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. 2024 Sep 26;7(10):6656–6664. doi: 10.1021/acsabm.4c00844

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

Yuki Ohishi †,*, Taiki Ichikawa †, Satoru Yokoyama †, Juri Yamashita ‡, Munetaka Iwamura ‡, Koichi Nozaki ‡, Yue Zhou †, Junya Chiba †, Masahiko Inouye †,*
PMCID: PMC11497202  PMID: 39326867

Abstract

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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.

Keywords: photodynamic therapy, photosensitizer, rotaxane, porphyrin, cyclodextrin

1. Introduction

Photodynamic therapy (PDT) is an effective cancer treatment method that utilizes the generation of reactive oxygen species through light irradiation to photosensitizers.1−4 The photosensitizers for PDT require high molar absorption coefficients and high generation efficiency of reactive oxygen species.5,6 Porphyrins and their related compounds are widely studied as photosensitizers for PDT because they can be excited by light in the long-wavelength region and exhibit high singlet oxygen (1O2) generation efficiency.7−11 However, porphyrin derivatives have mainly two drawbacks for use in PDT. First, they tend to aggregate by hydrophobic interaction and π–π stacking in aqueous solutions, causing a decrease in photosensitizing efficiency (Figure 1a). This problem can be improved by introducing anionic substituents; however, these substituents cause another problem of decreasing cell membrane permeability. Second, porphyrin derivatives show poor stability under photoirradiation (Figure 1b).12 These drawbacks require higher doses of photosensitizers and increase the risk of side effects. Therefore, effective strategies are needed to impart water solubility, cell membrane permeability, and photostability to porphyrin derivatives.

Figure 1.

Figure 1

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(a) Aggregation of porphyrins. (b) Photodegradation of porphyrins. (c) Schematic diagram of the cooperative capture synthesis of [5]rotaxane-type photosensitizers.

Macrocyclic host molecules have the potential to overcome these drawbacks of porphyrin derivatives.13−23 Especially, cyclodextrins (CDs) are optically transparent hosts above 200 nm and can solubilize porphyrin derivatives in water through complex formation.13−18 For example, Ikeda et al. reported that complexes of porphyrin derivatives with β-CD derivatives exhibit superior photodynamic activity to porfimer sodium, presently used as a PDT drug in clinical use.17 These reports may suggest that the use of macrocycles is a promising way to develop efficient photosensitizers for PDT.

Although such temporary complexes between a porphyrin derivative and macrocycles exhibit beneficial properties for PDT in vitro, these complexes would dissociate in real multimolecular crowding biosystems.24 Thus, for creating an ideal PDT drug, rotaxane architecture is expected to be a suitable answer, in which photosensitizers are encapsulated within macrocycles, and their dissociation is prohibited by bulky stopper units. Recently, we have established a high-yield synthesis for [5]rotaxane-type fluorescent dyes based on a cooperative capture strategy.25 The key point in this synthetic method is to additionally use cucurbit[6]uril (CB6), which enables the preferential arrangement of multiple components constructing rotaxanes and alkyne–azide cycloaddition inside CB6 without Cu(I) catalysts.26−31 This method could be applied to a variety of fluorescent dyes because CB6 versatilely attracts the dyes and CD derivatives through intermolecular interactions and promotes their complex formation. Against the backdrop of success, we planned to adapt the cooperative capture strategy to porphyrin derivatives (Figure 1c). These rotaxane-type photosensitizers are predicted to show high water solubility and photostability. Furthermore, we expected that the photosensitizers would show enough cell membrane permeability due to the effect of the four ammonium sites since cationic molecules tend to come close to anionic cell membranes and penetrate into cells.32 Herein, we report the syntheses of rotaxane-type photosensitizers and their excellent PDT activities as well as photophysical properties.

2. Materials and Methods

The Supporting Information presents a detailed exposition of the Materials and Methods Section.

3. Result and Discussion

We designed a porphyrin derivative as an axle precursor for a cooperative capture strategy (Figure 1c). Because the designed porphyrin core has two “trans-like” substituents at the four meso-positions, CDs are expected to be penetrated by the substituents and cover a wide area of the hydrophobic porphyrin core upon a 1:2 complex formation. Considering the size of the porphyrin core, we used heptakis(2,3-di-O-methyl)-β-cyclodextrin (2,3-Me-β-CD) and octakis(2,3-di-O-methyl)-γ-cyclodextrin (2,3-Me-γ-CD). These partially functionalized CDs have a wide hydrophobic rim (head) and a narrow hydrophilic rim (tail). These rims of the different features are essential for regulating the orientations of the dimeric CDs in the cooperative capture synthesis of [5]rotaxanes. In the dimeric CDs, the methoxy groups at the C2 and C3 positions interact with each other and with the porphyrin core by hydrophobic interaction, and the hydroxy groups at the C6 positions form hydrogen bonds with the carbonyl groups of two CB6s. As a result, the CDs preferentially could form the head-to-head orientation as depicted in Figure 1.

Scheme 1 shows the actual structures of the components in the [5]rotaxanes. The axial precursor 1 was synthesized using Rothemund-Lindsey porphyrin synthesis followed by Fukuyama amine synthesis (Scheme S1 in the Supporting Information), and the stopper molecule 2 was prepared according to the literature method.25 Because the water solubility of 1 was low, we first mixed 1 (3.6 × 10–3 M), 2 (8.4 × 10–3 M), and the CD derivatives (6.0 × 10–2 M) in H2O. Then, the mixture was stirred for 30 min at 60 °C to ensure the dissolution of 1, that is the complexation between 1 and the CDs. After the mixture was cooled to room temperature, CB6 (8.4 × 10–3 M) was added, and the resulting solution was stirred at 25 °C for 48 h. The crude product was purified using reversed-phase high-performance liquid chromatography (HPLC), and [5]rotaxanes β-3 and γ-3 were isolated as formates in high yields of 71 and 65%, respectively. In these reactions, we hardly observed side products such as [4]rotaxane lacking one CD component and [3]rotaxane 4 containing no CD (Figure 2). This is presumably because the reaction proceeded only when 1 was dissolved in water by forming the 1:2 complexes with the CDs. To confirm the effect of CDs on the properties of rotaxanes, a reference photosensitizer 4 was separately synthesized using a different method (Scheme S2 in the Supporting Information). While [3]rotaxane 4 was insoluble in buffers such as phosphate-buffered saline (PBS), [5]rotaxanes β-3 and γ-3 were soluble in PBS to demonstrate the CD shells improving the water solubility of the photosensitizers.

Scheme 1. Syntheses of the Rotaxanes β-3 and γ-3.

Scheme 1

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Figure 2.

Figure 2

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Structures of reference molecules used in this study.

NMR experiments revealed the spatial correlation between the porphyrin axle and the CD shells in the [5]rotaxanes β-3 and γ-3 (Figures 3 and S1–S4 in the Supporting Information). Two-dimensional NMR spectra allowed full assignment of the aromatic protons (Ha–e) in the porphyrin axle and the C–H protons (H1–6) and methoxy protons (Me2,3) in the CD shells. In the NOESY spectrum of β-3 (Figure 3), the signal of Ha at the meso-positions showed a NOE correlation only with that of Me3 at the wide rim in the 2,3-Me-β-CDs. In contrast, the signals of Hd and He at the outer benzene rings strongly correlated with those of H5 and H6 at the narrow rim in the 2,3-Me-β-CDs. These NOEs demonstrated the head-to-head orientation of CDs in rotaxane β-3. Similar NOEs were observed in the case of γ-3, and the orientation of CDs in γ-3 was also identified as head-to-head (Figure S4 in the Supporting Information).

Figure 3.

Figure 3

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NOESY spectrum of β-3. Conditions: [β-3] = 2.0 × 10–3 M in D2O, 25 °C, 500 MHz.

The ultraviolet–visible (UV–vis) absorption and fluorescence emission spectra revealed the optical properties of the [5]rotaxanes (Figure 4). The [5]rotaxanes β-3 and γ-3 displayed typical Soret bands around 407 nm and Q-bands in the region of 480–650 nm. The Q-bands of β-3 and γ-3 were sharper than those of [3]rotaxane 4 probably due to the isolation of porphyrin cores from external environments by the CD shells. The rotaxanes β-3 and γ-3 displayed fluorescence emission above 600 nm with two vibrational bands characteristic of porphyrins. The fluorescence quantum yields (Φf) of β-3 and γ-3 were low and similar to that of 4 (Table 1). These low Φf values suggest that most excited porphyrin cores undergo intersystem crossing from the singlet excited state (S1) to the triplet excited state (T1).

Figure 4.

Figure 4

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(a) Absorption and (b) emission spectra of β-3, γ-3, and 4. Conditions: (a) [β-3] = [γ-3] = [4] = 2.0 × 10–6 M in H2O, path length of 10 mm, 25 °C. (b) [β-3] = [γ-3] = [4] = 1.0 × 10–5 M in H2O, path length of 10 mm, 25 °C, λex = 543 nm.

Table 1. Fluorescence Quantum Yields (Φf), Singlet Oxygen Generation Efficiencies (ΦΔ), Triplet Excited State Lifetimes (τT), Decay Rate Constants (kd), and Quenching Rate Constants (kq) of Rotaxanes.

      under air
 under Ar
  
rotaxane Φfa ΦΔb τT(under,air) (s)c kd(under,air) (s–1)c τT(under,Ar) (s)c kd(under,Ar) (s–1)c kq (s–1)
β-3 0.012 0.84 5.6 × 10–6 1.8 × 105 3.4 × 10–3 2.9 × 102 1.8 × 105
γ-3 0.017 0.68 4.3 × 10–6 2.3 × 105 2.0 × 10–3 5.0 × 102 2.3 × 105
4 0.014   2.5 × 10–6 4.0 × 105 7.4 × 10–4 1.4 × 103 4.0 × 105
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a

[β-3] = [γ-3] = [4] = 1.0 × 10–5 M in H2O, path length of 10 mm, 25 °C, λex = 543 nm.

b

[ABDA] = 6.0 × 10–5 M, [β-3] = [γ-3] = 1.0 × 10–5 M in 0.1 M PBS(−), pH = 7.0, path length of 10 mm, 25 °C, λex = 631 nm.

c

[β-3] = [γ-3] = [4] = 2.0 × 10–5 M in H2O, path length of 10 mm, 25 °C, λex = 532 nm.

The sensitizing abilities (ΦΔ) of the [5]rotaxanes β-3 and γ-3 were evaluated by using 9,10-anthracenediyl-bis(methylene)dimalonic acid (ABDA) for a 1O2 scavenger through Diels–Alder reaction.33 Because the [3]rotaxane 4 did not dissolve in PBS, we used tetraphenylporphyrin tetrasulfonic acid (TPPS), known for its high performance for 1O2 generation (ΦΔ = 0.63), instead.34 PBS buffer was used as a solvent to prevent aggregation between cationic rotaxanes and anionic ABDA and to anticipate later cell experiments. The buffer solutions of the rotaxanes and ABDA were continuously irradiated with light using a 384 mW red light-emitting diode (LED) lamp (λex = 631 nm), and the absorbance change of ABDA (A/A0, 380 nm) was monitored over time (Figures 5 and S5 in the Supporting Information). The absorption band of ABDA decreased rapidly in the presence of the [5]rotaxanes, and the ΦΔ values of β-3 and γ-3 were comparable to that of TPPS (Table 1). The high ΦΔ values of β-3 and γ-3 prove that these rotaxanes sufficiently work as photosensitizers, even though the porphyrin cores are encapsulated by the CD shells.

Figure 5.

Figure 5

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Detection of 1O2 generation by rotaxanes. Conditions: [ABDA] = 6.0 × 10–5 M, [TPPS] = [β-3] = [γ-3] = 1.0 × 10–5 M in 0.1 M PBS(−), pH = 7.0, path length of 10 mm, 25 °C, λex = 631 nm.

The high ΦΔ values of the [5]rotaxanes should be explained from the standpoint of the mechanism for energy transfer. This type of sensitization typically occurs by the Dexter energy transfer mechanism from the T1 state of a photosensitizer to triplet ground state oxygen (3O2), producing a ground state (S0) of the photosensitizer and singlet oxygen (1O2).35 This energy transfer occurs only when the distance between a photosensitizer and 3O2 is within 1.0 nm. Based on this mechanism, one might imagine that the sensitizing abilities of the [5]rotaxanes become lower than that of TPPS because the CD shells suppress the contact between 3O2 and the porphyrin cores. However, as shown in Figure 5, the [5]rotaxanes produced 1O2 comparable to that of TPPS. To elucidate this issue, we investigated the deactivation processes from the triplet excited state of the porphyrin cores in the CD-encapsulated [5]rotaxanes β-3 and γ-3 and the CD-free [3]rotaxane 4 under air (Figure S6a in the Supporting Information). After the porphyrin cores of the rotaxanes were excited with a pulsed laser (λex = 532 nm) in aqueous solutions, the absorption decay of the triplet excited state observed at 430 nm was monitored over time. The triplet excited state lifetimes (τT(under,air)) and decay rate constants (kd(under,air)) were calculated from the absorption changes (Table 1). In addition, similar experiments were performed after argon gas bubbling (τT(under,Ar) and kd(under,Ar)) to determine the quenching rate constants (kq) due to oxygen (Figure S6b in the Supporting Information). The quenching rate constants originating from oxygen were calculated with the following equation: kq = kd(under,air) – kd(under,Ar). The kq values of β-3 and γ-3 were 2.2 and 1.7 times smaller than that of 4, respectively. This difference means that CD shells partially inhibited the contact between the porphyrin core and 3O2. On the other hand, the kq values of β-3, γ-3, and 4 were several hundred times larger than the corresponding kd(under,Ar) ones (Table 1). This definite difference disclosed that the energy transfer to 3O2 is much faster than other pathways such as radiative deactivation and vibrational relaxation in the T1 → S0 process of the porphyrin cores. This situation is true even in β-3 and γ-3 where the frequency of their contact is somewhat reduced by the CD shells. Therefore, the porphyrin cores of β-3 and γ-3 could transfer almost all of the excitation energy to 3O2 in the air-saturated aqueous solutions, maintaining the 1O2 generation efficiency (vide infra).

The [5]rotaxanes β-3 and γ-3 are concurrently expected to show high durability, in other words, photostability owing to the protection of the porphyrin core by the CD shells mostly against 1O2. We examined the stabilities of [5]rotaxanes β-3 and γ-3 and [3]rotaxane 4 under continuous photoirradiation. While the aqueous solutions of the rotaxanes were irradiated with light using a 250 W high-pressure mercury lamp with a 405 nm band-pass filter, the UV–vis spectra were monitored over time (Figure 6). The CD-free [3]rotaxane 4 was rapidly photobleached, whereas the absorption bands of CD-encapsulated β-3 and γ-3 only decreased insignificantly even after 120 min irradiation. The slightly higher photostability of γ-3 against β-3 would result from the larger cavity of the 2,3-Me-γ-CD shells. Indeed, MacroModel-based Monte Carlo simulation suggested that the 2,3-Me-γ-CD firmly covered the wider area of the porphyrin core including unsubstituted meso-positions than 2,3-Me-β-CD (Figure 7). The main pathway of porphyrin degradations is known to be cycloaddition of 1O2 to the C=C double bond at the meso-positions followed by cleavage of the resulting C–C bond.36,37 This would be a reason why γ-3 showed photostability superior to that of β-3. Compared with talaporfin sodium, presently used as a clinical photosensitizer, β-3 and γ-3 showed significantly high photostability (Figures 6d and S7 in the Supporting Information).

Figure 6.

Figure 6

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Absorption spectral changes of (a) β-3, (b) γ-3, and (c) 4 under photoirradiation. (d) Absorption changes of rotaxanes and talaporfin sodium at 407 nm. Conditions: [β-3] = [γ-3] = [4] = [talaporfin sodium] = 2.0 × 10–6 M in H2O, path length of 10 mm, 25 °C, light source: 250 W high-pressure mercury lamp with 405 nm filter.

Figure 7.

Figure 7

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Stable conformations of the complexes obtained from MacroModel-based Monte Carlo simulations. (a) Axle 1′ and 2,3-Me-β-CD. (b) Axle 1′ and 2,3-Me-γ-CD. The axle 1′ is virtual and a simple analogue of 1 (Figure S8). Conditions: OPSL3e, under water, 10,000 conformations.

In summary of the above photophysical characteristics, it seems to be contradictory that CD shells did not affect the 1O2 generation efficiency but did affect the photostability of the sensitizer against 1O2. In the evaluation of 1O2 generation efficiency, the following four-step event occurred: (i) photoexcitation of a porphyrin core in the sensitizer (S0 to S1), (ii) intersystem crossing of the resulting singlet excited state to the triplet one (S1 to T1 of the porphyrin core), (iii) energy transfer to 3O2 from the T1 state, and (iv) the Diels–Alder reaction between the generated 1O2 and ABDA. Among these steps, the third step of energy transfer could be influenced by CD shells, which was confirmed by the smaller quenching rate constants (kq) in the presence of CD shells (Table 1). However, this step has little effect on the overall event rate because the rate-determining step is the fourth step of the Diels–Alder reaction.33 The reaction rate (v1) of the fourth step is determined by the equation v1 = k1[ABDA][1O2]. Since the concentration of the photosensitizer is not involved in this equation, CD shells do not impact the reaction rate v1. Of course, the concentration of 1O2 is unrelated to the CD shells because the excited porphyrin cores of the [5]rotaxanes exclusively cause energy transfer to 3O2 as with the CD-free 4 (vide supra). Eventually, the v1 values were not affected in the presence of CD shells, so that the [5]rotaxanes exhibited high 1O2 generation efficiency comparable to that of TPPS as previously mentioned when explaining the high ΦΔ values of β-3 and γ-3. On the other hand, the rate-determining fourth step is the cycloaddition of 1O2 to the porphyrin core in the case of photostability measurements. Thus, the overall reaction rate (v2) is determined by the equation v2 = k2[porphyrin core][1O2]. The CD shells most likely decrease the apparent concentration of the porphyrin core because the porphyrin core is sealed by the CD shells, as shown in Figure 7. In this situation, the reaction rate v2 diminished in the presence of CD shells, and therefore the [5]rotaxanes revealed higher photostability than the CD-free 4.

The cellular uptake of [5]rotaxanes β-3 and γ-3 was studied using HeLa cells (Figure 8). The solutions of [5]rotaxanes in PBS (5.0 × 10–6 M) were added to cells soaked in the culture medium. After 24 h incubation, the cells were washed with PBS, followed by monitoring with fluorescence microscopy. The red fluorescence from porphyrins was observed in cells treated with β-3 and γ-3, confirming the cellular uptake (Figure 8f,8g). Confocal microscopy imaging demonstrated that β-3 was transported into the cells (Figure S9). Although a similar experiment was conducted using talaporfin sodium, no talaporfin fluorescence was observed (Figure 8h). Quantitative evaluation of the cellular uptake was performed using flow cytometry (Figure 8i). The fluorescence intensities of the cells with the [5]rotaxanes β-3 and γ-3 were significantly higher than those treated with talaporfin sodium. This finding indicates that β-3 and γ-3 were more easily transferred into cells than talaporfin sodium, even considering the slightly lower fluorescence quantum yield of talaporfin sodium (Φf = 0.008–0.01).38 This high cell membrane permeability of the [5]rotaxanes may be due to the high affinity of the cationic ammonium substituents for anionic cell membranes. Notably, β-3 was much more easily taken up into cells than γ-3. This difference can be explained based on the exposure area of the hydrophobic porphyrin cores. As shown in the stable conformations obtained by Monte Carlo simulations (Figure 7), the porphyrin core of β-3 is more exposed than that of γ-3. The exposed hydrophobic core would increase affinity with the cell membrane and induce cellular uptake of β-3.

Figure 8.

Figure 8

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Fluorescence of β-3, γ-3, and talaporfin sodium in HeLa cells. (a–d) Phase contrast and (e–h) fluorescence images of HeLa cells treated with (a, e) water (2 μL) and aqueous solution of (b, f) β-3, (c, g) γ-3, and (d, h) talaporfin sodium (2 μL) for 24 h at 37 °C. Conditions: [β-3] = [γ-3] = [talaporfin sodium] = 5.0 × 10–6 M, λex = 560 ± 40 nm, λem = 630 ± 75 nm. (i) The HeLa cells were pretreated with water (black dotted line) and aqueous solution of β-3 (red line), γ-3 (blue line), and talaporfin sodium (black solid line) for 24 h at 37 °C. The cells were excited at 488 nm, and fluorescence signals were detected at 670–735 nm. Representative flow cytometry histograms are shown in the left panel (ca. 2 × 104 cells per measurement). The right panel shows the median fluorescence intensity of each cell in four flow cytometry assays.

Finally, the photoinduced cytotoxicity of the [5]rotaxanes β-3 and γ-3 was assessed in cells in order to disclose their PDT efficacy (Figure 9). The HeLa cells were incubated with the [5]rotaxanes (from 3.1 × 10–8 to 1.6 × 10–5 M) for 24 h, and the cells were washed with PBS. After the photoirradiation with a 490 mW LED lamp (λex = 405 nm) for 30 min and incubation for 2 h, the cell survival rate was determined using a WST-8 assay with a Cell Counting Kit-8. The [5]rotaxanes were cytotoxic to HeLa cells under photoirradiation (Figure 9a), whereas they were not in the dark (Figure 9b). The IC50 values of the [5]rotaxanes β-3 and γ-3 were estimated to be 8.0 × 10–7 and 7.7 × 10–7 M, respectively. These values were much lower than the IC50 value of talaporfin sodium (2.9 × 10–5 M). These high photoinduced cytotoxic abilities of the [5]rotaxanes would be derived from not only their superior cell membrane permeability but also high photostability.

Figure 9.

Figure 9

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Cell viability with β-3 (red), γ-3 (blue), and talaporfin sodium (black) measured (a) under photoirradiation (405 nm) or (b) in the dark. Cell viability was measured by the WST-8 method. Error bars represent the mean ± standard deviation for n = 4.

4. Conclusions

In conclusion, we developed [5]rotaxane-type photosensitizers that have a porphyrin axle encapsulated by 2,3-Me-β-CD and 2,3-Me-γ-CD. The [5]rotaxanes showed higher water solubility than naked porphyrin-based photosensitizers. The singlet oxygen generation efficiency of the [5]rotaxanes was as high as that of the water-soluble porphyrin derivative, indicating that energy transfer to oxygen molecules efficiently occurs even in the presence of CD shells. In addition, the CD shells of the [5]rotaxanes improved the photostability of the porphyrin cores. More importantly, the [5]rotaxane-type photosensitizers showed higher cell membrane permeability and photoinduced cytotoxic abilities than talaporfin sodium. These results demonstrated that the rotaxane strategy for photosensitizers is an innovative method to impart beneficial functions to photosensitizers. We are now planning further improvements of the rotaxane-type photosensitizer to treat tumor tissues deeper in the body by encapsulating photosensitizers excitable by near-infrared light and by two-photon absorbing mode. Furthermore, the ability to accumulate in tumor tissue should be imparted by introducing a target ligand to the stopper sites.

Acknowledgments

The authors thank Prof. Takenori Tomohiro (Graduate School of Pharmaceutical Sciences, University of Toyama) and Dr. Masaru Tanioka (Graduate School of Pharmaceutical Sciences, University of Toyama) for providing them with a high-pressure mercury lamp and LED lamps, respectively. The authors thank financial support from Tamura Science and Technology Foundation, Tokuyama Science Foundation, and Yazaki Memorial Foundation for Science and Technology. This work was supported by JST SPRING Grant Number JPMJSP2145 and JSPS KAKENHI Grant Numbers JP24K08391 and JP19H02699.

Glossary

Abbreviations

PDT

photodynamic therapy

CD

cyclodextrin

CB6

cucurbit[6]uril

2,3-Me-β-CD

heptakis(2,3-di-O-methyl)-β-cyclodextrin

2,3-Me-γ-CD

octakis(2,3-di-O-methyl)-γ-cyclodextrin

PBS

phosphate-buffered saline

ABDA

9,10-anthracenediyl-bis(methylene)dimalonic acid

TPPS

tetraphenylporphyrin tetrasulfonic acid

Supporting Information Available

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsabm.4c00844.

  • Detailed synthetic procedures; chemical characterization; and 1H and 13C NMR spectra (PDF)

Author Contributions

The manuscript was written through contributions of all authors.

The authors declare no competing financial interest.

Supplementary Material

mt4c00844_si_001.pdf (3.4MB, pdf)

References

  1. Dolmans D. E. J. G. J.; Fukumura D.; Jain R. K. Photodynamic therapy for cancer. Nat. Rev. Cancer 2003, 3, 380–387. 10.1038/nrc1071. [DOI] [PubMed] [Google Scholar]
  2. Castano A. P.; Mroz P.; Hamblin M. R. Photodynamic therapy and anti-tumor immunity. Nat. Rev. Cancer 2006, 6, 535–545. 10.1038/nrc1894. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Celli J. P.; Spring B. Q.; Rizvi I.; Evans C. L.; Samkoe K. S.; Verma S.; Pogue B. W.; Hasan T. Imaging and photodynamic therapy: Mechanisms, monitoring, and optimization. Chem. Rev. 2010, 110, 2795–2838. 10.1021/cr900300p. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Fan W.; Huang P.; Chen X. Overcoming the Achilles’ heel of photodynamic therapy. Chem. Soc. Rev. 2016, 45, 6488–6519. 10.1039/C6CS00616G. [DOI] [PubMed] [Google Scholar]
  5. Pham T. C.; Nguyen V.-N.; Choi Y.; Lee S.; Yoon J. Recent strategies to develop innovative photosensitizers for enhanced photodynamic therapy. Chem. Rev. 2021, 21, 13454–13619. 10.1021/acs.chemrev.1c00381. [DOI] [PubMed] [Google Scholar]
  6. Nguyen V.; Yan Y.; Zhao J.; Yoon J. Heavy-atom-free photosensitizers: from molecular design to applications in the photodynamic therapy of cancer. Acc. Chem. Res. 2021, 54, 207–220. 10.1021/acs.accounts.0c00606. [DOI] [PubMed] [Google Scholar]
  7. Sternberg E. D.; Dolphin D. Porphyrin-based photosensitizers for use in photodynamic therapy. Tetrahedron 1998, 54, 4151–4202. 10.1016/S0040-4020(98)00015-5. [DOI] [Google Scholar]
  8. Chatterjee D. K.; Fong L. S.; Zhang Y. Nanoparticles in photodynamic therapy: An emerging paradigm. Adv. Drug Delivery Rev. 2008, 60, 1627–1637. 10.1016/j.addr.2008.08.003. [DOI] [PubMed] [Google Scholar]
  9. Yano S.; Hirohara S.; Obata M.; Hagiya Y.; Ogura S.; Ikeda A.; Kataoka H.; Tanaka M.; Joh T. Current states and future views in photodynamic therapy. J. Photochem. Photobiol., C 2011, 12, 46–67. 10.1016/j.jphotochemrev.2011.06.001. [DOI] [Google Scholar]
  10. Ethirajan M.; Chen Y.; Joshi P.; Pandey R. K. The role of porphyrin chemistry in tumor imaging and photodynamic therapy. Chem. Soc. Rev. 2011, 40, 340–362. 10.1039/B915149B. [DOI] [PubMed] [Google Scholar]
  11. Jeong H.-G.; Choi M.-S. Design and properties of porphyrin-based singlet oxygen generator. Isr. J. Chem. 2016, 56, 110–118. 10.1002/ijch.201500026. [DOI] [Google Scholar]
  12. Bonnett R.; Martínez G. Photobleaching of sensitizers used in photodynamic therapy. Tetrahedron 2001, 57, 9513–9547. 10.1016/S0040-4020(01)00952-8. [DOI] [Google Scholar]
  13. Kano K.; Tanaka N.; Minamizono H.; Kawakita Y. Tetraarylporphyrins as probes for studying mechanism of inclusion-complex formation of cyclodextrins. Effect of microscopic environment on inclusion of ionic guests. Chem. Lett. 1996, 25, 925–926. 10.1246/cl.1996.925. [DOI] [Google Scholar]
  14. Kano K.; Nishiyabu R.; Asada T.; Kuroda Y. Static and dynamic behavior of 2:1 inclusion complexes of cyclodextrins and charged porphyrins in aqueous organic media. J. Am. Chem. Soc. 2002, 124, 9937–9944. 10.1021/ja020253n. [DOI] [PubMed] [Google Scholar]
  15. Bonchio M.; Carofiglio T.; Carrao M.; Fornasier R.; Tonellato U. Efficient sensitized photooxygenation in water by a porphyrin–cyclodextrin supramolecular complex. Org. Lett. 2002, 4, 4635–4637. 10.1021/ol0270069. [DOI] [PubMed] [Google Scholar]
  16. Kitagichi H.; Hatada S.; Itakura T.; Maki Y.; Maeda Y.; Kano K. Cellular uptake of octaarginine-conjugated tetraarylporphyrin included by per-O-methylated β-cyclodextrin. Org. Biomol. Chem. 2013, 124, 3203–3211. 10.1039/c3ob27248f. [DOI] [PubMed] [Google Scholar]
  17. Ikeda A.; Satake S.; Mae T.; Ueda M.; Sugikawa K.; Shigeto H.; Funabashi H.; Kuroda A. Photodynamic activities of porphyrin derivative–cyclodextrin complexes by photoirradiation. ACS Med. Chem. Lett. 2017, 8, 555–559. 10.1021/acsmedchemlett.7b00098. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Yakavets I.; Lassalle H.-P.; Yankovsky I.; Ingrosso F.; Monari A.; Bezdetnaya L.; Zorin V. Evaluation of temoporfin affinity to β-cyclodextrins assuming self-aggregation. J. Photochem. Photobiol., A 2018, 367, 13–21. 10.1016/j.jphotochem.2018.07.046. [DOI] [Google Scholar]
  19. Kitagishi H.; Chai F.; Negi S.; Sugiura Y.; Kano K. Supramolecular intracellular delivery of an anionic porphyrin by octaarginine-conjugated per-O-methyl-β-cyclodextrin. Chem. Commun. 2015, 51, 2421–2424. 10.1039/C4CC09042J. [DOI] [PubMed] [Google Scholar]
  20. Özkan M.; Keser Y.; Hadi S. E.; Tuncel D. A [5]rotaxane-based photosensitizer for photodynamic therapy. Eur. J. Org. Chem. 2019, 2019, 3534–3541. 10.1002/ejoc.201900278. [DOI] [Google Scholar]
  21. Wang H.; Yang Y.; Yuan B.; Ni X.-L.; Xu J.-F.; Zhang X. Cucurbit[10]uril-encapsulated cationic porphyrins with enhanced fluorescence emission and photostability for cell imaging. ACS Appl. Mater. Interfaces 2021, 13, 2269–2276. 10.1021/acsami.0c18725. [DOI] [PubMed] [Google Scholar]
  22. Kashyap A.; Ramasamy E.; Ramalingam V.; Pattabiraman M. Supramolecular control of singlet oxygen generation. Molecules 2021, 26, 2673 10.3390/molecules26092673. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Riebe J.; Niemeyer J. Mechanically interlocked molecules for biomedical applications. Eur. J. Org. Chem. 2021, 2021, 5106–5116. 10.1002/ejoc.202100749. [DOI] [Google Scholar]
  24. Yakavets I.; Millard M.; Zorin V.; Lassalle H.-P.; Bezdetnaya L. Current state of the nanoscale delivery systems for temoporfin-based photodynamic therapy: Advanced delivery strategies. J. Controlled Release 2019, 304, 268–287. 10.1016/j.jconrel.2019.05.035. [DOI] [PubMed] [Google Scholar]
  25. Ohishi Y.; Nishioki K.; Miyaoka Y.; Serizawa K.; Sugawara S.; Hayashi K.; Inoue D.; Iwamura M.; Yokoyama S.; Chiba J.; Inouye M. A versatile synthetic method for photophysically and chemically stable [5]rotaxane-type fluorescence dyes of various colors by using a cooperative capture strategy. Adv. Opt. Mater. 2024, 12, 2301457 10.1002/adom.202301457. [DOI] [Google Scholar]
  26. Hou X.; Ke C.; Stoddart J. F. Cooperative capture synthesis: yet another playground for copper-free click chemistry. Chem. Soc. Rev. 2016, 45, 3766–3780. 10.1039/c6cs00055j. [DOI] [PubMed] [Google Scholar]
  27. Tse Y. C.; Au-Yueng H. Y. Catenane and rotaxane synthesis from cucurbit[6]uril-mediated azide-alkyne cycloaddition. Chem. - Asian J. 2023, 18, e202300290 10.1002/asia.202300290. [DOI] [PubMed] [Google Scholar]
  28. d’Orchymont F.; Holland J. P. Supramolecular rotaxane-based multi-modal probes for cancer biomarker imaging. Angew. Chem., Int. Ed. 2022, 61, e202204072 10.1002/anie.202204072. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. d’Orchymont F.; Holland J. P. A rotaxane-based platform for tailoring the pharmacokinetics of cancer-targeted radiotracers. Chem. Sci. 2022, 13, 12713–12725. 10.1039/D2SC03928A. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. d’Orchymont F.; Holland J. P. Asymmetric rotaxanes as dual-modality supramolecular imaging agents for targeting cancer biomarkers. Commun. Chem. 2023, 6, 107 10.1038/s42004-023-00906-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. d’Orchymont F.; Holland J. P. Cooperative capture synthesis of functionalized heterorotaxanes—Chemical scope, kinetics, and mechanistic studies. J. Am. Chem. Soc. 2023, 145, 12894–12910. 10.1021/jacs.3c04111. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Kumar N.; Oqmhula K.; Hongo K.; Takagi K.; Yusa S.; Rajan R.; Matsumura K. A mechanistic insights and importance of hydrophobicity in cationic polymers for cancer therapy. J. Mater. Chem. B 2023, 11, 1456–1468. 10.1039/D2TB02059A. [DOI] [PubMed] [Google Scholar]
  33. Entradas T.; Waldron S.; Volk M. The detection sensitivity of commonly used singlet oxygen probes in aqueous environments. J. Photochem. Photobiol., B 2020, 204, 111787 10.1016/j.jphotobiol.2020.111787. [DOI] [PubMed] [Google Scholar]
  34. Redmond R. W.; Gamlin J. N. A compilation of singlet oxygen yields from biologically relevant molecules. Photochem. Photobiol. 1999, 70, 391–475. 10.1562/0031-8655(1999)0702.3.co;2. [DOI] [PubMed] [Google Scholar]
  35. Dexter D. L. A theory of sensitized luminescence in solids. J. Chem. Phys. 1953, 21, 836–850. 10.1063/1.1699044. [DOI] [Google Scholar]
  36. Yamaguchi M.; Shioya K.; Li C.; Yonesato K.; Murata K.; Ishii K.; Yamaguchi K.; Suzuki K. Porphyrin–polyoxotungstate molecular hybrid as a highly efficient, durable, visible-light-responsive photocatalyst for aerobic oxidation reactions. J. Am. Chem. Soc. 2024, 7, 4549–4556. 10.1021/jacs.3c11394. [DOI] [PubMed] [Google Scholar]
  37. Wojaczyński J.; Popiel M.; Szterenberg L.; Latos-Grażyński L. Common origin, common fate: regular porphyrin and N-confused porphyrin yield an identical tetrapyrrolic degradation product. J. Org. Chem. 2011, 76, 9956–9961. 10.1021/jo201489z. [DOI] [PubMed] [Google Scholar]
  38. Li L.; Kodama K.; Saito K.; Aizawa K. Phase-resolved fluorescence study of mono-L-aspartyl chlorin E6. J. Photochem. Photobiol., B 2002, 67, 51–55. 10.1016/S1011-1344(02)00244-0. [DOI] [PubMed] [Google Scholar]

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