A Borondifluoride‐Complex‐Based Photothermal Agent with an 80 % Photothermal Conversion Efficiency for Photothermal Therapy in the NIR‐II Window

Abstract

Small organic photothermal agents (SOPTAs) that absorb in the second near‐infrared (NIR‐II, 1000–1700 nm) window are highly desirable in photothermal therapy for their good biocompatibility and deeper tissue penetration. However, the design of NIR‐II absorbing SOPTAs remains a great challenge. Herein, we report that molecular engineering of BF2 complex via strengthening the donor‐acceptor conjugation and increasing the intramolecular motions is an efficient strategy to achieve NIR‐II absorbing SOPTAs with high photothermal performance. Based on this strategy, a BF2 complex, BAF4, was designed and synthesized. BAF4 exhibits an intense absorption maximum at 1000 nm and negligible fluorescence. Notably, the nanoparticles of BAF4 achieve a high photothermal conversion efficiency value of 80 % under 1064 nm laser irradiation (0.75 W cm−2). In vitro and in vivo studies reveal the great potential of BAF4 nanoparticles in photoacoustic imaging‐guided photothermal therapy in the NIR‐II window.

Gold Nanostar@Polyaniline Theranostic Agent with High Photothermal Conversion Efficiency for Photoacoustic Imaging-Guided Anticancer Phototherapy at a Low Dosage

“…To realize highly efficient PAI and PTT, many metallic nanoparticles have been developed such as gold nanoparticles, , Pt or Pd-based nanoparticles, , semiconductor nanomaterials, and metal–organic frameworks . However, the PAI and PTT applications based on existing metallic photothermal agents still show some limitations like low signal sensitivity, unnecessary damages caused by laser overexposure, poor efficiency in deep tissue, and toxicity in vivo due to a high dosage, which can be largely overcome by improving the photothermal conversion efficiency (PCE) of metallic nanomaterials. , Until now, most of the photothermal agents including metallic and nonmetallic nanomaterials only exhibited a PCE of about 50%, which still shows a lot of room for further improvement.…”

“…23 However, the PAI and PTT applications based on existing metallic photothermal agents still show some limitations like low signal sensitivity, unnecessary damages caused by laser overexposure, poor efficiency in deep tissue, and toxicity in vivo due to a high dosage, which can be largely overcome by improving the photothermal conversion efficiency (PCE) of metallic nanomaterials. 24,25 Until now, most of the photothermal agents including metallic and nonmetallic nanomaterials only exhibited a PCE of about 50%, 26 which still shows a lot of room for further improvement. The drug dosage for patients is a great concern in clinical medicine due to the potential side effect and this problem is more significant in nanotechnology.…”

Multifunctional Bi NSs@BSA Nanoplatform Guided by CT Imaging for Effective Photothermal Therapy

“…The temperature-change behavior with the 808 nm lasers “on/off” further showed that Bi NSs@BSA possessed good temperature controllability with or without 808 nm laser irradiation, in which Bi NSs@BSA’s damaging of normal cells was reduced. To further explore its photothermal performance, the photothermal conversion efficiency (η) of Bi NSs@BSA was calculated via the previously reported method . In a word, η was obtained with the following formula η = h S ( T max − T s ) − Q 0 I ( 1 − 10 − A λ ) where h and S are the heat-transfer coefficient and vessel volume and T max and T s are the maximum temperature and ambient temperature, respectively.…”

Cancer therapeutics based on diverse energy sources

“…Heat can be generated by energy release through non-radiative relaxation. For effective photothermal therapy (PTT), several strategies have been carried out such as increasing the photothermal conversion efficiency to generate more heat [18][19][20][21] and reducing the thermal tolerance of cancer by blocking specific genes related to heat and repair. [22][23][24][25][26][27] Many review papers have described the photothermal properties of materials.…”