Conjugated-Polymer-Based Nanomaterials for Photothermal Therapy

Abstract

In the past few decades, the development of excellent materials for the treatment of disease via noninvasive photothermal therapy has received increasing attention. Among a number of kinds of nanomaterials, conjugated-polymer-based nanomaterials, which possess intense absorbance in the near-infrared region, could employed as useful photothermal agents for various disease treatments, such as cancer, bacterial infection therapy, and neurodegenerative disease. Moreover, conjugated-polymer-based nanomaterials can be easily combined with other imaging agents and drugs to construct multifunctional nanomaterials for cascading stimuli-responsiveness with precise medical treatment and enhanced therapy efficacy. Here, we mainly put attention on the recent advances of conjugated-polymer-based nanoparticles for photothermal therapy. First, we briefly summarized the mechanism of photothermal conversion of conjugated polymers and the relevant modified methods to improve their photothermal conversion efficiency. Second, we discussed the application of conjugated polymers in photothermal therapy as well as the strategies for developing conjugated-polymer-based nanomaterials with a targeted ability and an enhanced accumulation effect on the tumor region for cancer therapy. Moreover, further challenges and perspectives were also discussed for designing efficient conjugated-polymer-based nanosystems for photothermally assisted therapies.

Polymeric materials for solar water purification

“…In conjugated polymers, the close stacking properties can induce frequent intermolecular collisions to quench largely, the intersystem crossing, leading to high light-toheat conversion efficiency. 51 Compared to inorganic carbon materials, the simple synthetic process and excellent chemical stability of polymeric materials exhibit superb scalability and durability under practical working conditions. In addition, polymers can be easily integrated with other functional materials for enhanced water evaporation performance.…”

Construction of eight mixed-valence pentanuclear CuI4CuII clusters using ligands with inhomogeneous electron density distribution: synthesis, characterization and photothermal properties

“…Materials for photo-thermal applications have greatly drawn attention because they are widely used in cancer therapy, 1 water vaporization, 2,3 solar thermoelectric generation, 4 anti-counterfeiting, 5–7 etc . However, it is a big challenge for the rational design and synthesis of such materials because their molecular mechanisms are blurred.…”

Intramolecular Charge Transfer-Based Conjugated Oligomer with Fluorescence, Efficient Photodynamics, and Photothermal Activities

“…However, the depleting of local oxygen in the PDT process is an important obstacle that impedes further generation of ROS and weaken PDT efficiency in clinical application . However, PTT involves the use of photothermal agents which are able to convert light to heat, elevate local temperature, and destroy nearby microorganisms through hyperthermia effects. − Principally, it requires PTT to rise to a temperature of 50 °C to kill microbes, as higher than that causes cell apoptosis (45 °C), which will cause thermal damage to neighboring tissues and limit its practical use. These limitations motivate the need for developing photoactive materials with combinational capabilities of PDT and PTT for efficient sterilization, especially those guided by fluorescence imaging, which can precisely localize the cells and reduce side effects.…”

“…Conjugated polymers/oligomers have emerged as a competitive class of photoactive agents for phototriggered inactivation of cancer cells or microorganisms. − Due to its large π-conjugated structure, conjugated polymers/oligomers possess strong light-harvesting abilities which can motivate a cascade of photochemical reactions. Through radiative transition from singlet excited state, they display favorable fluorescence properties with high quantum yields, which makes them excellent probes for biological imaging and diagnosis. − Meanwhile, the excited triplet state formed by intersystem crossing can interact with the surrounding oxygen and other substrates to produce toxic ROS. − Moreover, their capacity to serve as photothermal agents has also been explored, which mainly focus on nonfluorescent polydopamine (PDA), polyaniline (PANI), polypyrrole (PPy), and poly­(3,4-ethyl-enedioxythiophene) (PEDOT), as well as some conjugated polymers/oligomers with a narrow bandgap that shifted their absorption into the NIR region. ,− In these cases, photon energy has been transferred into heat through nonradiative transition, and the radiative channel and ISC process are inhibited. Up to now, only a few examples of conjugated polymers/oligomers have been developed as photoactive agents integrating both PDT and PTT effects. , Since the radiative transition, singlet-to-triplet intersystem crossing, and nonradiative transition are the three main decay processes of a photoexcited fluorophore and are competitive with one another, how to balance these three processes and acquire a multifunctional photoactive agent is still a big challenge.…”