 and 42 °C. Cell viability of the treated MCF-7 human breast cancer cell line with free MTX, MNCPs, and MTX-loaded MNCPs or in combination with magnetic hyperthermia (MHT) and water-based hyperthermia was comparatively studied. The obtained results showed about 17% higher antiproliferative activity for the MTX-loaded MNCPs accompanied by MHT relative to that of free MTX.

Precision Harvesting of Medicinal Plants: Elements and Ash Content of Hyssop (Hyssopus officinalis L.) as Affected by Harvest Height.

To investigate the effect of harvest height on the amassed elements and ash content of Hyssop (Hyssopus officinalis L.), an experiment was conducted in a randomized complete block design with three replications. Treatments included four harvest heights, i.e., 15, 25, 35, and 45 cm (from the tip of the plant) and the residual stalks. The dependent variables were the amassed content of elements N, K, P, Ca, Mg, Cu, Zn, and Pb in different heights of the plant and the associated ash content (total ash (TA), acid-insoluble ash (AA), and water-insoluble ash (WA)). The results showed that by moving from the upper shoots toward the ground, the amassed content of Mg, Ca, Cu, Zn, and Pb increased by 22.67%, 43.74%, 12.87%, 39.02%, and 85.04%, respectively. Further, a downward trend was observed for N (50.16%) and K (6.41%) content, while an upward trend reported for P (29.06%) content. As for the residual stalks, by moving from the upper shoots toward the ground, Mg, Ca, Cu, Zn, and Pb contents decreased by 1.01%, 21.03%, 9.11%, 17.02%, and 51.06%, respectively, while N and P contents increased by 60.59% and 3.15%, respectively, and a 34.74% increase was seen in P content. With increasing harvest height, TA, AA, and WA values increased by 33.48%, 27.03%, and 18.25%, respectively. As for the residues, these variables increased by 11.44%, 6.35%, and 5.22%, respectively. Our results showed that 15 cm harvest height had the highest quality with the lowest heavy metal content. Graphical Abstract.

Anticounterfeiting and photoluminescent cellulosic papers based on fluorescent acrylic copolymer nanoparticles containing coumarin.

Fluorescent nanoparticles are widely exploited as probes in cell tracking, drug delivery systems and high-performance security devices nowadays. Herein, we report the synthesis of novel 7-acryloxycoumarin (7-AC) through modification reaction of 7-hydroxycoumarin with acryloyl chloride and its copolymerization with methyl methacrylate and glycidyl methacrylate to produce epoxy-functionalized fluorescent polymer nanoparticles through emulsion polymerization. Chemical modification of cellulose pulp papers with the as-prepared fluorescent latex nanoparticles was also assessed. Spherical nanoparticles with average particle size of 40-93 nm and their diffusion into cellulosic fibers with excellent wetting and coating were monitored. Fluorimetery analysis demonstrated that immobilization of 7-AC into the hydrophobic acrylic copolymer substrate enhanced its emission intensity significantly with respect to its molecularly solution due to the elimination of unwanted environmental effects and non-radiative processes such as probable internal conversions. The obtained products exhibited intensified fluorescence emission with potentiality of being used in anticounterfeiting inks and security documents.

Solid-state photochromism of spironaphthoxazine loaded microcapsules with photo-patterning and thermo-regulating features.

HYPOTHESIS: One of the biggest challenges in the field of photoresponsive spirooxazines is their fast reverse isomerization. Polar phase change materials beside spirooxazines not only stabilize their colored-form, but also induce thermo-regulating properties to the whole system. Moreover, encapsulation is a key route to protect them and provide safe application of photochromic materials in solid-state matrices. EXPERIMENTS: A solution of spironaphthoxazine in oleic acid was encapsulated through solvent evaporation technique and the obtained microcapsules were incorporated in a transparent polymeric coating and also non-woven cotton fabrics. A systematic study on the reverse isomerization rate of spironaphthoxazine, photo-patterning and thermo-regulating features of the microcapsules was performed. FINDINGS: Comprehensive analyses demonstrated successful encapsulation of oleic acid and spironaphthoxazine. Microcapsules showed reversible color changes upon UV-Vis irradiation below melting point of oleic acid and a 85% decrease in discoloration rate compared to those without oleic acid. They also exhibited excellent photoswitchability, making them suitable for anti-counterfeiting applications. Their thermo-regulating feature in cotton fabrics was studied by using of infrared camera and they represented energy saving potentiality. Optically monitoring of temperature around melting point of oleic acid is another feature of these microcapsules.

Alternating Magnetic Field and Ultrasound Waves as Size Controlling Parameters in Preparation of Superparamagnetic Fe3O4 Nanoparticles.

Magnetic nanoparticles have been studied extensively owing to their widespread applications. Here, a novel and simple co-precipitation method is introduced in the presence of an external alternating magnetic field along with ultrasound waves for the synthesis of uniform magnetite (Fe3O4) nanoparticles with an average particle size of below 10 nm, the results of which were compared further. These agitating probes were employed to induce nucleation process of Fe3O4 nanoparticles resulting in creation of such particles with remarkable magnetic properties. These were assessed by XRD, TEM, vibrating sample magnetometer (VSM), AFM, and magnetic force microscopy (MFM) analyses. XRD patterns revealed the spinel phase of the obtained magnetite. The size and morphology of the nanoparticles were determined by AFM, TEM, and HR-TEM. The results indicated efficient control over size distribution in such new processes. The magnetic properties of the prepared Fe3O4 nanoparticles were characterized by MFM and VSM, demonstrating their superparamagnetic behavior. They showed saturation magnetization ranging from 57.4 to 79.4 emu/g with coercivity of 11.9 to 12.55 Oe, depending on the applied procedure.

High performance cyanide sensing with tunable limit of detection by stimuli-responsive gold nanoparticles modified with poly (N,N-dimethylaminoethyl methacrylate).

Detection of cyanide ion (CN-) and design of new sensors with high sensitivity and selectivity are interesting topics in recent developments. Cyanide ions lead to immediate dissolution of gold nanoparticles (AuNPs) and distinct color changes from red to transparent colorless solution. The presence of any material e.g. stabilizer may affect dissolution mechanism and hence sensing properties. Here, we represent a novel sensor (Au-PDA) based on the AuNPs coated with poly (N,N-dimethylaminoethyl methacrylate) (PDMAEMA) for the detection of CN- with tunable sensitivity. PDMAEMA bearing tertiary amine groups not only induced stimuli-responsivity to the prepared Au-PDA as the sensor, but also influenced the sensing performance like linear response range and limit of detection (LOD). The detection process with the increase in CN- concentration in wide range of pHs as well as high ionic strength of the medium was monitored by reduction of the localized surface plasmon resonance band of AuNPs at 530 nm. In the optimized condition, this sensing approach exhibited excellent selectivity in contrary to other anions and cations. The highest sensitivity was obtained in basic media (i.e. pH 9) with a LOD of 4.7 × 10-6 µM and two linear ranges from 10-5-10-3 µM and 0.04-320 µM. The tunable sensitivity could be considered as the strength point of such sensor with lowest LOD for detection of CN- and such a controlled stimuli-responsivity will open up a promising route toward adjustable detection of other chemicals.

Emulsion and miniemulsion techniques in preparation of polymer nanoparticles with versatile characteristics.

In recent years, polymer nanoparticles (PNPs) have found their ways into numerous applications extending from electronics to photonics, conducting materials to sensors and medicine to biotechnology. Physical properties and surface morphology of PNPs are the most important parameters that significantly affect on their exploitations and can be controlled through the synthesis process. Emulsion and miniemulsion techniques are among the most efficient and wide-spread methods for preparation of PNPs. The objective of this review is to present and highlight the recent developments in the advanced PNPs with specific properties that are produced through emulsion and miniemulsion processes.

Controlled Release and Photothermal Behavior of Multipurpose Nanocomposite Particles Containing Encapsulated Gold-Decorated Magnetite and 5-FU in Poly(lactide-co-glycolide).

Nowadays, many research studies have been conducted to prepare multidisciplinary probes in drug delivery systems and cancer therapy with high performance and minimum side effects. Here, poly(lactide-co-glycolide) (PLGA) nanocomposite particles containing 5-fluorouracil (5-FU) and gold-decorated magnetite nanoparticles with a raspberry-like morphology were designed and prepared as a novel and anticancer probe. For this reason, Fe3O4 nanoparticles were synthesized by a coprecipitation method and modified with (3-mercaptopropyl) trimethoxysilane for the deposition of gold nanoparticles. Then, they were embedded in the PLGA matrix alone and accompanied by 5-FU with 92 and 88% loading efficiencies, respectively, through a multiple emulsion solvent evaporation method. Chemical structure and composition of the prepared samples in each step were completely characterized by several techniques. The morphology of the nanocomposite particles was assessed by field emission scanning electron microscopy, high-resolution transmission electron microscopy, and selected area electron diffraction patterns, and their particle size and colloidal stability after 1 week were evaluated by dynamic light scattering. Because of the coexistence of gold and Fe3O4 nanoparticles, the final probe provided enhanced dual magneto and photothermal responses by increasing the temperature up to 42.7 °C under 5 min external alternating magnetic field and to 42.1 °C within just 1 min near-infrared irradiation at 808 nm. Trypan blue dye exclusion assays showed that they are biocompatible with reasonable toxicity (IC50 of 0.62 mg/mL) with respect to DU145 prostate cancer cells. Drug release profile of the 5-FU-loaded nanocomposite particles demonstrated their controlled release at 37 °C in phosphate-buffered saline solution. These indicate multidisciplinary characteristics of such particles in cancer therapy by photothermal, magnetic hyperthermia, and chemotherapy according to the presence of various active components.

Photochromic properties of stimuli-responsive cellulosic papers modified by spiropyran-acrylic copolymer in reusable pH-sensors.

Photochromic chemosensors based on spiropyran have attracted great attentions in recent years. Here, stimuli-responsive papers were prepared by chemical attachment of epoxy functionalized latex particles containing spiropyran moieties on the cellulose fibers by a new strategy for design and preparation of an acrylic copolymer pH-sensor. pH-Responsivity, photo-switchablity, photofatigue resistant and kinetic of photoisomerization were investigated by soaking of the papers in water with different pHs and they were analyzed by solid-phase UV-vis spectroscopy. Photoisomerization rate constants were measured for the wet papers in acidic and basic media (kc = 0.11-0.14 s-1) and they were much faster than in the dry state (kc = 0.08 s-1). Remarkable photochromic properties with no negative photochromism were observed here and also not influenced by hydrogen bondings and dipolar interactions. SEM images and contact angle measurements revealed high resistance of such papers against their surrounding environment. Moreover, the immediate response to pH changes was accompanied with different distinct colors.

Enhanced Photogeneration of Reactive Oxygen Species and Targeted Photothermal Therapy of C6 Glioma Brain Cancer Cells by Folate-Conjugated Gold-Photoactive Polymer Nanoparticles.

Tumor-selective photodynamic therapy is a successful method for ablation of malignant and cancerous cells. Herein, we introduce the design and preparation of functionalized acrylic copolymer nanoparticles with spiropyran (SP) and imidazole groups through a facile semicontinuous emulsion polymerization. Then, Au3+ ions were immobilized and reduced on their surface to obtain photoresponsive gold-decorated polymer nanoparticles (PGPNPs). The prepared PGPNPs were surface-modified with folic acid as a site-specific tumor cell targeting agent and improve intracellular uptake via endocytosis. Fourier transform infrared spectroscopy and energy dispersive X-ray spectroscopy analyses, UV-vis spectroscopy, scanning electron microscopy, and high-resolution transmission electron microscopy images were employed to characterize their spectral and morphological properties. Fluorescence microscopy images and inductively coupled plasma analysis demonstrated the cell line labeling capability and improved targeting efficiency of folate-conjugated PGPNPs (FA-PGPNPs) toward rat brain cancer cells (C6 glioma) with 71.8% cell uptake in comparison with 28.8% for the nonconjugated ones. Nonpolar SP groups are converted to zwitterionic merocyanine isomers under UV irradiation at 365 nm and their conjugation with Au nanoparticles exhibited enhanced photogeneration of reactive oxygen species (ROS). These were confirmed by intracellular ROS analysis and cytotoxicity evaluation on malignant C6 glioma cells. Owing to the strong surface plasmon resonance absorption of gold nanoparticles, FA-PGPNPs provided elevated local photothermal efficiency under near-IR irradiation at 808 nm. The prepared multifunctional FA-PGPNPs with a comprehensive integration of prospective materials introduced promising nanoprobes with targeting ability, enhanced tumor photodynamic therapy, cell tracking, and photothermal therapy.

A step-wise self-assembly approach in preparation of multi-responsive poly(styrene-co-methyl methacrylate) nanoparticles containing spiropyran.

HYPOTHESIS: Surfactant-free emulsion polymerization has become favorable due to circumventing instability issues reasonably. Incorporation of an appropriate hydrophilic macroRAFT, could provide controlled in-situ self-assembly via copolymerization with hydrophobic monomers into polymer particles. So far, this approach has mostly been studied in dispersion systems and further studies are needed in emulsions. Beside the corresponding mechanistic studies, the prepared latex particles would potentially exhibit smart behaviors by choosing stimuli-responsive monomers. EXPERIMENTS: Poly(styrene-co-methyl methacrylate) latexes were prepared by utilizing pH-responsive polydimethylaminoethyl methacrylate as the hydrophilic segment through polymerization induced self-assembly (PISA). A systematic study on the effect of MMA amount, role of smart spiropyran ethylacrylate (SPEA) comonomer and the synthesized macroRAFT for inducing efficient assembly has been performed comparatively for the first time. FINDINGS: SEM and DLS analyses showed the effect of MMA content on the obtaining of spherical particles with bimodal or monodisperse size distributions in both series of samples. Kinetic studies through conversion measurements along with GPC analysis revealed that the incorporation of MMA and SPEA strongly affected the efficiency of in-situ self-assembly, particle formation and RAFT-controllability on molecular weights. Ultimately, acido/basochromism, pH-responsivity and UV-responsivity of the prepared latexes were verified and the results showed their facile and fast multi-responsivity.

Effects of Chain Parameters on Kinetics of Photochromism in Acrylic-Spiropyran Copolymer Nanoparticles and Their Reversible Optical Data Storage.

Chemical bonding between photochromic compounds and polymer matrices will induce several consitions such as photostability, photoreversibility, elimination of dye aggregation, and undesirable negative photochromism. In such polymeric systems, the switching rate and photoisomerization are closely dependent on several parameters like chain flexibility, steric restrictions, polarity, and even proticity of the surrounding medium. Here, copolymerization of a synthesized spiropyran-based monomer with butyl acrylate (BA) and methyl methacrylate (MMA) comonomers was carried out with various compositions of MMA and BA through emulsion polymerization, and the corresponding photoisomerization kinetics were studied. Particle sizes and their distributions were analyzed by dynamic light scattering, and morphologies were investigated by scanning and transmission electron microscopic analyses. The results showed the particles are spherical with diameter 62-82 nm. Differential scanning calorimetric thermograms were employed to determine Tg of the prepared copolymers, which ranged from -23 to 93 °C. The kinetics of photoisomerization was then studied by UV-vis spectroscopy. Finally, a latex containing spiropyran/acrylic copolymer with Tg of about 0 °C and optimum rate of coloration and decoloration was considered in reversible optical data storage studies due to its fast photochromism and good film-formation properties.

Stimuli-responsive cellulose modified by epoxy-functionalized polymer nanoparticles with photochromic and solvatochromic properties.

Photoresponsive papers are among the fast and simple tools for detection of polarity by solvatochromic and photochromic behaviors upon UV irradiation. Here, a new, green and facile modification strategy was employed to prepare novel stimuli-responsive cellulose materials containing spiropyran by mixing microcrystalline cellulose (MCC), as a model compound, with epoxy-functionalized photochromic latex. FTIR analysis, thermal and thermo-mechanical properties were used to confirm the microstructral properties. Crystallographic analysis revealed a decrease in crystallinity of cellulose matrix and approved the incorporation of photochromic copolymer. Then stimuli-responsive papers were prepared by using pulp paper as the cellulosic matrix and their smart characteristics were studied under UV irradiation while dried or immersed into some polar and non-polar solvents. Different color changes were observed and investigated by solid-state UV-vis spectroscopy. These significant results were attributed to the efficient chemical modification and confirmed by SEM, EDX and nitrogen mapping analyses.

Chitosan and functionalized acrylic nanoparticles as the precursor of new generation of bio-based antibacterial films.

This study represents a new method for preparation of acrylic/chitosan films with antibacterial activity and non-toxic properties through an environmental friendly process containing a water-base acrylic resin and chitosan as an abundant natural polymer. Functional and positively charged acrylic particles based on butyl acrylate (BA)-methyl methacrylate (MMA)-glycidyl methacrylate (GMA) terpolymer were prepared with layered structure via semi-continuous emulsion polymerization. FTIR spectroscopy confirmed the presence of epoxy functional groups and size distribution of particles were evaluated by DLS and SEM as well. Films were prepared through mixing of chitosan solution and the prepared latex for the first time. SEM and EDX analyses revealed that chitosan has been distributed through the polymeric matrix uniformly. TGA data showed that introducing chitosan increases the maximum degradation temperature. It was found that the obtained films including positively charged chitosan reveal enhanced antibacterial activity against Staphylococcus areus and Escherichia coli. Also cytotoxicity analysis shows reasonable non-toxic behavior of the obtained composite films.

Preparation of stimuli-responsive functionalized latex nanoparticles: the effect of spiropyran concentration on size and photochromic properties.

Incorporation of photochromic compounds to polymer matrix through chemical bonding results in an enhancement of photoactivity and stabilization of optical properties. Here, spiropyran ethyl acrylate monomer (SPEA) was synthesized, and then photochromic particles bearing epoxy functional groups were prepared through semicontinuous emulsion copolymerization. Dynamic light scattering (DLS) and scanning electron microscopy (SEM) results depicted an increase in particle size and particle size distribution with the increase in SPEA monomer-surfactants ratio. Studies on photochromic properties by UV-vis analysis demonstrated a decrease in the absorption intensity despite the increase in SPEA content due to the enhancement in particle size. The prepared acrylic copolymer particles showed reasonable photostability, photoreversibility, and fast photoresponsivness according to the convenient test methods under UV/vis irradiation. DSC and DMTA analyses indicate an increase in Tg of the obtained copolymers with the increase in SPEA content. Finally, stimuli-responsive cellulosic papers were prepared by impregnation, and their photochromic behavior was investigated in dry and wet forms in various media under UV radiation. Morphology studies, due to stabilization of the photochromic copolymer on cellulose fibers, were conducted by SEM micrographs and showed good adhesion and compatibility between the two phases.

Self-assembled nanomicelles using PLGA-PEG amphiphilic block copolymer for insulin delivery: a physicochemical investigation and determination of CMC values.

Self-assembled nanomicelles can be used as synthetic biomaterials and colloidal carriers for poorly water-soluble drug delivery systems. Some of these micellar systems have been introduced in clinical trials and showed hopeful results relating to their therapeutic index in patients. Biodegradable nanomicelle was prepared from self-assembling amphiphilic block copolymer composed of poly(DL-lactic-co-glycolic acid) (PLGA) as a core and polyethylene glycol (PEG) as a corona. The PLGA-PEG block copolymer was first synthesized and characterized by FTIR, (1)H NMR, GPC and inherent viscosity measurements. The nanomicelle formed by PLGA-PEG block copolymer in the aqueous solution was characterized by dynamic light scattering, zeta potential, scanning electron microscopy (SEM) and fluorescence excitation and emission spectra of pyrene probe. The critical micelle concentration of obtained nanomicelle was about 0.006 mg/mL, with the size of about 160 nm and the zeta potential of -29 mV. Insulin-loaded PLGA-PEG nanomicelles were prepared by modified dialysis method and the physicochemical parameters of the micelles such as drug content, entrapment efficiency and in vitro drug release were characterized. The results showed that insulin was entrapped into PLGA-PEG nanomicelles with drug loading of 3.9 wt% and entrapment efficiency of 55 wt%. The nanomicelles containing insulin exhibited a controlled release profile. These observations suggested that the PLGA-PEG block copolymers nanomicelles have been prepared by a new synthetic route are potent nanocarrier for poorly water-soluble drugs as insulin.