Bioinspired Applications of Porphyrin Derivatives

Abstract

Conspectus Porphyrin derivatives are ubiquitous in nature and have important biological roles, such as in light harvesting, oxygen transport, and catalysis. Owing to their intrinsic π-conjugated structure, porphyrin derivatives exhibit characteristic photophysical and electrochemical properties. In biological systems, porphyrin derivatives are associated with various protein molecules through noncovalent interactions. For example, hemoglobin, which is responsible for oxygen transport in most vertebrates, consists of four subunits of a globular protein with an iron porphyrin derivative prosthetic group. Furthermore, noncovalently arranged porphyrin derivatives are the fundamental chromophores in light-harvesting systems for photosynthesis in plants and algae. These biologically important roles originate from the functional versatility of porphyrin derivatives. Specifically, porphyrins are excellent host compounds, forming coordination complexes with various metal ions that adds functionality to the porphyrin unit, such as redox activity and additional ligand binding at the central metal ion. In addition, porphyrins are useful building blocks for functional supramolecular assemblies because of their flat and symmetrical molecular architectures, and their excellent photophysical properties are typically utilized for the fabrication of bioactive functional materials. In this Account, we summarize our endeavors over the past decade to develop functional materials based on porphyrin derivatives using bioinspired approaches. In the first section, we discuss several synthetic receptors that act as artificial allosteric host systems and can be used for the selective detection of various chemicals, such as cyanide, chloride, and amino acids. In the second section, we introduce multiporphyrin arrays as mimics of natural light-harvesting complexes. The active control of energy transfer processes by additional guest binding and the fabrication of organic photovoltaic devices using porphyrin derivatives are also introduced. In the third section, we introduce several types of porphyrin-based supramolecular assemblies. Through noncovalent interactions such as metal–ligand interaction, hydrogen bonding, and π–π interaction, porphyrin derivatives were constructed as supramolecular polymers with formation of fiber or toroidal assembly. In the last section, the application of porphyrin derivatives for biomedical nanodevice fabrication is introduced. Even though porphyrins were good candidates as photosensitizers for photodynamic therapy, they have limitations for biomedical application owing to aggregation in aqueous media. We suggested ionic dendrimer porphyrins and they showed excellent photodynamic therapy (PDT) efficacy.

Recent Advancements in Serum Albumin-Based Nanovehicles Toward Potential Cancer Diagnosis and Therapy

“…However, SDT suffers from some inherent limitations, such as the poor tumor accumulation of small-molecule sonosensitizers and the lower quantum yield of inorganic sonosensitizers ( Liang et al, 2020 ). Nowadays, porphyrin and its derivatives are the most extensively used sonosensitizers in SDT due to their various unique properties ( Park J. M. et al, 2021 ). Nevertheless, the small-molecule porphyrins have low chemical and biological stability and are toxic to sensitive skin, which may lead to decreased therapeutic efficacy ( Ma et al, 2019 ).…”

Assessing the In Vitro Activity of Selected Porphyrins in Human Colorectal Cancer Cells

“…ROS react with diffusion limited kinetics with a range of biochemical structures in cells such as lipids, aromatic amino acids, the heterocyclic bases, the backbone of nucleic acids, and flavonoids to induce oxidative damage to the cell, thereby causing cell death via apoptosis or necrosis [ 7 ]. Porphyrins are the most common and efficient photosensitizers used in PDT because of their absorption in the visible range of the electromagnetic spectrum, long-lived triplet excited state, and efficient phototoxicity toward cancer cells [ 8 ]. It is believed that these compounds selectively bind to and accumulate in tumor cells, thereby protecting normal tissue against a phototoxic effect.…”

NIR‐II Hydrogen‐Bonded Organic Frameworks (HOFs) Used for Target‐Specific Amyloid‐β Photooxygenation in an Alzheimer's Disease Model

“…Herein, we designed at wo-photon NIR-II-activated photooxygenation catalyst based on DSM-encapsulated HOF (denoted as DSM@n-HOF-6, DSM = 4-[p-(dimethylamino)styryl]-1-methylpyridinium). Meso-tetrakis(carboxyphenyl)porphyrin (TCPP), as aw idely used photosensitizer [73,74] and ac ommon linker for fabricating MOFs or COFs, [75,76] was chosen as the building blocks.P eriodic integration of TCPP into HOFs can not only effectively prevent the self-quenching effect and improve the accessibility of oxygen, [77][78][79] but also significantly enhance the solubility and biocompatibility.U nder 1040 nm NIR-II irradiation, the up-conversion fluorescence of DSM in n-HOF-6 could be absorbed by TCPP to generate singlet oxygen ( 1 O 2 ) for Ab oxygenation (Scheme 1). In vitro experiments demonstrated that Ab could be efficiently oxidized and aborted aggregation behavior.F urther,f or crossing the blood-brain barrier (BBB) and improving Ab selectivity,targeted peptide KLVFFAED (KD8) was conjugated to DSM@n-HOF-6 (denoted as DSM@n-HOF-6@KD8).…”