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Doan TKD, Umezawa M, Okubo K, Kamimura M, Soga K. Enhancing near-infrared fluorescence intensity and stability of PLGA-b-PEG micelles by introducing Gd-DOTA at the core boundary. J Biomed Mater Res B Appl Biomater 2024; 112:e35327. [PMID: 37732480 DOI: 10.1002/jbm.b.35327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 07/16/2023] [Accepted: 09/07/2023] [Indexed: 09/22/2023]
Abstract
Micelles have been extensively used in biomedicine as potential carriers of hydrophobic fluorescent dyes. Their small diameters can potentially enable them to evade recognition by the reticuloendothelial system, resulting in prolonged circulation. Nevertheless, their lack of stability in physiological environments limits the imaging utility of micelles. In particular, when a dye sensitive to water, such as IR-1061, is encapsulated in the micelle core, the destabilized structure leads to interactions between water and dye, degrading the fluorescence. In this study, we investigated a method to improve micelle stability utilizing the electrical effect of gadolinium (Gd3+ ) and tetraazacyclododecane tetraacetic acid (DOTA), introduced into the micelles. Three micellar structures, one containing a poly(lactic-co-glycolic acid)-block-poly(ethylene glycol) (PLGA-b-PEG) block copolymer, and two other structures, including PLGA-b-PEG with DOTA or Gd-DOTA introduced at the boundary of PLGA and PEG, were prepared with IR-1061 in the core. Structures that contained DOTA at the border of the PLGA core and PEG shell exhibited much higher fluorescence intensity than probes without DOTA. With Gd3+ ions at the DOTA center, fluorescence stability was enhanced remarkably in physiological environments. Most interesting is the finding that fluorescence is enhanced with increased Gd-DOTA concentrations. In conclusion, we found that overall fluorescence and stability are improved by introducing Gd-DOTA at the boundary of the PLGA core and PEG shell. Improving micelle stability is crucial for further biomedical applications of micellar probes such as bimodal fluorescence and magnetic resonance imaging.
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Affiliation(s)
- Thi Kim Dung Doan
- Research Institute for Biomedical Science, Tokyo University of Science, Chiba, Japan
- Division of Functional Imaging, Exploratory Oncology Research & Clinical Trial Center, National Cancer Center, Kashiwa, Japan
| | - Masakazu Umezawa
- Department of Material Science and Technology, Tokyo University of Science, Tokyo, Japan
| | - Kyohei Okubo
- Department of Material Science and Technology, Tokyo University of Science, Tokyo, Japan
| | - Masao Kamimura
- Department of Material Science and Technology, Tokyo University of Science, Tokyo, Japan
| | - Kohei Soga
- Research Institute for Biomedical Science, Tokyo University of Science, Chiba, Japan
- Department of Material Science and Technology, Tokyo University of Science, Tokyo, Japan
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Takeda K, Fujimoto K, Yoshii N, Okazaki S. Molecular dynamics study of solubilization of cyclohexane, benzene, and phenol into mixed micelles composed of sodium dodecyl sulfate and octaethylene glycol monododecyl ether. J Comput Chem 2019; 40:2722-2729. [PMID: 31429106 DOI: 10.1002/jcc.26047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 07/24/2019] [Accepted: 07/30/2019] [Indexed: 02/04/2023]
Abstract
Molecular dynamics calculations of a mixed micelle composed of sodium dodecyl sulfate (SDS) and octaethylene glycol monododecyl ether (C12 E8 ) were performed for six compositions (SDS/C12 E8 = 100/0, 80/20, 60/40, 40/60, 20/80, and 0/100) to investigate the composition dependence of the mixed micelle structure and solubilization of cyclohexane, benzene, and phenol molecules by the micelle. The radial density distribution of the hydrophilic polyoxyethylene (POE) group of C12 E8 as a function of distance from the micelle center is very sharp for micelles with high SDS content because the POE group captures a Na+ ion in solution and wraps around it to form a compact crown-ether-like complex. The hydrophobic dodecyl groups of SDS and C12 E8 were separately distributed in the mixed micelle core. ΔG(r) evaluated for each solute showed that despite the structural changes of the micelle the binding strength of the solute molecules to the micelle did not change significantly. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Kosuke Takeda
- Analytical Science Research Laboratories, Kao Corporation, 1334 Minato, Wakayama-Shi Wakayama, 640-8580, Japan.,Department of Materials Chemistry, Nagoya University, Furo-Cho, Chikusa-Ku, Nagoya, Aichi, 464-8603, Japan
| | - Kazushi Fujimoto
- Department of Materials Chemistry, Nagoya University, Furo-Cho, Chikusa-Ku, Nagoya, Aichi, 464-8603, Japan
| | - Noriyuki Yoshii
- Department of Materials Chemistry, Nagoya University, Furo-Cho, Chikusa-Ku, Nagoya, Aichi, 464-8603, Japan.,Center for Computational Science, Graduate School of Engineering, Nagoya University, Furo-Cho, Chikusa-Ku, Nagoya, Aichi, 464-8603, Japan
| | - Susumu Okazaki
- Department of Materials Chemistry, Nagoya University, Furo-Cho, Chikusa-Ku, Nagoya, Aichi, 464-8603, Japan.,Center for Computational Science, Graduate School of Engineering, Nagoya University, Furo-Cho, Chikusa-Ku, Nagoya, Aichi, 464-8603, Japan
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Khedr A, Striolo A. Quantification of Ostwald Ripening in Emulsions via Coarse-Grained Simulations. J Chem Theory Comput 2019; 15:5058-5068. [PMID: 31411875 DOI: 10.1021/acs.jctc.9b00296] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ostwald ripening is a diffusional mass transfer process that occurs in polydisperse emulsions, often with the result of threatening the emulsion stability. In this work, we design a simulation protocol that is capable of quantifying the process of Ostwald ripening at the molecular level. To achieve experimentally relevant time scales, the dissipative particle dynamics (DPD) simulation protocol is implemented. The simulation parameters are tuned to represent two benzene droplets dispersed in water. The coalescence between the two droplets is prevented via the introduction of membranes, which allow diffusion of benzene from one droplet to the other. The simulation results are quantified in terms of the changes in the droplet volume as a function of time. The results are in qualitative agreement with experiments. The agreement with the Lifshitz-Slyozov-Wagner theory becomes quantitative when the simulated solubility and diffusion coefficient of benzene-in-water are considered. The effect of two different surfactants was also investigated. In agreement with both experimental observations and theory, the addition of surfactants at moderate concentrations decreased the Ostwald ripening rate because of the reduction in the interfacial tension between benzene and water; as the surfactant film becomes dense, other phenomena are likely to further delay the Ostwald ripening. In fact, the results suggest that the surfactant that yields higher density at the benzene-water interface delayed more effectively Ostwald ripening. The formation of micelles can also affect the ripening rate, in qualitative agreement with experiments, although our simulations are not conclusive on such effects. Our simulations show that the coarse-grained DPD formalism is able to capture the molecular phenomena related to Ostwald ripening and reveal molecular level features that could help to understand experimental observations. The results could be useful for predicting and eventually controlling the long-term stability of emulsions.
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Affiliation(s)
- Abeer Khedr
- Department of Chemical Engineering , University College London , London WC1E 7JE , United Kingdom
| | - Alberto Striolo
- Department of Chemical Engineering , University College London , London WC1E 7JE , United Kingdom
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Fu D, Gao X, Huang B, Wang J, Sun Y, Zhang W, Kan K, Zhang X, Xie Y, Sui X. Micellization, surface activities and thermodynamics study of pyridinium-based ionic liquid surfactants in aqueous solution. RSC Adv 2019; 9:28799-28807. [PMID: 35529658 PMCID: PMC9071189 DOI: 10.1039/c9ra04226a] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 09/01/2019] [Indexed: 11/21/2022] Open
Abstract
The micellization and surface activity properties of long-chain pyridinium ionic liquids n-alkyl-3-methylpyridinium bromide ([Cnmpy][Br], n: the carbon numbers of hydrophobic tails, n = 12, 14, 16) in aqueous solution were systematically investigated through electronic conductivity measurement, surface tension, and ultraviolet-absorption spectra. The surface chemical parameters and thermodynamics parameters were obtained. The [Cnmpy][Br] ionic liquids exhibit higher surface activities than conventional surfactants with corresponding alkyl chain lengths. The effects of inorganic salts (LiBr, NaBr, MgBr2), organic alcohols (C2H5OH, C3H7OH, C4H9OH, C5H11OH) and temperature on the critical micelle concentration (CMC) values of [Cnmpy][Br] aqueous solutions were also investigated. The CMC values remarkably decreased with the addition of inorganic salts. The CMC values increased slightly in the presence of ethanol, but decreased gradually as the chain length of the alcohol increased. The CMC values assumed a trend of decreasing and then increasing with the increase of temperature. The calculation results of thermodynamic parameters show that both adsorption and micellization processes of [Cnmpy][Br] are spontaneous; the enthalpy of [C12mpy][Br] is negative at 293.15 K and becomes negative with temperature increasing. For [C14mpy][Br] and [C16mpy][Br] this transition occurs at 288.15 K and the micellization process is entropy-driven in the investigated temperature range. This paper contains details on the micellization, surface activity properties, thermodynamics and effects of additives of [Cnmpy][Br].![]()
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Affiliation(s)
- Dong Fu
- Heilongjiang Academy of Sciences Institute of Advanced Technology
- Harbin
- China
| | - Xiaoru Gao
- Harbin FRP Research Institute
- Harbin
- China
| | - Bo Huang
- Heilongjiang Academy of Sciences Institute of Advanced Technology
- Harbin
- China
| | - Jue Wang
- Heilongjiang Academy of Sciences Institute of Advanced Technology
- Harbin
- China
| | - Yao Sun
- Heilongjiang Academy of Sciences Institute of Advanced Technology
- Harbin
- China
| | - Weijun Zhang
- Heilongjiang Academy of Sciences Institute of Advanced Technology
- Harbin
- China
| | - Kan Kan
- Heilongjiang Academy of Sciences Institute of Advanced Technology
- Harbin
- China
| | - Xiaochen Zhang
- Heilongjiang Academy of Sciences Institute of Advanced Technology
- Harbin
- China
| | - Yang Xie
- Heilongjiang Academy of Sciences Institute of Advanced Technology
- Harbin
- China
| | - Xin Sui
- Heilongjiang Academy of Sciences Institute of Advanced Technology
- Harbin
- China
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