Pluronic Copolymer Research Articles

Hydrophilic-hydrophilic mixed micellar system: effect on solubilization of drug

Mixed micellar systems have been tried with the aim of achieving higher solubility of drugs compared to single micellar systems. Hydrophobic-hydrophilic mixed micellar systems have been used for the above purpose for the drug ciprofloxacin in the past. In the present study, a hydrophilic-hydrophilic binary micellar system comprising of pluronic copolymers pluronic F127 and pluronic L64 has been studied for its effect on solubilization of the drug Ciprofloxacin. The solutions of the two individual pluronic and their mixed micellar system with drugs were subjected to characterizations viz. UV-spectrophotometry, fluorimetry, FT-IR, dynamic light scattering (DLS), rheology, and partition coefficient. The mixed pluronic–drug system displayed greater solubility of the drug compared with the neat pluronic-drug systems in most of the characterizations. New C–OH bond formation was evidenced by FT-IR spectra due to drug micelle interaction. The values of free energy changes of micellization were found to be −25 kJ mol−1 for pluronic F127, −74.5kJmol−1 for L-64, and −170.4 kJ mol−1 for the mixed pluronic. This is suggestive of spontaneous and stronger binding of drug ciprofloxacin with mixed pluronic in comparison with that in single micellar systems.Graphic abstract

Nanoencapsulation of Chromolaena odorata Extract Using Pluronic F127 as an Effectively Herbal Delivery System for Wound Healing

Chromolaena odorata is a medicinal herb with prominent pharmacological properties. The therapeutic efficiency of Chromolaena odorata extracts and its ingredients have, however, been limited by various factors, including the lack of targeting capacity and poor bioavailability. To approach this drawback, ethyl acetate fraction extract of Chromolaena odorata- (EA.ChO-) encapsulated pluronic-based nanocarriers was disclosed herein. The most common pluronic triblock copolymer micelles (pluronic F127) was used for the nanosized formulation of Chromolaena odorata extract. The obtained results show that EA.ChO-encapsulated nanoparticles have a spherical morphology with a designed hydrodynamic size was about 183.7 nm and zeta potential -39.5 mV. The EA.ChO nanoparticles are stable in different aqueous solutions (water, PBS 2.8, and PBS 7.4). The lyophilized form of the EA.ChO nanoparticles exhibited excellent stability for long-term storage. Notably, the EA.ChO nanoparticles were 1.3-1.4 fold more effective in the growth of fibroblast than the free EA.ChO, verifying the potential of pluronic F127 nanoparticles to the increased function of EA.ChO in the proliferation of fibroblast cell. In addition, bleeding stopped within 55 ± 6 s which was 20 s faster than that of free EA.ChO and 38-44 s faster than that of negative control treatments. The EA.ChO nanoencapsulation processed a rapid blood clot formation compared to control, free EA.ChO, pluronic F127, and water, suggesting the excellent bioavailability of EA.ChO nanoencapsulation. The obtained results thus provided a promising prospect for raising the activity Chromolaena odorata extract in wound healing application.

A Novel TEPA-Load or PEI-Load Beta/KIT-6 Composite and their Application to CO2 Adsorption

An amine-modified Beta/KIT-6 (BK) micro/mesoporous composite for CO2 capture was synthesized using nonionic tri-block copolymer pluronic (P123) as a template, tetraethyl orthosilicate (TEOS) as a silicon source and Beta zeolite as part of silicon aluminum source by a two-step hydrothermal crystallization method. BK was modified by Tetraethylenepentamine (TEPA) or polyethyleneimine (PEI) to obtain solid amine adsorbent. The structure, uniformity and physical properties of the sample were characterized by FTIR, nitrogen adsorption/desorption and elemental analysis methods and CO2 adsorption/desorption behavior of adsorbents and regeneration performance were investigated by thermal gravimetric analysis (TGA). Experimental results showed that with the increase of amine loading the CO2 adsorption capacity of samples increased first and then decreased at [Formula: see text]C, TEPA-loaded BK and PEI-loaded BK both presented the largest saturated CO2 adsorption capacity when the amine loading reached 60%, and the maximum values were 4.21[Formula: see text]mmol[Formula: see text]g[Formula: see text] and 2.72[Formula: see text]mmol[Formula: see text]g[Formula: see text], respectively. BK-TEPA-60 and BK-PEI-60 reached the maximum adsorption capacity at [Formula: see text]C and [Formula: see text]C. The adsorption kinetics analysis showed that the adsorption process of amine-modified BK was dominated by both physical and chemical adsorption. After five cycles of adsorption/desorption, BK-PEI-60 kept better stability with the equilibrium adsorption capacity of exhibited just 2.9% attrition, whereas a 9.2% decrease was obtained for BK-TEPA-60. Compared with other amine-modified solid materials, the materials we designed show good CO2 adsorption performance, indicating that they are promising efficient adsorbents for CO2 capture.

Several Shapes of Single Crystalline Gold Nanomaterials Prepared in the Surfactant Mixture of CTAB and Pluronics.

Twin structures in gold nanomaterials are destined because they reduce the severe strains in the misfit region of nanostructures. Defect-free single crystalline plasmonic nanomaterials gain interests these days as the integration of plasmonic materials or plasmons into electronic devices and circuits becomes more common. In this study, without subtle experimental adjustments, such as pH or halide additives, several shapes of single crystalline gold nanoparticles (NPs) are prepared in the surfactant mixture of cetyltrimethylammonium bromide (CTAB) and Pluronic triblock copolymers. The synthesized NPs are primarily composed of {100} planes with small numbers of particles possessing a [110] zone axis. Pluronic copolymers with low number average molecular weights (Mn), such as L-31 (Mn ≈ 1100) and L-64 (Mn ≈ 2900), prefer anisotropic nanorods with the aspect ratios of 4.3 and 3.0, respectively, while Pluronics with high Mn values, such as F-68 (Mn ≈ 8400) and F-108 (Mn ≈ 14 600), favor more concentric and isotropic cube-like NPs. Extended micelles are believed to form in Pluronics with low Mn values in which hydrophobic cores are merged with the increase of temperature, while the corona regions that are composed of long tails of PEO prevent the merge of hydrophobic cores, and the growth of the micelles is limited in Pluronic copolymers with high Mn values. The catalytic degradation reactions of methyl orange are conducted, and rather than isotropic particles, gold nanorods exhibit better catalytic performances. More hydrophilic environment and the steric alignment of rigid aromatic structures of methyl orange along the nanorods are thought to contribute to the catalytic activities. Overall, highly confined geometries of the appropriately swollen micellar templates of Pluronics and CTAB, which is not so hydrophobic as for the formation of contracted deswollen templates and for the inhibition of the growth of NPs, and which is not so hydrophilic as for the formation of coarse templates and for the formation of isotropic spheres with varying sizes, are believed as the main factor for the formation of single crystalline gold NPs.

Using coarse-grained molecular dynamics to understand the effect of ionic liquids on the aggregation of Pluronic copolymer solutions.

This study is aimed to enhance the understanding of the interaction between ionic liquids (ILs) and non-ionic Pluronic triblock copolymers in aqueous two-phase micellar systems (ATPMS) used for the selective separation/purification of hydrophobic biomolecules. The ILs allow a precise control of the cloud point phase separation temperature (CPT), particularly important when the stability of the molecule is highly dependent on temperature. The effect of choline-based ILs, with two different counter-anions, chloride and hexanoate, was evaluated using molecular dynamics simulations (MD) for F-68 and L-35 Pluronic aqueous solutions. The simulations revealed the role played by the anions during the Pluronic self-assembly, with choline chloride hindering Pluronic aggregation and the choline hexanoate favouring micelle formation and coalescence, in agreement with the experimental data. A detailed study of the accessible surface area of Pluronic showed a progressive dehydration of the Pluronic hydrophilic micelle corona in choline hexanoate mixtures promoting inter-micelle interactions and, consequently, micelle coalescence. With the addition of choline hexanoate, it was observed that the hydrophilic segments, which form the micelle corona, twisted towards the Pluronic micelle core. The electrostatic interaction is also shown to play a key role in this IL-Pluronic aqueous solution, as the hexanoate anions are accommodated in the Pluronic micelle core, while the choline cations are hosted by the Pluronic micelle corona, with the ions interacting with each other during the self-assembly process. In addition, a comparison study of F-68 and L-35 aqueous solutions shows that the IL impact depends on the length of the Pluronic hydrophilic segment. This work provides a realistic microscopic scenario of the complex interactions between Pluronic copolymers and ILs.

Self-assemblies of pluronic micelles in partitioning of anticancer drugs and effectiveness of this system towards target protein.

Micelles formed by pluronic triblock copolymers are known to be a promising class of drug delivery vehicles. Quantitative mechanistic insights into the ability of pluronic micelles to improve the solubility of poorly water soluble drugs, encapsulation and delivery of hydrophilic drugs are not available. The current study evaluated the energetics of encapsulation of chemotherapeutic drugs gemcitabine, cytarabine, and hydroxyurea in pluronic F127 and F68 micelles. In addition, the interactions of the drugs released from pluronic micellar media with serum albumin, which is a major circulatory transport protein, and subsequent conformational changes have also been analyzed with the help of calorimetry and spectroscopy. All the drugs showed improved partitioning in F127 micelles, the extent of which slightly increased with temperature rise. Interestingly, drug–protein binding is enhanced upon delivery from pluronic micelles without affecting the conformational integrity of the protein. This study highlights the role of drug functionalities, hydrophobicity, and steric factors towards their partitioning in pluronic micelles. Such studies are important in understanding physicochemical aspects of drug encapsulation and release, and lead to establishing structure–property–energetics correlations for developing suitable nano-drug delivery vehicles.

S‐Doped Magnetic Mesoporous Carbon for Efficient Adsorption of Methyl Orange from Aqueous Solution

AbstractA simple and rapid soft‐templating coupled with one‐pot solvent thermal method is developed to synthesize S‐doped magnetic mesoporous carbon (S‐doped MMC). In this method, phenolic resin is used as a carbon precursor and Pluronic copolymer P123 is used as a template and 2,5‐dimercapto‐1,3,4‐thiadiazole is used as sulfur source. Prepared S‐doped MMC processes a high specific surface area, the Fe3O4 particles are well embedded in the mesoporous carbon walls that exhibit a strong magnetic response, and the hydrated iron nitrate loading amount of 0.808 g is the best. Batch adsorption experiments are carried out at different pH, initial concentration, temperature, and contact time on the adsorption of methyl orange (MO) by S‐doped MMC. The kinetic data of the adsorption process are better fitted with pseudo‐second‐order model than the pseudo‐first‐order model. Langmuir model is more suitable for the equilibrium data than Freundlich model. The thermodynamic parameters including ΔG0, ΔH0, and ΔS0 indicate that the adsorption is a feasible, spontaneous, and endothermic process. Finally, it is found that the coexistence of PO43−, NO3−, SO42−, Cl−, and CO32− does not influence the adsorption process. These results illustrate S‐doped MMC can be an efficient adsorbent for the removal of MO from wastewater.

Development of Hybrid and Templated Silica-P123 Membranes for Brackish Water Desalination.

Water scarcity is still a pressing issue in many regions. The application of membrane technology through water desalination to convert brackish to potable water is a promising technology to solve this issue. This study compared the performance of templated TEOS-P123 and ES40-P123 hybrid membranes for brackish water desalination. The membranes were prepared by the sol–gel method by employing tetraethyl orthosilicate (TEOS) for the carbon-templated silica (soft template) and ethyl silicate (ES40) for the hybrid organo-silica. Both sols were templated by adding 35 wt.% of pluronic triblock copolymer (P123) as the carbon source. The silica-templated sols were dip-coated onto alumina support (four layers) and were calcined by using the RTP (rapid thermal processing) method. The prepared membranes were tested using pervaporation set up at room temperature (~25 °C) using brackish water (0.3 and 1 wt.%) as the feed. It was found that the hybrid membrane exhibited the highest specific surface area (6.72 m2·g−1), pore size (3.67 nm), and pore volume (0.45 cm3·g−1). The hybrid ES40-P123 was twice thicker (2 μm) than TEOS-P123-templated membranes (1 μm). Lastly, the hybrid ES40-P123 displayed highest water flux of 6.2 kg·m−2·h−1. Both membranes showed excellent robustness and salt rejections of >99%.

An intrinsically disordered protein in F127 hydrogel: Fluorescence correlation spectroscopy and structural diversity of beta casein

Intrinsically Disordered Proteins (IDPs) switch between diverse structures which prevents them from crystallization. FCS of the IDP beta casein (β-CN), labeled with Alexa488, suggests that in buffer the structure fluctuates between a highly extended state (radius 34.5 ± 7 nm) and a highly collapsed state (radius 1 nm). To understand their behavior in a highly crowded environment, like the cell, β-CN was studied inside a pluronic copolymer (F127) where a 2-times higher rotational and 10–16 times higher translational friction were observed. Fluorescence emissions of Tryptophan indicate that the protein is localized at corona region exposing to the void region of the gel.

Folate-targeted nanomicelles containing silibinin as an active drug delivery system for liver cancer therapy

The majority of herbal anticancer drugs are insoluble in water or become unstable during their transport to tumor tissues, hence they require a special drug delivery system. The main target of this study was to evaluate the therapeutic efficacy of silibinin (SLB)-loaded folic acid (FA)-conjugated Pluronic F127 (SLB-F127-FA) nanomicelles as an active-targeted drug delivery platform for liver cancer treatment. To prepare SLB-F127-FA nanomicelles, folic acid was first conjugated to hydrophilic chains of Pluronic F127 copolymer by the Steglich esterification technique. Then, silibinin was encapsulated in the self-assembled hydrophobic core of FA-conjugated F127 to render SLB-F127-FA nanomicelles. The prepared nano micelles had an almost spherical shape with an average particle size of 17.7 nm. The average hydrodynamic size of non-targeted (SLB-F127) and targeted (SLB-F127-FA) nanomicelles, measured by dynamic light scattering analysis (DLS), was 19.6 and 29.2 nm, respectively. Also, the drug loading content as well as entrapment efficiency of SLB-F127-FA nanomicelles were obtained to be 2.36% and 79.43%, respectively. The in vitro release patterns of SLB from nanomicelles showed a slow and sustained release behavior in comparison to free SLB. Moreover, it was observed that the kinetic release of silibinin from the SLB-F127-FA nanomicelles at 37 °C conforms well to Korsmeyer-Peppas kinetic model (R2 = 0.99, n = 0.22), suggesting a dominate release mechanism of the Fickian diffusion type. Moreover, in vitro cytotoxic study indicated that the viability of human liver cancer cells (HepG2) exposed to SLB-PF127-FA nanomicelles was significantly lower than that of treated with non-targeted nanomicelles (SLB-F127) or free SLB. Our results suggest that SLB-F127-FA nanomicelles can be considered as a promising targeted drug delivery platform for liver cancer therapy and/or delivering other hydrophobic drugs to different types of cancers with folate-receptor overexpression.

Redox/NIR dual-responsive PEG-betulinic acid/pluronic-cypate prodrug micelles for chemophotothermal therapy

Betulinic acid (BA) is a new class of anticancer drug, but its relatively short half-life and poor water solubility limit its therapeutic effect and clinical application. Herein, to tackle the dilemma, BA prodrugs were prepared by conjugating BA onto the polyethylene glycol (PEG) polymer via cleavable disulfide bonds. The prodrugs exhibited high water solubility (270-fold of free BA) and a relatively high drug-loading efficiency of 14.2 %. To further endow the BA prodrugs with a photothermal therapeutic effect, the near-infrared (NIR) agent Cypate was grafted on the Pluronic triblock copolymer. The different PEG polymers and different Pluronic polymers were chosen to obtain the optimal drug loading efficiency and the photothermal generation effect. The P-SS-BA/F68-Cy prodrug micelles integrate the redox-responsive BA prodrugs and the NIR-responsive amphiphilic triblock polymer into one single nanocomposite. The release of BA was less than 20 % in pH 7.4 PBS in the absence of glutathione (GSH), whereas the release of BA was obviously accelerated in pH 5.0 PBS with 10 mM GSH. In addition, the release of BA was further accelerated under the NIR irradiation. The P-SS-BA/F68-Cy micelles showed an excellent photothermal heating effect under NIR irradiation. The prepared P-SS-BA/F68-Cy micelles showed the synergistic thermochemotherapeutic effect on tumors both in vitro and in vivo. Therefore, the present study shows the great potential of dual-triggered drug delivery and thermochemotherapy for combination therapy.

Sol–gel tantalum pentoxide thin films with tunable refractive index for optical sensing applications

Present study aims at development of thin films of sol–gel Ta2O5 with tunable refractive index that could be used as an active medium for volatile organic compound (VOCs) optical detection. In order to tune the refractive index, mesoporosity is introduced through soft templating approach where series of co-polymers (Pluronics) are utilized as structure-directing agents. Thin films are prepared by spin-coating method using tantalum sol synthesized from TaCl5 as a precursor and ethanol as a solvent. The temperature annealing at 320 °C finalizes the tantalum oxide lattice formation and decomposes the template being used. The morphology and elemental composition of the films are studied by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy in STEM, respectively, and the amorphous status of the films is confirmed by selected area electron diffraction. Non-linear curve fitting method and non-destructive UV–Vis reflectance measurements are used for determination of optical parameters of the films. The free volume fraction in the films is estimated through modeling of refractive index by Bruggeman effective medium approximation. The films are exposed to acetone vapors as a commonly studied VOC. The reaction of the film due to vapors’ exposure is recorded as a change in the reflection spectra of the film and the adsorbed acetone quantity is estimated. The influence of template composition on optical and sensing properties of Ta2O5 films is revealed and discussed.

NMR investigation of the thermogelling properties, anomalous diffusion, and structural changes in a Pluronic F127 triblock copolymer in the presence of gold nanoparticles

We studied the thermogelation of a triblock copolymer Pluronic F127 (poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)) in an aqueous solvent in the presence of gold nanoparticles, using pulsed field gradient diffusion, NMR temperature experiments, relaxation measurements, and 2D heteronuclear NMR experiments. Pulsed field gradient diffusion NMR is a powerful technique to study the transition between diffusive regimes in a polymer mesh which are modulated by phase transitions in the polymeric network. In the isotropic phase, the triblock copolymer diffusion is a classical Fickian process. As the onset of gelation occurs, diffusion in the system becomes anomalous and the mean square displacement in the direction of the applied magnetic field gradient shows a power law dependence. Our experiments show that the introduction of gold nanoparticles leads to a disruption of gelation and the shifting of the formation of the ordered phase of the triblock copolymer to a higher temperature.

In situ pocket-type microcarrier (PMc) as a therapeutic composite: Regeneration of cartilage with stem cells, genes, and drugs

We prepared pocket-type micro-carriers (PMc) with pores larger than 30 μm for use in cell delivery by adding 40 mg pluronic F-127 copolymers (F-127) to biodegradable PLGA dissolved in dichloromethane solution. The controlling the size of the pockets in this way facilitates the adhesion of cells by regulating the size of the pockets according to the cells having various sizes. The size of PMc pores could be controlled within a range of 2 to 30 μm by varying the F-127 content. The ratio of F-127 to DOPA-bPEI was most appropriate at 1: 1, and the pocket size at 10 mg/ml of F-127 was appropriate for adhering 20–30 μm stem cells. F-127 containing SOX9 pDNA, in combination with DOPA-polyethylene–coated gold nanoparticles and dexamethasone loaded in PMcs, promoted cartilage differentiation. Gold nanoparticles complex and dexamethasone (DEX) loaded in PMcs were identified by micro-CT imaging and fluorescence imaging, respectively. By captured in pore generated on/in microspheres, the stem cells were safe and stable for use in delivery, both in vitro and in an animal model. Thus, microsphere pores can safely capture stem cells, and at the same time provide a microenvironment in which the captured stem cells can differentiate into chondrocytes.

Mesoporous Titanium Oxynitride Monoliths from Block Copolymer-Directed Self-Assembly of Metal-Urea Additives.

This report describes a simple one-pot soft-templating and ammonolysis-free approach to synthesize mesoporous crystalline titanium oxynitride by combining block copolymer-directed self-assembly with metal sol and urea precursors. The Pluronic F127 triblock copolymer was employed to structure-direct titanium-oxo-acetate sol nanoparticles and urea-formaldehyde into ordered hybrid mesostructured monoliths. The hybrid composites were directly converted into mesoporous crystalline titanium oxynitride and retained macroscale monolithic integrity up to 800 °C under nitrogen. Notably, the urea-formaldehyde additive provided nitrogen and rigid support to the inorganic mesostructure during crystallization. The resultant mesoporous titanium oxynitride exhibited good electrochemical catalytic activity toward hydrogen evolution reaction in 1 M KOH aqueous medium under applied bias. Our results suggest an inexpensive and safe pathway to generate ordered mesoporous crystalline metal oxynitride structures suitable for catalyst and energy-storage applications.

Development of curcumin-loaded chitosan/pluronic membranes for wound healing applications

The emergence of new materials with improved antibacterial, anti-inflammatory and healing properties compared to conventional wound dressings has both social and economic appeal. In this study, novel chitosan-based (CTS) membranes containing curcumin (CUR) incorporated in Pluronic (PLU) copolymers were developed and characterized to obtain suitable properties for applications as a wound healing dressing. The mechanical, thermal, swelling, wettability, release and permeation properties were evaluated by DSC, TGA, water contact angle measurements, FTIR, fluorescence and microscopic techniques. Membranes containing PLU and CUR presented wettability close to the ideal range for interaction with cellular components (contact angle ~40–70°), improved mechanical properties, higher thermal stability, high swelling degree (>800%) and CUR release (~60%) compared to samples without PLU addition. A higher retention of CUR in the epidermis than in the dermis layer was observed, which also was confirmed by confocal microscopy. Furthermore, the CTS-PLU membranes loaded with CUR showed to be active against Staphylococcus aureus and Pseudomonas aeruginosa (MIC = 25 and 100 mg mL−1, respectively), the microbial species most present in chronic wounds. Overall, the CTS-PLU-CUR membranes presented suitable properties to act as a new wound healing dressing formulation and in vivo studies should be performed to confirm these benefits.

Activation of carbon at different concentration microsphere adsorbent and its application for ibuprofen adsorption

A synthesis is presented in this research, microspheres carbon by mixing Pluronic F127 triblock copolymer, which was used as a main pore size direction, gelatine as a codirecting agent, Sucrose becomes the main ingredient of carbon precursor and H2SO4 be a catalyst. The mixture solution carried out at hydrothermal reactor followed by evaporation, partial carbonization, and pyrolysis under nitrogen flow. After being microspheres carbon have activated by KOH solution at room temperature for 24 h using a variation of the KOH concentration at 5, 10, 15 and 20 (%w/v), respectively. Activated Microspheres carbon have characterized by SEM and FTIR. In this study, it was found that carbon mass after activation is increased due to the deposition of potassium and a free water molecule. The morphology of microspheres carbon after activation process observed as soccer balls-like with pore size 0.5-15 µm with numerous of carbonyl and hydroxyl group. In this study, it was found that the greater the activator concentration, the greater the adsorption capacity, due to potassium deposition and water molecules. Maximum adsorb capacity is at 20% KOH concentration at 35 minutes. Microspheres for drug delivery systems are interesting to study.

Pluronic-coated nanoparticles for enhanced spatial distribution and increased softness of nanocomposite hydrogels

Several factors govern the improvement in the mechanical, thermal, and conductive properties, when a nanoscale filler is incorporated into a polymer matrix. These factors include the concentration, size of the filling, distribution, etc. In this research, we present how to improve the distribution of nanoparticles using nanoparticles stabilized with block copolymers of different molar masses. For this purpose, Pluronic L35 and Pluronic F68 copolymers were used to stabilize nanoparticles in order to improve their distribution in a hydrogel of poly(2-hydroxyethyl methacrylate) through an entropic mechanism of interfacial control. The nanoparticles were labelled with fluorescein, and using confocal fluorescence microscopy, it was quantitatively demonstrated that both stabilizers led to a more homogeneous distribution. The nanocomposite hydrogels presented interesting viscoelastic properties. While the hydrogels stabilized with Pluronic L35 did not present significant changes in the rheological properties (e.g. stiffness and shear thinning), the most significant rheological effects were observed for the hydrogels prepared with Pluronic F68-stabilized nanoparticles. These hydrogels exhibited a diminution in the shear complex modulus, viscosity, and critical shear rate to give rise to the shear-thinning region, which was attributed to the differences in the molar masses of the stabilizers and favoured slipping of polymer chains because of unfavourable wetting with the stabilizer coating.

Exploring NIR Aza-BODIPY-Based Polarity Sensitive Probes with ON-and-OFF Fluorescence Switching in Pluronic Nanoparticles.

Because of their deep penetration capability in tissue, red or near infrared (NIR) fluorophores attract much attention in bio-optical imaging. Among these fluorophores, the ones that respond to the immediate microenvironment (i.e., temperature, polarity, pH, viscosity, hypoxia, etc.) are highly desirable. We studied the response of six NIR aza-BODIPY-based and structurally similar fluorophores to polarity and viscosity for incorporation inside Pluronic nanoparticles as switchable fluorescent probes (SFPs). Based on our results, all of these fluorophores were moderately to strongly sensitive to the polarity of the microenvironment. We concluded that attaching amine groups to the fluorophore is not necessary for having strong polarity sensitive probes. We further studied the response of the fluorophores when embedded inside Pluronic nanoparticles and found that four of them qualified as SFPs. We also found that the switching ratio of the fluorophore-encapsulated Pluronic nanoparticles (ION-to-IOFF) is related to the length of the hydrophobic chain of the Pluronic tri-block copolymers. As such, the highest switching ratio pertained to F-68 with the lowest hydrophobic block poly (propylene oxide) (PPO chain of only 30 units).

Biomass material derived hierarchical porous TiO2: Adjustable pore size for protein adsorption

In this paper, a simple and reproducible approach combining biomass materials Acacia mangium tannin extract (BA tannin) and triblock copolymer pluronic (P123) as dual template was first presented to synthesize hierarchically porous TiO2. Nontoxic and low-cost titanium sulfate (Ti(SO4)2) replaced conventional poisonous and costly organic alkoxide. Attractively, biomass materials BA tannin processed sulfonic group and phenolic hydroxyl group, which played an important role to act as coordinating ligands to control hydrolysis rate of metal salt. Thermogravimetric (TG) analysis was used to evaluate the calcination temperature and X-ray photoelectron spectra (XPS), X-ray powder diffraction (XRD), nitrogen sorption isotherms, mercury intrusion porosimetry, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the chemical composition, crystalline structure and pore architecture features of TiO2. The results showed that TiO2 possessed multiscale porous structure with macropore of about 4 μm and mesopore of about 13 nm, and the pore structure can be adjusted by varying the ratio of P123 and BA tannin. Batch adsorption experiment exhibited the satisfied adsorption capacity of 42 mg/g for lysozyme (Lyz). And the real application of TiO2 was also tested using leather softening wastewater, which indicated that dual-templated TiO2 with hierarchical porosity was a good candidate for use as an adsorbent for biomacromolecule in wastewater treatment.