Polyaniline Nanovesicles for Photoacoustic Imaging‐Guided Photothermal‐Chemo Synergistic Therapy in the Second Near‐Infrared Window

Abstract

Photoacoustic imaging‐guided photothermal therapy in the second near‐infrared (NIR‐II) window shows promise for clinical deep‐penetrating tumor phototheranostics. However, ideal photothermal agents in the NIR‐II window are still rare. Here, the emeraldine salt of polyaniline (PANI‐ES), especially synthesized by a one‐pot enzymatic reaction on sodium bis(2‐ethylhexyl) sulfosuccinate (AOT) vesicle surface (PANI‐ES@AOT, λmax ≈ 1000 nm), exhibits excellent dispersion in physiological environment and remarkable photothermal ability at pH 6.5 (photothermal conversion efficiency of 43.9%). As a consequence of the enhanced permeability and retention effect of tumors and the doping‐induced photothermal effect of PANI‐ES@AOT, this pH‐sensitive NIR‐II photothermal agent allows tumor acidity phototheranostics with minimized pseudosignal readout and subdued normal tissue damage. Moreover, the enhanced fluidity of vesicle membrane triggered by heating is beneficial for drug release and allows precise synergistic therapy for an improved therapeutic effect. This study highlights the potential of template‐oriented (or interface‐confined) enzymatic polymerization reactions for the construction of conjugated polymers with desired biomedical applications.

Application of an enzymatic cascade reaction for the synthesis of the emeraldine salt form of polyaniline

“…Further studies on the enzymatic synthesis of conducting PANI, for example by using an AOT/SDS (sodium dodecylsulfate) bicontinuous cubic phase as template (Jin et al 2020), are certainly worth pursuing. Depending on application, enzyme inactivation might not be a crucial problem (Zhang et al 2020), because enzymes are biological and biodegradable macromolecules. Preliminary experiments showed that the cascade reaction we elaborated is a useful extension to the reference reaction applied so far in the study of artificial cell-like systems, as briefly mentioned in the introduction (Kurisu et al 2019).…”

“…Toward possible applications of enzymatically prepared polyaniline, in a recent study it was shown that PANI-ES obtained from aniline in the presence of AOT vesicles with horseradish peroxidase (HRP) and H 2 O 2 might by suitable as photothermal agent for tumor theranostics (Zhang et al 2020). In another area of research, an artificial cell-like reproduction system is being developed, which is based on the AOT vesicle-guided, HRPC/H 2 O 2 -catalyzed synthesis of PANI-ES products (Kurisu et al 2019).…”

Biomedical Photoacoustic Imaging for Molecular Detection and Disease Diagnosis: “Always‐On” and “Turn‐On” Probes

“…[135] Zhang et al used a one-pot approach to encapsulate polyaniline around bis(2-ethylhexyl)sulfosuccinate vesicles for pH-sensitive NIR-II (1064 nm) PTT and PA imaging (970 nm). [136] However, both PPy and polyaniline have drawbacks, including difficult surface modification. Additionally, polyaniline alone is only stable at very low pH values, while PPy has limited water solubility.…”

Intelligent design of polymersomes for antibacterial and anticancer applications

“…Phototherapy has been considered to be a promising anticancer approach due to the high lethality to cancer cells. Light with deep tissue penetration and biosafety, mostly near‐infrared laser, is usually utilized to promote phototherapy (Wei et al, 2021; Zhang et al, 2020). Phototherapy includes photodynamic therapy and photothermal therapy.…”