Synthesis of a Polyaniline Nanoparticle Using a Solution Plasma Process with an Ar Gas Bubble Channel

The dynamic therapeutic effect of a targeted photothermal nanovaccine incorporating toll-like receptor 7 agonist enhanced cancer immunotherapy

Photothermal therapy (PTT) is a noninvasive and effective thermal therapeutic approach. Near-infrared (NIR) light responsive organic nanoparticles (NPs) have been shown to enhance the efficacy of cancer PTT. However, photothermal ablation induced NPs are currently more effective in treating primary and metastatic cancer. Herein, we designed a NIR light responsive theranostic nanosystem that combines PTT with immunotherapy. The caffeic acid doped polyaniline NPs (CA-PANi) were explored for their potential as PTT agents and their ability to mediate immunogenic cell death (ICD). The nano-theranostic agent of CA-PANi functionalized with the RGD (Arg-Gly-Asp) peptide plays a functional role in targeting integrin receptor overexpressed cancer cells. Furthermore, to enhance the immune response in the immune suppressive tumor microenvironment (iTME), imiquimod (R837) a Toll-like receptor 7 agonist that can promote dendritic cell (DC) maturation greatly inhibits tumor growth and tumor recurrence by initiating a strong antitumor immune response. Therefore, combination of PTT and immunotherapy involving CA-PANi-R837-RGD (denoted as CPRR) to improve the therapeutic effect will provide a nanovaccine strategy for targeted antitumor therapy.

Plasma Electrochemistry for Carbon-Carbon Bond Formation via Pinacol Coupling

The formation of carbon-carbon bonds by pinacol coupling of aldehydes and ketones requires a large negative reduction potential, often realized with a stoichiometric reducing reagent. Here, we use solvated electrons generated via a plasma-liquid process. Parametric studies with methyl-4-formylbenzoate reveal that selectivity over the competing reduction to the alcohol requires careful control over mass transport. The generality is demonstrated with benzaldehydes, benzyl ketones, and furfural. A reaction-diffusion model explains the observed kinetics, and ab initio calculations provide insight into the mechanism. This study opens the possibility of a metal-free, electrically-powered, sustainable method for reductive organic reactions.

Intrinsic Light-Activated Oxidase Mimicking Activity of Conductive Polyaniline Nanofibers: A Class of Metal-Free Nanozyme

In recent decades, studies have focused on inorganic nanozymes to overcome the intrinsic drawbacks of bioenzymes due to the demands of improving the reaction conditions and lack of robustness to harsh environmental factors. Many biochemical reactions catalyzed by enzymes require light activation. Light-activated nanozymes have distinct advantages, including being regulated by light stimuli, activating the molecular oxygen to produce reactive oxygen species (ROS) without interfering supplementary oxidants, and often showing a synergistic effect to catalyze some challenging reactions. Only a few studies have been done on this connection. Therefore, it is still a big challenge to develop a nanozyme regulated by light activation. Herein, we uncovered the light-activated oxidase mimicking activity of a conducting polymer polyaniline nanofibers (PANI-NFs). PANI-NFs exhibit intrinsic light-activated brilliant oxidase-like activity, can catalyze the colorless tetramethyl benzidine (TMB) to produce a blue product TMBox, and have a distinct K_m = 0.087 mM and a high V_max = 2.32 μM min^-1 value, measured by using Hanes-Woolf kinetics. We also report the light-activated oxidase activity of some other renowned carbocatalysts graphene oxide and graphitic carbon nitride and compare them with PANI-NFs. This type of property shown by the conductive polymer is amazing. The density functional theory is used to verify the stability and the mode of adsorption of the PANI NFs-TMB composite, which corroborates the experimental results. Furthermore, the current nanozyme demonstrated a significant ability to kill both Gram-negative and Gram-positive bacteria as well as effectively destroy biofilms under physiological conditions. We believe that this work provides the motivation to create a link between optoelectronics and biological activity in the near future.

A Review of Plasma Synthesis Methods for Polymer Films and Nanoparticles under Atmospheric Pressure Conditions

In this paper, we present an overview of recent approaches in the gas/aerosol-through-plasma (GATP) and liquid plasma methods for synthesizing polymer films and nanoparticles (NPs) using an atmospheric-pressure plasma (APP) technique. We hope to aid students and researchers starting out in the polymerization field by compiling the most commonly utilized simple plasma synthesis methods, so that they can readily select a method that best suits their needs. Although APP methods are widely employed for polymer synthesis, and there are many related papers for specific applications, reviews that provide comprehensive coverage of the variations of APP methods for polymer synthesis are rarely reported. We introduce and compile over 50 recent papers on various APP polymerization methods that allow us to discuss the existing challenges and future direction of GATP and solution plasma methods under ambient air conditions for large-area and mass nanoparticle production.

In-Situ Iodine Doping Characteristics of Conductive Polyaniline Film Polymerized by Low-Voltage-Driven Atmospheric Pressure Plasma

In-situ iodine (I₂)-doped atmospheric pressure (AP) plasma polymerization is proposed, based on a newly designed AP plasma reactor with a single wire electrode that enables low-voltage-driven plasma polymerization. The proposed AP plasma reactor can proceed plasma polymerization at low voltage levels, thereby enabling an effective in-situ I₂ doping process by maintaining a stable glow discharge state even if the applied voltage increases due to the use of a discharge gas containing a large amount of monomer vapors and doping materials. The results of field-emission scanning electron microscopy (FE-SEM) and Fourier transformation infrared spectroscopy (FT-IR) show that the polyaniline (PANI) films are successfully deposited on the silicon (Si) substrates, and that the crosslinking pattern of the synthesized nanoparticles is predominantly vertically aligned. In addition, the in-situ I₂-doped PANI film fabricated by the proposed AP plasma reactor exhibits excellent electrical resistance without electrical aging behavior. The developed AP plasma reactor proposed in this study is more advantageous for the polymerization and in-situ I₂ doping of conductive polymer films than the existing AP plasma reactor with a dielectric barrier.

Effects of a Dielectric Barrier Discharge (DBD) on Characteristics of Polyaniline Nanoparticles Synthesized by a Solution Plasma Process with an Ar Gas Bubble Channel

The quality of polyaniline nanoparticles (PANI NPs) synthesized in plasma polymerization depends on the discharge characteristics of a solution plasma process (SPP). In this paper, the low temperature dielectric barrier discharge (DBD) is introduced to minimize the destruction of aniline molecules induced by the direct current (DC) spark discharge. By adopting the new electrode structure coupled with a gas channel, a low temperature DBD is successfully implemented in a SPP, for the first time, thus inducing an effective interaction between the Ar plasma and aniline monomer. We examine the effects of a low temperature DBD on characteristics of polyaniline nanoparticles synthesized by a SPP with an Ar gas bubble channel. As a result, both carbonization of aniline monomer and erosion of the electrode are significantly reduced, which is confirmed by analyses of the synthesized PANI NPs.