Advanced smart-photosensitizers for more effective cancer treatment

Current status and prospects of gelatin and its derivatives in oncological applications: Review

Treating cancer remains challenging due to the substantial side effects and unfavourable pharmacokinetic characteristics of antineoplastic medications, despite the progress made in comprehending the properties and actions of tumour cells in recent years. The advancement of biomaterials, such as stents, implants, personalised drug delivery systems, tailored grafts, cell sheets, and other transplantable materials, has brought about a significant transformation in healthcare and medicine in recent years. Gelatin is a very adaptable natural polymer that finds extensive application in healthcare-related industries owing to its favourable characteristics, including biocompatibility, biodegradability, affordability, and the presence of accessible chemical groups. Gelatin is used as a biomaterial in the biomedical sector for the creation of drug delivery systems (DDSs) since it may be applied to various synthetic procedures. Gelatin nanoparticles (NPs) have been extensively employed as carriers for drugs and genes, specifically targeting diseased tissues such as cancer, tuberculosis, and HIV infection, as well as treating vasospasm and restenosis. This is mostly due to their biocompatibility and ability to degrade naturally. Gelatins possess a diverse array of potential applications that require more elucidation. This review focuses on the use of gelatin and its derivatives in the diagnosis and treatment of cancer. The advancement of biomaterials and bioreactors, coupled with the increasing understanding of emerging applications for biomaterials, has enabled progress in enhancing the efficacy of tumour treatment.

Supramolecular self-sensitized dual-drug nanoassemblies potentiating chemo-photodynamic therapy for effective cancer treatment

Chemo-photodynamic synergistic therapy (CPST) holds tremendous promise for treating cancers. Unfortunately, existing CPST applications suffer from complex synthetic procedures, low drug co-loading efficiency, and carrier-related toxicity. To address these issues, we have developed a supramolecular carrier-free self-sensitized nanoassemblies by co-assembling podophyllotoxin (PTOX) and chlorin e6 (Ce6) to enhance CPST efficiency against tumors. The nanoassemblies show stable co-assembly performance in simulative vivo neural environment (∼150 nm), with high co-loading ability for PTOX (72.2 wt%) and Ce6 (27.8 wt%). In vivo, the nanoassemblies demonstrate a remarkable ability to accumulate at tumor sites by leveraging the enhanced permeability and retention (EPR) effect. The disintegration of nanoassemblies following photosensitizer bioactivation triggered by the acidic tumor environment effectively resolves the challenge of aggregation-caused quenching (ACQ) effect. Upon exposure to external light stimulation, the disintegrated nanoassemblies not only illuminate cancer cells synergistically but also exert a more potent antitumor effect when compared with PTOX and Ce6 administered alone. This self-sensitized strategy represents a significant step forward in CPST, offering a unique co-delivery paradigm for clinic cancer treatment.

Use of photosensitive molecules in the crosslinking of biopolymers: applications and considerations in biomaterials development

The development of diverse types of biomaterials has significantly contributed to bringing new biomedical strategies to treat clinical conditions. Applications of these biomaterials can range from mechanical support and protection of injured tissues to joint replacement, tissue implants, and drug delivery systems. Among the strategies commonly used to prepare biomaterials, the use of electromagnetic radiation to initiate crosslinking stands out. The predominance of photo-induced polymerization methods relies on a fast, efficient, and straightforward process that can be easily adjusted to clinical needs. This strategy consists of irradiating the components that form the material with photons in the near ultraviolet-visible wavelength range (i.e., ∼310 to 750 nm) in the presence of a photoactive molecule. Upon photon absorption, photosensitive molecules can generate excited species that initiate photopolymerization through different reaction mechanisms. However, this process could promote undesired side reactions depending on the target zone or treatment type (e.g., oxidative stress and modification of biomolecules such as proteins and lipids). This review explores the basic concepts behind the photopolymerization process of ex situ and in situ biomaterials. Particular emphasis was put on the photosensitization initiated by the most employed photosensitizers and the photoreactions that they mediate in aqueous media. Finally, the undesired oxidation reactions at the bio-interface and potential solutions are presented.

Catalytic Dual-Mode Immunotherapy: Anisotropic AuPt Heterostructure Decorated with Starry Pt Nanoclusters for Robust Cancer Photometalloimmunotherapy

To overcome current limitations in photoimmunotherapy, such as insufficient tumor antigen generation and a subdued immune response, a novel photo-/metallo dual-mode immunotherapeutic agent (PMIA) is introduced for potent near-infrared (NIR) light-triggered cancer therapy. PMIA features a dumbbell-like AuPt heterostructure decorated with starry Pt nanoclusters, meticulously engineered for enhancing plasmonic catalysis through multi-dimensional regulation of Pt growth on Au nanorods. Under NIR laser exposure, end-tipped Pt nanoclusters induce efficient electron-hole spatial separation along the longitudinal axis, resulting in radial and axial electron distribution polarization, conferring unique anisotropic properties to PMIA. Additionally, starry Pt nanoclusters on the sides of Au nanorods augment the local electron enrichment field. Validated through finite-difference time-domain analysis and Raman scattering, this configuration fosters local electron enrichment, facilitating robust reactive oxygen species generation for potent photoimmunotherapy. Moreover, Pt nanoclusters facilitate Pt2+ ion release, instigating intranuclear DNA damage and inducing synergistic immunogenic cell death (ICD) for metalloimmunotherapy. Consequently, PMIA elicits abundant danger-associated molecular patterns, promotes T cell infiltration, and triggers systemic immune responses, effectively treating primary and distant tumors, inhibiting metastasis in vivo. This study unveils a pioneering dual-mode ICD amplification strategy driven by NIR light, synergistically integrating photoimmunotherapy and metalloimmunotherapy, culminating in potent cancer photometalloimmunotherapy.

Repeated photodynamic therapy using a chlorin e6-embedded device to prolong the therapeutic effects on obesity

OBJECTIVE

This study aimed to investigate the efficacy and safety of repeated photodynamic therapy (PDT) with a chlorin e6 (Ce6)-embedded intragastric satiety-inducing device (ISD) to maintain therapeutic effects of obesity in a juvenile pig.

METHODS

The Ce6-embedded ISD was fabricated with a dipping method. Twelve pigs were divided into four groups of three and were administered control, single, biweekly, or weekly PDT, respectively. The therapeutic effects were assessed by comparing the results of phototoxicity, endoscopy, fluoroscopy, hormone and weight changes, and histological examination.

RESULTS

The percentage of total body weight gain was significantly suppressed in PDT-treated pigs compared with control pigs (all p < 0.001). This suppression persisted in the repeated PDT groups, but percentage of total body weight gain gradually increased when PDT was stopped. Ghrelin levels in the PDT-treated groups were significantly lower and leptin levels were significantly higher than those in the control group (all p < 0.05). Inflammatory cell infiltration, collagen, TUNEL, and anti-ghrelin-positive deposition in the weekly group were significantly higher than those in the control, single, and biweekly groups (all p < 0.01).

CONCLUSIONS

Repeated and periodic PDT was technically feasible and safe and successfully maintained the therapeutic effects against obesity while eliminating the indwelling time and reducing ISD-related complications in pigs.

Multifunctional Nanoparticles for Enhanced Chemodynamic/Photodynamic Therapy through a Photothermal, H2O2-Elevation, and GSH-Consumption Strategy

Chemodynamic therapy (CDT) has witnessed significant advancements in recent years due to its specific properties. Its association with photodynamic therapy (PDT) has also garnered increased attention due to its mutually reinforcing effects. However, achieving further enhancement of the CDT/PDT efficacy remains a major challenge. In this study, we have developed an integrated nanosystem comprising a Fenton catalyst and multifunctional photosensitizers to achieve triply enhanced CDT/PDT through photothermal effects, H2O2 elevation, and GSH consumption. We prepared nano-ZIF-8 vesicles as carriers to encapsulate ferrocene-(phenylboronic acid pinacol ester) conjugates (Fc-BE) and photosensitizers IR825. Subsequently, cinnamaldehyde-modified hyaluronic acid (HA-CA) was coated onto ZIF-8 through metal coordination interactions, resulting in the formation of active targeting nanoparticles (NPs@Fc-BE&IR825). Upon cellular internalization mediated by CD44 receptors, HA-CA elevated H2O2 levels, while released Fc-BE consumed GSH and catalyzed H2O2 to generate highly cytotoxic hydroxyl radicals (·OH). Furthermore, NIR irradiation led to increased ·OH production and the generation of singlet oxygen (1O2), accompanied by a greater GSH consumption. This accelerated and strengthened amplification of oxidative stress can be harnessed to develop highly effective CDT/PDT nanoagents.

Cellular Mechanisms of Singlet Oxygen in Photodynamic Therapy

In this review, we delve into the realm of photodynamic therapy (PDT), an established method for combating cancer. The foundation of PDT lies in the activation of a photosensitizing agent using specific wavelengths of light, resulting in the generation of reactive oxygen species (ROS), notably singlet oxygen (1O2). We explore PDT's intricacies, emphasizing its precise targeting of cancer cells while sparing healthy tissue. We examine the pivotal role of singlet oxygen in initiating apoptosis and other cell death pathways, highlighting its potential for minimally invasive cancer treatment. Additionally, we delve into the complex interplay of cellular components, including catalase and NOX1, in defending cancer cells against PDT-induced oxidative and nitrative stress. We unveil an intriguing auto-amplifying mechanism involving secondary singlet oxygen production and catalase inactivation, offering promising avenues for enhancing PDT's effectiveness. In conclusion, our review unravels PDT's inner workings and underscores the importance of selective illumination and photosensitizer properties for achieving precision in cancer therapy. The exploration of cellular responses and interactions reveals opportunities for refining and optimizing PDT, which holds significant potential in the ongoing fight against cancer.

Aptamer-based targeted delivery systems for cancer treatment using DNA origami and DNA nanostructures

Due to the limitations of conventional cancer treatment methods, nanomedicine has appeared as a promising alternative, allowing improved drug targeting and decreased drug toxicity. In the development of cancer nanomedicines, among various nanoparticles (NPs), DNA nanostructures are more attractive because of their precisely controllable size, shape, excellent biocompatibility, programmability, biodegradability, and facile functionalization. Aptamers are introduced as single-stranded RNA or DNA molecules with recognize their corresponding targets. So, incorporating aptamers into DNA nanostructures led to influential vehicles for bioimaging and biosensing as well as targeted cancer therapy. In this review, the recent developments in the application of aptamer-based DNA origami and DNA nanostructures in advanced cancer treatment have been highlighted. Some of the main methods of cancer treatment are classified as chemo-, gene-, photodynamic- and combined therapy. Finally, the opportunities and problems for targeted DNA aptamer-based nanocarriers for medicinal applications have also been discussed.

Recent advances in fluorescence imaging-guided photothermal therapy and photodynamic therapy for cancer: From near-infrared-I to near-infrared-II

Phototherapy (including photothermal therapy, PTT; and photodynamic therapy, PDT) has been widely used for cancer treatment, but conventional PTT/PDT show limited therapeutic effects due to the lack of disease recognition ability. The integration of fluorescence imaging with PTT/PDT can reveal tumor locations in a real-time manner, holding great potential in early diagnosis and precision treatment of cancers. However, the traditional fluorescence imaging in the visible and near-infrared-I regions (VIS/NIR-I, 400-900 nm) might be interfered by the scattering and autofluorescence from tissues, leading to a low imaging resolution and high false positive rate. The deeper near-infrared-II (NIR-II, 1000-1700 nm) fluorescence imaging can address these interferences. Combining NIR-II fluorescence imaging with PTT/PDT can significantly improve the accuracy of tumor theranostics and minimize damages to normal tissues. This review summarized recent advances in tumor PTT/PDT and NIR-II fluorophores, especially discussed achievements, challenges and prospects around NIR-II fluorescence imaging-guided PTT/PDT for cancers.

Beyond traditional light: NIR-II light-activated photosensitizers for cancer therapy

With increasing demand for the accurate and safe treatment of cancer, non-invasive photodynamic therapy (PDT) has received widespread attention. However, most conventional photosensitizers are typically excited by short-wavelength visible light (400-700 nm), thus substantially hindering the penetration of light and the therapeutic effectiveness of the PDT procedure. Fortunately, near-infrared (NIR) light (>700 nm), in particular, light in the second near-infrared region (NIR-II, 1000-1700 nm) has a higher upper radiation limit, greater tissue tolerance, and deeper tissue penetration compared with traditional short-wavelength light excitation, and shows considerable potential in the clinical treatment of cancer. Therefore, it is of paramount importance and clinical value to develop photosensitizers that are excited by NIR-II light. In this review, for the first time we focus completely on recent progress made with various NIR-II photosensitizers for cancer treatment via PDT, and we briefly present the ongoing challenges and prospects of currently developed NIR-II photosensitizers for clinical practice in the near future. We believe that the above topics will inspire broad interest in researchers from interdisciplinary fields that include chemistry, materials science, pharmaceuticals, and clinical medicine, and provide insightful perspectives for exploiting new NIR-II photosensitizers for biomedical applications.

Advanced Light Source Technologies for Photodynamic Therapy of Skin Cancer Lesions

Photodynamic therapy (PDT) is an increasingly popular dermatological treatment not only used for life-threatening skin conditions and other tumors but also for cosmetic purposes. PDT has negligible effects on underlying functional structures, enabling tissue regeneration feasibility. PDT uses a photosensitizer (PS) and visible light to create cytotoxic reactive oxygen species, which can damage cellular organelles and trigger cell death. The foundations of modern photodynamic therapy began in the late 19th and early 20th centuries, and in recent times, it has gained more attention due to the development of new sources and PSs. This review focuses on the latest advancements in light technology for PDT in treating skin cancer lesions. It discusses recent research and developments in light-emitting technologies, their potential benefits and drawbacks, and their implications for clinical practice. Finally, this review summarizes key findings and discusses their implications for the use of PDT in skin cancer treatment, highlighting the limitations of current approaches and providing insights into future research directions to improve both the efficacy and safety of PDT. This review aims to provide a comprehensive understanding of PDT for skin cancer treatment, covering various aspects ranging from the underlying mechanisms to the latest technological advancements in the field.

Chemo-Photothermal Combination Therapy of HER-2 Overexpressing Breast Cancer Cells with Dual-Ordered Mesoporous Carbon@Silica Nanocomposite

In cancer treatment, the complexity of tumors seriously affects the therapeutic potential of the treatment. Treatments with combination therapy result in more potent effects than monotherapy or their theoretical combination in cancer treatment. Photothermal therapy (PTT) includes applying phototherapeutic agents that cause local hyperthermia responsible for the thermal ablation of tumor cells after applying near-infrared light and is often applied with other combination therapies. In this study, the chemo-PTT potential of synthesized drug-loaded and targeted GEM/TRA-MC@Si nanocomposite on Her2 positive breast cancer cell line (SK-BR-3) and human triple-negative breast cancer cell line (MDA-MB-231) was investigated using NIR application as in vitro. First, the cell viability (IC₅₀) value of the GEM/TRA-MC@Si nanocomposite was determined as 25 µg/µL. Then, chemo-PTT was performed, and the viability of the cells was evaluated. In addition, the live/dead cell rate was established by staining with the Calcein-AM and EthD-1, and apoptosis tests were completed. When the surface temperature of Her2 positive SK-BR-3 cells exceeded 47 °C during PTT with an irradiation time of > 100 s, it caused cell death. In this study, it was demonstrated that in vitro PTT (1 W/cm², 180 s) was applied using GEM/TRA-MC@Si nanocomposite (25 µg/mL) on her2 + SK-BR-3 cell line, which contributed to the reduction of cell viability. In addition, this study demonstrates that chemo-PTT with targeted GEM/TRA-MC@Si nanocomposite induced SK-BR-3 cell viability and can initiate cell death through the apoptosis pathway under optimized irradiation conditions. Herewith chemo-PTT combination therapy of targeted GEM-TRA/MC@Si nanocomposite was found to be effective on SK-BR-3 cells as in vitro.

An oxygen-generating metal organic framework nanoplatform as a “synergy motor” for extricating dilemma over photodynamic therapy

Photodynamic therapy (PDT) combined with metal organic frameworks (MOFs) addresses current obstacles.

Spatiotemporally Controlled Formation and Rotation of Magnetic Nanochains In Vivo for Precise Mechanotherapy of Tumors

Systemic cancer therapy is always accompanied with toxicity to normal tissue, which has prompted concerted efforts to develop precise treatment strategies. Herein, we firstly develop an approach that enables spatiotemporally controlled formation and rotation of magnetic nanochains in vivo, allowing for precise mechanotherapy of tumor. The nanochain comprised nanocomposites of pheophorbide-A (PP) modified iron oxide nanoparticle (IONP) and lanthanide-doped down-conversion NP (DCNP). In a permanent magnetic field, the nanocomposites would be aligned to form nanochain. Next, MnO₂ NPs were subsequently administered to accumulate in tumor as suppliers of Mn²⁺ , which coordinates with PP to immobilize the nanochain. In a rotating magnetic field, the nanochain would rapidly rotate, leading to apoptosis/necrosis of tumor cell. The nanochain showed high T₂ -MR and NIR-II fluorescence imaging signals, which facilitated guided therapy. The strategy has great potential in practical applications.

Complexation Nanoarchitectonics of Carbon Dots with Doxorubicin toward Photodynamic Anti-Cancer Therapy

Carbon dots (Cdots) are known as photosensitizers in which the nitrogen doping is able to improve the oxygen-photosensitization performance and singlet-oxygen generation. Herein, the characteristics of nanoconjugates of nitrogen-doped Cdots and doxorubicin were compared with the property of nitrogen-doped Cdots alone. The investigation was performed for the evaluation of pH-dependent zeta potential, quantum yield, photosensitization efficiency and singlet-oxygen generation, besides spectroscopy (UV-visible absorption and fluorescence spectra) and cytotoxicity on cancer model (HeLa cells). Encapsulation efficiency, drug loading, and drug release without and with light irradiation were also carried out. These investigations were always pursued under the comparison among different nitrogen amounts (ethylenediamine/citric acid = 1-5) in Cdots, and some characteristics strongly depended on nitrogen amounts in Cdots. For instance, surface charge, UV-visible absorbance, emission intensity, quantum yield, photosensitization efficiency and singlet-oxygen generation were most effective at ethylenediamine/citric acid = 4. Moreover, strong conjugation of DOX to Cdots via π-π stacking and electrostatic interactions resulted in a high carrier efficiency and an effective drug loading and release. The results suggested that nitrogen-doped Cdots can be considered promising candidates to be used in a combination therapy involving photodynamic and anticancer strategies under the mutual effect with DOX.

Reactive Oxygen Species Responsive Cleavable Hierarchical Metallic Supra-Nanostructure

A reactive oxygen species (ROS) responsive cleavable hierarchical metallic supra-nanostructure (HMSN) is reported. HMSN structured with thin branches composed of primary gold (Au) nanocrystals and silver (Ag) nano-linkers is synthesized by a one-pot aqueous synthesis with a selected ratio of Au/Ag/cholate. ROS responsive degradability of HMSN is tested in the presence of endogenous and exogeneous ROS. Significant ROS-responsive structural deformation of HMSN is observed in the ROS exposure with hydrogen peroxide (H2 O2 ) solution. The ROS responsiveness of HMSN is significantly comparable with negligible structural changes of conventional spherical gold nanoparticles. The demonstrated ROS responsive degradation of HMSN is further confirmed in various in vitro ROS conditions of each cellular endogenous ROS and exogeneous ROS generated by photodynamic therapy (PDT) or X-ray radiation. Then, in vivo ROS responsive degradability of HMSN is further evaluated with intratumoral injection of HMSN and exogeneous ROS generation via PDT in a mouse tumor model. Additional in vivo biodistribution and toxicity of intravenously administrated HMSN at 30-day post-injection are investigated for potential in vivo applications. The observed ROS responsive degradability of HMSN will provide a promising option for a type of ROS responsive-multifunctional nanocarriers in cancer treatment and various biomedical applications.

Semiconductor quantum dots for photodynamic therapy: Recent advances

Photodynamic therapy is a promising cancer treatment that induces apoptosis as a result of the interactions between light and a photosensitizing drug. Lately, the emergence of biocompatible nanoparticles has revolutionized the prospects of photodynamic therapy (PDT) in clinical trials. Consequently, a lot of research is now being focused on developing non-toxic, biocompatible nanoparticle-based photosensitizers for effective cancer treatments using PDT. In this regard, semiconducting quantum dots have shown encouraging results. Quantum dots are artificial semiconducting nanocrystals with distinct chemical and physical properties. Their optical properties can be fine-tuned by varying their size, which usually ranges from 1 to 10 nm. They present many advantages over conventional photosensitizers, mainly their emission properties can be manipulated within the near IR region as opposed to the visible region by the former. Consequently, low intensity light can be used to penetrate deeper tissues owing to low scattering in the near IR region. Recently, successful reports on imaging and PDT of cancer using carbon (carbon, graphene based) and metallic (Cd based) based quantum dots are promising. This review aims to summarize the development and the status quo of quantum dots for cancer treatment.

Enhanced Permeability and Retention Effect: A key facilitator for solid tumor targeting by nanoparticles

Exploring the enhanced permeability and retention (EPR) effect through therapeutic nanoparticles has been a subject of considerable interest in tumor biology. This passive targeting based phenomenon exploits the leaky blood vasculature and the defective lymphatic drainage system of the heterogeneous tumor microenvironment resulting in enhanced preferential accumulation of the nanoparticles within the tumor tissues. This article reviews the fundamental studies to assess how the EPR effect plays an essential role in passive targeting. Further, it summarizes various therapeutic modalities of nanoformulation including chemo-photodynamic therapy, intravascular drug release, and photothermal immunotherapy to combat cancer using enhanced EPR effect in neoplasia region.

Triggering Immune System With Nanomaterials for Cancer Immunotherapy

Cancer is a major cause of incidence rate and mortality worldwide. In recent years, cancer immunotherapy has made great progress in the preclinical and clinical treatment of advanced malignant tumors. However, cancer patients will have transient cancer suppression reaction and serious immune related adverse reactions when receiving immunotherapy. In recent years, nanoparticle-based immunotherapy, which can accurately deliver immunogens, activate antigen presenting cells (APCs) and effector cells, provides a new insight to solve the above problems. In this review, we discuss the research progress of nanomaterials in immunotherapy including nanoparticle-based delivery systems, nanoparticle-based photothermal and photodynamic immunotherapy, nanovaccines, nanoparticle-based T cell cancer immunotherapy and nanoparticle-based bacteria cancer immunotherapy. We also put forward the current challenges and prospects of immunomodulatory therapy.

Combined Action of Hyper-Harmonized Hydroxylated Fullerene Water Complex and Hyperpolarized Light Leads to Melanoma Cell Reprogramming In Vitro

(1) Background: Their unique structure and electron deficiency have brought fullerenes into the focus of research in many fields, including medicine. The hyper-harmonized hydroxylated fullerene water complex (3HFWC) formulation has solved the limitations of the poor solubility and bioavailability of fullerenes. To achieve better antitumor activity, 3HFWC was combined with short-term irradiation of cells with hyperpolarized light (HPL) generated by the application of a nanophotonic fullerene filter in a Bioptron^® device. The benefits of HPL were confirmed in the microcirculation, wound healing and immunological function. (2) Methods: B16, B16-F10 and A375 melanoma cells were exposed to a wide spectrum of 3HFWC doses and to a single short-term HPL irradiation. (3) Results: Apart from the differences in the redox status and level of invasiveness, the effects of the treatments were quite similar. Decreased viability, morphological alteration, signs of melanocytic differentiation and cellular senescence were observed upon the successful internalization of the nanoquantum substance. (4) Conclusions: Overall, 3HFWC/HPL promoted melanoma cell reprogramming toward a normal phenotype.

Graphene quantum dots-porphyrins/phthalocyanines multifunctional hybrid systems: from interfacial dialogue to applications

Engineered well-ordered hybrid nanomaterials are at a symbolically pivotal point, just ahead of a long-anticipated human race transformation. Incorporating newer carbon nanomaterials like graphene quantum dots (GQDs) with tetrapyrrolic porphyrins...

A HET-CAM based vascularized intestine tumor model as a screening platform for nano-formulated photosensitizers

The development of new tumor models for anticancer drug screening is a challenge for preclinical research. Conventional cell-based in vitro models such as 2D monolayer cell cultures or 3D spheroids allow an initial assessment of the efficacy of drugs but they have a limited prediction to the in vivo effectiveness. In contrast, in vivo animal models capture the complexity of systemic distribution, accumulation, and degradation of drugs, but visualization of the individual steps is challenging and extracting quantitative data is usually very difficult. Furthermore, there are a variety of ethical concerns related to animal tests. In accordance with the 3Rs principles of Replacement, Reduction and Refinement, alternative test systems should therefore be developed and applied in preclinical research. The Hen's egg test on chorioallantoic membrane (HET-CAM) model provides the generation of vascularized tumor spheroids and therefore, is an ideal test platform which can be used as an intermediate step between in vitro analysis and preclinical evaluation in vivo. We developed a HET-CAM based intestine tumor model to investigate the accumulation and efficacy of nano-formulated photosensitizers. Irradiation is necessary to activate the phototoxic effect. Due to the good accessibility of the vascularized tumor on the CAM, we have developed a laser irradiation setup to simulate an in vivo endoscopic irradiation. The study presents quantitative as well as qualitative data on the accumulation and efficacy of the nano-formulated photosensitizers in a vascularized intestine tumor model.

Dynamic nanoassemblies of nanomaterials for cancer photomedicine

Photomedicine has long been used for treating cancerous diseases. With advances in chemical and material sciences, various types of light-activated photosensitizers (PSs) have been developed for effective photodynamic therapy (PDT) and photothermal therapy (PTT). However, conventional organic/inorganic materials-based PSs lack disease recognition capability and show limited therapeutic effects in addition to side effects. Recently, intelligent dynamic nanoassemblies that are activated in a tumor environment have been extensively researched to target diseased tissues more effectively, for increasing therapeutic effectiveness while minimizing side effects. This paper presents the latest dynamic nanoassemblies for effective PDT or PTT and combination phototherapies, including immunotherapy and image-guided therapy. Dynamic self-assembly exhibits great potential for clinical translation in diagnosis and treatment through its integrated versatility. Nanoassemblies based on multidisciplinary technology are a promising technique for treating incurable cancerous diseases in the future.

Liposome Photosensitizer Formulations for Effective Cancer Photodynamic Therapy

Photodynamic therapy (PDT) is a promising non-invasive strategy in the fight against that which circumvents the systemic toxic effects of chemotherapeutics. It relies on photosensitizers (PSs), which are photoactivated by light irradiation and interaction with molecular oxygen. This generates highly reactive oxygen species (such as ¹O₂, H₂O₂, O₂, ·OH), which kill cancer cells by necrosis or apoptosis. Despite the promising effects of PDT in cancer treatment, it still suffers from several shortcomings, such as poor biodistribution of hydrophobic PSs, low cellular uptake, and low efficacy in treating bulky or deep tumors. Hence, various nanoplatforms have been developed to increase PDT treatment effectiveness and minimize off-target adverse effects. Liposomes showed great potential in accommodating different PSs, chemotherapeutic drugs, and other therapeutically active molecules. Here, we review the state-of-the-art in encapsulating PSs alone or combined with other chemotherapeutic drugs into liposomes for effective tumor PDT.

Indoleamine 2,3-dioxygenase (Ido) inhibitors and their nanomedicines for cancer immunotherapy

Indoleamine 2,3-dioxygenase (IDO) as a principle enzyme in tryptophan (Trp) catabolism, modulates immune responses and promotes cancer progression. In recent decades, the newly emerging IDO inhibitors are regarded as the breakthrough for cancer immunotherapy. Intensified efforts have been increasingly made to, on the one hand, optimize the IDO inhibitors-based combination therapy in clinical trials; on the other hand, develop IDO inhibitors nanomedicines for tumor-targeted delivery in preclinical studies. This review will discuss the types of IDO inhibitors and the relevant clinical trials, especially those of the feasible combined therapeutic modalities. Moreover, it would be the first time to overview the cutting-edge nanomedicines that combine IDO inhibitors with other therapeutic modalities (e.g., chemotherapy, radiotherapy, photodynamic therapy (PDT), photothermal therapy (PTT) and immune checkpoint blockade) to effectively improve the effect of cancer therapy. Lastly, the prospects of IDO inhibitors in terms of clinical application and potential breakthroughs will be briefly discussed.

Harnessing Innate Immunity Using Biomaterials for Cancer Immunotherapy

The discovery of immune checkpoint blockade has revolutionized the field of immuno-oncology and established the foundation for developing various new therapies that can surpass conventional cancer treatments. Most recent immunotherapeutic strategies have focused on adaptive immune responses by targeting T cell-activating pathways, genetic engineering of T cells with chimeric antigen receptors, or bispecific antibodies. Despite the unprecedented clinical success, these T cell-based treatments have only benefited a small proportion of patients. Thus, the need for the next generation of cancer immunotherapy is driven by identifying novel therapeutic molecules or new immunoengineered cells. To maximize the therapeutic potency via innate immunogenicity, the convergence of innate immunity-based therapy and biomaterials is required to yield an efficient index in clinical trials. This review highlights how biomaterials can efficiently reprogram and recruit innate immune cells in tumors and ultimately initiate activation of T cell immunity against advanced cancers. Moreover, the design and specific biomaterials that improve innate immune cells' targeting ability to selectively activate immunogenicity with minimal adverse effects are discussed.

Transforming growth factor-β blockade modulates tumor mechanical microenvironments for enhanced antitumor efficacy of photodynamic therapy

Photodynamic therapy (PDT) is frequently used in cancer treatment in clinical settings. However, its applications in stroma-rich solid tumors, e.g., triple negative breast cancer, are limited by abnormal mechanical microenvironments. Solid stress accumulated in stroma-rich solid tumors compresses tumor blood vessels, hampers the delivery of photosensitizers (PSs) in tumor tissues, and poses a major challenge for potent PDT. Here, we report a novel combination strategy to augment PDT based cancer therapy by combining hydroxyethyl starch-chlorin e6 conjugate self-assembled nanoparticles (HES-Ce6 NPs) with the transforming growth factor-β (TGFβ) inhibitor LY2157299 (LY). HES-Ce6 conjugates, as synthesized by one step esterification reaction, could self-assemble into uniform HES-Ce6 NPs, which exhibited enhanced photostability and generated more reactive oxygen species (ROS) under 660 nm laser irradiation than free Ce6. Prior to PDT, intragastric administration of LY decreased collagen deposition, alleviated solid stress, and decompressed tumor blood vessels. As a result, the reconstructed tumor mechanical microenvironment promoted accumulation and penetration of HES-Ce6 NPs into tumor tissues, contributing to augmented antitumor efficacy of HES-Ce6 NP mediated PDT. Modulating tumor mechanical microenvironments using TGFβ blockade to enhance the delivery of PSs in tumors with excessive extracellular matrix represents an efficient strategy for treating stroma-rich solid tumors.

Recent Advances in the Use of Iron-Gold Hybrid Nanoparticles for Biomedical Applications

Recently, there has been an increased interest in iron-gold-based hybrid nanostructures, due to their combined outstanding optical and magnetic properties resulting from the usage of two separate metals. The synthesis of these nanoparticles involves thermal decomposition and modification of their surfaces using a variety of different methods, which are discussed in this review. In addition, different forms such as core-shell, dumbbell, flower, octahedral, star, rod, and Janus-shaped hybrids are discussed, and their unique properties are highlighted. Studies on combining optical response in the near-infrared window and magnetic properties of iron-gold-based hybrid nanoparticles as multifunctional nanoprobes for drug delivery, magnetic-photothermal heating as well as contrast agents during magnetic and optical imaging and magnetically-assisted optical biosensing to detect traces of targeted analytes inside the body has been reviewed.

Photodynamic Therapy—An Up-to-Date Review

The healing power of light has attracted interest for thousands of years. Scientific discoveries and technological advancements in the field have eventually led to the emergence of photodynamic therapy, which soon became a promising approach in treating a broad range of diseases. Based on the interaction between light, molecular oxygen, and various photosensitizers, photodynamic therapy represents a non-invasive, non-toxic, repeatable procedure for tumor treatment, wound healing, and pathogens inactivation. However, classic photosensitizing compounds impose limitations on their clinical applications. Aiming to overcome these drawbacks, nanotechnology came as a solution for improving targeting efficiency, release control, and solubility of traditional photosensitizers. This paper proposes a comprehensive path, starting with the photodynamic therapy mechanism, evolution over the years, integration of nanotechnology, and ending with a detailed review of the most important applications of this therapeutic approach.

Tailor-Made Nanomaterials for Diagnosis and Therapy of Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers worldwide due to its aggressiveness and the challenge to early diagnosis and treatment. In recent decades, nanomaterials have received increasing attention for diagnosis and therapy of PDAC. However, these designs are mainly focused on the macroscopic tumor therapeutic effect, while the crucial nano-bio interactions in the heterogeneous microenvironment of PDAC remain poorly understood. As a result, the majority of potent nanomedicines show limited performance in ameliorating PDAC in clinical translation. Therefore, exploiting the unique nature of the PDAC by detecting potential biomarkers together with a deep understanding of nano-bio interactions that occur in the tumor microenvironment is pivotal to the design of PDAC-tailored effective nanomedicine. This review will introduce tailor-made nanomaterials-enabled laboratory tests and advanced noninvasive imaging technologies for early and accurate diagnosis of PDAC. Moreover, the fabrication of a myriad of tailor-made nanomaterials for various PDAC therapeutic modalities will be reviewed. Furthermore, much preferred theranostic multifunctional nanomaterials for imaging-guided therapies of PDAC will be elaborated. Lastly, the prospects of these nanomaterials in terms of clinical translation and potential breakthroughs will be briefly discussed.

Functionalized Scintillating Nanotubes for Simultaneous Radio- and Photodynamic Therapy of Cancer

As a model radio-photodynamic therapy (RPDT) agent, we developed a multicomponent nanomaterial by anchoring conjugated chromophores on the surface of scintillating chrysotile nanotubes. Its ultimate composition makes the system a scintillation-activated photosensitizer for the singlet oxygen production. This nanomaterial shows a remarkable ability to enhance the production of singlet oxygen in an aqueous environment, under X-ray irradiation, boosting its production by almost 1 order of magnitude. Its efficiency as a coadjutant for radiotherapy has been tested in vitro, showing a striking efficacy in enhancing both the prompt cytotoxicity of the ionizing radiation and the long-term cytotoxicity given by radiation-activated apoptosis. Notably, the beneficial activity of the RPDT agent is prominent at low levels of delivered doses comparable to the one employed in clinical treatments. This opens the possibility of effectively reducing the therapy exposure and consequently undesired collateral effects due to prolonged exposure of patients to high-energy radiation.

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.

Facile Synthesis of Cyclic Peptide-Phthalocyanine Conjugates for Epidermal Growth Factor Receptor-Targeted Photodynamic Therapy

A facile procedure for in situ peptide cyclization and phthalocyanine conjugation was developed by utilizing a bifunctional linker incorporated with a bis(bromomethyl)benzene unit and a cyclopentadiene moiety. These functional groups facilitated the nucleophilic substitution with the two cysteine residues of the linear peptides followed by the Diels-Alder reaction with the maleimide moiety attached to a zinc(II) phthalocyanine. With this approach, three cyclic peptide-phthalocyanine conjugates were prepared in 20-26% isolated yield via a one-pot procedure. One of the conjugates containing a cyclic form of the epidermal growth factor receptor (EGFR)-binding peptide sequence CMYIEALDKYAC displayed superior features as an advanced photosensitizer. It showed preferential uptake by two EGFR-positive cancer cell lines (HT29 and HCT116) compared with two EGFR-negative counterparts (HeLa and HEK293), resulting in significantly higher photocytotoxicity. Intravenous administration of this conjugate into HT29 tumor-bearing nude mice resulted in selective localization in tumor and effective inhibition of tumor growth upon photodynamic treatment.

Advances in stent therapy for malignant biliary obstruction

Malignant biliary obstruction (MBO), result of pancreatobiliary diseases is a challenging condition. Most patients with MBO are inoperable at the time of diagnosis, and the disease is poorly controlled using external-beam radiotherapy and chemotherapy. Biliary stent therapy emerged as a promising strategy for alleviating MBO and prolonging life. However, physicians find it difficult to determine the optimal type of biliary stent for the palliation of MBO. Here, we review the safety and efficacy of available biliary stents, used alone or in combination with brachytherapy, photodynamic therapy and advanced chemotherapeutics, in patients with pancreatobiliary malignancies and put forward countermeasures involving stent obstruction. Furthermore, 3D-printing stents and nanoparticle-loaded stents have broad application prospects for fabricating tailor-made biliary stents.

The application of aluminium phthalocyanine AlPs-4-mediated photodynamic therapy against human soft tissue sarcoma (RMS) cell line

The main challenge in the cancer treatment is the on-target drug delivery to the affected cells. Various therapies have been designed to target the affected cells efficiently but still the success is awaited. An iron and cobalt nanocomposite for the effective drug delivery to target cells was designed. The photodynamic effect of anticancer drugs loaded with iron oxide and cobalt ferrite nanomaterials coated with polyvinyl alcohol (PVA) was studied. The iron oxide nanoparticles (IONPs) and cobalt ferrite (CF) NPs without the loaded drugs were characterized by UV, XRD, FTIR, SEM and EDX techniques. The photodynamic effect of the photosensitizer, doxorubicin, and dacarbazine loaded nanomaterials were screened against human rhabdomyosarcoma (RMS) cells after incubation for 3 h, 24 h, and 48 h using MTT assay. The combination of photodynamic therapy (PDT) with chemo drugs is studied over different doses. When RMS cells were exposed to nanomaterials loaded with chemo drugs and PDT alone, it resulted in less cell killing compared to chemo drugs followed by PDT. These results revealed that in the case of combined treatment (combination therapy) the cell viability decreases as compared to individual treatment (monotherapy). The in vitro studies showed positive results which give a new pathway for the in vivo studies.

Bacterial elimination via the photodynamic activity of a fullerene/light-harvesting antenna molecule assembled system integrated into liposome membranes

Ease of transmission and exceptionally high mortality rates make pathogen-based infections an ongoing global threat. Herein, a facile bacterial elimination process is described which is based on the photodynamic activity of fullerenes composed of light-harvesting antenna molecules integrated into liposome membranes. This was done to expand the absorption capabilities of fullerene derivatives. Efficient energy transfer from the photoactivated antenna molecules to the fullerenes enhanced antimicrobial activity without any harmful lytic activity against red blood cells even under irradiation.

Photosensitizer-stabilized self-assembling nanoparticles potentiate chemo/photodynamic efficacy of patient-derived melanoma

Development of injectable nanoparticles for delivery of active anticancer compounds often requires complicated schemes that involve tedious synthetic protocols and nanoformulations. In particular, clinical translation of synergistic nanoparticles that can facilitate multimodal therapies remains a considerable challenge. Herein, we describe a self-assembling, small-molecule nanosystem with unique properties, including near-infrared (NIR) light-responsive drug activation, size transformability, combinatorial synergy, and substantially reduced toxicity. Ligation of anticancer cabazitaxel (CTX) drugs via a reactive oxygen species-activatable thioketal linkage generates a dimeric TKdC prodrug, and subsequent coassembly with a photosensitizer, chlorin e6 (Ce6), forms colloidal-stable nanoassemblies (termed psTKdC NAs). Upon NIR laser irradiation, psTKdC NAs are transformed into smaller size particles and facilitate production of pharmacologically active CTX. Importantly, reactive oxygen species yielded by coassembled Ce6 can synergize with chemotherapy to achieve potent combinatorial effects. In a preclinical orthotopic model of an aggressive, human melanoma patient-derived xenograft (PDX), we show that administration of psTKdC NAs followed by laser irradiation produced durable tumor regression, with the tumors being completely eradicated in three of six PDXs. Furthermore, low systemic toxicity of this smart, photo-activatable nanotherapy was observed in animals. The new self-deliverable combinatorial system addresses essential requirements for high efficacy, safety, and translational capacity and deserves further investigation.

AIE based GSH activatable photosensitizer for imaging-guided photodynamic therapy

A novel ferrocene decorated vinyl pyridinium-substituted tetraphenylethylene (TPEPY-S-Fc) linked by a disulfide bond was designed as a GSH activatable photosensitizer by aggregation-induced emission for imaging-guided photodynamic therapy of cancer cells.

Tumor Microenvironment Targeting Nano-Bio Emulsion for Synergistic Combinational X-Ray PDT with Oncolytic Bacteria Therapy

Various cancer therapies have been developed, but tumor recurrence with incomplete tumor killing and remaining tumor cells/tissues is frequent in monotherapies. Herein, a nano-bio therapeutic emulsion formulated with multifunctional nanoscintillators and anaerobic Clostridium novyi-NT spores for synergistic image-guided combinational cancer therapy is reported. MRI visible nanoscintillators (NSs) are synthesized with a NaGdF4 :Tb,Ce@NaGdF4 core/shell structure for an image-guided X-ray photodynamic therapy (PDT) of the normoxic peripheral tumor. An anaerobic oncolytic bacterium (C. novyi-NT) therapy is combined to treat the hypoxic central tumor tissues. Photosensitizer-coated NSs (PS-NSs) and C. novyi-NT spores are emulsified with clinically available ethiodized oil (Lipiodol) to be the nano-bio therapeutic emulsion and injected into the tumor with computed tomography image guidance. The distribution of nano-bio therapeutic emulsion, including PS-NSs and anaerobic C. novyi-NT spores in the tumor site, is confirmed by both X-ray and T1 -weighted magnetic resonance imaging. Following the image-guided X-ray PDT and anaerobic C. novyi- NT combination treatment, apoptotic cell death in cancer tissues, including both peripheral and central tumor regions, is significantly higher than in the control groups. This combination therapy approach using a nano-bio therapeutic emulsion is expected to overcome the limitations of conventional cancer therapy, resulting in increased cancer-therapeutic efficacy.

Near Infrared Light Triggered Photo/Immuno-Therapy Toward Cancers

Nanomaterials-based phototherapies, mainly including photothermal therapy (PTT), photodynamic therapy (PDT) and photoimmunotherapy (PIT), present high efficacy, minimal invasion and negligible adverse effects in cancer treatment. The integrated phototherapeutic modalities can enhance the efficiency of cancer immunotherapy for clinical application transformation. The near-infrared (NIR) light source enables phototherapies with the high penetration depth in the biological tissues, less toxic to normal cells and tissues and a low dose of light irradiation. Mediated via the novel NIR-responsive nanomaterials, PTT and PDT are able to provoke cancer cells apoptosis from the generated heat and reactive oxygen species, respectively. The released cancer-specific antigens and membrane damage danger signals from the damaged cancer cells trigger immune responses, which would enhance the antitumor efficacy via a variety of immunotherapy. This review summarized the recent advances in NIR-triggered photo-/immune-therapeutic modalities and their synergistic mechanisms and applications toward cancers. Furthermore, the challenges, potential solutions and future directions of NIR-triggered photo-/immunotherapy were briefly discussed.

A smart theranostic platform for photoacoustic and magnetic resonance dual-imaging-guided photothermal-enhanced chemodynamic therapy

The use of smart theranostic agents in multimodal imaging and treatment is a promising strategy to overcome the limitations of single mode diagnosis and treatment, and can greatly improve the diagnosis and effects of treatment. In this study, a gold@manganese dioxide (Au@MnO2) core-shell nanostructure was designed as a glutathione (GSH)-triggered smart theranostic agent for photoacoustic and magnetic resonance (MR) dual-imaging-guided photothermal-enhanced chemodynamic therapy. Both in vitro and in vivo experiments demonstrated not only that the photoacoustic and MR imaging function of Au@MnO2 could be activated by a high endogenous GSH concentration, but also that after being triggered by the endogenous GSH, Au@MnO2 had an excellent synergistic treatment effect in photothermal-enhanced chemodynamic therapy under the guidance of photoacoustic and MR imaging. This study demonstrated that the use of GSH-triggered Au@MnO2 in photoacoustic and MR dual-imaging-guided photothermal-enhanced chemodynamic therapy is a smart theranostic nanoplatform for the accurate diagnosis and efficient treatment of cancer.

Novel photosensitizing properties of porphyrin–chrysin derivatives with antitumor activity in vitro

Photodynamic therapy is a promising cancer treatment with the advantages of low toxicity, high efficiency, and noninvasiveness. In this study, 23 novel porphyrin–chrysin derivatives are synthesized using alkyl carbon chains as bridges. We use human gastric cancer cells (MGC-803) and human cervical cancer cells to evaluate the in vitro antitumor activity of all the porphyrin–chrysin derivatives, with 5-fluorouracil (5-Fu) as a positive control. Several of the prepared compounds showed effective photodynamic killing effects, among which 5-hydroxy-2-phenyl-7-(2-(4-(10,15,20-tris(4-hydroxyphenyl)porphyrin-5-yl)phenoxy)ethoxy)-4 H-chromen-4-one shows the highest antiproliferation activity on human cervical cancer cells, with a half maximal inhibitory concentration of 26.51 ± 1.15 µM. Flow cytometry analysis showed that human cervical cancer cell apoptosis might be induced by G1 phase arrest.

Enhancing doxorubicin anticancer activity with a novel polymeric platform photoreleasing nitric oxide

Combination of Doxorubicin with light-regulated NO release achieved through formulation strategy of tailored polymeric conjugate nanoparticles may open new treatment modalities to improve cancer therapies.