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.

Solution photo-copolymerization of acrylic acid and itaconic acid: The effect of polymerization parameters on mechanical properties of glass ionomer cements.

OBJECTIVE: To synthesize a series of poly (acrylic acid-co-itaconic acid) (P(AA-co-IA)) copolymers with different molecular weights (MWs) through a facile water-based solution photopolymerization and to investigate the operational and mechanical properties of the experimental glass-ionomer (GI) cements made of the ionomers. METHODS: Thioglycolic acid (TGA) was used as a chain transfer agent to synthesize P(AA-co-IA) ionomers with different MWs through the solution photopolymerization. The chemical structure, MWs, and rheological properties of the copolymers were fully characterized. The GI cements were prepared using the ionomer solutions in different MWs and concentrations. Finally, the operating and mechanical properties of the experimental GI cements were investigated and compared with those of a commercially available GI cement. RESULTS: The synthesis and composition of the P(AA-co-IA) were approved by spectroscopy analyses. The results revealed that by increasing the TGA content, MW and polydispersity index (PDI) of the synthesized copolymers demonstrate a decreasing trend from 4.5 × 104 g/mol (PDI of 2.45) to 7.4 × 103 g/mol (PDI of 1.62). Accordingly, the viscosity of copolymers decreased with increasing the TGA concentration in the polymerization recipes. Setting times of the cements increased with reducing the MWs and ionomer concentration. The compressive and flexural strengths of GI cements were improved by increasing the MWs, ionomers concentration, and storage time. SIGNIFICANCE: The solution photopolymerization provides a facile and environmentally safe method to synthesize P(AA-co-IA) copolymers with controlled MWs. The structure-property relationships presented in the study also provide valuable information in the production and improvement of the GI cements.

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.

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.

Enhanced radiosensitivity of LNCaP prostate cancer cell line by gold-photoactive nanoparticles modified with folic acid.

BACKGROUND: Conventional cancer treatment methods suffer from many limitations such as non-specificity in discrimination between healthy and malignant cells. The aim of this study was to investigate the role of polymeric gold-photoactive nanoparticles (PGPNPs) conjugated with folic acid (FA) as theranostic nanoparticles for active targeting, real-time fluorescence tracing and radiosensitivity inducition in LNCaP prostate cancer cells. METHODS: The cellular uptake and cytotoxicity effect of gold nanoparticles (PGPNPs and PGPNPs-FA) after 2 and 24 h treatment were evaluated in in both cancer (LNCaP) and normal (HUVEC) cells using fluorescent microscopy, Induced coupled plasma optical emission spectrometry (ICP-OES) and Tetrazolium bromide dye (MTT), respectively. The therapeutic efficacy was analyzed on the LNCaP cells. For this purpose, LNCaP cells were treated by nanoparticles and ionizing radiation, and the synergistic effect of treatment methods were evaluated by colony formation assay (CFA) and Flow cytometry analysis. RESULTS: The results of fluorescence imaging and ICP-OES data showed that the LNCaP cells absorbed PGPNP-FA nanoparticles more than PGPNP (P < 0.001). Also, the uptake of nanoparticles was significantly greater in cancer cells than in healthy ones (P < 0.01). MTT assay results indicated higher cytotoxic effect of nanoparticles conjugated with FA in folate-receptor overexpressing LNCaP cancer cells compared to HUVEC normal cells (P < 0.01). Furthermore, CFA and Flow cytometry results demonstrated that combinatorial therapy of polymeric gold nanoparticles with/without FA and ionizing radiation at various doses (2, 4 and 6 Gy) had a synergistic effect on survival fraction and induction of apoptotic and necrotizing cell death (P < 0.01). CONCLUSION: PGPNPs-FA nanoparticles led to higher and more specific uptake and accumulation of nanoparticles in LNCaP cells, thereby increasing the ability of gold nanoparticles as radio-sensitizer.

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.

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.