In Situ Construction and Characterization of Chlorin-Based Supramolecular Aggregates in Tumor Cells

Abstract

We demonstrate in situ construction and characterization of supramolecular aggregates from chlorin p6 (Cp6) molecules in tumor cells. Fully deprotonated Cp6 molecules in neutral condition were partially protonated inside the acidic lysosomes of cells and significantly increased the hydrophobicity of them that resulted in simultaneous formation of J-type aggregates. Importantly, the formation of J-aggregates was fully characterized in artificial tissues by UV-vis, circular dichroism (CD) and transmission electron microscope (TEM) techniques. Compared to the monomers, the J-aggregates exhibited 55-fold enhanced thermal conversion efficiency (η) at the optimal excitation wavelength (690 nm). The remarkably increased heat effect contributed to the stronger photoacoustic (PA) signals, leading to at least 2 orders of magnitude increase of the tumor-to-normal tissue ratio (T/N), which was defined as the PA signal ratio between tumor site and surrounding normal tissue. We envision that this proof-of-concept study will open a new way to develop tumor environment-induced self-assembly for variable biomedical applications.

Expanded porphyrins: functional photoacoustic imaging agents that operate in the NIR-II region

“…Cancer, broadly speaking represents another area where monitoring pH via PAI could be beneficial in the context of diagnostic and therapeutic applications. 8,36 It is well-known that the extracellular tumor microenvironment is slightly acidic, pH = 6.4–7.0. 37 Most cancer environments are also highly reducing.…”

“…low pH, enzymes, and hydrogen peroxide (H 2 O 2 )). [7][8][9][10] However, most tetrapyrrolic PA systems are limited to the NIR region. 7,11 Absorption greater than 1000 nm, termed the second near-infrared region (NIR-II: 1000-1350 nm), allows for deeper tissue penetration and reduced light scattering than the NIR-I region (700−950 nm).…”

In Situ Monitoring Intracellular Structural Change of Nanovehicles through Photoacoustic Signals Based on Phenylboronate-Linked RGD-Dextran/Purpurin 18 Conjugates

“…PA signals of RDNP conjugates have the positive correlation with molar extinction coefficient presented in UV–vis spectra (Figure S5). , According to the lowest and highest PA intensity ratio, the suitable wavelengths for analyzing aggregation were 710 and 750 nm, which could be more rational to monitor the aggregation index (Figure D). The I 750 / I 710 values of PA signals for P1 and P2 were 0.34 and 0.41, respectively.…”

Novel Nanohybrids Based on Supramolecular Assemblies of Meso-tetrakis-(4-sulfonatophenyl) Porphyrin J-aggregates and Amine-Functionalized Carbon Nanotubes

“…Unlike from the others families of hybrid carbon nanomaterials [9], the potential applications in biological/pharmaceutical field of carbon based nanomaterials-porphyrins appear still scarcely investigated, especially for J-aggregates self-assemblies as well as their intracellular trafficking, therapeutic and imaging properties. In the literature, it was observed that hybrids nanomaterials based on porphyrinoids [24,63] were prepared at pH different from physiological conditions, and then treated with cells. In this context, future work will be devoted to studying the biocompatibility and cellular uptake of our hybrid MWCNTs/J-aggregates supramolecular systems.…”