Hybrid Polypyrrole and Polydopamine Nanosheets for Precise Raman/Photoacoustic Imaging and Photothermal Therapy

Abstract

The development of near‐infrared light responsive conductive polymers provides a useful theranostic platform for malignant tumors by maximizing spatial resolution with deep tissue penetration for diagnosis and photothermal therapy. Herein, the self‐assembly of ultrathin 2D polypyrrole nanosheets utilizing dopamine as a capping agent and a monolayer of octadecylamine as a template is demonstrated. The 2D polypyrrole‐polydopamine nanostructure has tunable size distribution which shows strong absorption in the first and second near‐infrared windows, enabling photoacoustic imaging and photothermal therapy. The hybrid double‐layer is demonstrated to increase Raman intensity for 3D Raman imaging (up to two orders of magnitude enhancement and spatial resolution up to 1 µm). The acidic environment drives reversible doping of polypyrrole, which can be detected by Raman spectroscopy. The combined properties of the nanosheets can substantially enhance performance in dual‐mode Raman and photoacoustic guided photothermal therapy, as shown by the 69% light to heat conversion efficiency and higher cytotoxicity against cancer spheroids. These pH‐responsive features highlight the potential of 2D conductive polymers for applications in accurate, highly efficient theranostics.

Advancing Evidence-Based Data Interpretation in UV–Vis and Fluorescence Analysis for Nanomaterials: An Analytical Chemistry Perspective

“…There are countless ambiguous and even erroneous UV–vis spectral interpretations and analyses in nano research. It has been common practice to interpretate, explicitly or implicitly, the UV–vis spectra obtained with solutions containing nanoscale and larger materials as absorbance spectra for quantification of nanomaterials’ absorption activities, − nanocrystal band gaps, − as well as for identification of broadband absorbers. − The latter is based on the observation that the sample UV–vis spectrum exhibits a similar intensity across a broad range of wavelengths. This approach is problematic, because UV–vis measurements do not directly provide a direct measurement of absorbance or absorption extinction.…”

Advances in the two-dimensional layer materials for cancer diagnosis and treatment: unique advantages beyond the microsphere

“…BN and MOFs, on the other hand, have the unique ability to bind and release therapeutic agents onto cancer cells and have been utilized to deliver photothermal therapy in cancer treatment. Geng et al (2023) applied two-dimensional therapeutic nanosheets composed of PD and PPy through a simple self-assembly method ( Figure 4 ). The introduction of PD and PPy makes two-dimensional nanostructures with high biocompatibility, flexibility and stability.…”

“…(E, F) SEM images of DPPy nanosheets and the corresponding height profiles. Reproduced from Geng et al (2023) with permission Copyright 2023, Wiley.…”

“…In the context of biomedicine, 2D layer materials have the potential to revolutionize the way that clinical doctors diagnose, monitor, and treat diseases. Due to the significant physicochemical advantages and solution stability of these materials, they can easily be widely used in various biosensor components and drug delivery fields ( Geng et al, 2023 ; Luo et al, 2023 ).…”

Effects of Polydopamine Incorporation on the Nanostructure and Electrochemical Performance of Electrodeposited Polypyrrole Films

“…Recently, several groups have explored the codeposition of PPY films with dopamine (DA) to form polydopamine (PDA) in order to impart favourable properties such as biocompatibility [11] and greater adhesion across a variety of substrates [12]. PDA is a well-known bioinspired material which, like PPY, is facile to deposit and has been proposed for myriad applications in domains ranging from biotechnology to energy [13][14][15][16][17]. The structure of PDA is highly complex, but is generally thought to comprise subunits rich in (poly)catecholamines, (poly)dopaminequinone, and (poly)dopaminechrome-like subunits [13].…”