Low Dark Toxicity Research Articles

The photodynamic activity of 131-[2′-(2-pyridyl)ethylamine] chlorin e6 photosensitizer in human esophageal cancer

A novel 131-pyridine substituted chlorin e6 derivative (Chlorin A) was synthesized. It has characteristic long wavelength absorption at 664 nm and the emission wavelength at 667 nm. The generation rate of singlet oxygen of this compound is higher than Temoporfin. In vitro, Chlorin A showed higher phototoxicity against the human esophageal cancer cells than Temoporfin while with lower dark-toxicity. Its accumulation effect in mitochondria, lysosomes and endoplasmic reticulum was traced in subcellular localization tests. In flow cytometry obvious apoptosis cells were observed after 2 h irradiation. Significant in vivo photodynamic anti-tumor efficacy was also exhibited on mice bearing esophageal cancer. So Chlorin A could be suggested as a promising anti-tumor drug candidate in photodynamic therapy.

Iron(III) Complexes of Vitamin B6 Schiff Base with Boron‐Dipyrromethene Pendants for Lysosome‐Selective Photocytotoxicity

Iron(III) complexes of a vitamin B6 Schiff base and NNN‐donor ligands with pendant boron‐dipyrromethene (BODIPY) moieties; namely, [Fe(L1–3)(L4,5)](NO3) (1–4), where L1 is benzyl‐bis[(pyridin‐2‐yl)methyl]methanamine (bzdpa in 1), L2 is a noniodinated BODIPY‐appended dipicolylamine ligand (in 2, 3), L3 is the diiodinated BODIPY analogue in 4, L4 is a vitamin B6 Schiff base, namely 3‐hydroxy‐5(hydroxymethyl)‐4‐{[(2‐hydroxyphenyl)imino]methyl}‐2‐methylpyridine (in 1, 3, and 4), and L5 is 2‐[(2‐hydroxyphenylimino)‐methyl]phenol (in 2) as a nonpyridoxal Schiff base, were prepared, characterized, and their cellular localization and cytotoxic activity in light and in the dark were studied. The diiodo–BODIPY complex 4 displays remarkable photoinduced cytotoxicity in visible light (400–700 nm), with IC50 values within 0.11–0.25 µm and about 200‐fold lower dark toxicity. Complex 3, being fluorescent, was used for cellular imaging by confocal microscopy. Complex 4 shows supercoiled pUC19 DNA cleavage activity through the generation of singlet oxygen (1O2) as the reactive oxygen species (ROS). Selective uptake of the complexes is observed from competitive cellular incorporation assays in cancer and noncancer cells. The complexes also show no apparent toxicity up to 100 µm in the immortal human lung epithelial cells HPL1D in both light and the dark. Complex 3 shows preferential accumulation in lysosomes, giving a Pearson's correlation coefficient value of about 0.7.

A hematoporphyrin and indocyanine green co-delivery system with NIR triggered-controllable photoactivities for photodynamic therapy

Photodynamic therapy (PDT) was hindered by the poor water solubility and long-enduring photoactivities of photosensitizers. Here, we developed a novel controllable photodynamic agent CPHI based on β-cyclodextrin modified polyamidoamine (PAMAM) dendrimer (CP) co-delivery of indocyanine green (ICG) and hematoporphyrin (HP). The CPHI possessed appropriate particle sizes and zeta potentials, considerable photostability, and NIR-triggered release property. The fluorescence of HP could be quenched by ICG when HP and ICG were co-loaded inside the CP, and the quenching efficiency was related with the weight ratio of HP and ICG. When the feeding weight proportion of HP and ICG is 1/10, the fluorescence of HP was quenched by 87.3% in CPHI. Under 808 nm laser irradiation, the ICG in CP was degraded, and the fluorescence of HP could recover. The recovered HP was capable of generating reactive oxygen species (ROS) for PDT with 606 nm laser irradiation. The cytotoxicity and cell apoptosis studies showed that CPHI could effectively induce MCF-7 cells apoptosis with PDT effects under 808/660 nm laser. These results suggested that CPHI could be an efficient cancer therapeutic agent for controllable PDT with low dark toxicity.

EGFR-targeted photodynamic therapy by curcumin-encapsulated chitosan/TPP nanoparticles.

BackgroundPhotodynamic therapy (PDT) is an effective therapy for cancers and is a minimally invasive therapy with low dark toxicity and limited side effects. PDT employs the combination of photosensitizers with a specific light source to produce reactive oxygen species (ROS) to damage tumor cells.MethodsWe fabricated nanoparticles encapsulating curcumin through crosslinking chitosan and tripolyphosphate (TPP). Additionally, the chitosan was conjugated to epidermal growth factor in order to target the epidermal growth factor receptor (EGFR), overexpressed on cancer cells. To investigate PDT using fabricated nanoparticles, we measured cell viabilities and ROS production in relation to EGFR-overexpressing gastric cancer cells and non-cancer gastric cells.ResultsThe targeting nanoparticles displayed a superior PDT effect in the cancer cell, with a resultant approximately fourfold decrease in the IC50. The PDT mechanism of curcumin-encapsulated nanoparticles is further identified as the generation of 1O2, the major pathway in PDT.ConclusionThese curcumin-encapsulated chitosan/TPP nanoparticles are a promising targeted-PDT against EGFR-overexpressing cancers.

A light-induced nitric oxide controllable release nano-platform based on diketopyrrolopyrrole derivatives for pH-responsive photodynamic/photothermal synergistic cancer therapy.

Emerging treatment approaches, such as gas therapy (GT), photodynamic therapy (PDT) and photothermal therapy (PTT), have received widespread attention. The development of an intelligent multifunctional nano-platform responding to tumor microenvironments for multimodal therapy is highly desirable. Herein, a near-infrared (NIR) light-responsive nitric oxide (NO) photodonor (4-nitro-3-trifluoromethylaniline, NF) and a pH-sensitive group (dimethylaminophenyl) have been introduced into a diketopyrrolopyrrole core (denoted as DPP-NF). The DPP-NF nanoparticles (NPs) can be activated under weakly acidic conditions of lysosomes (pH 4.5-5.0) to generate reactive oxygen species (ROS) and enhance photothermal efficiency. The fluorescence detection demonstrated that NO controllable release can be realized by "on-off" switching of the NF unit under NIR light irradiation or dark conditions. The controllable NO release of DPP-NF NPs can not only trigger tumor cell death by DNA damage, but also overcome PDT inefficiencies caused by hypoxia in tumors. Additionally, DPP-NF NPs displayed 45.6% photothermal conversion efficiency, making them superior to other reported DPP derivatives. In vitro studies showed that DPP-NF NPs possessed low dark toxicity and high phototoxicity with a half-maximal inhibitory concentration of about 38 μg mL-1. In vivo phototherapy indicated that DPP-NF NPs exhibited excellent tumor phototherapeutic efficacy with passive targeting of the tumor site via the enhanced permeability and retention (EPR) effect. These results highlight that the nano-platform has promising potential for NO-mediated multimodal synergistic phototherapy in clinical settings.

Zinc(II) Metalated Porphyrins as Photothermogenic Photosensitizers for Cancer Photodynamic/Photothermal Synergistic Therapy.

Porphyrin derivatives are the first-generation photosensitizers, and to design a strong near-infrared (NIR)-absorbing porphyrin with good water solubility is highly desired for better therapeutic effect to treat tumors. Herein, three new porphyrin derivatives, 5,10,15,20-tetrakis(3,4-dimethoxyphenyl) porphyrin (P1), 5,10,15,20-tetrakis(3,4-dimethoxyphenyl) zinc porphyrin (ZnP1), and 5,15-bis(3,4-dimethoxyphenyl)-10,20-bis((4-methoxyphenyl)ethynyl) zinc porphyrin (ZnP2) have been synthesized. Among them, ZnP2 shows the longest and most intensive Q-bands in the near-infrared (NIR) region, as it endows the strongest light-harvesting capability and deepest tumor tissue penetration. The three porphyrin derivatives were prepared into nanoparticles (NPs) via nanoprecipitation method, and the NPs exhibit good water dispersibility and passive tumor-targeting property through enhanced permeability and retention effect. Furthermore, these NPs demonstrate both photodynamic and photothermal effects. Through a systematic study of the singlet oxygen quantum yield and cytotoxicity of P1, ZnP1, and ZnP2 NPs in vitro on Hela cells, it is found that ZnP2 shows the highest singlet oxygen quantum yield (79%), and its NPs show the best therapeutic efficacy in vitro. In vivo experiments disclosed that ZnP2 NPs present high phototoxicity, low dark toxicity, and excellent biocompatibility, and could be used as promising photothermogenic photosensitizer for cancer treatment.

Synthesis of a Ruthenium(II) Compound based on 5‐(2‐Pyrimidyl)‐1H‐tetrazole for Photodynamic Therapy

RuII compounds have been universally investigated due to their unique physical and chemical properties. In this paper, a new RuII compound based on 2,2′‐bipy and Hpmtz [2,2′‐bipy = 2,2′‐bipyridine, Hpmtz = 5‐(2‐pyrimidyl)‐1H‐tetrazole], namely [Ru(2,2′‐bipy)2(pmtz)][PF6]·0.5H2O was prepared and characterized by elemental analysis, IR and single‐crystal X‐ray diffraction. [Ru(2,2′‐bipy)2(pmtz)][PF6]·0.5H2O shows a mononuclear structure and forms a three‐dimensional network by non‐classic hydrogen bonds. The ability of generation of ROS (reactive oxygen species) makes it has a low phototoxicity IC50 (half‐maximal inhibitory concentration) after Xenon lamp irradiation on Hela cells in vitro. The results demonstrate that [Ru(2,2′‐bipy)2(pmtz)][PF6]·0.5H2O with high light toxicity and low dark toxicity may be a potential candidate for photodynamic therapy.

Novel Cyclometalated Fe(II) Complex with NCN Pincer and BODIPY‐Appended 4'‐Ethynyl‐2,2':6',2”‐terpyridine as Mitochondria‐Targeted Photodynamic Anticancer Agents

BODIPY (boron dipyrromethene) derivatives and iron complexes are two types of functional compounds that have found wide applications in the fields of biology and medicine. The new class of cyclometalated Fe(II) complex with NCN pincer and meso‐phenyl‐4'‐ethynyl‐2,2':6',2”‐terpyridine BODIPY ligands of formula [Fe(L)(tpy‐BODIPY)], 1, in which HL:5‐methoxy‐1,3‐bis (1‐methyl‐1H‐benzo[d]imidazol‐2‐yl)benzene, tpy‐BODIPY: 8‐(4‐phenyl‐4'‐ethynyl‐2,2':6',2”‐terpyridine) BODIPY, has been synthesized and studied as mitochondria‐targeted photodynamic therapy (PDT). Complex 1 showed photocytotoxicity in HeLa cells at 500 nm with low dark toxicity. The phototoxicity of complex 1 on the nontumorigenic MRC‐5 cell line showed the same trend observed for HeLa cells, that is moderately photocytotoxic against the nontumorigenic MRC‐5 cell line (IC50 = 36.21 μM). Moreover, complex 1 selectively localizes into mitochondria of the HeLa cells. The photophysical properties, cellular uptake, reactive oxygen species (ROS) generation, and cellular apoptosis of complex 1 have also been studied.Overall, the new Fe(II) complex with BODIPY moiety is significantly photocytotoxic in HeLa cells when irradiated with visible light of 500 nm giving as mitochondria targeting. Therefore, we present cyclometalated Fe(II) pincer complex induced mitochondria‐targeted PDT involving the BODIPY moiety that develops persuasively designed photoactivatable Fe(II) complexes.

A theranostic plaster combining photothermal therapy and photodynamic therapy based on chlorin e6/gold nanorods (Ce6/Au nrs) composite

In this work, a new type of plaster based on chlorin e6 (Ce6)-gold nanorods (Au nrs) complex was developed for near-infrared (NIR) cancer therapy. The cancer treatment could be performed by applying the plaster to the tumor site and using dual-wavelength laser irradiation, 660nm and 808nm. The plaster could be irradiated repeatedly during the treatment and was completely noninvasive. It has exhibited broad, strong absorption in the NIR region, excellent photothermal efficiency and high singlet oxygen generation. The prepared plaster had low dark toxicity, while under irradiation, it showed high cell killing ability using human squamous cell carcinoma cells. The combinational effect of photothermal therapy (PTT) and photodynamic therapy (PDT) was also demonstrated in vivo. The plaster-treated tumor bearing mice showed highest therapeutic efficiency, compared to that treated with single PTT or PDT. The tumors have been destroyed completely after 16days treatment with the double phototherapy treatment. Therefore, the developed system might be potential as a dual-modal phototherapy way for cancer treatment in clinical application.

Singlet Oxygen Production and Biological Activity of Hexanuclear Chalcocyanide Rhenium Cluster Complexes [{Re6Q8}(CN)6]4– (Q = S, Se, Te)

Octahedral rhenium cluster complexes have recently emerged as relevant building blocks for the design of singlet oxygen photosensitizing materials toward biological applications such as blue-light photodynamic therapy. However, their singlet oxygen generation ability as well as biological properties have been studied only superficially. Herein we investigate in detail the singlet oxygen photogeneration, dark and photoinduced cytotoxicity, cellular uptake kinetics, cellular localization and in vitro photoinduced oxidative stress, and photodynamic cytotoxicity of the series of octahedral rhenium cluster complexes [{Re6Q8}(CN)6]4-, where Q = S, Se, Te. Our results demonstrate that the selenium-containing complex possesses optimal properties in terms of absorption and singlet oxygen productivity. These features coupled with the cellular internalization and low dark toxicity lead to the first photoinduced cytotoxic effect observed for a molecular [{M6Q8}L6] complex, making it a promising object for further study in terms of blue-light PDT.

The photodynamic therapy activity of 3-(1-hydroxylethyl)-3-devinyl-131-(dicyanomethylene) pyropheophorbide-a methyl ester (HDCPPa) against HeLa cell in vitro

Photodynamic therapy (PDT) has been a potential therapeutic method for the treatment of various cancers, with photosensitizer being the key component in photodynamic therapy. In this paper, we prepared a photosensitizer 3-(1-hydroxylethyl)-3-devinyl-131-(dicyanomethylene) pyropheophorbide-a methyl ester (HDCPPa), based on chlorophyll pyropheophorbide-a according to the previous report, and systematically investigated the fluorescence emission spectrum and ultraviolet absorption spectrum HDCPPa has long absorption in the near-infrared spectral region (around 695 nm). The excitation wavelength and the emission wavelength were 415 nm and 699 nm respectively in dichloromethane, 1O2 quantum yield was 63.5%. HDCPPa also had high stability in PBS solution, DMEM cell culture medium and normal saline (NS) in vitro. After irradiation by the light of 675 nm (10 J.cm[Formula: see text]) for 70 min the degradation rate of HDCPPa was 12.5%, which indicated that the target compound showed high stability under light. The in vitrophotodynamic therapy activities against HeLa cells were also studied, which showed that HDCPPa had extremely low dark toxicity but great phototoxicity, and the cell viability is lower than 10% under the light irradiation of 675 nm (10 J.cm[Formula: see text]). Moreover, HDCPPa can quickly enter the cell after being incubated with HeLa cells in less than 30 min. We also evaluated the mechanism of the photochemical reaction, which had proved that Type II is primarily responsible for the cell death. Therefore HDCPPa could serve as a very promising photosensitizer for photodynamic therapy.

NIR Ratiometric Luminescence Detection of pH Fluctuation in Living Cells with Hemicyanine Derivative-Assembled Upconversion Nanophosphors.

It is crucial for cell physiology to keep the homeostasis of pH, and it is highly demanded yet challenging to develop luminescence resonance energy transfer (LRET)-based near-infrared (NIR) ratiometric luminescent sensor for the detection of pH fluctuation with NIR excitation. As promising energy donors for LRET, upconversion nanoparticles (UCNPs) have been widely used to fabricate nanosensors, but the relatively low LRET efficiency limits their application in bioassay. To improve the LRET efficiency, core/shell/shell structured β-NaGdF4@NaYF4:Yb,Tm@NaYF4 UCNPs were prepared and decorated with hemicyanine dyes as an LRET-based NIR ratiometric luminescent pH fluctuation-nanosensor for the first time. The as-developed nanosensor not only exhibits good antidisturbance ability, but it also can reversibly sense pH and linearly sense pH in a range of 6.0-9.0 and 6.8-9.0 from absorption and upconversion emission spectra, respectively. In addition, the nanosensor displays low dark toxicity under physiological temperature, indicating good biocompatibility. Furthermore, live cell imaging results revealed that the sensor can selectively monitor pH fluctuation via ratiometric upconversion luminescence behavior.

Conjugate of biotin with silicon(IV) phthalocyanine for tumor-targeting photodynamic therapy

In order to improve the efficacy of photodynamic therapy (PDT), biotin was axially conjugated with silicon(IV) phthalocyanine (SiPc) skeleton to develop a new tumor-targeting photosensitizer SiPc-biotin. The target compound SiPc-biotin showed much higher binding affinity toward BR-positive (biotin receptor overexpressed) HeLa human cervical carcinoma cells than its precursor SiPc-pip. However, when the biotin receptors of HeLa cells were blocked by free biotin, >50% uptake of SiPc-biotin was suppressed, demonstrating that SiPc-biotin could selectively accumulate in BR-positive cancer cells via the BR-mediated internalization. The confocal fluorescence images further confirmed the target binding ability of SiPc-biotin. As a consequence of specificity of SiPc-biotin toward BR-positive HeLa cells, the photodynamic effect was also largely dependent on the BR expression level of HeLa cells. The photodynamic activities of SiPc-biotin against HeLa cells were dramatically reduced when the biotin receptors were blocked by the free biotin (IC50: 0.18μM vs. 0.46μM). It is concluded that SiPc-biotin can selectively damage BR-positive cancer cells under irradiation. Furthermore, the dark toxicity of SiPc-biotin toward human normal liver cell lines LO2 was much lower than that of its precursor SiPc-pip. The targeting photodynamic activity and low dark toxicity suggest that SiPc-biotin is a promising photosensitizer for tumor-targeting photodynamic therapy.

A Highly Efficient and Photostable Photosensitizer with Near-Infrared Aggregation-Induced Emission for Image-Guided Photodynamic Anticancer Therapy.

Photodynamic therapy (PDT), which relies on photosensitizers (PS) and light to generate reactive oxygen species to kill cancer cells or bacteria, has attracted much attention in recent years. PSs with both bright emission and efficient singlet oxygen generation have also been used for image-guided PDT. However, simultaneously achieving effective 1 O2 generation, long wavelength absorption, and stable near-infrared (NIR) emission with low dark toxicity in a single PS remains challenging. In addition, it is well known that when traditional PSs are made into nanoparticles, they encounter quenched fluorescence and reduced 1 O2 production. In this contribution, these challenging issues have been successfully addressed through designing the first photostable photosensitizer with aggregation-induced NIR emission and very effective 1 O2 generation in aggregate state. The yielded nanoparticles show very effective 1 O2 generation, bright NIR fluorescence centered at 820 nm, excellent photostability, good biocompatibility, and negligible dark in vivo toxicity. Both in vitro and in vivo experiments prove that the nanoparticles are excellent candidates for image-guided photodynamic anticancer therapy.

Phthalocyanines and Tetrapyrazinoporphyrazines with Two Cationic Donuts: High Photodynamic Activity as a Result of Rigid Spatial Arrangement of Peripheral Substituents.

High photodynamic activity was observed for hexadeca-cationic zinc, magnesium, and metal-free phthalocyanines (Pcs) and tetrapyrazinoporphyrazines with EC50 values as low as 5 nM (MCF-7 cells) for the best compound; this activity was several times better than that of clinically established photosensitizers verteporfin, temoporfin, S3AlOHPc, or protoporphyrin IX. This lead compound was characterized by low dark toxicity (TC50 = 369 μM), high efficiency against other cell lines (HCT 116 and HeLa), and possible activation by light above 680 nm. The excellent photodynamic activity resulted from the rigid spatial arrangement of the quaternized triazole moieties above and below the Pc core, as confirmed by X-ray crystallography. The triazole moieties thus formed two "cationic donuts" that protected the hydrophobic core against aggregation in water. The lysosomes were found to be the site of subcellular localization and were consequently the primary targets of photodynamic injury, resulting in predominantly necrotic cell death.

Quinacridone derivative as a new photosensitizer: Photodynamic effects in cells and in vivo

The lack of ideal photosensitizers is the major limitation for clinical photodynamic therapy (PDT). Quinacridone (QA) is a mass-produced industrial organic pigment. QA derivatives are widely investigated for many applications in various fields, but rarely involved in biological applications. Here we report the PDT effects of N,N'-bis(methylpiperazinylpentyl) QA (QAP) in cells and in vivo. QAP shows low dark-toxicity and high photo-toxicity in cells through generating reactive oxygen species (ROS) under irradiation; and greatly inhibits the tumor growth in a mouse subcutaneous xenograft model after irradiation with a 532 nm laser. The high photodynamic efficiency of QAP shows the great potential of QA derivatives to be a new class of leading compound of photosensitizers in PDT.

Synthesis and effect on SMMC-7721 cells of new benzo[c, d]indole rhodanine complex merocyanines as PDT photosensitizers

Photodynamic therapy (PDT) represents a modern and noninvasive therapeutic approach, however, it relies on the development of photosensitizers. Here five new benzo[c,d]indole rhodamine complex merocyanines (BIRCM) D1-D5, displaying low dark toxicity and significant photo toxicity, were synthesized as PDT photosensitizers, and characterized by 1H NMR, IR, UV–Vis and HRMS. The investigation of their absorption spectra in different solvents showed that the absorption maxima and molar extinction coefficient were in the region 507–679 nm and 0.21 × 104–1.27 × 105 L · mol−1cm−1, respectively. The evaluation of PDT activity showed that only irradiation could not kill SMMC-7721 cells, and the cell survival rate and inhibition rate at the application dose and duration was 92%–87% and 78%–49%, respectively. Especially, using D2, absorbed in the red zone, as photosensitizer for PDT analyzed its effect on SMMC-7721 cells survival, it could be found that the cell survival rate was 92% without irradiating and the cell inhibited rate was 78% under irradiating at concentrations of 2.5 × 10−6 mol/L, displaying low dark toxicity and high photo toxicity, which was valuable for PDT of some microvascular diseases or other superficial diseases.

Unimolecular micelles from POSS-based star-shaped block copolymers for photodynamic therapy

A biotin-functionalized amphiphilic star-shaped block copolymer, POSS-(PCL-b-PDMAEMA)8-biotin, with an inorganic POSS nucleus, a hydrophobic poly(ɛ-caprolactone) (PCL) middle layer, a hydrophilic poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) outer corona was synthesized for the targeting delivery and pH-responsive release of hydrophobic pheophorbide A (PPa) photosensitizers. In aqueous solution, this amphiphilic copolymer was able to form unimolecular micelles as determined by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The biotin-functionalized unimolecular micelles were responsive to pH and further utilized in encapsulation and release of PPa for photodynamic therapy (PDT). The PPa release from PPa-loaded unimolecular micelles could be enhanced at acidic condition. Additionally, confocal laser scanning microscopy (CLSM) and flow cytometry results revealed that PPa-loaded tumor-targeted unimolecular micelles could boost the internalization rate in HeLa cells effectively. Moreover, PPa-loaded unimolecular micelles showed low dark toxicity and high PDT efficacy towards HeLa cells according to the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Thus, PPa-loaded POSS-(PCL-b-PDMAEMA)8-biotin would have presented the potential application in PDT.

Syntheses and PDT activity of new mono- and di-conjugated derivatives of chlorin e6.

Syntheses of three new chlorin e6 conjugates for PDT of tumors are reported. One of the new compounds 17 is conjugated with lysine at the 131-position, but the others are mono-conjugated 14 or diconjugated 15 with the non-amino acid species ethanolamine. Cellular experiments with the three new compounds and previously synthesized non-amino acid 152-conjugates (7-10), 131-monoconjugates 14, 16, and a 131,152-diconjugate 12 are reported. In vitro cytotoxicity experiments show that the 131-conjugates are more toxic than the 152-conjugates, and the most toxic derivative (dark- and photo-toxicity) is the 131-ethylenediamine conjugate 11. The most useful PDT photosentitizers appear to be the ethanolamine derivatives, conjugated at the 152- and the 131,152-positions; these show high phototoxicity but relatively low dark toxicity compared with 11, and also the highest dark/photo cytotoxicity ratios.

Versatile Polymer Nanoparticles as Two-Photon-Triggered Photosensitizers for Simultaneous Cellular, Deep-Tissue Imaging, and Photodynamic Therapy.

Clinical applications of current photodynamic therapy (PDT) photosensitizers (PSs) are often limited by their absorption in the UV-vis range that possesses limited tissue penetration ability, leading to ineffective therapeutic response for deep-seated tumors. Alternatively, two-photon excited PS (TPE-PS) using NIR light triggered is one the most promising candidates for PDT improvement. Herein, multimodal polymer nanoparticles (PNPs) from polythiophene derivative as two-photon fluorescence imaging as well as two-photon-excited PDT agent are developed. The prepared PNPs exhibit excellent water dispersibility, high photostability and pH stability, strong fluorescence brightness, and low dark toxicity. More importantly, the PNPs also possess other outstanding features including: (1) the high 1 O2 quantum yield; (2) the strong two-photon-induced fluorescence and efficient 1 O2 generation; (3) the specific accumulation in lysosomes of HeLa cells; and (4) the imaging detection depth up to 2100 µm in the mock tissue under two-photon. The multifunctional PNPs are promising candidates as TPE-PDT agent for simultaneous cellular, deep-tissue imaging, and highly efficient in vivo PDT of cancer.