Charged Micelles Research Articles

Self-assembly of positively charged polymer patchy micelles in organic solutions and the reversible ultrasound responsivity of the assemblies

Positively charged patchy micelles in organic solutions can self-assemble into vesicles with positively charged walls and the vesicles dissociate into transient nanostructures under sonication.

Synthesis and evaluation of polymeric micelle containing piperacillin/tazobactam for enhanced antibacterial activity

Infections caused by multidrug-resistant bacteria such as P. aeruginosa are important therapeutic complications. Piperacillin/Tazobactam is considered a safe antimicrobial agent. But we should not ignore the prevalence of resistant strains to this drug. In this work, a new polymeric micelle composed of Piperacillin/Tazobactam-loaded Poly (ethylene glycol) methyl ether-block-poly (lactide-co-glycolide) (PLGA-PEG) was developed to improve the antimicrobial performance of P/T. The SEM and TEM studies of PLGA-PEG micelle showed, semi-spherical morphology with a mean diameter of below 30 nm. Zeta potential results indicated that the surface charge of PLGA-PEG micelle was −2.98 mV, while after encapsulation of P/T, the surface charge decreases to −4.13 mV. Clinical strains of P. aeruginosa were isolated and their resistance pattern against different antibiotics was evaluated. The MIC of free and P/T -Loaded PLGA-PEG micelles was determined. Also, the effect of free or P/T micelle against minimal biofilm eradication concentration and motility inhibition was evaluated. The bacterial isolates were resistant to most common antibiotics. The MIC of the free drug form and micelle form ranged from 4 to 512 µg/ml and 2 to 256 µg/ml, respectively. Generally, micelle showed more effective antibiofilm activities, inhibition of bacterial motility and reducing the MIC than that free drug form.

Polyelectrolyte-micelle coacervates: intrapolymer-dominant vs. interpolymer-dominant association, solute uptake and rheological properties.

The effects of polyelectrolyte charge density, polyelectrolyte-to-surfactant ratio, and micelle species on coacervation were studied by turbidity, dynamic light scattering, and zeta potential measurements to examine the coacervation of the weak polyelectrolyte branched polyethylenimine (BPEI) and oppositely charged sodium dodecyl sulfate (SDS) micelles as well as BPEI and mixed micelles composed of SDS and poly(ethylene glycol) 4-nonylphenyl 3-sulfopropyl ether potassium salt (PENS). The results of dynamic light scattering and zeta potential measurements are discussed in terms of pH and BPEI-to-surfactant ratio. An intrapolymer-dominant to interpolymer-dominant association model for the BPEI-micelle coacervates was proposed based on the variation of size and zeta potential of coacervate particles by their BPEI-to-surfactant ratio. The partition coefficient of solutes into BPEI-micelle coacervates was determined using UV-vis measurements as a function of pH, BPEI-to-surfactant ratio, and mixed micelle composition. Both the hydrophobicity of solutes and micelles, as well as the association mode of coacervates, impact the solute uptake efficiency. Dynamic rheological measurements on the coacervates suggest that the rheological properties of the complex coacervates are impacted by the association mode of the coacervates as well as the charge density on BPEI chains during coacervation.

Application of Recycling Products of Aluminum Slags in Investment Casting Technology

Based on studies of fractional, chemical, and phase compositions of Al-containing slags of different origin, it is established that they are multicomponent systems consisting of metal and nonmetal parts. The nonmetal part includes water-soluble and water-insoluble compounds. A practical flowsheet of recycling of Al-containing slags is proposed with the purpose of its further use as the secondary refractory dusting material (SRDM). The positive effect of the SRDM on the quality of refractory ceramic molds for investment casting and the surface finish of aluminum pilot castings is established. Its use promotes a ninefold increase in strength of refractory ceramic molds when compared with the quartz sand mold and an increase in gas permeability by 15 and 33% when compared with molds made of fused alumina and quartz sand, respectively. The formation of refractory ceramic mold formed based on the SRDM is investigated. The interaction mechanism of the dusting material particles with the suspension is substantiated from the viewpoint of colloidal chemistry. When forming the layers of the ceramic mold using the SRDM, negatively charged aluminum hydroxide micelles are formed. The interaction of oppositely charged Al(OH)3 and SiO2 micelles promotes the close engagement of the secondary refractory dusting material particles to each other. The theoretical substantiation of the formation of the ceramic mold layers with the application of the SRDM makes it possible to explain the decrease in the roughness characteristics on the surface of AK9ch alloy castings for the investment casting by a factor of 3.7 when compared with standard production processes.

Enhanced stability of crosslinked and charged unimolecular micelles from multigeometry triblock copolymers with short hydrophilic segments: dissipative particle dynamics simulation.

High micellar stability and well-performed drug loading and release are two conflicting factors for unimolecular micelles as an ideal drug delivery system. Achieving the formation of unimolecular micelles with short hydrophilic blocks is a challenging and promising approach to solve this bottleneck and limitation of current unimolecular micelle systems. In this work, dissipative particle dynamics (DPD) simulation is used to study the synergetic effect of crosslinking and electrostatic repulsion on stability of unimolecular micelles and to analyze the micro-mechanism and factors influencing this synergetic stabilization strategy. The strategy can generate unimolecular micelles with extremely high stability for various supramolecular polymers with short hydrophilic chains. Protonation of DEAEMA blocks leads to a large improvement in micellar hydrophilicity. The protonated middle layer further shrinks through crosslinking to produce the largest charge density, enlarging the electrostatic repulsion between colloidal particles. Additionally, the crosslinking and protonation treatment maximizes the extension degree of hydrophilic EO segments due to the increasing steric hindrance and poor compatibility between DEAHEMA and EO blocks. In this study, the relation between shrinkage degree of hydrophobic cores and stability of unimolecular micelles is first reported. The above-mentioned transition of micellar structures and properties results in the maximum degree of core shrinkage (Rg of MMA blocks) corresponding to the high stability of unimolecular micelles. Further study shows that the increasing cyclization degree, the mode of end cyclization, and the crosslinking and electrostatic repulsion of the middle layer all exert favorable effects on the stability of unimolecular micelles due to controlled shrinkage of hydrophobic cores.

From Structure to Function: pH-Switchable Antimicrobial Nano-Self-Assemblies.

Stimuli-responsive nanocarriers based on lipid self-assemblies have the potential to provide targeted delivery of antimicrobial peptides, limiting their side effects while protecting them from degradation in the biological environments. In the present study, we design and characterize a simple pH-responsive antimicrobial nanomaterial, formed through the self-assembly of oleic acid (OA) with the human cathelicidin LL-37 as a model for an amphiphilic antimicrobial peptide. Colloidal transformations from core-shell cylindrical micelles with a cross-sectional diameter of ∼5.5 nm and a length of ∼23 nm at pH 7.0 to aggregates of branched threadlike micelles at pH 5.0 were detected using synchrotron small-angle X-ray scattering, cryogenic transmission electron microscopy, and dynamic light scattering. Biological in vitro assays using an Escherichia coli bacteria strain showed high antimicrobial activity of the positively charged LL-37/OA aggregates at pH 5.0, which was not caused by the pH conditions themselves. Contrary to that, negligible antimicrobial activity was observed at pH 7.0 for the negatively charged cylindrical micelles. The nanocarrier's ability to switch its biological activity "on" and "off" in response to changes in pH could be used to focus the antimicrobial peptides' action to areas of specific pH in the body. The presented findings contribute to the fundamental understanding of lipid-peptide self-assembly and may open up a promising strategy for designing simple pH-responsive delivery systems for antimicrobial peptides.

Enrichment and Separation of Cationic, Neutral, and Chiral Analytes by Micelle to Cyclodextrin Stacking-Micellar Electrokinetic Chromatography.

Analyte focusing by micelle to cyclodextrin stacking (MCDS) in micellar electrokinetic chromatography (MEKC) using sodium dodecyl sulfate (SDS) and fused silica capillaries is demonstrated for neutral, cationic, and chiral analytes. The stacking was at a dynamic boundary formed between the injected charged SDS micelles and neutral γ-cyclodextrin (γ-CD) zones, where the analytes bound inside micelles were released due to the formation of stable SDS-CD inclusion complexes. The complex formation reduced or eliminated the affinity of the analytes to the micellar phase. There was reversal (for charged) or nulling (for neutrals) of the analyte's effective electrophoretic mobility that caused the analytes to accumulate at the boundary. Under the conditions where the SDS micelles velocity is faster than the electroosmotic flow (using acidic buffer), MCDS was conducted by injection of a long plug of sample in a micellar diluent after injection of a CD solution plug into a capillary that was filled with MEKC background solution. By simply extending the length of the CD plug, chiral separations of chlorpheniramine and phenoxyacid herbicides were achieved without optimizing the MEKC conditions. The analytical figures of merit including linearity and repeatability for the tested compounds were found acceptable, and the sensitivity enhancement factors were up to 171. The stacking strategy in MEKC was applied to metabolic stability studies of small molecules with HepG2 cell line, where the samples were only treated with acetonitrile and then diluted with the micellar diluent (demonstrating the reduction of tedious sample preparation requirements for biological samples prior to chemical analysis).

THE USE OF ALUMINUM SLAG RECYCLING PRODUCTS IN INVESTMENT CASTING TECHNOLOGIES

The studies of fractional, chemical and phase compositions of aluminum-containing slags of different origin found that slags are multi-component systems consisting of metal and non-metal parts. The non-metal part contains water-soluble and water-insoluble components. A practical scheme for recycling aluminum-containing slags was proposed in order to isolate the water-insoluble component to be further used a secondary refractory dusting material. It was found that the secondary refractory dusting material has a positive effect on the quality of refractory ceramic molds in investment casting and the surface finish of experimental aluminum castings. This material improves the strength of refractory ceramic molds by 9 times in comparison with silica sand molds and increases gas permeability by 15 % to 33 % in comparison with fused alumina and silica sand molds, respectively. The study covers the processes used to produce refractory ceramic molds based on the secondary refractory dusting material. The mechanism of interaction between dusting material particles and suspension is theoretically justified in terms of colloid chemistry. Negatively charged aluminum hydroxide micelles appear when ceramic mold layers are formed using the secondary refractory dusting material. Interaction between differently charged Al(OH)3 and SiO2 micelles makes secondary refractory dusting material particles come in close contact with each other. The theoretically justified processes of ceramic mold layer formation with the secondary refractory dusting material make it possible to explain the reduction in the surface roughness of castings made of AK9ch aluminum casting alloy using investment casting by 3.7 times compared with standard production processes.

Stretch and Breakage of Wormlike Micelles under Uniaxial Strain: A Simulation Study and Comparison with Experimental Results.

We use coarse-grained (CG) molecular dynamics simulations to determine the effect of uniaxial strain on the stress, scission stress, and scission energy of solutions of wormlike micelles of cetyltrimethylammonium chloride/sodium salicylate (NaSal). We find that the breaking stress, stretch modulus, and scission energy of the charged micelles are nonmonotonic functions of oppositely charged hydrotrope (NaSal) concentration. While the stretch modulus shows a peak at a value of surfactant-to-hydrotrope concentration ratio ( R) close to unity as expected due to neutralization of head-group charge at R = 1, the breaking stress and scission energy produce a peak at R < 1.0 because of thinning of the micelle diameter with increased R. The breaking stress from the simulations depends on the rate of deformation and roughly agrees with the experimental values of Rothstein ( J. Rheol. 2003 , 47 , 1227 ) after extrapolation to the much lower experimental rates. The method and results can be used to predict the effects of flow and mechanical stress on rates of micellar breakage, which is important in the rheology of wormlike micellar solutions.

Dissecting the mechanism of action of actinoporins. Role of the N-terminal amphipathic α-helix in membrane binding and pore activity of sticholysins I and II.

Actinoporins sticholysin I and sticholysin II (St I, St II) are proposed to lyse model and biomembranes via toroidal pore formation by their N-terminal domain. Based on the hypothesis that peptide fragments can reproduce the structure and function of this domain, the behavior of peptides containing St I residues 12–31 (StI12-31), St II residues 11–30 (StII11-30), and its TOAC-labeled analogue (N-TOAC-StII11-30) was examined. Molecular modeling showed a good match with experimental structures, indicating amphipathic α-helices in the same regions as in the toxins. CD spectra revealed that the peptides were essentially unstructured in aqueous solution, acquiring α-helical conformation upon interaction with micelles and large unilamellar vesicles (LUV) of variable lipid composition. Fluorescence quenching studies with NBD-containing lipids indicated that N-TOAC-StII11-30’s nitroxide moiety is located in the membranes polar head group region. Pyrene-labeled phospholipid inter-leaflet redistribution suggested that the peptides form toroidal pores, according to the mechanism of action proposed for the toxins. Binding occurred only to negatively charged LUV, indicating the importance of electrostatic interactions; in contrast the peptides bound to both negatively charged and zwitterionic micelles, pointing to a lesser influence of these interactions. In addition, differences between bilayers and micelles in head group packing and in curvature led to differences in peptide-membrane interaction. We propose that the peptides topography in micelles resembles that of the toxins in the toroidal pore. The peptides mimicked the toxins permeabilizing activity, St II peptides being more effective than StI12-31. To our knowledge, this is the first demonstration that differences in the toxins N-terminal amphipathic α-helix play a role in the difference between St I and St II activities.

Synthesis, self-assembly and micellization characteristics of choline alkanoate ionic liquids in association with a star block copolymer

Herein, alkyl chain dependent self-assembly of choline carboxylate ionic liquids (ILs) and their effect on micellar characteristics of a star block copolymer (Tetronic®T1304) are reported. The ILs showed good aqueous solubility (low Kraft point) and formed spherical micelles. Small angle neutron scattering (SANS) analyses revealed a reduction in the critical micelle concentration (CMC) and elevation in the aggregation number (Nagg) upon increasing alkyl chain length of ILs. More importantly, ILs demonstrated good biocompatibility in murine erythrocytes and A549 cells, irrespective of the chain length.Furthermore, the effect of IL addition on micellar behaviour of T1304 was examined through thermal and scattering studies. We observed alkyl chain dependent increase in the cloud point (CP), critical micellization temperature (CMT), micelle size (Rh, Rc, Rhs) and Nagg. In association with T1304, long chain ILs (n = C12–C18) formed charged mixed micelles with a lower Nagg which showed enhanced solubilization of quercetin, a hydrophobic drug. Mixed micelles, composed with such biocompatible ILs, can further be tuned to explore their drug delivery applications.

Nonmonotonic Scission and Branching Free Energies as Functions of Hydrotrope Concentration for Charged Micelles.

Using coarse-grained molecular dynamics simulations and an umbrella sampling method that uses local surfactant density as a reaction coordinate, we directly calculate, for the first time, both the scission and branching free energies of a model charged micelle [cationic cetyltrimethylammonium chloride (CTAC)] in the presence of inorganic and organic salts (hydrotropes). We find that while inorganic salt only weakly affects the micelle scission energy, organic hydrotropes produce a strong, nonmonotonic dependence of both scission energy and branching on salt concentration. The nonmonotonicity in scission energy is traced to a competition between electrostatic screening of the repulsions among the surfactant head groups and thinning of the micellar core, which result from attachment of the hydrotropes to the micelle surface. We are able to correlate the nonmonotonicity in the scission energy of CTAC micelles with the peak observed experimentally in viscosity versus hydrotrope concentration and the location of this peak in CTAC solutions.

Unique silica enclosures form on micelles

Researchers have created “silicages,” 10-nm-diameter dodecahedral silica enclosures that could serve as carriers for therapeutic drugs or diagnostic agents. Ulrich Wiesner and coworkers at Cornell University created the objects by mixing tetramethyl orthosilicate with pore-expanded cetyltrimethylammonium bromide micelles (Nature 2018, DOI: 10.1038/s41586-018-0221-0). In the mechanism they propose for the process, the silicate starting material forms negatively charged silica clusters that self-assemble into dodecahedra on surfaces of the positively charged micelles. The micelles end up inside the cages but can be removed later to generate hollow enclosures. Wiesner and coworkers used cryo-electron microscopy to confirm the symmetrical structure of the self-assembled objects. In preliminary results, the group shows that vanadium oxide, gold, and silver also self-assemble into cages, suggesting that the approach may extend to a range of inorganic starting materials. The discovery “is a major fundamental achievement,” comments functional nanosystems expert Thomas Bein of the University of Munich. “Packaging and

Imidazole-Bearing Polymeric Micelles for Enhanced Cellular Uptake, Rapid Endosomal Escape, and On-demand Cargo Release

The complex design of multifunctional nanomedicine is beneficial to overcome the multiple biological barriers of drug delivery, but it also presents additional hurdles to clinical translation (e.g., scaling-up and quality control). To address this dilemma, we employed a simple imidazole-bearing polymer micelle for enhanced cellular uptake, facilitated endosomal escape, and on-demand release of a model drug, SN-38. The micelles were crosslinked by the reversible imidazole/Zn2+ coordination with a drug loading of ca. 4% (w/w) and a diameter less than 200nm. Under mimicked tumor microenvironment (pH6.8), the surface charge of micelles reversed from negative to positive, leading to enhanced micellesuptake by model 4T1 cells. Such effect was verified by fluorescent labelling of micelles. Compared to imidazole-free nanocarriers, the charge-reversal micelles delivered significantly more SN-38 to 4T1 cells. Due to the proton sponge effect, imidazole-bearing micelles could rapidly escape from endosomes compared to the control micelles, as evidenced by the kinetic analysis of micelle/endosome co-localization. The coordination crosslinking also enabled the acid-triggered drug release. This work provides a "three birds with one stone" approach to achieve the multifunctionality of nanocarriers without complicated particle design, and opens new avenues of advancing nanomedicine translation via simple tailored nanocarriers.

Influence of cationic and anionic micelles in the (sono)chemical synthesis of stable Ni(OH)2 nanoparticles: “In situ” zeta-potential measurements and electrochemical properties

In this work, we report the synthesis of Ni(OH)2 nanoparticles in the presence of the micelles formed by sodium dodecylbenzene sulfonate and cetyltrimethylammonium bromide. Key aspects about the particle formation and stability were studied by means of “in situ” zeta-potential measurements during the formation and dissolution of the nanoparticles. It was found that the intense electrostatic interaction between the positively charged Ni(OH)2 sheets and the negative DBS− micelles provides a remarkable colloidal and electrochemical stability, on the other hand, positively charged micelles presented weak interaction with Ni(OH)2. By this way, it is presented a comprehensive interpretation of the interaction of the surfactants during the formation and stability of Ni(OH)2 nanoparticles based on the intense superficial electric charge of the nanoparticles and how the interfacial and electrochemical properties are affected by. Also, electrodes were modified by using Electrophoretic Deposition and properly characterized by Atomic Force Microscopy and cyclic voltammetry.

Self-assembly of highly symmetrical, ultrasmall inorganic cages directed by surfactant micelles.

Nanometre-sized objects with highly symmetrical, cage-like polyhedral shapes, often with icosahedral symmetry, have recently been assembled from DNA1-3, RNA 4 or proteins5,6 for applications in biology and medicine. These achievements relied on advances in the development of programmable self-assembling biological materials7-10, and on rapidly developing techniques for generating three-dimensional (3D) reconstructions from cryo-electron microscopy images of single particles, which provide high-resolution structural characterization of biological complexes11-13. Such single-particle 3D reconstruction approaches have not yet been successfully applied to the identification of synthetic inorganic nanomaterials with highly symmetrical cage-like shapes. Here, however, using a combination of cryo-electron microscopy and single-particle 3D reconstruction, we suggest the existence of isolated ultrasmall (less than 10nm) silica cages ('silicages') with dodecahedral structure. We propose that such highly symmetrical, self-assembled cages form through the arrangement of primary silica clusters in aqueous solutions on the surface of oppositely charged surfactant micelles. This discovery paves the way for nanoscale cages made from silica and other inorganic materials to be used as building blocks for a wide range of advanced functional-materials applications.

Concentration-dependent changes to diffusion and chemical shift of internal standard molecules in aqueous and micellar solutions.

Sodium 4,4-dimethyl-4-silapentane-1-sulfonate (DSS) is the most widely accepted internal standard for protein NMR studies in aqueous conditions. Since its introduction as a reference standard, however, concerns have been raised surrounding its propensity to interact with biological molecules through electrostatic and hydrophobic interactions. While DSS has been shown to interact with certain proteins, membrane protein studies by solution-state NMR require use of membrane mimetics such as detergent micelles and, to date, no study has explicitly examined the potential for interaction between membrane mimetics and DSS. Consistent with its amphipathic character, we show DSS to self-associate at elevated concentrations using pulsed field gradient-based diffusion NMR measurements. More critically, DSS diffusion is significantly attenuated in the presence of either like-charged sodium dodecyl sulfate or zwitterionic dodecylphosphocholine micelles, the two most commonly used detergent-based membrane mimetic systems used in solution-state NMR. Binding to oppositely charged dodecyltrimethylammonium bromide micelles is also highly favourable. DSS-micelle interactions are accompanied by a systematic, concentration- and binding propensity-dependent change in the chemical shift of the DSS reference signal by up to 60ppb. The alternative reference compound 4,4-dimethyl-4-silapentane-1-ammonium trifluoroacetate (DSA) exhibits highly similar behaviour, with reversal of the relative magnitude of chemical shift perturbation and proportion bound in comparison to DSS. Both DSS and DSA, thus, interact with micelles, and self-assemble at high concentration. Chemical shift perturbation of and modulation of micellar properties by these molecules has clear implications for their use as reference standards.

Aqueous electrophoretic deposition of drugs using bile acids as solubilizing, charging and film-forming agents

A new electrophoretic deposition (EPD) technique is reported for the fabrication of composite coatings containing drugs, which have low solubility in water. We present a conceptually new approach, which is based on the use of bile salts (BS) as solubilizing, charging and film forming agents. Composite films are obtained using tetracycline and ibuprofen as model drugs with commercial BS, such as cholic acid sodium salt and deoxycholic acid sodium salt. The suggested mechanism involves the solubilization of drugs in BS solutions, followed by the formation of mixed charged micelles, containing drugs and charged BS, which allow electrophoretic transport of the drugs to the electrode surface. The EPD mechanism involves pH decrease at the anode surface, protonation of carboxylic groups of BS and formation of water insoluble films. The approach can be used for deposition of other functional organic molecules and inorganic nanoparticles.

Mechanism of Initial Film Formation during Cathodic Electrodeposition of Coatings

Electrodeposition of coatings is an effective way to form a protective layer on metal surfaces of complex shape. The uniformity of the deposit is a function of the current distribution, and depends on the induction time (time prior to “initiation” of deposition), the local deposition rate and the resistivity of the film that is formed. In cathodic electrodeposition, hydrogen gas evolves on the deposition surface, leading to an increase in the local pH. The change in pH reduces the solubility of the positively charged resin-containing micelles and causes a coating to form on the surface. The induction time, which is a key factor in the prediction of film thickness, has been attributed to the time that is required to increase the local pH to about 12 [1, 2]. The deposition rate, which is initially low, changes significantly during the induction period and eventually increases to a steady value that is proportional to the charge passed. An increased fundamental understanding is needed to improve our ability to accurately model E-coat systems in order to optimize performance. The purpose of this study is to develop a detailed understanding of the initial stages of deposit growth. Of particular interest are the changes that take place during the induction time. Experiments designed to elucidate the role of pH change clearly show that the local change in pH alone is not responsible for the induction time. This observation was further supported by additional experiments where the induction time at a specified current was observed to vary with the type of substrate used for deposition. Consequently, scanning electron microscopy was used to study the morphology of the initial deposit on different substrate surfaces including bare steel, galvanized steel, and phosphated steel. It was found that the initial film tends to form preferentially on defects and scratches in the metals. This observation was validated by experiments with intentionally scratched surfaces. The initial film also appeared to form around gas bubbles that were present on the substrate surface. The mechanism for preferred deposition at defects and bubbles is currently under investigation. As part of this effort, deposition on “defect free” surfaces has been performed. Microscopic images are used to track deposit formation as a function of time during the initial stages of deposition before formation of a highly resistive film. The rate of deposition increases with time, which may be connected to an increase in the local current density in the deposit free areas. The additional insight provided by this study will provide the basis for an improved model of the early stages of E-coat deposition. This model will then be incorporated into a large-scale simulation tool to enable improved process prediction and optimization. Acknowledgment The authors gratefully acknowledge funding from the Ford Motor Company under their University Research Program (URP). References Miskovic-Stankovic, V.B. and M.D. Maksimovic, The effect of concentration on the cathodic electrodeposition process. Process in Organic Coating, 1988. 16: p. 255-263.Pierce, P.E., The physical chemistry of the cathodic electrodeposition process. Journal of Coatings Technology and Research, 1981. 53: p. 52.

Low-Power All-Organic Electrophoretic Display Using Self-Assembled Charged Poly( t-butyl methacrylate) Microspheres in Isoparaffinic Fluid.

The increasing demands for display devices with low power consumption and outdoor readability have stimulated comprehensive research into full-color reflective displays that employ color-tunable photonic crystal technologies. Although the recently developed crystalline colloidal arrays (CCAs) of the charged microspheres have shown the outstanding color tunability, the practical application is limited because the use of highly polar liquid medium such as water is required to maintain the charges on the surface of microsphere, whereas it is not suitable for long-term use in an electric field. Herein, a self-assembled CCA from charged poly( t-butyl methacrylate) microspheres was successfully fabricated, which was stabilized by the charged inverse micelles of sodium di-2-ethylhexyl-sulfosuccinate in a nonpolar isoparaffinic fluid. A charged all-organic CCA was found to exhibit full-color tunability with a 1000-fold reduction in the power consumption (∼6 μW cm-2) under a direct current voltage bias of 4 V in comparison to that in an aqueous system, which is a promising feature for a low-power-consumption display device.