Nonaromatic Organonickel(II) Phototheranostics

Area of Science:

• Materials Chemistry
• Nanotechnology
• Biomedical Engineering

Background:

• Earth-abundant metal-based theranostics offer a path to low-cost personalized medicine.
• Developing agents that combine diagnostic and therapeutic functions is a key goal.

Purpose of the Study:

• To report novel O-linked nonaromatic benzitripyrrin (C^N^N^N) macrocyclic organonickel(II) complexes for theranostic applications.
• To investigate their photothermal and photoacoustic imaging properties.
• To evaluate their efficacy in treating thrombi in vitro and in vivo.

Main Methods:

• Synthesis and characterization of organonickel(II) complexes (Ni-1-4).
• Structural studies of Ni-1.
• Ultrafast transient absorption spectroscopy and theoretical calculations.
• Encapsulation of Ni-1 into DSPE-PEG2000 nanoparticles (Ni-1@DSPE).
• In vitro and in vivo thrombus treatment models using photoirradiation and photoacoustic imaging (PAI).

Main Results:

• Organonickel(II) complexes Ni-1-4 exhibit square-planar geometry and strong M-C bonds.
• Ni-1 shows red-shifted absorption into the near-infrared region compared to traditional porphyrins.
• Ni-1@DSPE nanoparticles demonstrate efficient photothermal conversion (~45%) and red-shifted absorption.
• Successful in vitro and in vivo thrombus removal using Ni-1@DSPE with 785 nm photo-irradiation, monitored by PAI.

Conclusions:

• Organonickel(II) complexes are promising candidates for theranostic applications.
• Manipulation of excited-state features through modified π-conjugation enhances theranostic potential.
• These complexes offer a viable route towards cost-effective personalized photothermal therapy and imaging.