Nanobody-mediated targeting of zinc phthalocyanine with polymer micelles as nanocarriers

Photodynamic therapy (PDT) is a suitable alternative to currently employed cancer treatments. However, the hydrophobicity of most photosensitizers (e.g., zinc phthalocyanine (ZnPC)) leads to their aggregation in blood. Moreover, non-specific accumulation in skin and low clearance rate of ZnPC leads to long-lasting skin photosensitization, forcing patients with a short life expectancy to remain indoors. Consequently, the clinical implementation of these photosensitizers is limited. Here, benzyl-poly(ε-caprolactone)-b-poly(ethylene glycol) micelles encapsulating ZnPC (ZnPC-M) were investigated to increase the solubility of ZnPC and its specificity towards cancers cells. Asymmetric flow field-flow fractionation was used to characterize micelles with different ZnPC-to-polymer ratios and their stability in human plasma. The ZnPC-M with the lowest payload (0.2 and 0.4% ZnPC w/w) were the most stable in plasma, exhibiting minimal ZnPC transfer to lipoproteins, and induced the highest phototoxicity in three cancer cell lines. Nanobodies (Nbs) with binding specificity towards hepatocyte growth factor receptor (MET) or epidermal growth factor receptor (EGFR) were conjugated to ZnPC-M to facilitate cell targeting and internalization. MET- and EGFR-targeting micelles enhanced the association and the phototoxicity in cells expressing the target receptor. Altogether, these results indicate that ZnPC-M decorated with Nbs targeting overexpressed proteins on cancer cells may provide a better alternative to currently approved formulations.

Dressing and undressing MOF nanophotosensitizers to manipulate phototoxicity for precise therapy of tumors

Photodynamic therapy (PDT) is a clinically approved treatment for tumors, and it relies on the phototoxicity of photosensitizers by producing reactive oxygen species (ROS) to destroy cancer cells under light irradiation. However, such phototoxicity is a double-edged sword, which is also harmful to normal tissues. To manipulate phototoxicity and improve the therapy effect, herein we have proposed a dressing-undressing strategy for de-activating and re-activating therapy functions of photosensitizer nanoparticles. One kind of metal organic framework (PCN-224), which is composed of Zr(IV) cation and tetrakis (4-carboxyphenyl) porphyrin (TCPP), has been prepared as a model of photosensitizer, and it has size of ∼70 nm. These PCN-224 nanoparticles are subsequently coated with a mesoporous organic silica (MOS) shell containing tetrasulfide bonds (-S-S-S-S-), realizing the dressing of PCN-224. MOS shell has the thickness of ∼20 nm and thus can block 1O2 (diffusion distance: <10 nm), deactivating the phototoxicity and preventing the damage to skin and eyes. Furthermore, PCN-224@MOS can be used to load chemotherapy drug (DOX·HCl). When PCN-224@MOS-DOX are mixed with glutathione (GSH), MOS shell with -S-S-S-S- bonds can be reduced by GSH and then be decomposed, which results in the undressing and then confers the exposure of PCN-224 with good PDT function as well as the release of DOX. When PCN-224@MOS-DOX dispersion is injected into the mice and accumulated in the tumor, endogenous GSH also confers the undressing of PCN-224@MOS-DOX, realizing the in-situ activation of PDT and chemotherapy for tumor. Therefore, the present study not only demonstrates a general dressing-undressing strategy for manipulating phototoxicity of photosensitizers, but also provide some insights for precise therapy of tumors without side-effects. STATEMENT OF SIGNIFICANCE: Photosensitizers can generate reactive oxygen species (ROS) under light radiation to destroy cancer cells. However, this phototoxicity is a double-edged sword and also harmful to normal tissues such as the skin and eyes. To control phototoxicity and improve therapeutic efficacy, we prepared a PCN-224@MOS-DOX nanoplatform and proposed a dressing and undressing strategy to deactivate and reactivate the therapeutic function of the photosensitizer nanoparticles. The MOS shell can block the diffusion of 1O2, eliminate phototoxicity, and prevent damage to the skin and eyes. When injected into mice and accumulated in tumors, PCN-224@MOS-DOX dispersions are endowed with an endogenous GSH-driven undressing effect, achieving in situ activation of PDT and tumor chemotherapy.

Supramolecular Aggregation of Carbon Nanodots

Supramolecular aggregation has provided the archetype concept to understand the variants in an emerging systems property. Herein, we have achieved the supramolecular assembly of carbon nanodots (CDs) for the first time and employ supramolecular aggregation to understand their alteration in photophysical properties. In detail, we have employed the CDs as a block to construct the supramolecular assembly of aggregates in the CDs' antisolvent of ethanol. The CD-based aggregates exhibit complex and organized morphologies with another long-wavelength excitation-dependent emission band. The experimental results and density functional theoretical calculations reveal that the supramolecular assembly of CDs can decrease the energy gap between the ground and excited states, contributing to the new long-wavelength excitation-dependent emission. The supramolecular aggregation can be employed as one universal strategy to manipulate and understand the luminescence of CDs. These findings cast new light to build the emerging systems and understand the light emission of CDs through supramolecular chemistry.

Hyperbranched polyphthalocyanine micelles with dual PTT/PDT functions for bacteria eradication under an NIR window

A Zinc phthalocyanine-based (ZnPc-PA) polymeric micelle around 70 nm and with dual-modal PTT/PDT functions for non-antibiotic bacteria eradication was developed. It showed an excellent bacterial killing efficiency of 95.2% and 96.7% in vitro against Methicillin-resistant Staphylococcus aureus (MRSA) and its biofilm, respectively. Furthermore, the in vivo experiments proved its great potential for implant-associated infection (IAI).

Phthalocyanine aggregates in the photodynamic therapy: dogmas, controversies, and future prospects

Photodynamic therapy (PDT), a rapidly developing method for the treatment of cancer and bacterial diseases, is based on the photosensitization of oxygen to generate reactive oxygen species (ROS) that destroy specific biological targets. Among the various photosensitizers, phthalocyanines (Pc) have attracted particular attention due to their excellent photophysical properties, most of which meet the therapeutic requirements. The statement that aggregation of Pc-based photosensitizers is undesirable because it suppresses ROS generation has become commonplace in PDT. In this review, we have collected and discussed a number of works whose results refute this well-established axiom and show that aggregated forms of phthalocyanines can still exhibit photodynamic activity, in some cases in synergy with the photothermal and optoacoustic effects. In addition, ROS generation can be induced by aggregates under the conditions of sonodynamic therapy.

Rh(III)-Catalyzed Synthesis of Substituted Isoindoles through a Direct C-H Activation/[4 + 1] Annulation and Acyl Migration Cascade of Oxadiazolones with Diazo Compounds

A Rh(III)-catalyzed C-H bond activation for the synthesis of fused 2H-isoindole scaffolds from oxadiazolones with diazo compounds was developed. The reaction proceeded through C-H activation of oxadiazolones/[4 + 1] annulation, intramolecular cyclization, and an unusual acyl migration cascade to afford target scaffolds with good yields. These 2H-isoindole derivatives could be further transformed into intriguing drug privileged scaffolds.

X-ray Activated Nanoplatforms for Deep Tissue Photodynamic Therapy

Photodynamic therapy (PDT), the use of light to excite photosensitive molecules whose electronic relaxation drives the production of highly cytotoxic reactive oxygen species (ROS), has proven an effective means of oncotherapy. However, its application has been severely constrained to superficial tissues and those readily accessed either endoscopically or laparoscopically, due to the intrinsic scattering and absorption of photons by intervening tissues. Recent advances in the design of nanoparticle-based X-ray scintillators and photosensitizers have enabled hybridization of these moieties into single nanocomposite particles. These nanoplatforms, when irradiated with diagnostic doses and energies of X-rays, produce large quantities of ROS and permit, for the first time, non-invasive deep tissue PDT of tumors with few of the therapeutic limitations or side effects of conventional PDT. In this review we examine the underlying principles and evolution of PDT: from its initial and still dominant use of light-activated, small molecule photosensitizers that passively accumulate in tumors, to its latest development of X-ray-activated, scintillator-photosensitizer hybrid nanoplatforms that actively target cancer biomarkers. Challenges and potential remedies for the clinical translation of these hybrid nanoplatforms and X-ray PDT are also presented.

Strong π-π Stacking Stabilized Nanophotosensitizers: Improving Tumor Retention for Enhanced Therapy for Large Tumors in Mice

Conventional photosensitizers (PSs) often show poor tumor retention and are rapidly cleared from the bloodstream, which is one of the key hindrances to guarantee precise and efficient photodynamic therapy (PDT) in vivo. In this work, a photosensitizer assembly nanosystem that sharply enhances tumor retention up to ≈10 days is present. The PSs are synthesized by meso-substituting anthracene onto a BODIPY scaffold (AN-BDP), which then self-assembles into stable nanoparticles (AN-BDP NPs) with amphiphilic block copolymers due to the strong intermolecular π-π interaction of the anthracene. Additionally, the incorporated anthracene excites the PSs, producing singlet oxygen under red-light irradiation. Although AN-BDP NPs can completely suppress regular test size tumors (≈100 mm³ ) by one-time radiation, only 12% tumor growth inhibition rate is observed in the case of large-size tumors (≈350 mm³ ) under the same conditions. Due to the long-time tumor retention, AN-BDP NPs allow single-dose injection and three-time light treatments, resulting in an inhibition rate over 90%, much more efficient than single-time radiation of conventional clinically used PSs including chlorin-e6 (Ce6) and porphyrin with poor tumor retention. The results reveal the importance of long tumor retention time of PSs for efficient PDT, which can accelerate the clinical development of nanophotosensitizers.

Ruthenium-based assemblies incorporating tetrapyridylporphyrin panels: a photosensitizer delivery strategy for the treatment of rheumatoid arthritis by photodynamic therapy

Ruthenium-based assemblies containing tetrapyridylporphyrin derivatives in their structures have been evaluated as photosensitizers to treat rheumatoid arthritis by photodynamic therapy.

Recent Strategies to Develop Innovative Photosensitizers for Enhanced Photodynamic Therapy

This review presents a robust strategy to design photosensitizers (PSs) for various species. Photodynamic therapy (PDT) is a photochemical-based treatment approach that involves the use of light combined with a light-activated chemical, referred to as a PS. Attractively, PDT is one of the alternatives to conventional cancer treatment due to its noninvasive nature, high cure rates, and low side effects. PSs play an important factor in photoinduced reactive oxygen species (ROS) generation. Although the concept of photosensitizer-based photodynamic therapy has been widely adopted for clinical trials and bioimaging, until now, to our surprise, there has been no relevant review article on rational designs of organic PSs for PDT. Furthermore, most of published review articles in PDT focused on nanomaterials and nanotechnology based on traditional PSs. Therefore, this review aimed at reporting recent strategies to develop innovative organic photosensitizers for enhanced photodynamic therapy, with each example described in detail instead of providing only a general overview, as is typically done in previous reviews of PDT, to provide intuitive, vivid, and specific insights to the readers.

Recent Progress in Phthalocyanine-Polymeric Nanoparticle Delivery Systems for Cancer Photodynamic Therapy

This perspective article summarizes the last decade’s developments in the field of phthalocyanine (Pc)-polymeric nanoparticle (NP) delivery systems for cancer photodynamic therapy (PDT), including studies with at least in vitro data. Moreover, special attention will be paid to the various strategies for enhancing the behavior of Pc-polymeric NPs in PDT, underlining the great potential of this class of nanomaterials as advanced Pcs’ nanocarriers for cancer PDT. This review shows that there is still a lot of research to be done, opening the door to new and interesting nanodelivery systems.

Recent advances in nanoparticles mediated photothermal therapy induced tumor regression

Photothermal therapy (PTT) is a minimally invasive procedure for treating cancer. The two significant prerequisites of PTT are the photothermal therapeutic agent (PTA) and near-infrared radiation (NIR). The PTA absorbs NIR, causing hyperthermia in the malignant cells. This increased temperature at the tumor microenvironment finally results in tumor cell damage. Nanoparticles play a crucial role in PTT, aiding in the passive and active targeting of the PTA to the tumor microenvironment. Through enhanced permeation and retention effect and surface-engineering, specific targeting could be achieved. This novel delivery tool provides the advantages of changing the shape, size, and surface attributes of the carriers containing PTAs, which might facilitate tumor regression significantly. Further, inclusion of surface engineering of nanoparticles is facilitated through ligating ligands specific to overexpressed receptors on the cancer cell surface. Thus, transforming nanoparticles grants the ability to combine different treatment strategies with PTT to enhance cancer treatment. This review emphasizes properties of PTAs, conjugated biomolecules of PTAs, and the combinatorial techniques for a better therapeutic effect of PTT using the nanoparticle platform.

A lysosome-targeted near-infrared photosensitizer for photodynamic therapy and two-photon fluorescence imaging

Organelle-targeted two-photon near-infrared photosensitizers are highly desirable for photodynamic therapy (PDT) of cancer. Herein, in this contribution, we have developed a 2-dicyanomethylenethiazole-based D-π-A structured near-infrared photosensitizer (TTR). TTR exhibits near-infrared emission (704 nm), a large Stokes shift (200 nm), and smaller ΔE_S1-_T1 (the energy gap between S₁ and T₁) (0.717 eV). In vitro results show that TTR can specifically target lysosomes in living cells for near-infrared fluorescence imaging. With efficient ROS generation, excellent biocompatibility, two-photon imaging capability, and depth imaging (21 μm in vitro and 210 μm in vivo), TTR can effectively kill tumor cells and inhibit the growth of subcutaneous tumors. The hematoxylin-eosin (H&E) staining and blood biochemical parameter results further prove the biocompatibility of TTR. Hence, TTR can be a promising photosensitizer for PDT.

Silicon Tetrapyrazinoporphyrazine Derivatives-Incorporated Carbohydrate-Based Block Copolymer Micelles for Photodynamic Therapy

Developing nonaggregated photosensitizers (PSs) for efficient photodynamic therapy (PDT) using polymeric micelles (PMs) has been challenging. In this study, axially substituted nonaggregated silicon tetrapyrazinoporphyrazine (SiTPyzPz) derivatives in carbohydrate-based block glycopolymer-based PMs were designed and used as PSs for PDT. To achieve the nonaggregated PSs, SiTPyzPz was axially substituted with trihexylsiloxy (THS) groups to form SiTPyzPz-THS, which exhibited highly monomeric behaviors in organic solvents. Moreover, three block copolymers were prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization. Each copolymer comprised hydrophobic polystyrene blocks and loadable SiTPyzPz-THS, and one or two consisted of two possible hydrophilic blocks, polyethylene glycol or poly(glucosylethyl methacrylate). The self-assembly of SiTPyzPz-THS and the block copolymers in aqueous solvents induced the formation of spherical PMs with core-shell or core-shell-corona structures. The SiTPyzPz-THS in the PMs exhibited monomeric state, intense fluorescence emission, and outstanding singlet oxygen generation; moreover, it did not form aggregates. During the in vitro test, which was performed to investigate the PDT efficiency, the PMs, which consisted of poly(glucosylethyl methacrylate) shells, exhibited high photocytotoxicity and cellular internalization ability. Consequently, the PM systems of nonaggregated PSs and carbohydrate-based block copolymers could become very promising materials for PDT owing to their photophysicochemical properties and considerable selectivity against cancer cells.

A phthalocyanine-based self-assembled nanophotosensitizer for efficient in vivo photodynamic anticancer therapy

To develop highly efficient photosensitizers for photodynamic therapy, herein a zinc(II) phthalocyanine-folate conjugate (PcN-FA) used to construct an activatable nanophotosensitizer (NanoPcN-FA) through a facile self-assembly. The self-assembled nanophotosensitizer (NanoPcN) without folate-modification was used as a negative control. After self-assembly, the photoactivities of NanoPcN-FA was quenched. The in vitro studies showed that NanoPcN-FA could be taken in by folate-receptor (FR)-positive SKOV3 cells and activated in the cells. It also exhibited slightly higher photocytotoxicity against SKOV3 cells than NanoPcN. Moreover, the competitive assay confirmed that the cellular uptake of NanoPcN-FA was through a FR-mediated process. Finally, the in vivo results indicated that NanoPcN-FA could target tumor tissue of S180 rat ascitic tumor-bearing mice due to the folic acid (FA) ligand, leading to a highly efficient antitumor photodynamic efficacy with the tumor inhibition rate of 95%.

Strategies for the synthesis of block copolymers with biodegradable polyester segments

Oxygenated block copolymers with biodegradable polyester segments can be prepared in one-pot through sequential or simultaneous addition of monomers. This review highlights the state of the art in this area.

Rational design of block copolymer self-assemblies in photodynamic therapy

Photodynamic therapy is a technique already used in ophthalmology or oncology. It is based on the local production of reactive oxygen species through an energy transfer from an excited photosensitizer to oxygen present in the biological tissue. This review first presents an update, mainly covering the last five years, regarding the block copolymers used as nanovectors for the delivery of the photosensitizer. In particular, we describe the chemical nature and structure of the block copolymers showing a very large range of existing systems, spanning from natural polymers such as proteins or polysaccharides to synthetic ones such as polyesters or polyacrylates. A second part focuses on important parameters for their design and the improvement of their efficiency. Finally, particular attention has been paid to the question of nanocarrier internalization and interaction with membranes (both biomimetic and cellular), and the importance of intracellular targeting has been addressed.

Enhanced photodynamic therapy based on an amphiphilic branched copolymer with pendant vinyl groups for simultaneous GSH depletion and Ce6 release

An amphiphilic branched copolymer with pendent vinyl groups was synthesized to enhance the efficacy of photodynamic therapy through “thio–ene“ click reaction for simultaneous GSH depletion and Ce6 release.

Synthesis and biological evaluation of an epidermal growth factor receptor-targeted peptide-conjugated phthalocyanine-based photosensitiser

A peptide-conjugated zinc(ii) phthalocyanine containing the epidermal growth factor receptor-targeted heptapeptide QRHKPRE has been prepared. The conjugate labelled as ZnPc-QRH* can selectively bind to the cell membrane of HT29 human colorectal adenocarcinoma cells in 10 min followed by internalisation upon prolonged incubation via receptor-mediated endocytosis, leading to localisation in lysosomes eventually. By manipulating the incubation time, the subcellular localisation of the conjugate can be varied and the cell-death pathways induced upon irradiation can also be altered. It has been found that photosensitisation initiated at the cell membrane and in the lysosomes would trigger cell death mainly through necrosis and apoptosis respectively. Intravenous administration of the conjugate into HT29 tumour-bearing nude mice resulted in higher accumulation in the tumour than in most major organs. The selective binding of this conjugate to tumour has also been demonstrated by comparing the results with those of the analogue with a scrambled peptide sequence (EPRQRHK). The overall results indicate that ZnPc-QRH* is a promising EGFR-targeted photosensitiser for photodynamic therapy.

Photosensitizers for Photodynamic Therapy

As an emerging clinical modality for cancer treatment, photodynamic therapy (PDT) takes advantage of the cytotoxic activity of reactive oxygen species (ROS) that are generated by light irradiating photosensitizers (PSs) in the presence of oxygen (O₂ ). However, further advancements including tumor selectivity and ROS generation efficiency are still required. Substantial efforts are devoted to design and synthesize smart PSs with optimized properties for achieving a desirable therapeutic efficacy. This review summarizes the recent progress in developing intelligent PSs for efficient PDT, ranging from single molecules to delicate nanomaterials. The strategies to improve ROS generation through optimizing photoinduced electron transfer and energy transfer processes of PSs are highlighted. Moreover, the approaches that combine PDT with other therapeutics (e.g., chemotherapy, photothermal therapy, and radiotherapy) and the targeted delivery in cancer cells or tumor tissue are introduced. The main challenges for the clinical application of PSs are also discussed.

Liquid-Crystalline Hydroxyapatite/Polymer Nanorod Hybrids: Potential Bioplatform for Photodynamic Therapy and Cellular Scaffolds

Recently, we found that self-organization of hydroxyapatite (HAp) with poly(acrylic acid) (PAA) leads to the formation of liquid-crystalline (LC) nanorod hybrids that form aligned films and show stimuli-responsive properties. Here, we demonstrate that these biocompatible HAp/PAA hybrid nanorods represent a platform technology as drug nanocarriers for photodynamic cancer therapy and as bioscaffolds for the control of cellular alignment and growth. To use hybrid nanorods as a drug nanocarrier, we introduced methylene blue (MB), a typical photosensitizer for photodynamic therapy, into the PAA nanolayer covering the surface of the HAp nanocrystals through electrostatic interactions. The stable MB-loaded HAp/PAA hybrid nanorods efficiently produced singlet oxygen from MB upon light irradiation and showed remarkable photodynamic therapeutic effects in cancer cells. Moreover, taking advantage of the mechanically responsive LC alignment properties of the HAp/PAA hybrid nanorods, macroscopically oriented bioscaffolds were prepared through a spin-coating process. The cells cultured on the oriented scaffolds showed cellular alignment and elongation along the oriented direction of the hybrid nanorods. The HAp/PAA hybrid nanorods demonstrate potential in drug delivery and tissue engineering. These unique LC HAp/PAA hybrid nanorods have significant potential as a platform for the development of various types of biomaterial.

Coordination Nanosheets of Phthalocyanine as Multifunctional Platform for Imaging-Guided Synergistic Therapy of Cancer

"All-in-one" nanodrugs integrating various functionalities into one nanosystem are highly desired for cancer treatment. Coordination nanosheets as one type of two dimensional (2D) nanomaterials offer great opportunities, but there is lack of enough candidates. Here, a new kind of coordination nanosheets based on phthalocyanine are constructed. Manganese phthalocyanine (MnPc) tetracarboxylic acid is employed as photoactive ligand to form MnPc nanosheets; meanwhile, hyaluronic acid (HA) is coated on their surface. The obtained MnPc@HA nanosheets exhibit superior near-infrared (NIR) photothermal effect with photothermal conversion efficiency of 72.3%, much higher than those of the previously reported photothermal agents. Due to their 2D nanostructures, MnPc@HA nanosheets possess superhigh drug-loading capacity for chemotherapy drug curcumin. With HA as a targeting group, the nanosheets selectively accumulated in CD44 overexpressed tumors, followed by drug release under the control of NIR light. Moreover, MnPc@HA nanosheets with intrinsic paramagnetism can serve as T₁ contrast agent for magnetic resonance imaging. The synergistic effect of phototherapy and chemotherapy endows curcumin-loaded MnPc@HA nanosheets with superior tumor-eradicating efficacy. Besides, MnPc@HA nanosheets are biocompatible and safe for biomedical applications. This work provides novel insight for developing new multifunctional platforms based on 2D coordination nanosheets to synergistically combat cancer.

Preparation of NIR absorbing axial substituted tin(iv) porphyrins and their photocytotoxic properties

Sn(iv) porphyrins ([Sn(iv)TTP(3PyO)2] (5) and [Sn(iv)TPP(3PyO)2] (6) [tetrathienylporphyrin (TTP), tetraphenylporphyrin (TPP), and pyridyloxy (PyO)]) were prepared and characterized and their photocytotoxicity upon irradiation with 625 nm light has been studied. The presence of the 3PyO axial ligands was found to limit the aggregation and enhance the solubility of 5 and 6 in DMF/H2O (1 : 1). The photophysical properties and photodynamic therapy (PDT) activity of the meso-2-thienyl and meso-phenyl-substituted Sn(iv) porphyrins are compared. 5 and 6 were found to be photocytotoxic in MCF-7 cancer cells when irradiated with a Thorlabs M625L3 LED at 625 nm but remained nontoxic in the dark. The PDT activity of Sn(iv) meso-tetra-2-thienylporphyrin 5 was found to be significantly enhanced relative to its analogous tetraphenylporphyrin 6. There is a marked red-shift of the Q00 band of 5 into the therapeutic window due to the meso-2-thienyl rings, and 5 has an unusually high singlet oxygen quantum yield value of 0.83 in DMF. The results demonstrate that readily synthesized axially ligated Sn(iv) meso-arylporphyrins are potentially suitable for use as singlet oxygen photosensitizers in biomedical applications and merit further in depth investigation in this context.

Cyclomatrix Polyphosphazene Porous Networks with J-Aggregated Multiphthalocyanine Arrays for Dual-Modality Near-Infrared Photosensitizers

Here, we have developed a kind of cyclomatrix polyphosphazene with excellent photophysical properties and pursued their potential of being organic photosensitizers for dual-modality phototherapy. Briefly, hexachlorocyclophosphazene (HCCP) with D_{3 h} symmetry is adopted as a synthon to attach Zn(II) phthalocyanine (ZnPc) to form dendritic units that are covalently expanded into a soluble porous network through the nucleophilic substitution reaction. Molecular simulation reveals that the multi-ZnPc units around HCCP can be oriented in a side-by-side manner, leading to the remarkably red-shifted and intense absorbance in the near-infrared (NIR) region. To validate the potential in bioapplication, such ZnPc-based polyphosphazenes are assembled by incorporation of polyvinylpyrrolidone (PVP) to produce the uniform nanoparticles with aqueous dispersibility and biocompatibility. From the in vitro results, the PVP-stabilized photosensitizing nanoparticles can undergo the photothermal/photodynamic processes to concurrently generate heat and singlet oxygen for efficiently killing cancer cells upon exposure to a single-bandwidth NIR laser (785 nm). Compared with the known organic photosensitizers, cyclomatrix polyphosphazene would be a promising platform to configure a diversity of reticular arrays with dense and oriented arrangement of dye molecules, leading to their largely enhanced photophysical and photochemical properties.