A Comparative Study of the Photothermal Efficiency of Electrically Conducting Poly(3,4-ethylenedioxythiophene)-Based Nanomaterials with Cancer Cells

Abstract

The photothermal efficiency of two similar organic nanomaterials, poly(3,4-ethylenedioxythiophene):poly(4-styrene-sulfonate) (PEDOT:PSS) nanoparticles and poly(3,4-ethylenedioxythiophene) (PEDOT) nanotubes, are compared. The PEDOT:PSS nanoparticles ranged from 100-200 nm in diameter, while the PEDOT nanotubes ranged from 200-400 nm in diameter and 4-10 microm in length. By changing the aspect ratio of the PEDOT nanomaterials from a spherical to a tubular shape, interesting differences in the optical and electronic properties of the materials were realized. Because of this, the PEDOT nanotubes were shown to generate on average approximately to 10 degrees C better internal heating for similar concentrations compared to the PEDOT:PSS nanoparticles. Cytotoxicity studies of both nanomaterials showed no significant toxicity towards RKO or HCT116 colorectal cancer cells in the absence of NIR light. The NIR-mediated photothermal efficiency of the PEDOT:PSS nanoparticles and the PEDOT nanotubes were compared in-vitro. A cell viability assay was performed and at the highest concentration (0.1 mg/mL) of nanomaterial, cell survival was close to 20% for the PEDOT:PSS nanoparticles with both RKO and HCT116 cells. Consequently, cell survival for the PEDOT nanotubes was less than 5% for both RKO and HCT116 cells. An in-vitro three dimensional tumor model was assembled using collagen gel tissue phantoms. The depth of heat penetration from the PEDOT nanotubes into the tissue phantoms, along with cell viability of RKO and HCT116 cells was determined and quantified.

Shaping PEDOT nanoparticles for use in 3D tissue phantoms

“…Syntheses 6 and 8 were chosen to best represent these groups respectively and then tested them in vitro to determine their cytocompatibility. The addition of surfactant Pluronic F127 to the collagen gel to help maintain dispersion of the nanoparticles most likely does not affect their morphology, as the concentration is very low (100 fold less than the amount of surfactant required for nanoparticle formation), and based on previous literature that conjugated polymer nanotubes and stable after formation and excess surfactant is inert . Figure shows that for the mouse cells, the particles show no difference from the control group regardless of the aspect ratio or 10‐fold difference in concentration tested.…”

“…PEDOT nanofibers can be custom made using a hard template method to control nucleation and growth, but this method can require large investments in technology . It would be advantageous to be able to make a variety of sizes and shapes in a simple manner because both overall size and relative dimensions (aspect ratio) govern particle properties, including optical and electrical effects for displays, and with biological applications such as synthetic cell interfaces, administration of heat, and pharmaceutical therapy …”

“…Alternatively, mild hyperthermia (38–44 °C) has been used to augment drug delivery and wound healing . Previous work done by our group has shown that PEDOT nanoparticles can be incorporated into tissue phantoms for evaluation of photothermal ablation of cancer cells by capitalizing on the infrared absorption properties inherent in PEDOT . In the previous work, commercially purchased PEDOT ellipsoids were used.…”

“…7 It would be advantageous to be able to make a variety of sizes and shapes in a simple manner because both overall size and relative dimensions (aspect ratio) govern particle properties, including optical and electrical effects for displays, and with biological applications such as synthetic cell interfaces, administration of heat, and pharmaceutical therapy. [7][8][9][10][11][12] Soft template methods take advantage of the thermodynamic equilibrium of catonic, anionic, or non-ionic solute concentrations. 3 Surfactants, such as sodium dodecylsulfate (SDS) or sodium bis (2-ethylhexyl) sulfosuccinate (AOT), can be used to generate a micellar template, and the shape of the micelles is dependent upon the hydrophobic nature of the material, solvents, and concentrations used.…”

“…[20][21][22][23][24][25][26][27] Previous work done by our group has shown that PEDOT nanoparticles can be incorporated into tissue phantoms for V C 2016 Wiley Periodicals, Inc. evaluation of photothermal ablation of cancer cells by capitalizing on the infrared absorption properties inherent in PEDOT. 11 In the previous work, commercially purchased PEDOT ellipsoids were used. The limitations of commercially produced PEDOT nanoparticles include the lack of control over the shape and corresponding optical properties.…”