Porphyrin Derivatives Research Articles

Substituent Regulating Porphyrin Derivatives for Efficient Photocatalytic Hydrogen Evolution

AbstractPorphyrin and its derivatives have been seen as a type of potential organic photocatalyst for photocatalytic hydrogen evolution. Substituent regulation as a simple method can effectively regulate the photoelectric characteristic of organic semiconductors. Herein, we designed three porphyrin derivatives attached with different substituents (PP‐NH2, PP‐OH and PP‐COOH). Through a facile substituent optimization strategy, the photoelectric properties of these porphyrin derivatives show an obvious difference, which leads an optimized photocatalytic hydrogen evolution efficiency. The porphyrin derivative with carboxyl presents a reduced impedance, and a better charge separation. Compared to the amino group, PP‐COOH with carboxyl, achieved a high hydrogen evolution rate of 2.20 mmol g−1 h−1 (over 20 times than that of PP‐NH2). Moreover, enhanced stability was observed in PP‐COOH rather than PP‐OH, because of the lower HOMO energy level. And the ionization of carboxyl in water negatively charges the porphyrin derivatives and forms a relatively stable sol. This result further increases the operation stability of PP‐COOH, during photocatalytic hydrogen evolution. This study presents a promising design strategy for long‐lifetime photocatalysts for hydrogen evolution.

Functionalized porphyrin as a carrier bridge and a passivator for perovskite solar cells

Interfacial modification becomes one of the most emerging strategies in the state-of-the-art perovskite solar cells (PSCs). Here, two porphyrin derivatives (p-MeOTPP, m-DMeOTPP) with different methoxy groups are employed as the modifiers between perovskite and the hole transporting layer (HTL). The interaction at both of perovskite/modifier and modifier/HTL interfaces, and the hole-transfer ability of the modifier molecule are comprehensively studied, which are jointly responsible for the significant improvement in the optoelectronic properties of the device. More importantly, discussion on a molecular level reveals the distinct roles of modifiers with highly similar structures. A highest power conversion efficiency (PCE) of 24.56% is achieved for m-DMeOTPP modified PSCs, which is attributed to a synergy of efficient passivation effect at perovskite/modifier interface, sufficient built-in potential at modifier/HTL interface and minimal reorganization energy of hole hopping process. p-MeOTPP has a stronger passivation ability, but causes unfavorable interfacial dipole at modifier/HTL interface and a large energy barrier when hole’s hopping, only resulting in a smaller enhancement. Additionally, both modifers improve the device stability by strongly suppress the immigration of iodine species and moisture penetration. This work presents a synergy mechanism for interfacial engineering to pursue PSCs with high efficiency and stability, and provides practical guidelines at a molecular level to design a modifier not only as an efficient passivator but also as a high-speed carrier bridge.

Design and characterization of novel A2B2 porphyrins: Solar cell applications, antimicrobial properties, and molecular docking insights

We synthesized novel A2B2 porphyrin derivatives (5a-e, 7a,b) with yields of 60–73 %. Porphyrin 2 was prepared by reacting dipyrromethane 1 with p-bromobenzaldehyde. Porphyrin 2 was then treated with n-BuLi in DMF at -15 °C to produce porphyrin 3. The final compounds, 5a-e and 7a,b, were synthesized by reacting porphyrin 3 with activated nitriles (4a-e) and thiazolone derivatives (6a,b). The structures of the novel compounds were confirmed using infrared (IR) spectroscopy, proton nuclear magnetic resonance (1H NMR), carbon-13 nuclear magnetic resonance (13C NMR), mass spectrometry (MS), and elemental analysis. DFT calculations were used to explore the electronic structures and energy levels of the synthesized compounds. Compounds 7a and 7b showed improved electron transfer efficiency compared to 5a-e, with HOMO and LUMO levels aligned for optimal DSSC performance. The HOMO levels are below the electrolyte's redox potential (-5.2 eV), and the LUMO levels are above TiO2's conduction band (-4.2 eV), facilitating efficient electron injection and dye regeneration. Key parameters such as open-circuit voltage (VOC), free energy of injection (ΔGinj), and regeneration (ΔGreg) were calculated, highlighting these compounds' potential for DSSC applications. The newly synthesized compounds were tested for antibacterial activity against C. albicans, B. subtilis, and E. coli. Compounds 5e (MIC50 3.125 µg/mL, with inhibition zone 45 mm against B. subtilis) and (MIC50 12.5 µg/mL, with inhibition zone 31 mm against E. coli) and 7a (MIC50 3.125 µg/mL, with inhibition zone 44 mm against B. subtilis) and (MIC50 12.5 µg/mL, with inhibition zone 30 mm against E. coli) showed the highest antimicrobial activity. Compound 5e's carboxylic acid group likely enhances activity through strong hydrogen bonding and improved solubility, aiding interaction with microbial enzymes or cell walls. Compound 7a's dimalononitrile groups, being highly electron-withdrawing, increase reactivity, while phenylthiazolidine rings offer additional binding sites through hydrogen bonding and pi-stacking interactions. Docking studies of the most potent antibacterial porphyrin analogues, 5e and 7a, against the target protein PDB: 1ECl showed promising results. Compound 5e achieved a docking score of ‐7.9559 kcal/mol with an RMSD of 1.9743 Å, while compound 7a had an even better score of ‐8.9174 kcal/mol. Compound 7a formed interactions with two H-acceptors from its cyano groups, binding to Arg136 and Lys488, and a Pi-H interaction between the thiazolone ring and Asn158, with distances of 3.19, 3.63, and 3.71 Å, respectively.

Capped Plasmonic Gold and Silver Nanoparticles with Porphyrins for Potential Use as Anticancer Agents—A Review

Photothermal therapy (PTT) and photodynamic therapy (PDT) are potential cancer treatment methods that are minimally invasive with high specificity for malignant cells. Emerging research has concentrated on the application of metal nanoparticles encapsulated in porphyrin and their derivatives to improve the efficacy of these treatments. Gold and silver nanoparticles have distinct optical properties and biocompatibility, which makes them efficient materials for PDT and PTT. Conjugation of these nanoparticles with porphyrin derivatives increases their light absorption and singlet oxygen generation that create a synergistic effect that increases phototoxicity against cancer cells. Porphyrin encapsulation with gold or silver nanoparticles improves their solubility, stability, and targeted tumor delivery. This paper provides comprehensive review on the design, functionalization, and uses of plasmonic silver and gold nanoparticles in biomedicine and how they can be conjugated with porphyrins for synergistic therapeutic effects. Furthermore, it investigates this dual-modal therapy’s potential advantages and disadvantages and offers perspectives for future prospects. The possibility of developing gold, silver, and porphyrin nanotechnology-enabled biomedicine for combination therapy is also examined.

Water-Soluble Rotaxane-Type Porphyrin Dyes as a Highly Membrane-Permeable and Durable Photosensitizer Suitable for Photodynamic Therapy.

Porphyrins have emerged as highly effective photosensitizers in the field of photodynamic therapy (PDT) because of their high singlet oxygen generation efficiency. However, most porphyrin derivatives do not have adequate water solubility and cell membrane permeability suitable for use in PDT. In addition, they frequently suffer from low durability under photoirradiation. Here, we propose rotaxane-type photosensitizers, in which a porphyrin axle is irreversibly encapsulated within cyclodextrins (CDs), to overcome the drawbacks of porphyrins for PDT. The rotaxane-type photosensitizers were synthesized in high yields by employing a cooperative capture strategy. The CD derivatives worked as a transparent shell to impart a porphyrin axle not only with water solubility but also with photostability. These rotaxanes showed higher cell membrane permeability and photoinduced cytotoxic abilities than talaporfin sodium, presently used as a clinical photosensitizer. The rotaxane-based photosensitizer could have potential for being ideal PDT drugs.

Better in the Near Infrared: Sulfonamide Perfluorinated-Phenyl Photosensitizers for Improved Simultaneous Targeted Photodynamic Therapy and Real-Time Fluorescence Imaging.

Tetraphenyloporphyrin derivatives are a useful scaffold for developing new pharmaceuticals for photodynamic therapy (PDT) and the photodiagnosis (PD) of cancer. We synthesized new sulfonamide fluorinated porphyrin derivatives and investigated their potential as photosensitizers and real-time bioimaging agents for cancer. We found that 5,10,15,20-tetrakis-[2',3',5',6'-tetrafluoro-4'-methanesulfamidyl)phenyl]bacteriochlorin (F4BMet) has intense absorption and fluorescence in the near-infrared, efficiently generates singlet oxygen and hydroxyl radicals, has low toxicity in the dark, and high phototoxicity. We increased its bioavailability with encapsulation in Pluronic-based micelles, which also improved the photodynamic effect. F4BMet exhibits pH-dependent properties (lower pH promoted its aggregation), and a GlyGly buffer was used to effectively solubilize the compound. In vitro findings with 2D cell culture were complemented with human-induced pluripotent stem cell (hiPSC)-derived organoids. F4BMet in P123 micelles showed enhanced efficacy compared to F4BMet in the GlyGly formulation. F4BMet was further evaluated in real-time bioimaging and PDT of BALB/c mice bearing CT26 tumors. After i.v. injection, the photosensitizer was visible in the tumor area 3 h after injection. The most successful therapeutic approach proved to be tumor-targeted PDT using P123-encapsulated F4BMet illuminated 24 h after administration with a light dose of 42 J/cm2, which led to a 30% long-term cure rate.

Synthesis and Antitumor Activity of Photosensitizer Eugenol Porphyrin Derivatives: A Combination Therapy of Chemotherapy and Photodynamic Therapy

ABSTRACTPhotodynamic therapy (PDT) is a promising treatment for cancer. At present, the development of photosensitizers has become a hot spot for research at home and abroad. In this study, 20 porphyrin‐butylphenol compounds were synthesized, and the structures of the target compounds were analyzed by means of 1H NMR, IR, mass spectrometry, and other analytical methods. The quantum yield of the target compound as a photosensitizer for the production of singlet oxygen was determined by using a DPBF reactive oxygen probe (1,3‐diphenylisobenzofuran). The anticancer activity of the synthesized target compounds was studied using HepG2 cells and A549 cells. The results of the singlet oxygen experiments showed that the Zn metal chelated compound had better singlet oxygen production than the free‐base porphyrin. The cellular activity assays showed that the metal‐chelated compounds exhibited better in vitro antitumor activity.

Sonodynamic therapy for adult-type diffuse gliomas: past, present, and future.

Intra-axial brain tumors persist as significant clinical challenges. Aggressive surgical resection carries risk of morbidity, and the blood-brain barrier (BBB) prevents optimal pharmacological interventions. There is a clear clinical demand for innovative and less invasive therapeutic strategies for patients, especially those that can augment established treatment protocols. Focused ultrasound (FUS) has emerged as a promising approach to manage brain tumors. Sonodynamic therapy (SDT), a subset of FUS, utilizes sonosensitizers activated by ultrasound waves to generate reactive oxygen species (ROS) and induce tumor cell death. This review explores the historical evolution and rationale behind SDT, focusing on its mechanisms of action and potential applications in brain tumor management. A systematic review was conducted using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Preclinical studies have demonstrated the efficacy of various sonosensitizers, including 5-aminolevulinic acid (5-ALA), fluorescein, porphyrin derivatives, and nanoparticles, in conjunction with FUS for targeted tumor therapy and BBB disruption. Clinical trials have shown promising results in terms of safety and efficacy, although further research is needed to fully understand the potential adverse effects and optimize treatment protocols. Challenges such as skull thickness affecting FUS penetration, and the kinetics of BBB opening require careful consideration for the successful implementation of SDT in clinical practice. Future directions include comparative studies of different sonosensitizers, optimization of FUS parameters, and exploration of SDT's immunomodulatory effects. SDT represents a promising frontier in the treatment of aggressive brain tumors, offering hope for improved patient outcomes.

Introduction of methoxy and trifluoromethyl groups into zinc porphyrin sensitizers applications in self-assembled dye-sensitized solar cells

In this study, we have successfully constructed two novel self-assembled composites, the ZnPx-ZnPAc (x = 1,2), which based on zinc porphyrin derivatives, and applied them to the development of dye-sensitized solar cells. The upper dye of these self-assembly’s features zinc porphyrin (ZnPx) as the core unit, while two different electron donors, methoxy (P1) and trifluoromethyl (P2), are introduced to enhance their photovoltaic properties. Photoelectrochemical studies showed that the power conversion efficiency of ZnP1-ZnPAc was superior to that of ZnP2-ZnPAc because ZnP1-ZnPAc had larger Jsc and Voc, which could be attributed to the stronger electron-donating ability of methoxy than trifluoromethyl. To further validate the photoelectrochemical results, we also characterized the assembly mode by spectroscopy, theoretical calculations and electrochemical impedance spectroscopy. And the measurements were consistent with the conclusions.

Porphyrin-based nanoporous materials for photocatalytic applications

Alongside the unique photophysical properties, porphyrin derivatives play key roles in light harvesting of photosynthetic organisms. Due to their symmetrical structure, porphyrin derivatives serve as excellent building blocks for various porous materials, encompassing metal-organic frameworks, covalent organic frameworks, hydrogen-bonded organic frameworks, and amorphous porous organic polymers. These materials capitalize on the beneficial characteristics of porphyrins, such as their absorption capabilities, redox activity, and coordination chemistry, while leveraging the surface area and porosity inherent in porous frameworks. Porphyrin-based porous materials are explored for diverse applications including gas storage, energy storage, catalysis, separation, sensing, and environmental remediation. Owing to their excellent photophysical properties, these nanoporous materials are suitable for light harvesting and photocatalysis applications. This review emphasizes the potential of artificial light-harvesting catalysts based on porphyrin-based porous materials for solar energy applications. Researchers aim to optimize material properties and design innovative architectures to enhance performance in solar energy conversion and photocatalytic applications, making this a rapidly evolving field. Specific applications discussed in the review include photocatalytic CO2 reduction, photocatalytic water splitting, and perspectives on future developments in the field of porphyrin-based nanoporous materials for artificial light harvesting.

Synthesis, Electrochemistry and Photochemistry of Hypervalent Phosphorus(V) Porphyrin and Antimony(V) Porphyrin Black Dyes

In the last few years, our focus has been on push-pull type hypervalent Group 15 porphyrins with intramolecular charge transfer (ICT) properties. Insertion of P(V) or Sb(V) ion in the porphyrin cavity results in a highly electron-deficient porphyrin center, under this condition the presence of electron-rich units in porphyrin meso-positions results in charge transfer within the molecules. Recently, we extended this strategy to 5,10,5,20-tetrakis(triphenylamine)porphyrin derivative where strong electron donor triphenylamine (TPA) units are in meso-positions. Upon insertion of the P(+5) and Sb(+5) ion, the resulting hypervalent Group 15 porphyrins manifested a strong ICT from the TPA units to the central porphyrin ring. The existence of ICT makes the absorption profiles cover the entire visible region with high molar extinction coefficients. Due to this reason, the studied hypervalent Group 15 porphyrins appear as black dyes. Here, I will present these porphyrins and discuss their structural, redox, and remarkable photophysical properties. Figure 1

Structural Diversity Enables Dramatic Changes in Photocatalytic Efficiency of Porphyrinosilica Particles in Chem-Bio Binary Applications

Because of their potential applications in catalysis, separation, and gas storage, porous materials such as metal–organic frameworks (MOFs), porous coordination polymers (PCPs), porous organic polymers (POPs), and polymers with intrinsic microporosity (PIMs) have received much attention. Various building blocks have been introduced with various functional groups. Among the various organic building blocks, porphyrin has become one of the most important building blocks for the construction of such materials witnessed by a wide range of molecular architectures using porphyrin derivatives with various applications. In addition, they are often used to modify the surface of porous silica materials such as SBA-15, MCM-41 and MCM-48, because these porous silica materials exhibit narrow pore size distributions, high thermal stability and easy accessibility.In this presentation, a series of highly ordered mesoporous porphyrinosilicas akin to MCM-41 will be discussed, as novel recyclable heterogeneous photocatalysts, demonstrating their efficacy in the selective oxidation. Porphyrins are recognized as efficient photocatalysts for oxidation reactions, attributed to their capacity to generate reactive oxygen species (ROS). Integrating them into a mesoporous silica framework can mitigate self-degradation, thereby yielding an efficient catalytic system with an extended operational lifetime.

Synthesis, molecular docking, drug‐likeness analysis, and ADMET prediction of nickel and zinc tetraphenyl‐porphyrin complexes as possible antioxidant agents

AbstractNickel tetraphenyl‐porphyrin (NiTPPH₂) and zinc tetra(4‐methophenyl)‐porphyrin (ZnTPPH₂(p‐methyl)) were successfully synthesized and characterized using 1H NMR spectroscopy. Their antioxidant activities and interactions with the superoxide anion radical () were evaluated using cyclic voltammetry. Remarkably, NiTPPH₂ displayed superior antioxidant activity with an IC50 value of 54.57 μg mL−1, significantly outperforming α‐tocopherol (IC50 = 353.27 μg mL−1), indicating its potential as a potent antioxidant. Binding free energy calculations demonstrated that electrostatic interactions predominantly govern the binding, with values of −23.47 kJ mol−1 for NiTPPH₂ and −22.50 kJ mol−1 for ZnTPPH₂(p‐methyl). These values suggest robust binding affinities with . Quantum chemical parameters, obtained through density functional theory (DFT), showed a strong correlation with experimental results, validating the computational approach. Additionally, ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) and drug‐likeness assessments, alongside molecular docking studies, highlighted favorable pharmacokinetic profiles and binding affinities. These findings underscore the potential of NiTPPH₂ and ZnTPPH₂(p‐methyl) as promising candidates for antioxidant therapy, exhibiting drug‐like properties and favorable pharmacokinetics. This research advances the understanding of these porphyrin derivatives and their application in the development of novel antioxidant therapeutics.

Porphyrin-based fluorescent probes for imaging mitochondria in living cells

Porphyrins are well known photosensitizers for clinical applications for cancers. Herein, a series of porphyrin derivatives NTP1-3, which designed as porphyrin conjugated with pyridinium ion and various number of triethylene glycol tails, were synthesized for targeting mitochondria. Solution based experiments show that the probes exhibit a minimal differences of photophysical properties between each probes. When the probes applied into the cancer cells, NTP2 entered inside of the cells and accumulated inside of the mitochondria in cells with a most efficiency, confirmed with co-staining experiment of mitochondria selective rhodamine dye, showing great potential as fluorescent imaging probes. Furthermore, results shows that NTP series probes can be functioned as photodynamic therapy(PDT) agent with red laser light irradiation experiment.

Substituent Effects in the Photophysical and Electrochemical Properties of Meso-Tetraphenylporphyrin Derivatives.

Porphyrins were identified some years ago as a promising, easily accessible, and tunable class of organic photoredox catalysts, but a systematic study on the effect of the electronic nature and of the position of the substituents on both the ground-state and the excited-state redox potentials of these compounds is still lacking. We prepared a set of known functionalized porphyrin derivatives containing different substituents either in one of the meso positions or at a β-pyrrole carbon, and we determined their ground- and (singlet) excited-state redox potentials. We found that while the estimated singlet excited-state energies are essentially unaffected by the introduction of substituents, the redox potentials (both in the ground- and in the singlet excited-state) depend on the electron-withdrawing or electron-donating nature of the substituents. Thus, the presence of groups with electron-withdrawing resonance effects results in an enhancement of the reduction facility of the photocatalyst, both in the ground and in the excited state. We next prepared a second set of four previously unknown meso-substituted porphyrins, having a benzoyl group at different positions. The reduction facility of the porphyrin increases with the proximity of the substituent to the porphine core, reaching a maximum when the benzoyl substituent is introduced at a meso position.

Pick and Choose the Coordinated Metal Ion to Tune the Porphyrin Supramolecular Chirogenesis

AbstractThe solvent‐driven aggregation of metalloporphyrin derivatives, bearing an L‐ or D‐prolinate appendage, results in the stereospecific formation of chiral species that are strictly influenced by the aminoacid chirality and, above all, by the metal axial coordination capability. The Pd porphyrin derivatives self‐assemble in hydroalcoholic mixtures in fractal‐like suprastructures, displaying intense, specular dichroic bands and peculiar UV‐Vis spectral features, accounting for the formation of J‐type aggregates of complex morphology. Spectroscopic and kinetic studies gave important information on the aggregation process, allowing for a comparison with previously reported systems achieved from the free base and Zn derivatives in the same aggregative conditions. Analyzing the self‐aggregation process for the three porphyrin derivatives highlights the remarkable influence of porphyrin inner core features on the chirogenesis of the final systems, revealing an easy tunability of the asymmetry of the assemblies upon metal choosing.

Synthesis and photophysical properties of symmetrical tetraaryltetranaphtho[2,3]porphyrin derivatives

The discovery of new photosensitizers with strong absorption near-infrared region, obvious fluorescence emission, and high reactive oxygen generation ability has attracted great attention as optical agents in life science and material industry. Herein a series of meso-tetraaryltetranaphtho[2,3]porphyrins (Ar 4TNPs) with different substitutions were designed and synthesized. They had strong absorptions at ∼730 nm and fluorescence emission at ∼760 nm after excitation with ∼503 nm light. All compounds possessed excellent reactive oxygen species (ROS) generation ability. The singlet oxygen generation rate of compound 10m (meso-5,10,15,20-tetra[2-(2-hydroxyethoxy)ethylbenzoate]tetrana-phthoporphyrin) is 0.1898 s−1 with a Φ△ value of 0.73, which is significantly higher than that of verteporfin. Therefore, Ar4TNPs have great potential as an effective optical material, bio-tracker, and photodynamic drug candidate.

The third-order nonlinear optical responses of zinc porphyrin oligomers: Cycles vs linear chains

Porphyrins are widely used as potential nonlinear optical (NLO) materials because of their highly delocalized π electrons and feasible synthesis and functionalization with broad biological applications. A variety of linear and cyclic porphyrin derivatives have been synthesized, and the correlation between their structures and NLO properties awaits being disclosed. In this work, the electronic structures and third-order NLO properties of linear and cyclic butadiyne-linked zinc porphyrin oligomers have been studied by quantum chemical methods and sum-over-states model. The static second hyperpolarizability (<γ0>) increases exponentially with the number of zinc porphyrin units ([<γ0>n] = 0.67[<γ0>1]n2.63, n = 2 ∼ 6) in linear π-conjugated oligomers, and the <γ0> of the linear hexamer is about 74 times that of the monomer. Such enhancement of <γ0> in linear oligomers originates from closely-lying frontier molecular orbitals available for low energy electron excitations and strong charge transfer-based excitations across porphyrins. The <γ0>s of cyclic porphyrins are lower than that of the linear hexamer, though the interaction between the ring and the ligand enhances the <γ0> of some cyclic zinc porphyrin complexes. The large two-photon absorption cross sections confer on these zinc porphyrin derivatives excellent candidates for two-photon absorption applications.

Suzuki‐Miyaura Reaction of Glycals with Base‐Labile Protecting Groups as a New Route to Glycoporphyrins

AbstractGlycoporphyrins are considered promising photosensitisers of new generation. Herein, we describe a metal‐catalysed synthetic method towards porphyrin‐carbohydrate C−C conjugates. The protocol of Suzuki‐Miyaura reaction has been developed and it was compatible with peracetylated 2‐iodoglycals. The utility of the reaction was exemplified on 15 different (C‐2)‐arylated sugar derivatives. Then it was applied on more challenging starting materials, namely, porphyrin boronates in which we addressed the issues of difficult transmetalation step usually observed on palladium‐catalysed processes of porphyrin derivatives. The efficiency of the protocol was finally applied to synthesize the library of glycoporphyrins proving the versatile character of this strategy. Finally, the methodology was transferred onto A4‐type porphyrin to efficiently obtain an interesting example of a multivalent glycoconjugate.

TMPyP binding evokes a complex, tunable nanomechanical response in DNA.

TMPyP is a porphyrin capable of DNA binding and used in photodynamic therapy and G-quadruplex stabilization. Despite its broad applications, TMPyP's effect on DNA nanomechanics is unknown. Here we investigated, by manipulating λ-phage DNA with optical tweezers combined with microfluidics in equilibrium and perturbation kinetic experiments, how TMPyP influences DNA nanomechanics across wide ranges of TMPyP concentration (5-5120 nM), mechanical force (0-100 pN), NaCl concentration (0.01-1 M) and pulling rate (0.2-20 μm/s). Complex responses were recorded, for the analysis of which we introduced a simple mathematical model. TMPyP binding, which is a highly dynamic process, leads to dsDNA lengthening and softening. dsDNA stability increased at low (<10 nM) TMPyP concentrations, then decreased progressively upon increasing TMPyP concentration. Overstretch cooperativity decreased, due most likely to mechanical roadblocks of ssDNA-bound TMPyP. TMPyP binding increased ssDNA's contour length. The addition of NaCl at high (1 M) concentration competed with the TMPyP-evoked nanomechanical changes. Because the largest amplitude of the changes is induced by the pharmacologically relevant TMPyP concentration range, this porphyrin derivative may be used to tune DNA's structure and properties, hence control the wide array of biomolecular DNA-dependent processes including replication, transcription, condensation and repair.