The use of photothermal agents (PTAs) in cancer photothermal therapy (PTT) has shown promising results in clinical studies. The rapid degradation of PTAs may address safety concerns but usually limits the photothermal stability required for efficacious treatment. Conversely, PTAs with high photothermal stability usually degrade slowly. The solutions that address the balance between the high photothermal stability and rapid degradation of PTAs are rare. Here, we report that the inherent Cu²⁺-capturing ability of black phosphorus (BP) can accelerate the degradation of BP, while also enhancing photothermal stability. The incorporation of Cu²⁺into BP@Cu nanostructures further enables chemodynamic therapy (CDT)-enhanced PTT. Moreover, by employing⁶⁴Cu²⁺, positron emission tomography (PET) imaging can be achieved for in vivo real-time and quantitative tracking. Therefore, our study not only introduces an “ideal” PTA that bypasses the limitations of PTAs, but also provides the proof-of-concept application of BP-based materials in PET-guided, CDT-enhanced combination cancer therapy.

Peptide-based materials that have diverse structures and functionalities are an important type of biomaterials. In former times, peptide-based nanomaterials with excellent stability were constructed through self-assembly. Compared with individual peptides, peptide-based self-assembly nanomaterials that form well-ordered superstructures possess many advantages such as good thermo- and mechanical stability, semiconductivity, piezoelectricity and optical properties. Moreover, due to their excellent biocompatibility and biological activity, peptide-based self-assembly nanomaterials have been vastly used in different fields. In this review, we provide the advances of peptide-based self-assembly nanostructures, focusing on the driving forces that dominate peptide self-assembly and assembly mechanisms of peptides. After that, we outline the synthesis and properties of peptide-based nanomaterials, followed by the applications of functional peptide nanomaterials. Finally, we provide perspectives on the challenges and future of peptide-based nanomaterials.

2-((1E,3E)-4-(6-(¹¹C-methylamino)pyridin-3-yl)buta-1,3-dienyl)benzo[d]thiazol-6-ol (¹¹C-PBB3) is a clinically useful PET probe that we developed for in vivo imaging of tau pathology in the human brain. To ensure the availability of this probe among multiple PET facilities, in the present study we established protocols for the radiosynthesis and quality control of ¹¹C-PBB3 and for the characterization of its photoisomerization, biodistribution, and metabolism. Methods: ¹¹C-PBB3 was synthesized by reaction of the tert-butyldimethylsilyl desmethyl precursor (1) with ¹¹C-methyl iodide using potassium hydroxide as a base, followed by deprotection. Photoisomerization of ¹¹C-PBB3 under fluorescent light was determined. The biodistribution and metabolite analysis of ¹¹C-PBB3 was determined in mice using the dissection method. Results: ¹¹C-PBB3 was synthesized with 15.4% ± 2.8% radiochemical yield (decay-corrected, n = 50) based on the cyclotron-produced ¹¹C-CO₂ and showed an averaged synthesis time of 35 min from the end of bombardment. The radiochemical purity and specific activity of ¹¹C-PBB3 were 98.0% ± 2.3% and 180.2 ± 44.3 GBq/μmol, respectively, at the end of synthesis (n = 50). ¹¹C-PBB3 showed rapid photoisomerization, and its radiochemical purity decreased to approximately 50% at 10 min after exposure to fluorescent light. After the fluorescent light was switched off, ¹¹C-PBB3 retained more than 95% radiochemical purity over 60 min. A suitable brain uptake (1.92% injected dose/g tissue) of radioactivity was observed at 1 min after the probe injection, which was followed by rapid washout from the brain tissue. More than 70% of total radioactivity in the mouse brain homogenate at 5 min after injection represented the unchanged ¹¹C-PBB3, despite its rapid metabolism in the plasma. Conclusion: ¹¹C-PBB3 was produced with sufficient radioactivity and high quality, demonstrating its clinical utility. The present results of radiosynthesis, photoisomerization, biodistribution, and metabolite analysis could be helpful for the reliable production and application of ¹¹C-PBB3 in diverse PET facilities.