Polyaniline-loaded γ-polyglutamic acid nanogels as a platform for photoacoustic imaging-guided tumor photothermal therapy

Abstract

We report the facile synthesis of polyaniline (PANI)-loaded γ-polyglutamic acid (γ-PGA) nanogels (NGs) for photoacoustic (PA) imaging-guided photothermal therapy (PTT) of tumors. In this work, γ-PGA NGs were first formed via a double emulsion approach, followed by crosslinking with cystamine dihydrochloride (Cys) via 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride coupling chemistry. The formed γ-PGA/Cys NGs were employed as a nanoreactor to load aniline monomers via an electrostatic interaction for subsequent in situ polymerization in the presence of ammonium persulfate. The resulting γ-PGA/Cys@PANI NGs were thoroughly characterized. It is shown that the γ-PGA/Cys@PANI NGs with an average size of 71.9 nm are dispersible in water, colloidally stable, and cytocompatible and hemocompatible in the concentration range studied. The strong near-infrared (NIR) absorbance renders the NGs with good PA imaging contrast enhancement and photothermal conversion properties. With these excellent properties and biocompatibility, the developed γ-PGA/Cys@PANI NGs are able to be used for PA imaging-guided PTT of cancer cells in vitro and a xenografted tumor model in vivo. This unique theranostic nanoplatform may be further loaded with other imaging or therapeutic elements, or modified with targeting ligands, thereby providing a ubiquitous platform for multimode imaging and combinational therapy of different biosystems.

Emulsion Techniques for the Production of Pharmacological Nanoparticles

“…Under NIR irradiation, photosensitizers can generate high singlet oxygen quantum yield, showing photothermal conversion efficiency and outstanding photoacoustic response–guided simultaneous PDT and PTT. Zhou et al reported the synthesis of polyaniline (PANI)‐loaded γ‐polyglutamic acid (γ‐PGA) nanogels for photoacoustic imaging–guided PTT of tumors …”

“…Zhou et al reported the synthesis of polyaniline (PANI) loaded γpolyglutamic acid (γPGA) nanogels for photoacoustic imaging-guided PTT of tumors. [73] γPGA nanogels were first synthesized via a double emulsionsolvent evaporation process, followed by crosslinking with cystamine dihydrochloride. γPGA/ Cys nanogels were then used as nanoreactors for polymerizing aniline.…”

Tumor pH‐Responsive Albumin/Polyaniline Assemblies for Amplified Photoacoustic Imaging and Augmented Photothermal Therapy

“…However, the bad stability of the NIR dyes due to the photobleaching limits their application. Polyaniline (PANI) was the first reported organic polymer‐based photothermal agent with good stability and has been widely applied in photoacoustic imaging (PAI) and photothermal therapy (PTT) of tumors . PANI exists in two states, emeraldine base (EB) and emeraldine salt (ES), which can be interconverted through protonation and deprotonation reactions in different pH microenvironment .…”

“…PANI exists in two states, emeraldine base (EB) and emeraldine salt (ES), which can be interconverted through protonation and deprotonation reactions in different pH microenvironment . Under strongly acidic condition, the conversion of PANI from EB to ES state will cause its redshift absorption from visible to near‐infrared (NIR) region, promising for PAI and PTT . However, this conversion pH is considerably lower than that of tumor acidic microenvironment (5.4–7.0), which severely limits the application of PANI as a pH‐responsive agent for cancer theranostics .…”

Cellular Uptake Behaviors of Rigidity-Tunable Dendrimers

“…The design and synthesis of desirable nanoparticles (NPs) is an important task for developing efficient carriers in the biomedical field. Till now, NPs with distinct physicochemical properties including size, shape, composition, surface potential, and surface chemistry have been developed for various biomedical applications [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. When using nanomaterials in the biomedical field, it is critical to understand their interaction with cells [ 11 , 12 , 13 ].…”