A protocol is presented for the synthesis and preparation of nanoparticles consisting of electroactive polymers.
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Method Article
Electroactive Polymer Nanoparticles Exhibiting Photothermal Properties
In This Article
Summary
Abstract
A method for the synthesis of electroactive polymers is demonstrated, starting with the synthesis of extended conjugation monomers using a three-step process that finishes with Negishi coupling. Negishi coupling is a cross-coupling process in which a chemical precursor is first lithiated, followed by transmetallation with ZnCl2. The resultant organozinc compound can be coupled to a dibrominated aromatic precursor to give the conjugated monomer. Polymer films can be prepared via electropolymerization of the monomer and characterized using cyclic voltammetry and ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy. Nanoparticles (NPs) are prepared via emulsion polymerization of the monomer using a two-surfactant system to yield an aqueous dispersion of the polymer NPs. The NPs are characterized using dynamic light scattering, electron microscopy, and UV-Vis-NIR-spectroscopy. Cytocompatibility of NPs is investigated using the cell viability assay. Finally, the NP suspensions are irradiated with a NIR laser to determine their effectiveness as potential materials for photothermal therapy (PTT).
Introduction
Electroactive polymers change their properties (color, conductivity, reactivity, volume, etc.) in the presence of an electric field. The rapid switching times, tunability, durability, and lightweight characteristics of electroactive polymers have led to many proposed applications, including alternative energy, sensors, electrochromics, and biomedical devices. Electroactive polymers are potentially useful as flexible, light-weight battery and capacitor electrodes.1 Applications of electroactive polymers in electrochromic devices include glare-reduction systems for buildings and automobiles, sunglasses, protective eyewear, optical storage devices, an....
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Protocol
Caution: Please consult all relevant Safety Data Sheets (SDS) before use. Several of the reagents used in these syntheses are potentially hazardous. Please use all appropriate safety practices including personal protective equipment (safety glasses, gloves, lab coat, long pants, and closed-toe shoes), and perform syntheses in fume hoods. Lithiation is particularly hazardous and should only be performed by properly trained individuals with supervision.
1. Monomer Synthesis
Note: Figure 1 shows the chemical route for the preparation of precursors and monomers whose synthesis is described in Sections ....
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Results
The reaction protocol yielding M1 and M2 is shown in Figure 1. The monomers can be characterized by 1H and 13C NMR spectroscopy, melting point, and elemental analysis. The 1H NMR spectrum provides information regarding the connectivity of atoms and their electronic environments; thus, it is routinely used to verify that reactions have been completed successfully. Negishi coupling reactions involve coupling of the phenyl ring to the EDOT, c.......
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Discussion
In this work, electroactive polymer NPs have been synthesized as potential PTT agents for cancer treatment. The preparation of the NPs is described, starting with the synthesis of the monomers followed by emulsion polymerization. While the preparation of NPs using electroactive polymers such as EDOT and pyrrole has been described before, this paper describes the preparation of polymeric NPs starting with unique extended conjugation monomers, demonstrating that this process can be extended to larger, more complex monomers.......
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Disclosures
The authors have nothing to disclose.
Acknowledgements
This work was funded in part by the Texas Emerging Technology Fund (Startup to TB), the Texas State University Research Enhancement Program, the Texas State University Doctoral Research Fellowship (to TC), the NSF Partnership for Research and Education in Materials (PREM, DMR-1205670), The Welch Foundation (AI-0045), and National Institutes of Health (R01CA032132).
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Materials
| Name | Company | Catalog Number | Comments |
|---|---|---|---|
| 2 mm diameter platinum working electrode | CH Instruments | CH102 | Polished using very fine sandpaper |
| 3,4-ethylenedioxythiophene | Sigma-Aldrich | 483028 | Purified by vacuum distillation |
| 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) 98% | Alfa Aesar | L11939 | |
| 505 Sonic Dismembrator | Fisher Scientific™ | FB505110 | 1/8“ tip and rated at 500 watts |
| 808 nm laser diode | ThorLabs | L808P1WJ | Rated at 1 W |
| Acetonitrile anhydrous 99% | Acros | 61022-0010 | |
| Avanti J-26 XPI | Beckman Coulter | 393127 | |
| Bromohexane 98% | MP Biomedicals | 202323 | |
| Dialysis (100,000) MWCO | SpectrumLabs | G235071 | |
| Dimethyl sulfoxide 99% (DMSO) | BDH | BDH1115 | |
| Dimethylformamide anhydrous (DMF) 99% | Acros | 326870010 | |
| Dodecyl benzenesulfonate (DBSA) | TCI | D0989 | |
| Dulbecco’s modified eagle medium (DMEM) | Corning | 10-013 CV | |
| EMS 150 TES sputter coater | Electron Microscopy Sciences | ||
| Ethanol (EtOH) 100% | BDH | BDH1156 | |
| ethyl 4-bromobutyrate (98%) | Acros | 173551000 | |
| Ethyl acetate 99% | Fisher | UN1173 | |
| Fetal bovine serum (FBS) | Corning | 35-010-CV | |
| Helios NanoLab 400 | FEI | ||
| Hexane | Fisher | H306-4 | |
| Hydrochloric acid (HCl) | Fisher | A142-212 | |
| Hydroquinone 99.5% | Acros | 120915000 | |
| Hydrozine anhydrous 98% | Sigma-Aldrich | 215155 | |
| Indium tin oxide (ITO) coated galss | Delta Technologies | CG-41IN-CUV | 4-8 Ω/sq |
| Iron chloride 97% FeCl3 | Sigma-Aldrich | 157740 | |
| Magnesium sulfate (MgSO4) | Fisher | 593295 | Dried at 100 °C |
| SKOV-3 | ATCC | HTB-26 | |
| Methanol | BDH | BHD1135 | |
| n-Butlithium (2.5 M) | Sigma-Aldrich | 230707 | Pyrophoric |
| Poly(styrenesulfonate-co-malic acid) (PSS-co-MA) 20,000 MW | Sigma-Aldrich | 434566 | |
| Potassium carbonate | Sigma-Aldrich | 209619 | Dried at 100 °C |
| Potassium hydroxide | Alfa Aesar | A18854 | |
| Potassium iodide | Fisher | P410-100 | |
| RO-5 stirplate | IKA-Werke | ||
| SC4000 IR camera | FLIR | ||
| Synergy H4 Hybrid Reader | Biotek | ||
| Tetrabutylammonium perchlorate (TBAP) 99% | Sigma-Aldrich | 3579274 | Purified by recrystallization in ethyl acetate |
| Tetrahydrofuran anhydrous (THF) 99% | Sigma-Aldrich | 401757 | |
| tetrakis(triphenylphosphine) palladium(0) | Sigma-Aldrich | 216666 | Moisture sensitive |
| Thermomixer | Eppendorf | ||
| USB potentiostat/galvanostat | WaveNow | AFTP1 | |
| Zetasizer Nano Zs | Malvern | Optical Arrangment 175° | |
| Zinc chloride (1 M) ZnCl2 | Acros | 370057000 |
References
- Irvin, J., Irvin, D., Stenger-Smith, J. Electrically active polymers for use in batteries and supercapacitors. Handbook of Conducting Polymers. , (2007).
- Amb, C. M., Dyer, A. L., Reynolds, J. R. Navigating the color palette of solution-processable electrochrom....
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