Photothermal Conjugated Polymers and Their Biological Applications in Imaging and Therapy

Abstract

Conjugated polymers have been developed as candidates with great potential for biological and biomedical applications due to the excellent properties, including strong light absorption, high photostability, good biocompatibility, and tunable spectra. By design of the backbone structure, photothermal polymers can be obtained with narrow band gaps and high photothermal conversion efficiencies. As promising photothermal agents, photothermal conjugated polymers have been synthesized to be water-soluble or in the form of nanoparticles for biological applications of imaging, phototherapy, and photoactivation. This review summarizes the recent (2018–2020) progress on photothermal conjugated polymers with regard to molecular design, preparation, and photothermal biological applications, especially NIR imaging (fluorescence and photoacoustic)-guided photothermal therapy and combined therapy for cancer and antibacterial photothermal therapy. Further challenges and the outlook for photothermal conjugated polymers in biological applications are also discussed at the end.

Nanophysical Antimicrobial Strategies: A Rational Deployment of Nanomaterials and Physical Stimulations in Combating Bacterial Infections

“…mal effect causes irreparable damage to the structure of bacteria as well as biofilms, resulting in efficient bacterial elimination without causing resistance. [70] With the advancement of nanotechnology, a slew of well-designed antimicrobial nPTT systems have been developed either by coupling conventional photothermal agents with nanomaterials to improve their photostability and pharmacokinetics, or by synthesizing and exploiting novel nanoparticles with higher photothermal conversion efficiency. [71] Organic dyes that can generate heat in the energy dissipation process after NIR light excitation offer a good platform for nPTT.…”

Conjugated Polymers for Gene Delivery and Photothermal Gene Expression

“…In recent years, the research on CPs especially WSCPs have been developed rapidly because of their excellent photostability, adjustable structures, well biocompatibility, which lead to a comprehensive applications in biomedical fields, such as gene delivery, [37] bio-imaging, [38,39] cancer therapy. [40][41][42][43][44] poly(fluorine-co-phenylene) (PFP), poly(p-phenylenevinylene) (PPV), polythiophene (PT) and poly(p-phenyleneethynylene) (PPE) are conventional CPs for gene delivery, which have low cytotoxicity and the cationic side chains facilitate the binding to gene segment, besides the process of gene delivery can be traced by fluorescence imaging. There are many reasons why nucleic acids bind to conjugated polymers (Scheme 1).…”

880 nm NIR-Triggered Organic Small Molecular-Based Nanoparticles for Photothermal Therapy of Tumor

“…PTAs are one of the most important factors determining the efficiency of PTT, and many kinds of PTA have been developed in recent years. Current PTAs can be classified as inorganic and organic materials, and compared to inorganic PTAs, the organic PTAs with easy chemical structure tuning, good biocompatibility, low-toxicity and an easy metabolism in the biological system are more desirable for clinical photo-theranostics [ 2 , 3 , 4 , 5 , 6 , 7 ], such as cyanine dyes [ 8 , 9 , 10 , 11 , 12 , 13 ], diketopyrrolopyrrole derivatives [ 14 , 15 ], croconaine-based agents [ 16 , 17 ], porphyrin-based agents [ 18 , 19 , 20 , 21 ], conjugated polymers [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ], squaraine derivatives [ 30 , 31 ], boron dipyrromethane (BODIPY) dyes [ 32 ] and so on. In organic PTAs, the polymeric PTA was limited due to its complicated fabrication processes, indistinct biodegradation and potential biosafety [ 21 ].…”