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Thiophene-based nanoparticles (TNPs) are promising therapeutic and imaging agents. Here, using an innovative phage-templated synthesis, a strategy able to bypass the current limitations of TNPs in nanomedicine applications is proposed. The phage capsid is decorated with oligothiophene derivatives, transforming the virus in a 1D-thiophene nanoparticle (1D-TNP). A precise control of the shape/size of the nanoparticles is obtained exploiting the well-defined morphology of a refactored filamentous M13 phage, engineered by phage display to selectively recognize the Epidermal Growth Factor Receptor (EGFR). The tropism of the phage is maintained also after the bioconjugation of the thiophene molecules on its capsid. Moreover, the 1D-TNP proved highly fluorescent and photoactive, generating reactive oxygen species through both type I and type II mechanisms. The phototheranostic properties of this platform are investigated on biosystems presenting increasing complexity levels, from in vitro cancer cells in 2D and 3D architectures, to the in vivo tissue-like model organism Hydra vulgaris. The phage-templated 1D-TNP showed photocytotoxicity at picomolar concentrations, and the ability to deeply penetrate 3D spheroids and Hydra tissues. Collectively the results indicate that phage-templated synthesis of organic nanoparticles represents a general strategy, exploitable in many diagnostic and therapeutic fields based on targeted imaging and light mediated cell ablation., (© 2024 The Author(s). Small published by Wiley‐VCH GmbH.)

Photodynamic therapy (PDT) represents an emerging strategy to treat various malignancies, including colorectal cancer (CC), the third most common cancer type. This work presents an engineered M13 phage retargeted towards CC cells through pentavalent display of a disulfide-constrained peptide nonamer. The M13 CC nanovector was conjugated with the photosensitizer Rose Bengal (RB), and the photodynamic anticancer effects of the resulting M13 CC -RB bioconjugate were investigated on CC cells. We show that upon irradiation M13 CC -RB is able to impair CC cell viability, and that this effect depends on i) photosensitizer concentration and ii) targeting efficiency towards CC cell lines, proving the specificity of the vector compared to unmodified M13 phage. We also demonstrate that M13 CC -RB enhances generation and intracellular accumulation of reactive oxygen species (ROS) triggering CC cell death. To further investigate the anticancer potential of M13 CC -RB, we performed PDT experiments on 3D CC spheroids, proving, for the first time, the ability of engineered M13 phage conjugates to deeply penetrate multicellular spheroids. Moreover, significant photodynamic effects, including spheroid disruption and cytotoxicity, were readily triggered at picomolar concentrations of the phage vector. Taken together, our results promote engineered M13 phages as promising nanovector platform for targeted photosensitization, paving the way to novel adjuvant approaches to fight CC malignancies., (© 2024. The Author(s).)

Growing antibiotic resistance has encouraged the revival of phage-inspired antimicrobial approaches. On the other hand, photodynamic therapy (PDT) is considered a very promising research domain for the protection against infectious diseases. Yet, very few efforts have been made to combine the advantages of both approaches in a modular, retargetable platform. Here, we foster the M13 bacteriophage as a multifunctional scaffold, enabling the selective photodynamic killing of bacteria. We took advantage of the well-defined molecular biology of M13 to functionalize its capsid with hundreds of photo-activable Rose Bengal sensitizers and contemporarily target this light-triggerable nanobot to specific bacterial species by phage display of peptide targeting moieties fused to the minor coat protein pIII of the phage. Upon light irradiation of the specimen, the targeted killing of diverse Gram(-) pathogens occurred at subnanomolar concentrations of the phage vector. Our findings contribute to the development of antimicrobials based on targeted and triggerable phage-based nanobiotherapeutics., Competing Interests: There are no conflicts to declare., (© 2023 The Author(s).)

The combination of photodynamic therapy with chemotherapy (photochemotherapy, PCT) can lead to additive or synergistic antitumor effects. Usually, two different molecules, a photosensitizer (PS) and a chemotherapeutic drug are used in PCT. Doxorubicin is one of the most successful chemotherapy drugs. Despite its high efficacy, two factors limit its clinical use: severe side effects and the development of chemoresistance. Doxorubicin is a chromophore, able to absorb light in the visible range, making it a potential PS. Here, we exploited the intrinsic photosensitizing properties of doxorubicin to enhance its anticancer activity in leukemia, breast, and epidermoid carcinoma cells, upon irradiation. Light can selectively trigger the local generation of reactive oxygen species (ROS), following photophysical pathways. Doxorubicin showed a concentration-dependent ability to generate peroxides and singlet oxygen upon irradiation. The underlying mechanisms leading to the increase in its cytotoxic activity were intracellular ROS generation and the induction of necrotic cell death. The nuclear localization of doxorubicin represents an added value for its use as a PS. The use of doxorubicin in PCT, simultaneously acting as a chemotherapeutic agent and a PS, may allow (i) an increase in the anticancer effects of the drug, and (ii) a decrease in its dose, and thus, its dose-related adverse effects.

Temoporfin (mTHPC) is approved in Europe for the photodynamic treatment of head and neck squamous cell carcinoma (HNSCC). Although it has a promising profile, its lipophilic character hampers the full exploitation of its potential due to high tendency of aggregation and a reduced ROS generation that compromise photodynamic therapy (PDT) efficacy. Moreover, for its clinical administration, mTHPC requires the presence of ethanol and propylene glycol as solvents, often causing adverse effects in the site of injection. In this paper we explored the efficiency of a new mTHPC formulation that uses human serum albumin (HSA) to disperse the photosensitizer in solution (mTHPC@HSA), investigating its anticancer potential in two HNSCC cell lines. Through a comprehensive characterization, we demonstrated that mTHPC@HSA is stable in physiological environment, does not aggregate, and is extremely efficient in PDT performance, due to its high singlet oxygen generation and the high dispersion as monomolecular form in HSA. This is supported by the computational identification of the specific binding pocket of mTHPC in HSA. Moreover, mTHPC@HSA-PDT induces cytotoxicity in both HNSCC cell lines, increasing intracellular ROS generation and the number of γ-H2AX foci, a cellular event involved in the global response to cellular stress. Taken together these results highlight the promising phototoxic profile of the complex, prompting further studies to assess its clinical potential.

Photodynamic therapy (PDT) is a potential synergistic approach to chemotherapy for treating ovarian cancer, the most lethal gynecologic malignancy. Here we used M13 bacteriophage as a targeted vector for the efficient photodynamic killing of SKOV3 and COV362 cells. The M13 phage was refactored (M13 r ) to display an EGFR binding peptide in its tip that is frequently overexpressed in ovarian cancer. The refactored phage was conjugated with chlorin e6 (Ce6), one of the most widely used photosensitizers (M13 r -Ce6). The new platform, upon irradiation, generated ROS by type I mechanism and showed activity in killing SKOV3 and COV362 cells even at concentrations in which Ce6 alone was ineffective. A microscopy analysis demonstrated an enhanced cellular uptake of M13 r -Ce6 compared to free Ce6 and its mitochondrial localization. Western blot analysis revealed significant downregulation in the expression of EGFR in cells exposed to M13 r -Ce6 after PDT. Following PDT treatment, autophagy induction was supported by an increased expression of LC3II, along with a raised autophagic fluorescent signal, as observed by fluorescence microscopy analysis for autophagosome visualization. As a conclusion we have herein proposed a bacteriophage-based receptor targeted photodynamic therapy for EGFR-positive ovarian cancer., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Photodynamic therapy (PDT) represents a promising therapeutic modality for cancer. Here we used an orthogonal nanoarchitectonics approach (genetic/chemical) to engineer M13 bacteriophages as targeted vectors for efficient photodynamic killing of cancer cells. M13 was genetically refactored to display on the phage tip a peptide (SYPIPDT) able to bind the epidermal growth factor receptor (EGFR). The refactored M13 EGFR phages demonstrated EGFR-targeted tropism and were internalized by A431 cancer cells, that overexpress EGFR. Using an orthogonal approach to the genetic display, M13 EGFR phages were then chemically modified, conjugating hundreds of Rose Bengal (RB) photosensitizing molecules on the capsid surface, without affecting the selective recognition of the SYPIPDT peptides. Upon internalization, the M13 EGFR -RB derivatives generated intracellularly reactive oxygen species, activated by an ultralow intensity white light irradiation. The killing activity of cancer cells is observed at picomolar concentrations of the M13 EGFR phage.

The epidermal growth factor receptor (EGFR) plays a pivotal role in the proliferation and metastatization of cancer cells. Aberrancies in the expression and activation of EGFR are hallmarks of many human malignancies. As such, EGFR-targeted therapies hold significant potential for the cure of cancers. In recent years, photodynamic therapy (PDT) has gained increased interest as a non-invasive cancer treatment. In PDT, a photosensitizer is excited by light to produce reactive oxygen species, resulting in local cytotoxicity. One of the critical aspects of PDT is to selectively transport enough photosensitizers to the tumors environment. Accordingly, an increasing number of strategies have been devised to foster EGFR-targeted PDT. Herein, we review the recent nanobiotechnological advancements that combine the promise of PDT with EGFR-targeted molecular cancer therapy. We recapitulate the chemistry of the sensitizers and their modes of action in PDT, and summarize the advantages and pitfalls of different targeting moieties, highlighting future perspectives for EGFR-targeted photodynamic treatment of cancer.

Colorectal cancer (CRC) is a widespread and lethal disease. Relapses of the disease and metastasis are very common in instances of CRC, so adjuvant therapies have a crucial role in its treatment. Systemic toxic effects and the development of resistance during therapy limit the long-term efficacy of existing adjuvant therapeutic approaches. Consequently, the search for alternative strategies is necessary. Photothermal therapy (PTT) represents an innovative treatment for cancer with great potential. Here, we synthesize branched gold nanoparticles (BGNPs) as attractive agents for the photothermal eradication of colon cancer cells. By controlling the NP growth process, large absorption in the first NIR biological window was obtained. The FBS dispersed BGNPs are stable in physiological-like environments and show an extremely efficient light-to-heat conversion capability when irradiated with an 808-nm laser. Sequential cycles of heating and cooling do not affect the BGNP stability. The uptake of BGNPs in colon cancer cells was confirmed using flow cytometry and confocal microscopy, exploiting their intrinsic optical properties. In dark conditions, BGNPs are fully biocompatible and do not compromise cell viability, while an almost complete eradication of colon cancer cells was observed upon incubation with BGNPs and irradiation with an 808-nm laser source. The PTT treatment is characterized by an extremely rapid onset of action that leads to cell membrane rupture by induced hyperthermia, which is the trigger that promotes cancer cell death.