Pluronic Concentration Research Articles

Injectable Nanosponge-Loaded Pluronic F127 Hydrogel for Pore-Forming Toxin Neutralization.

PurposePore-forming toxins (PFTs) perform important functions during bacterial infections. Among various virulence-targeting therapies, nanosponges (NSs) have excellent neutralization effects on multiple PFTs. To enhance treatment efficacy, NSs tend to be incorporated into other biomaterials, such as hydrogels.MethodsIn the present work, red blood cell (RBC) vesicles were harvested to wrap polymer nanoparticles, leading to the formation of NSs, and the optimal Pluronic F127 hydrogel concentration was determined for gelation. Then, a novel detoxification system was constructed by incorporating NSs into an optimized Pluronic F127 hydrogel (NS-pGel). Next, the system was characterized by rheological and sustained release behavior as well as micromorphology. Then, the in vitro neutralization effect of NS-pGel on various PFTs was examined by a hemolysis protocol. Finally, therapeutic and prophylactic detoxification efficiency was evaluated in a mouse subcutaneous infection model in vivo.ResultsA thermosensitive, injectable detoxification system was successfully constructed by loading NSs into a 30% Pluronic F127 hydrogel. Characterization results demonstrated that the NS-pGel hybrid system sustained an ideal fluidity and viscosity at lower temperatures but exhibited a quick sol-gel transition capacity near body temperature. In addition, this hybrid system had a sustained release behavior accompanied by good biocompatibility and biodegradability. Finally, the NS-pGel system showed neutralization effects similar to those of NSs both in vitro and in vivo, indicating a good preservation of NS functionality.ConclusionIn conclusion, we constructed a novel temperature-sensitive detoxification system with good biocompatibility and biodegradability, which may be applied to the clinical treatment of PFT-induced local lesions and infections.

3D Printed Perfusable Renal Proximal Tubule Model With Different Extracellular Matrix Compositions

This paper describes the design of a chip modeling the proximal renal tubule, namely the nephron segment that is most targeted by drug toxicants. The tubule model is based on a 3D convoluted geometry whose printing parameters and Pluronic concentration were optimized to achieve a diameter of 320 μm without discontinuities. A perfusion system guaranteeing a 1 μL/min flow was also integrated. Moreover, the tubule model was integrated into a gel recapitulating the composition and the elastic properties of the human kidney extracellular matrix. Different formulations containing Matrigel, Collagen I and transglutaminase were investigated and compared in terms of rheometric properties and renal cell viability and ability to form a compact layer on them. Optimal results were found with a matrix composed of Matrigel and Collagen I (especially in the ratios 1:1), with the addition of 2.7% transglutaminase and 0.9% CaCl <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> .

A Fluorescence Study of the Interaction of Anticancer Drug Molecule Doxorubicin Hydrochloride in Pluronic P123 and F127 Micelles.

Drug delivery systems for the sustained and target delivery of doxorubicin to tumor cells are a topic of interest due to the efficacy of the doxorubicin in cancer treatment. The use of polymers such as Pluronic is being studied widely for the formulation of doxorubicin hydrochloride. However, the basic understanding of the physicochemical properties of pluronic micelles in presence of doxorubicin hydrochloride is a very essential topic of study. Doxorubicin hydrochloride is fluorescent; this helped us to study its sensitivity towards the Pluronic microenvironment using the fluorescence technique. In this work, the interaction and place of location of doxorubicin hydrochloride in Pluronic F127 and P123 micelles has been studied extensively using steady-state fluorescence intensity, dynamic fluorescence lifetime, quenching studies, dynamic light scattering, and zeta potential measurements, at different Pluronic concentrations. Using a fluorescence quenching experiment, doxorubicin hydrochloride was found to reside near the hydrophilic PEO corona region of the Pluronic micelles. For both the Pluronic, in the concentration range of study, the micellar size was found to be below 30nm; this may have a greater advantage for various applications.

Modulating chitosan-PLGA nanoparticle properties to design a co-delivery platform for glioblastoma therapy intended for nose-to-brain route.

Nose-to-brain delivery is a promising approach to target drugs into the brain, avoiding the blood-brain barrier and other drawbacks related to systemic absorption, and enabling an effective and safer treatment of diseases such as glioblastoma (GBM). Innovative materials and technologies that improve residence time in the nasal cavity and modulate biological interactions represent a great advance in this field. Mucoadhesive nanoparticles (NPs) based on poly(lactic-co-glycolic acid) (PLGA) and oligomeric chitosan (OCS) were designed as a rational strategy and potential platform to co-deliver alpha-cyano-4-hydroxycinnamic acid (CHC) and the monoclonal antibody cetuximab (CTX) into the brain, by nasal administration. The influence of formulation and process variables (O/Aq volume ratio, Pluronic concentration, PLGA concentration, and sonication time) on the properties of CHC-loaded NPs (size, zeta potential, PDI and entrapment efficiency) was investigated by a two-level full factorial design (24). Round, stable nano-sized particles (213-875nm) with high positive surface charge (+ 33.2 to + 58.9mV) and entrapment efficiency (75.69 to 93.23%) were produced by the emulsification/evaporation technique. Optimal process conditions were rationally selected based on a set of critical NP attributes (258nm, + 37mV, and 88% EE) for further conjugation with CTX. The high cytotoxicity of CHC-loaded NPs and conjugated NPs was evidenced for different glioma cell lines (U251 and SW1088). A chicken chorioallantoic membrane assay highlighted the expressive antiangiogenic activity of CHC-loaded NPs, which was enhanced for conjugated NPs. The findings of this work demonstrated the potential of this nanostructured polymeric platform to become a novel therapeutic alternative for GBM treatment. Graphical abstract.

Effect of Pyrrolidinium Formate Ionic Liquid on Micellization of Direct and Reverse Pluronics in Aqueous Solutions.

The behavior of direct and reverse Pluronic, copolymer nonionic surfactants, poly(ethylene oxide) PEO, and poly(propylene oxide) PPO copolymers, in aqueous solution and in the pyrrolidinium formate ([pyrr][F]) ionic liquid, was investigated using Fourier transform infrared spectroscopy (FTIR spectroscopy). The study was performed for a fixed Pluronic concentration at room temperature. We showed that in aqueous solution, the spectra associated with the direct and reverse Pluronics are similar irrespective of the difference in length of the various PPO and PEO blocks, their positions and the PPO:PEO ratio. The study of those same Pluronics dissolved in a pure pyrrolidinium formate solution showed that the Pluronic types were soluble and that the micellization process can take place at room temperature. The interaction between the Pluronic 10R5 aqueous solutions and the [pyrr][F] for various ionic liquid volumes is reported.

Thermosensitive mucoadhesive in situ gel for intranasal delivery of Almotriptan malate: Formulation, characterization, and evaluation

The present investigation deals with development, characterization, and evaluation of thermosensitive in-situ nasal gel of Almotriptan malate (selective serotonin 5-HT1 receptor agonist), serving as a substitute for drug delivery to the brain. Gels were prepared by cold technique varying the concentration of Pluronics (PF127 and PF68) and carboxymethyl chitosan as thermoreversible and mucoadhesive polymers respectively. Drug content before and after gelation was ranged between 96.42-98.92% and 95.8–98.66% respectively. The pH value was observed in the range of 5.56–6.31. Notably, the results obtained were in agreement with the phase transition and formulations exhibited pseudoplastic rheology. Mucoadhesive strengths of all the formulations increased with the chitosan concentration and were in the range of 3300–5193.65 dyn/cm2. The in-vitro drug diffusion data of the optimized formulation i.e. 17% w/v PF127, 2% w/v PF68, 0.1% w/v carboxymethyl chitosan, revealed 89.36% release at the end of 6 h. Histopathological studies confirmed the non-toxic effect of optimized formulation on the microscopic structure of nasal mucosa during ex-vivo permeation studies. Short term stability study exhibited 4±1 °C as an appropriate storage condition for the formulations. In nutshell, a thermosensitive in-situ gel of Almotriptan malate can be intended as an effective approach of migraine treatment.

Comparative evaluation of 2% turmeric extract with nanocarrier and 1% chlorhexidine gel as an adjunct to scaling and root planing in patients with chronic periodontitis: A pilot randomized controlled clinical trial.

Context:Nanoparticles, owing to their smaller size, penetrate regions inaccessible to other delivery systems, such as periodontal pockets. Thus, the present study aimed to comparatively evaluate efficacy of 2% curcumin with nanocarrier and 1% chlorhexidine gel as a local drug delivery (LDD) in the treatment of periodontal pockets.Materials and Methods:Forty-five chronic periodontitis patients with pocket depth 5–7 mm in two or more teeth were selected. Full-mouth scaling and root planing (SRP) was done for all patients followed by random allocation to the three treatment groups, namely SRP group (Group 1), 2% curcumin with nanogel (Group 2), and 1% chlorhexidine gel (Group 3). Clinical parameter assessment and microbiological analysis of subgingival plaque samples for Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), and Tannerella forsythia (Tf) was done at baseline, 21st day, and 45th day.Results:The results showed that when the two LDD agents were used as an adjunct to SRP in chronic periodontitis, there was an improvement in all clinical parameters. Evaluation of microbiological parameters also showed a significant reduction in Aa, Pg, and Tf levels. Comparison of 2% turmeric extract with a nanocarrier system with 1% chlorhexidine gel showed that both the agents had a comparable antibacterial effect on the three selected periodontopathic bacteria.Conclusion:The present study showed that both the LDD agents showed an effective improvement of clinical and microbiologic parameters. 2% curcumin delivered with a nanocarrier system showed results comparable to chlorhexidine gel and hence shows promising future as an LDD agent in the treatment of periodontal pockets.

Pluronic gel-based burrowing assay for rapid assessment of neuromuscular health in C. elegans

Whole-organism phenotypic assays are central to the assessment of neuromuscular function and health in model organisms such as the nematode C. elegans. In this study, we report a new assay format for engaging C. elegans in burrowing that enables rapid assessment of nematode neuromuscular health. In contrast to agar environments that pose specific drawbacks for characterization of C. elegans burrowing ability, here we use the optically transparent and biocompatible Pluronic F-127 gel that transitions from liquid to gel at room temperature, enabling convenient and safe handling of animals. The burrowing assay methodology involves loading animals at the bottom of well plates, casting a liquid-phase of Pluronic on top that solidifies via a modest temperature upshift, enticing animals to reach the surface via chemotaxis to food, and quantifying the relative success animals have in reaching the chemoattractant. We study the influence of Pluronic concentration, gel height and chemoattractant choice to optimize assay performance. To demonstrate the simplicity of the assay workflow and versatility, we show its novel application in multiple areas including (i) evaluating muscle mutants with defects in dense bodies and/or M-lines (pfn-3, atn-1, uig-1, dyc-1, zyx-1, unc-95 and tln-1), (ii) tuning assay conditions to reveal changes in the mutant gei-8, (iii) sorting of fast burrowers in a genetically-uniform wild-type population for later quantitation of their distinct muscle gene expression, and (iv) testing proteotoxic animal models of Huntington and Parkinson’s disease. Results from our studies show that stimulating animals to navigate in a dense environment that offers mechanical resistance to three-dimensional locomotion challenges the neuromuscular system in a manner distinct from standard crawling and thrashing assays. Our simple and high throughput burrowing assay can provide insight into molecular mechanisms for maintenance of neuromuscular health and facilitate screening for therapeutic targets.

Relaxation Behavior and Nonlinear Surface Rheology of PEO-PPO-PEO Triblock Copolymers at the Air-Water Interface.

Surface dilatational viscoelasticity of adsorbed layers of pluronics triblock copolymers at the air-water interface was measured using the oscillating barrier technique. The effect of molecular architecture and concentration on surface viscoelasticity was explored for two different types of pluronics with different degrees of hydrophobicity, Pluronic F-108 (Mw ≈ 14 600 g/mol) and Pluronic P-123 (Mw ≈ 5800 g/mol), the former exhibiting a larger hydrophilic to hydrophobic block length ratio. Frequency sweeps in the linear regime suggested that interfacial films of F-108 have higher surface limiting elasticity and larger in-plane and out-of-plane relaxation times at the same bulk concentration (the former possibly related to in-plane microstructure rearrangements, the latter to surface/bulk diffusion). Increasing the bulk concentration of pluronics from 1 to 100 μM led to a decrease in both in- and out-of-plane relaxation times. Large amplitude oscillatory dilatation (LAOD) tests were performed to capture nonlinear behavior of these interfacial films by means of elastic and viscous Lissajous plots. Nonlinearities in elastic responses were quantified through calculation of the strain-stiffening indices in extension SE and compression SC. Both pluronics exhibited strain softening in extension. In compression, P-123 showed strain-hardening and F-108 displayed a relatively linear response. Apparent strain hardening in extension was observed for the P-123 adsorbed film, at high strain, at a bulk concentration of 100 μM. However, at these strains, the response was dominated by the viscous contribution and calculation of strain rate-thickening factors in extension and compression showed that the overall response was strain rate-thinning in extension and strain rate-thickening in compression.

Hydrophobic Modification of Copper Nanospheres for Incorporation into Poloxamer Micelles, Aggregated Micellar Nanocages and Supramolecular Assemblies

Background: Polymer nanogels are increasingly used for the encapsulation of nano-solids and quantum dots such as in advanced forms of drug and therapeutic isotope delivery. Objective: Unlike ex vivo application of systems in vivo application and internalization are likely to suffer from aspects of failure to ensure safety and biocompatibility. Biocompatible hydrophilic poloxamer (Pluronic F108 and F68) micelles were studied by light scattering and tensiometry. Methods: The micelles of nano-gels are synthetic heteropolymer aggregates, which are used to encapsulate drugs but in this study chemically-modified (hydrophobized) copper nano-spheres, for the purposes of demonstration for further application and medical use. Copper benzoate nano-particles (CuBzNPs) were produced by maceration and subsequently stabilized in Pluronic F108 solution was added at different concentrations. Results: The resulting particle size increase was studied by dynamic light scattering. Moderate size increase was observed at low Pluronic F108 concentrations, which indicated successful coating, but at higher F108 concentrations large size agglomerates formed. Coated copper benzoate nano-particles (CuBzNPs) were fabricated as a proof-of-principle and as a substitute for bare metal nano-particles (MNs), which were not successfully entrained in the poloxamer nano-gel. As part of the synthesis copper benzoate (CuBz) beads and their characterization through contact angle measurements were performed. Conclusion: Micelles sizes of 4 nm for F68 Pluronic at equilibrium surface tensions of 36 mNm-1 were captured in weak, 1.25 to 2.0 Pas pseudoplastic gels fabricated from hydroxypropylmethylcellulose (HPMC).

Vibration Characteristics and Persistence of Poloxamer- or Phospholipid-Coated Single Microbubbles under Ultrasound Irradiation.

Microbubbles shelled with soft materials are expected to find applications as ultrasound-sensitive drug delivery systems, including through sonoporation. Microbubbles with specific vibrational characteristics and long intravascular persistence are required for clinical uses. To achieve this aim, the kinetics of the microbubble shell components at the gas/liquid interface while being subjected to ultrasound need to be better understood. This paper investigates the vibration characteristics and lifetime of single microbubbles coated with a poloxamer surfactant, Pluronic F-68, and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) under ultrasound irradiation. Air- and perfluorohexane (PFH)-filled microbubbles coated with Pluronic F-68 and DMPC at several concentrations (0 to 10-2 mol L-1) were produced. An optical measurement system using a laser Doppler vibrometer and microscope was used to observe the radial vibration mode of single microbubbles. The vibrational displacement amplitude and resonance radius of Pluronic- or DMPC-coated microbubbles were found to depend very little on the concentrations. The resonance radius was around 65 μm at 38.8 kHz under all the experimental conditions investigated. The lifetime of the microbubbles was investigated simultaneously by measuring their temporal change in volume, and it was increased with Pluronic concentration. Remarkably, the oscillation amplitude of the bubble has an effect on the bubble lifetime. In other words, larger oscillation under the resonance condition accelerates the diffusion of the inner gas.

Sustained delivery of a camptothecin prodrug - CZ48 by nanosuspensions with improved pharmacokinetics and enhanced anticancer activity.

Background and aim: We have synthesized a novel lactone-stabilized camptothecin (CPT) analog named CZ48 and demonstrated its potent anticancer effects via bioconversion to the active CPT in earlier studies. Herein, we aimed to develop, optimize and characterize CZ48 nanosuspensions, for a sustained delivery of this drug in humans with an intravenous (i.v.) administration.Methods and materials: A three-factor, five-level central composite design (CCD) was employed to establish the impacts of the critical influencing factors (concentrations (wt%) of CZ48, polysorbate 80 (Tween-80), and Pluronic® F-108 (F-108)) on the responses (particle size and zeta potential). Based on the quantitative influencing factor–response relationships, two optimized CZ48 nanosuspensions of 197.22 ± 7.12 nm (NS-S) and 589.35 ± 23.27 nm (NS-L) were developed with the zeta potential values of –26.5 mV and –27.9 mV, respectively.Results: CZ48 released from the nanosuspensions in a sustained manner in contrast to the rapid release from cosolvent in both PBS and human plasma. Moreover, NS-S exhibited more favored pharmacokinetic properties than NS-L, with a 31-fold prolonged elimination half-life of CPT, and a 2.4-fold enhanced CPT exposure over cosolvent. In efficacy study, NS-S exhibited significant tumor suppression and an improved survival rate with a higher tolerable dose, compared to CZ48 cosolvent.Conclusion: We have successfully developed CZ48 nanosuspensions with significantly favorable pharmacokinetics and improved efficacy using CCD approach. The formulation offers potential merits as a preferred candidate for clinical trials with the prolonged CPT exposure, which is known to correlate with the clinical efficacy.

Size-Controlled Preparation of Microsized Perfluorocarbon Emulsions as Oxygen Carriers via the Shirasu Porous Glass Membrane Emulsification Technique.

We have developed microsized perfluorocarbon (PFC) emulsions with different sizes as artificial oxygen carriers (OCs) via Shirasu porous glass membrane emulsification. Monodispersed PFC emulsions with narrow size distribution were obtained. By changing the membrane pore size, we were able to precisely control the size of emulsions and fabricate emulsions similar in size to human red blood cells. Behaviors of Pluronics with different physiochemical properties (F127, F68, P85, and P103) as surfactants were also investigated, which evidenced that the type and concentration of Pluronics have a major impact on the size of emulsions and the response to different thermal conditions. The F127-stabilized microsized PFC emulsions were stable even during autoclave sterilization. The emulsions were loaded with Ru(ddp)-an oxygen-sensitive probe-on their surfaces to indicate oxygen concentration. Finally, incubations with HeLa cells that show fluorescence in response to hypoxia cultured in 2D and 3D suggested promising potential of our emulsions for OCs.

One-pot Synthesis of LiFePO4 Nano-particles Entrapped in Mesoporous Melamine-Formaldehyde Matrix as the Promising Cathode Materials for the Next Generation Lithium Ion Batteries

Abstract LiFePO4 is considered as the promising cathode material for a large-scale Li batteries used in electrical vehicles (EVs). However, a practical use of LiFePO4 cathode is limited by its low ionic conductivity, resulting in low battery’s power performance. In this work, a facile approach to promote ionic conductivity and capacity of LiFePO4 was developed by dispersing LiFePO4 nanoparticle into a porous nitrogen-riched carbon matrix, facilitated by practical one-pot synthesis The N-containing carbon porous matrix was prepared by utilizing pluronic F127 as the porous template and melamine-formaldehyde (MF) resin as the N-containing carbon precusor. The pseudocapacitive effect attributed from lone-pair electrons into melamine functional group was expected to support Li ion transport. Carbonization at 600 °C could provide uniform LiFePO4 composites cluster with an average size of about 100-200 nm. The influence of the pluronic F127 concentration (i.e. 0:1, 0.03:1, 0.3:1, F127:MF molar ratio) on the LiFePO4 nanocomposite’s morphology and crystalline structure was investigated by using scanning electron microscope and X-ray diffraction technique. Increasing the concentrations of pluronic F127 can support more porous structure formation, leading to a higher surface area, while sustain the nanocrystalline structure of LiFePO4. The result of a specific capacity is 158.1 mAh g-1, at a rate of 0.1 C was achieved for a Swagelok-type cell battery prepared from our LiFePO4 nano-composite.

Aripiprazole-Loaded Polymeric Micelles: Fabrication, Optimization and Evaluation using Response Surface Method.

The fundamental objective of current study was to encapsulate Aripiprazole (ARP) within Pluronic F127 micelles to improve its aqueous solubility. The recent patents on Aripiprazole (JP2013136621) and micelles (WO2016004369A1) facilitated selection of drug and polymer. The drug-laden micelles were fabricated using thin-film hydration technique. Optimization of the micellar formulation was done by using response surface method (RSM). The Pluronic F127 concentration of 150 mg and 75 rpm rotational speed of rotary evaporator were found to be optimized conditions for formulating micelles. The prepared batches were further characterized for PDI (polydispersity index), zeta potential, % DLC (% Drug loading content), % EE (% Entrapment Efficiency) and % drug release study; results of these parameters were found to be 0.228, -4.04 mV and 76.50 % and 18.56 % respectively. It was observed from the In vitro release study that 97.37 ± 1.81 % drug had released from micelles after 20h which were found about thrice as compared to that of pure drug. The optimized ARP micellar formulation was characterized using DSC (Differential Scanning Colorimetry), FT-IR (Fourier Transformed Infrared Spectroscopy), P-XRD (Powdered X-ray Diffraction Study) and TEM (Transmission Electronic Microscopy) studies. ARP-loaded micelles displayed a hydrodynamic diameter of 170.3 nm and a sphere-shaped morphology as determined by dynamic light scattering as well as TEM study. It is concluded that the prepared polymeric micellar system has an excellent potential to be used as a delivery carrier for Aripiprazole with increased solubility.

ID: 1059 Biomimetic release of growth factor from porous beads for enhanced bone regeneration

Three dimensional scaffolds which allow sustained release of bioactive molecules have been considered as an essential component for enhanced bone regeneration. In recent years, combination system of various bioactive molecules has been extensively investigated to reconstruct more sophisticated bone regeneration. It is well-known that if the certain bioactive molecules with appropriate dose and stimulation periods are applied to bone defect, the physiological processes in bone regeneration may be accelerated. However, many studies were not concerned stimulation periods of bioactive molecules occurred in body during new bone formation because of absence of proper release system for the bioactive molecules. In this study, we selected three bioactive molecules (PDGF-BB, VEGF, BMP-2) which widely used for effective bone healing, and developed a porous bead with leaf-stacked structure which can allow controlled release of growth factors by concentration and composition of Pluronics. The morphology, each growth factor release profiles, migration (boyden chamber assay), angiogenic differentiation (tube formation, ICC, and RT-PCR), osteogenic differentiation (ALP activity, calcium deposition, alizarin/ALP staining, ICC, and RT-PCR) of human periosteum-derived cells and new bone formation of rat calvarial defect model by controlled release of growth factors were estimated

The components of shear stress affecting insect cells used with the baculovirus expression vector system.

Insect-based expression platforms such as the baculovirus expression vector system (BEVS) are widely used for the laboratory- and industrial-scale production of recombinant proteins. Thereby, major drawbacks to gain high-quality proteins are the lytic infection cycle and the shear sensitivity of infected insect cells due to turbulence and aeration. Smaller bubbles were formerly assumed to be more harmful than larger ones, but we found that cell damage is also dependent on the concentration of protective agents such as Pluronic®. At the appropriate concentration, Pluronic forms a layer around air bubbles and hinders the attachment of cells, thus limiting the damage. In this context, we used microaeration to vary bubble sizes and confirmed that size is not the most important factor, but the total gas surface area in the reactor is. If the surface area exceeds a certain threshold, the concentration of Pluronic is no longer sufficient for cell protection. To investigate the significance of shear forces, a second study was carried out in which infected insect cells were cultivated in a hollow fiber module to protect them from shear forces. Both model studies revealed important aspects of the design and scale-up of BEVS processes for the production of recombinant proteins.

Effects of amphiphilic pluronic F127 on the performance of PS/SPEEK blend ultrafiltration membrane: Characterization and antifouling study

The effect of amphiphilic Pluronic F127 additive on the ultrafiltration performance of polysulfone (PSf)/sulfonated poly (ether ether ketone) (SPEEK) blend flat sheet membranes was investigated in the present work. Fixed amount of SPEEK was used throughout the experiments to improve the PSf membrane surface performance and permeability properties. The addition of various proportions of Pluronic F127 was used to improve the hydrophilic characteristics of blend PSf/SPEEK membranes. It was found that membranes surface hydrophilicity, surface roughness, equilibrium water content and pores size increased with increasing Pluronic F127 concentration in the blend. The increase of Pluronic F127 additive in the blend changed the membrane morphology from finger-like to sponge-like structure. performance of the membranes were evaluated in terms of pure water, humic acid (HA) and bovine serum albumin (BSA) permeation fluxes which were found to increase with increased Pluronic F127 concentration. The BSA was used as a model foulant to investigate flux rejection and flux recovery ratio (FRR%). The PLU-5.5 membrane achieved the highest BSA rejection (97.55%) with FRR (78.18%) values.

Partitioning of Small Molecules in Hydrogen-Bonding Complex Coacervates of Poly(acrylic acid) and Poly(ethylene glycol) or Pluronic Block Copolymer

Complex coacervation of polymers can be a route to the compartmentalization of aqueous solutions. Presented here is a study of the hydrogen-bonded complex coacervation of poly(acrylic acid) and poly(ethylene glycol) or Pluronic block copolymers and the ability of these coacervates to encapsulate various ionic and nonionic dyes as well as a pharmaceutical compound within them. The formation of complex coacervate driven by hydrogen bonding is studied as a function of both pH and salt content with turbidimetry and isothermal calorimetry. Small-angle X-ray scattering shows the presence of micelles within Pluronic containing coacervate materials formed with a Pluronic block copolymer concentration higher than its critical micelle concentration. Although dyes generally partition to the coacervate phase, in the absence of salt, dyes that are able to hydrogen bond with the coacervate components are better incorporated into the coacervate. It is observed that the addition of salt to the polymer solutions increases...

Unbiased High-Precision Cell Mechanical Measurements with Microconstrictions

We describe a quantitative, high-precision, high-throughput method for measuring the mechanical properties of cells in suspension with a microfluidic device, and for relating cell mechanical responses to protein expression levels. Using a high-speed (750 fps) charge-coupled device camera, we measure the driving pressure Δp, maximum cell deformation εmax, and entry time tentry of cells in an array of microconstrictions. From these measurements, we estimate population averages of elastic modulus E and fluidity β (the power-law exponent of the cell deformation in response to a step change in pressure). We find that cell elasticity increases with increasing strain εmax according to E ∼ εmax, and with increasing pressure according to E ∼ Δp. Variable cell stress due to driving pressure fluctuations and variable cell strain due to cell size fluctuations therefore cause significant variability between measurements. To reduce measurement variability, we use a histogram matching method that selects and analyzes only those cells from different measurements that have experienced the same pressure and strain. With this method, we investigate the influence of measurement parameters on the resulting cell elastic modulus and fluidity. We find a small but significant softening of cells with increasing time after cell harvesting. Cells harvested from confluent cultures are softer compared to cells harvested from subconfluent cultures. Moreover, cell elastic modulus increases with decreasing concentration of the adhesion-reducing surfactant pluronic. Lastly, we simultaneously measure cell mechanics and fluorescence signals of cells that overexpress the GFP-tagged nuclear envelope protein lamin A. We find a dose-dependent increase in cell elastic modulus and decrease in cell fluidity with increasing lamin A levels. Together, our findings demonstrate that histogram matching of pressure, strain, and protein expression levels greatly reduces the variability between measurements and enables us to reproducibly detect small differences in cell mechanics.