Novel Donor–Acceptor Conjugated Polymer-Based Nanomicelles for Photothermal Therapy in the NIR Window

Abstract

In this study, a novel donor−acceptor conjugated polymer PDPPDTP was designed and synthesized by D−A polymerization using 2,6di(trimethyltin)-N-dithieno [3,2-b:20,30-d]pyrrole as the electron-donating (D) unit and 3,6-bis(5-bromothiophen-2-yl)-2,5-dihexadecylpyrrolo[3,4-c]pyrrole-1,4-dione as the electron-accepting (A) unit. The prepared polymer has strong absorption in the near-infrared (NIR) range of 700−900 nm. Moreover, it shows excellent photothermal performance under irradiation at 808 nm. Next, the biodegradable amphiphilic polymer polyethylene glycol− polycaprolactone was used to encapsulate the new conjugated polymer into nanomicelles by the microemulsion method. The obtained PDPPDTP-loaded micelles exhibited a regular spherical structure, and their hydrodynamic diameter was about 78 nm, characterized by transmission electron microscopy and dynamic light scattering. Notably, the micelles exhibited good stability, and the encapsulation efficiency of the conjugated polymer in the micelles was ∼80%. In vitro cell experiments demonstrated that the nanomicelles not only showed good biocompatibility and low toxicity but also could effectively inhibit the proliferation of breast cancer cells 4T1 under the NIR light irradiation of 808 nm. Furthermore, in vivo studies of photothermal therapy (PTT) efficacy showed that the PDPPDTP-loaded micelles exhibited a remarkable tumor growth inhibition in a syngeneic murine tumor model, indicating that the nanomicelles loaded with this novel conjugated polymer could be further explored as a new type of theranostic agent and applied in the PTT of tumors.

A Novel NQO1 Enzyme-Responsive Polyurethane Nanocarrier for Redox-Triggered Intracellular Drug Release

“…The hemolysis assay was conducted to evaluate the hemocompatibility of free DOX and DOX-loaded micelles according to the previous protocol . Specific steps are as follows: (1) Separating red blood cells.…”

Photothermal Nanomaterials: A Powerful Light-to-Heat Converter

“…The construction of conjugated polymers can partly quench molecular fluorescence and enhance nonradiative relaxation, resulting in efficient photothermal conversion . Moreover, donor–acceptor (D-A) strategies have been proposed to develop a new series of conjugated polymers for further extending light absorption and improving light-to-heat conversion efficiencies. − Figure b presents a typical class of polymer-based photothermal materials with D-A structures consisting of diketopyrrolopyrrole (DPP) as an acceptor and a series of electron-donating polymers as donors . While a conjugated polymer serves as a donor for absorbing light, another polymer accepts the excited electrons from the conjugated polymer and further releases them through nonradiative decay.…”

Review of quantitative and qualitative methods for monitoring photopolymerization reactions

“…The high time resolution and high sensitivity of the measurement, non-destructive character, simplicity, and speed of analysis are satisfactory features for monitoring conversions in fast photopolymerization reactions, with the additional advantage of inexpensive and reliable spectrophotometers. [150][151][152][153][154][155][156] However, in quantitative terms, the NIR technique requires the use of chemometric methods, due to the multidimensionality of data, photometric noise, and significant influence of many external factors such as the temperature, humidity, thickness, and optical properties of the sample on the shape and intensity of NIR spectra. In addition, when testing thin films, the molecular absorption coefficients in near-infrared are quite small, requiring a larger sample volume to obtain an unintended signal.…”