Nanomaterials-based photosensitizers and delivery systems for photodynamic cancer therapy

Cationic liposomes as a drug-free system for efficient anticancer therapy by intracytoplasmic delivery of sodium bicarbonate

Developing the delivery systems with high therapeutic efficacy and low side effects is of great interest and significance for anticancer therapy. Compared to the high cost in synthesizing new chemotherapeutic drugs, exploring the anticancer potentials of existing chemicals is more convenient and efficient. Sodium bicarbonate (BC), a simple inorganic salt, has shown its tumor inhibition capacity via regulating the acidity of tumor microenvironment. However, the effects of intracytoplasmic BC on tumor growth and the potentials of BC to serve as an anticancer agent are still unknown. Herein, we developed a BC-loaded cationic liposome system (BC-CLP) to deliver BC into the cytosol of cancer cells. The in vitro studies showed that the BC-CLP containing 1% BC (w/v) had a size of 112.9 nm and a zeta potential of 19.1 mV, which reduced the viability of the model cancer cells (human oral squamous cell carcinoma HSC-3 cells) to 13.7%. In contrast, the neutral BC-LP caused less than 50% viability reduction. We further found that BC-CLP released BC directly into cytoplasm via membrane fusion pathway rather than endocytosis, leading to the remarkable increase of cytosolic pH, which may contribute to the anticancer effect of BC-CLP. Our findings indicate that BC-CLP is a potential system for high-efficiency cancer therapy without causing drug-related side effects or resistance.

Photodynamic Therapy in the Treatment of Cancer-The Selection of Synthetic Photosensitizers

Photodynamic therapy (PDT) is a promising cancer treatment method that uses photosensitizing (PS) compounds to selectively destroy tumor cells using laser light. This review discusses the main advantages of PDT, such as its low invasiveness, minimal systemic toxicity and low risk of complications. Special attention is paid to photosensitizers obtained by chemical synthesis. Three generations of photosensitizers are presented, starting with the first, based on porphyrins, through the second generation, including modified porphyrins, chlorins, 5-aminolevulinic acid (ALA) and its derivative hexyl aminolevulinate (HAL), to the third generation, which is based on the use of nanotechnology to increase the selectivity of therapy. In addition, current research trends are highlighted, including the search for new photosensitizers that can overcome the limitations of existing therapies, such as heavy-atom-free nonporphyrinoid photosensitizers, antibody-drug conjugates (ADCs) or photosensitizers with a near-infrared (NIR) absorption peak. Finally, the prospects for the development of PDTs are presented, taking into account advances in nanotechnology and biomedical engineering. The references include both older and newer works. In many cases, when writing about a given group of first- or second-generation photosensitizers, older publications are used because the properties of the compounds described therein have not changed over the years. Moreover, older articles provide information that serves as an introduction to a given group of drugs.

Amphiphilic Single-Chain Polymer Nanoparticles as Imaging and Far-Red Photokilling Agents for Photodynamic Therapy in Zebrafish Embryo Xenografts

This work introduces rationally designed, improved amphiphilic single-chain polymer nanoparticles (SCNPs) for imaging and photodynamic therapy (PDT) in zebrafish embryo xenografts. SCNPs are ultrasmall polymeric nanoparticles with sizes similar to proteins, making them ideal for biomedical applications. Amphiphilic SCNPs result from the self-assembly in water of isolated synthetic polymeric chains through intrachain hydrophobic interactions, mimicking natural biomacromolecules and, specially, proteins (in size and when loaded with drugs, metal ions or fluorophores also in function). These ultrasmall, soft nanoparticles have various applications, including catalysis, sensing, and nanomedicine. Initial in vitro experiments with nonfunctionalized, amphiphilic SCNPs loaded with a photosensitizing Zn phthalocyanine with four nonperipheral isobutylthio substituents, ZnPc, showed promise for PDT. Herein, the preparation of improved, amphiphilic SCNPs containing ZnPc as highly efficient photosensitizer encapsulated within the nanoparticle and surrounded by anthracene units is disclosed. The amount of anthracene groups and ZnPc molecules within each single-chain nanoparticle controls the imaging and PDT properties of these nanocarriers. Critically, this work opens the way to improved PDT applications based on amphiphilic SCNPs as a first step toward ideal, long-term artificial photo-oxidases (APO).

2D nanomaterials-based delivery systems and their potentials in anticancer synergistic photo-immunotherapy

As the field of cancer therapeutics evolves, integrating two-dimensional (2D) nanomaterials with photo-immunotherapy has emerged as a promising approach with significant potential to augment cancer treatment efficacy. These 2D nanomaterials include graphene-based 2D nanomaterials, 2D MXenes, 2D layered double hydroxides, black phosphorus nanosheets, 2D metal-organic frameworks, and 2D transition metal dichalcogenides. They exhibit high load capacities, multiple functionalization pathways, optimal biocompatibility, and physiological stability. Predominantly, they function as anti-tumor delivery systems, amalgamating diverse therapeutic modalities, most notably phototherapy and immunotherapy, and the former is a recognized non-invasive treatment modality, and the latter represents the most promising anti-cancer strategy presently accessible. Thus, integrating phototherapy and immunotherapy founded on 2D nanomaterials unveils a novel paradigm in the war against cancer. This review delineates the latest developments in 2D nanomaterials as delivery systems for synergistic photo-immunotherapy in cancer treatment. We elaborate on the burgeoning realm of photo-immunotherapy, exploring the interplay between phototherapy and enhanced immune cells, immune response modulation, or immunosuppressive tumor microenvironments. Notably, the strategies to augment photo-immunotherapy have also been discussed. Finally, we discuss the challenges and future perspectives of these 2D nanomaterials in photo-immunotherapy.

Nanomaterials-based advanced systems for photothermal / photodynamic therapy of oral cancer

The traditional clinical approaches for oral cancer consist of surgery, chemotherapy, radiotherapy, immunotherapy, and so on. However, these treatments often induce side effects and exhibit limited efficacy. Photothermal therapy (PTT) emerges as a promising adjuvant treatment, utilizing photothermal agents (PTAs) to convert light energy into heat for tumor ablation. Another innovative approach, photodynamic therapy (PDT), leverages photosensitizers (PSs) and specific wavelength laser irradiation to generate reactive oxygen species (ROS), offering an effective and non-toxic alternative. The relevant combination therapies have been reported in the field of oral cancer. Simultaneously, the advancement of nanomaterials has propelled the clinical application of PTT and PDT. Therefore, a comprehensive understanding of PTT and PDT is required for better application in oral cancer treatment. Here, we review the use of PTT and PDT in oral cancer, including noble metal materials (e.g., Au nanoparticles), carbon materials (e.g., graphene oxide), organic dye molecules (e.g., indocyanine green), organic molecule-based agents (e.g., porphyrin-analog phthalocyanine) and other inorganic materials (e.g., MXenes), exemplify the advantages and disadvantages of common PTAs and PSs, and summarize the combination therapies of PTT with PDT, PTT/PDT with chemotherapy, PTT with radiotherapy, PTT/PDT with immunotherapy, and PTT/PDT with gene therapy in the treatment of oral cancer. The challenges related to the PTT/PDT combination therapy and potential solutions are also discussed.

Spatiotemporally-controlled hydrophobic drug delivery via photosensitizer-driven assembly-disassembly for enhanced triple-negative breast cancer treatment

Therapeutic approaches for triple-negative breast cancer (TNBC) have been continuously advancing, but inadequate control over release behavior, insufficient tumor selectivity, and limited drug availability continue to impede therapeutic outcomes in nanodrug systems. In this study, we propose a general hydrophobic antineoplastic delivery system, termed spatiotemporally-controlled hydrophobic antineoplastic delivery system (SCHADS) for enhanced TNBC treatment. The key feature of SCHADS is the formation of metastable photosensitive-antineoplastic complexes (PACs) through the self-assembly of hydrophobic drugs driven by photosensitive molecules. With the further decoration of tumor-targeting peptides coupled with the EPR effect, the PACs tend to accumulate in the tumor site tremendously, promoting drug delivery efficiency. Meanwhile, the disassembly behavior of the metastable PACs could be driven by light on demand to achieve in situ drug release, thus promoting chemotherapeutics availability. Furthermore, the abundant ROS generated by the photosensitizer could effectively kill tumor cells, ultimately realizing an effective combination of photodynamic and chemotherapeutic therapy. As an exemplary presentation, chlorin e6 has been chosen to drive the formation of PACs with the system xc- inhibitor sorafenib. Compared with pure drug treatment, the PACs with the above-described preponderances exhibit superior therapeutic effects both in vitro and in vivo and circumvent the side effects due to off-target. By manipulating the laser irradiation, the PACs-treated cell death mechanism could be dynamically regulated, thus providing the potential to remedy intrinsic/acquired resistance of tumor. Collectively, this SCHADS achieves spatio-temporal control of the drug that greatly enhances the availability of anticarcinogen and realizes synergistic antitumor effect in TNBC treatment, even ultimately being extended to the treatment of other types of tumors.

Multifunctionality of cyclodextrin-based polymeric nanoparticulate delivery systems for chemotherapeutics, combination therapy, and theranostics

As cancer being the most difficult disease to treat, different kinds of medications and therapeutic approaches have been prominently developed by scientists. For certain families of drugs, such as immuno-therapeutics or antibody-drug conjugates, efficient delivery systems are required during administration to protect the drugs from chemical degradation or biological inactivation. Delivery systems with the ability to carry different therapeutics or diagnostic agents or both, hold promising potential to tackle the abnormalities behind cancer. In this context, this review provides updated insights on how cyclodextrin-based polymeric nanosystems have become an effective treatment approach against cancer. Cyclodextrins (CDs) are natural oligosaccharides that are famously exploited in pharmaceutical research due to their exceptional quality of entrapping water-insoluble molecules inside their hydrophobic core and providing enhanced solubility with the help of their hydrophilic exterior. Combining the properties of CDs with polymeric nanoparticles (PNPs) brings out excellent versatile and tunable profiles, thanks to the submicron-sized PNPs. By introducing the significance of CD as a delivery system, a collective discussion on different binding approaches and release mechanisms of CD-drug complexation, followed by their characterization studies has been done in this review. Further, in light of recent studies, the article majorly focuses on conveying how promoting CD to a polymeric and nanoscale elevates the multifunctional advantages against cancer that can be successfully applied in combination therapy and theranostics. Moreover, CD-based delivery systems including CALAA-01, CRLX101, and CRLX301, have demonstrated improved tumor targeting, reduced side effects, and prolonged drug release in preclinical studies and clinical trials.

Nanoplatform-based strategies for enhancing the lethality of current antitumor PDT

Photodynamic therapy (PDT) exhibits great application prospects in future clinical oncology due to its spatiotemporal controllability and good biosafety. However, the antitumor efficacy of PDT is seriously hindered by many factors, including tumor hypoxia, limited light penetration ability, and strong defense mechanisms of tumors. Considering that it is difficult to completely solve the first two problems, enhancing the lethality of antitumor PDT has become a good idea to extend its clinical application. Herein, we summarize the nanoplatform-involved strategies to effectively amplify the tumoricidal capability of current PDT and then discuss the present bottlenecks and prospects of the nanoplatform-based PDT sensitization strategies in tumor therapy. We hope this review will provide some references for others to design high-performance PDT nanoplatforms for tumor therapy.

Bispecific aptamer-decorated and light-triggered nanoparticles targeting tumor and stromal cells in breast cancer derived organoids: implications for precision phototherapies

BACKGROUND

Based on the established role of cancer-stroma cross-talk in tumor growth, progression and chemoresistance, targeting interactions between tumor cells and their stroma provides new therapeutic approaches. Dual-targeted nanotherapeutics selectively acting on both tumor and stromal cells may overcome the limits of tumor cell-targeting single-ligand nanomedicine due to the complexity of the tumor microenvironment.

METHODS

Gold-core/silica-shell nanoparticles embedding a water-soluble iridium(III) complex as photosensitizer and luminescent probe (Iren-AuSiO2_COOH) were efficiently decorated with amino-terminated EGFR (CL4) and PDGFRβ (Gint4.T) aptamers (Iren-AuSiO2_Aptamer). The targeting specificity, and the synergistic photodynamic and photothermal effects of either single- and dual-aptamer-decorated nanoparticles have been assessed by confocal microscopy and cell viability assays, respectively, on different human cell types including mesenchymal subtype triple-negative breast cancer (MES-TNBC) MDA-MB-231 and BT-549 cell lines (both EGFR and PDGFRβ positive), luminal/HER2-positive breast cancer BT-474 and epidermoid carcinoma A431 cells (only EGFR positive) and adipose-derived mesenchymal stromal/stem cells (MSCs) (only PDGFRβ positive). Cells lacking expression of both receptors were used as negative controls. To take into account the tumor-stroma interplay, fluorescence imaging and cytotoxicity were evaluated in preclinical three-dimensional (3D) stroma-rich breast cancer models.

RESULTS

We show efficient capability of Iren-AuSiO2_Aptamer nanoplatforms to selectively enter into target cells, and kill them, through EGFR and/or PDGFRβ recognition. Importantly, by targeting EGFR+ tumor/PDGFRβ+ stromal cells in the entire tumor bulk, the dual-aptamer-engineered nanoparticles resulted more effective than unconjugated or single-aptamer-conjugated nanoparticles in either 3D spheroids cocultures of tumor cells and MSCs, and in breast cancer organoids derived from pathologically and molecularly well-characterized tumors.

CONCLUSIONS

Our study proposes smart, novel and safe multifunctional nanoplatforms simultaneously addressing cancer-stroma within the tumor microenvironment, which are: (i) actively delivered to the targeted cells through highly specific aptamers; (ii) localized by means of their luminescence, and (iii) activated via minimally invasive light, launching efficient tumor death, thus providing innovative precision therapeutics. Given the unique features, the proposed dual targeted nanoformulations may open a new door to precision cancer treatment.

Mitochondria targeted biomimetic platform for chemo/photodynamic combination therapy against osteosarcoma

Clinical treatment for osteosarcoma (OS) is still lacking effective means, and no significant progress in OS treatment have been made in recent years. Single chemotherapy has serious side effects and can produce drug resistance easily, resulting poor therapeutic effect. As a modern and non-invasive treatment form, photodynamic therapy (PDT) is widely used to treat diverse cancers. Chemotherapy in combination with PDT is a particularly efficient antitumor method that could overcome the defects of monotherapies. Since mitochondria is a key subcellular organelle involved in cell apoptosis regulation, targeting tumor cells mitochondria for drug delivery has become an important entry point for anti-tumor therapy. Herein, we rationally designed a core-shell structured biomimetic nanoplatform, i.e., D@SLNP@OSM-IR780, to achieve tumor homologous targeting and mitochondria targeted drug release for chemotherapy combined with PDT against OS. Upon 808 nm laser irradiation, D@SLNP@OSM-IR780 exhibited excellent photo-cytotoxicity in vitro. The excellent targeting effect of D@SLNP@OSM-IR780 in tumor tissues produced a tumor inhibition rate of 98.9% in vivo. We further indicated that synergistic chemo-photodynamic effect induced by D@SLNP@OSM-IR780 could activate mitochondria-mediated apoptosis pathway, along with host immune response and potential photothermal effect. On the whole, D@SLNP@OSM-IR780 is revealed to be a promising platform for OS targeted combination therapeutics.

Environmental stimulus-responsive mesoporous silica nanoparticles as anticancer drug delivery platforms

Currently, cancer poses a significant health challenge in the medical community. Traditional chemotherapeutic agents are often accompanied by toxic side effects and limited therapeutic efficacy, restricting their application and advancement in cancer treatment. Therefore, there is an urgent need for developing intelligent drug release systems. Mesoporous silica nanoparticles (MSNs) have many advantages, such as a large specific surface area, substantial pore volume and size, adjustable mesoporous material pore size, excellent biocompatibility, and thermodynamic stability, making them ideal carriers for drug delivery and release. Additionally, they have been widely used to develop novel anticancer drug carriers. Recently, MSNs have been employed to design responsive systems that react to the tumor microenvironment and external stimuli for controlled release of anticancer drugs. This includes factors within the intratumor environment, such as pH, temperature, enzymes, and glutathione as well as external tumor stimuli, such as light, magnetic field, and ultrasound, among others. In this review, we discuss the research progress on environmental stimulus-responsive MSNs in anticancer drug delivery systems, including internal and external environment single stimulus-responsive release and combined stimulus-responsive release. We also summarize the current challenges associated with environmental stimulus-responsive MSNs and elucidate future directions, providing a reference for the functionalization modification and practical application of these MSNs.

Platelet membrane-based biochemotactic-targeting nanoplatform combining PDT with EGFR inhibition therapy for the treatment of breast cancer

Presently, the commonly used anti-tumor drugs lack targeting ability, resulting in a limited therapeutic efficacy and significant side effects. In this view, platelet membranes (PMs) not only exhibit specific binding of its P-selectin protein with CD44, which is highly expressed on breast cancer cells, to promote tumor-active targeting by PM biomimetic nanoplatforms, but also respond to vascular damage, thus inducing biochemotactic targeting to further facilitate the aggregation of these nanoplatforms. Therefore, in this study, a PM was applied to construct a biochemotactic-targeting nanotherapeutic platform based on dendritic large pore mesoporous silica nanoparticles (DLMSNs) co-loaded with chlorin e6 (Ce6) and lapatinib (LAP) to achieve the combination of photodynamic therapy (PDT) and EGFR inhibition therapy for breast cancer. Under laser irradiation, PM@DLMSN/Ce6/Lap could not only effectively kill breast tumor cells by the PDT, but also damage blood vessels. By combining the EGFR inhibition of LAP, PM@DLMSN/Ce6/Lap could better inhibit the migration and movement of tumor cells. In vitro and in vivo results showed that PM@DLMSN/Ce6/Lap could achieve active-targeting drug delivery to breast tumors and further recruit more nanoparticles to accumulate at tumor sites after the PDT-induced damage of blood vessels through biochemotactic targeting, achieving continuous EGFR inhibition to prevent tumor proliferation and metastasis. In conclusion, this study not only provides a new strategy for the clinical treatment of breast cancer, but also provides a design idea for improving the targeted delivery of anti-tumor drugs.

Bibliometric analysis of photodynamic therapy and immune response from 1989-2023

Objective: Photodynamic therapy (PDT) is a minimally invasive treatment approach for precancerous and cancerous lesions, known for its ability to activate the host immune response. This study conducted a bibliometric analysis to identify the research trends and hotspots related to the immune response in PDT. Methods: We analyzed articles and reviews published from 1989 to 2023, retrieved from the Web of Science database. Using Citespace and VOSviewer, we visualized the distribution patterns of these studies in time and space. Results: The analysis revealed a substantial increase in the number of publications on PDT-related immune response since 1989. A total of 1,688 articles from 1,701 institutions were included in this analysis. Among thei nstitutions, the Chinese Academy of Sciences demonstrated exceptional productivity and a willingness to collaborate with others. Additionally, 8,567 authors contributed to the field, with Mladen Korbelik, Michael R. Hamblin, and Wei R. Chen being the most prolific contributors. The current research focus revolves around novel strategies to enhance antitumor immunity in PDT, including PDT-based dendritic cell vaccines, combination therapies with immune checkpoint inhibitors (ICIs), and the use of nanoparticles for photosensitizer delivery. Furthermore, genes such as CD8A, TNF, CD4, IFNG, CD274, IL6, IL10, CALR, HMGB1, and CTLA4 have been evaluated in the context of PDT-related immunity. Conclusion: PDT not only achieves tumor ablation but also stimulates the immune response, bolstering antitumor immunity. This study highlights the emerging hotspots in PDT-related immune response research and provides valuable insights for future investigations aimed at further enhancing antitumor immunity.

A NIR-driven green affording-oxygen microrobot for targeted photodynamic therapy of tumors

Photodynamic therapy (PDT) is a light-activated local treatment modality that has promising potential in cancer therapy. However, ineffective delivery of photosensitizers and hypoxia in the tumor microenvironment severely restrict the therapeutic efficacy of PDT. Herein, phototactic Chlorella (C) is utilized to carry photosensitizer-encapsulated nanoparticles to develop a near-infrared (NIR) driven green affording-oxygen microrobot system (CurNPs-C) for enhanced PDT. Photosensitizer (curcumin, Cur) loaded nanoparticles are first synthesized and then covalently attached to C through amide bonds. An in vitro study demonstrates that the developed CurNPs-C exhibits continuous oxygen generation and desirable phototaxis under NIR treatment. After intravenous injection, the initial 660 nm laser irradiation successfully induces the active migration of CurNPs-C to tumor sites for higher accumulation. Upon the second 660 nm laser treatment, CurNPs-C produces abundant oxygen, which in turn induces the natural product Cur to generate more reactive oxygen species (ROS) that significantly inhibit the growth of tumors in 4T1 tumor-bearing mice. This contribution showcases the ability of a light-driven green affording-oxygen microrobot to exhibit targeting capacity and O2 generation for enhancing photodynamic therapy.

Omic Evaluation of Nanomaterial-Based Photodynamic Therapy of Cancer

Photodynamic therapy (PDT), a noninvasive cancer treatment, relies on three components: light source, oxygen, and photosensitizer (PS). When PS is excited by a specific wavelength of light in the presence of oxygen, it leads to the generation of reactive oxygen species (ROS), which results in targeted destruction of cancer cells. The success of PDT mainly depends on the properties of the chosen PS, emphasizing selectivity, high absorbance, drug conjugation, controlled biodistribution, and low toxicity. Nanomaterials not only play an important role in photochemical activity by maximizing the absorption of photons from the light source but can also adjust the pharmacokinetics and tumor selectivity of photoactive molecules. Therefore, they can be used as a PS on their own and conjugated with other PS molecules. When combined with selectivity, high targeting capacity, and finally, light of the appropriate wavelength, the scenario results in localized ROS formation and cell death. However, the signaling pathways of PDT-induced cell death may differ depending on the cell type or nanomaterial properties. For this reason, omics analyses are needed to clarify the mechanisms underlying photodynamic reactions. Proteomics, crucial in molecular sciences, sheds light on cancer mechanisms, identifying biomarkers and therapeutic targets. Examining nanoparticle-based PDT in cancer cell lines in vitro, this chapter aims to molecularly evaluate efficacy, utilizing proteomic analysis to understand the underlying mechanisms.

Research Progress of Photodynamic Therapy in Wound Healing: A Literature Review

Light is an efficient technique that has a significant influence on contemporary medicine. Photodynamic therapy (PDT), which involves the combined action of photosensitizers (PSs), oxygen, and light, has emerged as a therapeutically promising method for treating a broad variety of solid tumors and infectious diseases. Photodynamic therapy is minimally invasive, has few side effects, lightens scars, and reduces tissue loss while preserving organ structure and function. In particular, PDT has a high healing potential for wounds (PDT stimulates wound healing by enhancing re-epithelialization, promoting angiogenesis as well as modulating skin homeostasis). Wound healing involves interactions between many different processes, including coagulation, inflammation, angiogenesis, cellular migration, and proliferation. Poor wound healing with diabetes or extensive burns remains a difficult challenge. This review emphasizes PDT as a potential research field and summarizes PDT's role in wound healing, including normal wounds, chronic wounds, and aging wounds.

Reactive oxygen species creation by laser-irradiated indocyanine green as photodynamic therapy modality: an in vitro study

Applications of lasers in phototherapy have been the trend for the last few decades. The photodynamic therapy process normally depends on photosensitizers and laser beams. Through this study, indocyanine green has been used as a photosensitizer, which is normally activated using laser lines between 750 and 805 nm. The activity of the indocyanine green to do fluorescence by other pulsed laser sources has been tested by fluorescence technique, and it has been proven that the laser lines at 810, 940, and 980nm are able to excite the indocyanine green with different extents. The indocyanine green activation has been tested by several laser lines (810, 940, and 980 nm) commonly used as surgical lasers. The generated oxygen has been measured after irradiating the indocyanine green with the different laser lines. A comparison has been made between laser irradiation as a pinpoint and a broad beam. It is found that the wide beam is more effective in activating oxygen production. In the end, it is concluded that lines 810 and 940nm were effective in activating the used dye, while the 980nm activity did not show enough efficiency.

Nanomaterials in tumor immunotherapy: new strategies and challenges

Tumor immunotherapy exerts its anti-tumor effects by stimulating and enhancing immune responses of the body. It has become another important modality of anti-tumor therapy with significant clinical efficacy and advantages compared to chemotherapy, radiotherapy and targeted therapy. Although various kinds of tumor immunotherapeutic drugs have emerged, the challenges faced in the delivery of these drugs, such as poor tumor permeability and low tumor cell uptake rate, had prevented their widespread application. Recently, nanomaterials had emerged as a means for treatment of different diseases due to their targeting properties, biocompatibility and functionalities. Moreover, nanomaterials possess various characteristics that overcome the defects of traditional tumor immunotherapy, such as large drug loading capacity, precise tumor targeting and easy modification, thus leading to their wide application in tumor immunotherapy. There are two main classes of novel nanoparticles mentioned in this review: organic (polymeric nanomaterials, liposomes and lipid nanoparticles) and inorganic (non-metallic nanomaterials and metallic nanomaterials). Besides, the fabrication method for nanoparticles, Nanoemulsions, was also introduced. In summary, this review article mainly discussed the research progress of tumor immunotherapy based on nanomaterials in the past few years and offers a theoretical basis for exploring novel tumor immunotherapy strategies in the future.

Photothermal and natural activity-based synergistic antibacterial effects of Ti3C2Tx MXene-loaded chitosan hydrogel against methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) has strong resistance to antibiotic therapy. In this regard, developing antibiotic-free antibacterial agents is of great significance to treat MRSA infections. Herein, we loaded Ti₃C₂T_x MXene nanomaterial in the non-crosslinked chitosan (CS) hydrogel. The obtained MX-CS hydrogel is expected to not only adsorb MRSA cells via CS-MRSA interactions, but also gather the MXene-induced photothermal hyperthermia, achieving the efficient and intensive anti-MRSA photothermal therapy. As a result, under NIR irradiation (808 nm, 1.6 W/cm², 5 min), MX-CS showed a greater photothermal effect than MXene alone did (30 μg/mL, 49.9 °C for MX-CS and 46.5 °C for MXene). Importantly, MRSA cells were rapidly adsorbed on MX-CS hydrogel (containing 30 μg/mL MXene) and completely inhibited (99.18 %) under NIR irradiation for 5 min. In contrast, MXene (30 μg/mL) and CS hydrogel alone only inhibited 64.52 % and 23.72 % MRSA, respectively, significantly lower than the inhibition caused by MX-CS (P < 0.001). Interestingly, when the hyperthermia was depleted by a 37 °C water bath, the bacterial inhibition rate of MX-CS significantly decreased to 24.65 %. In conclusion, MX-CS hydrogel has a remarkable synergistic anti-MRSA activity by gathering MRSA cells and MXene-induced hyperthermia, and may have great potentials in treating MRSA-infected diseases.

NI-BODIPY-GO Nanocomposites for Targeted PDT

Three multifunctional targeted NI-BODIPYs (10-12) and GO-(10-12) nanocarriers were fabricated. NI-BODIPYs are designed to facilitate non-covalent interaction with graphene oxide (GO) and target toward cancer cells for specific recognition with glucose moieties while efficiently producing singlet oxygen. We probed detailed characterization, fundamental photophysical/photochemical properties, and interactions with GO of such triplet photosensitizers and nanocarriers. The effect of the formation of nanohybrids with GO on singlet oxygen formation as well as on the efficacies of the molecules in terms of in vitro killing of cancer cells was evaluated with K562 human chronic myelogenous leukemia cells. Amazingly, it was observed that GO exhibited favorable interactions with the NI-BODIPY dyads and promoted the formation of singlet oxygen, while not showing any dark toxicity.

Nanomaterials: Breaking through the bottleneck of tumor immunotherapy

Immunotherapy exerts its excellent anti-tumor effects by stimulating and enhancing the immune response of the body, and has become another important class of anti-tumor therapy besides chemotherapy, targeted therapy and radiotherapy. Various types of immunotherapeutic drugs have gained their clinical values, but the in vivo delivery of drugs still faces many challenges, such as poor tumor permeability and low tumor cell uptake rate. In recent years, owing to highly targeting properties, better biocompatibility, and easy functionalization, nanomaterials have been widely applicated in tumor treatment, especially in tumor immunotherapy. Furthermore, nanomaterials have large drug loading capacity, strong tumor targeting and easy modification, which can effectively overcome the drawbacks of traditional immunotherapy. This paper reviews the progress of nanomaterial-based tumor immunotherapy in recent years and provides a theoretical basis for exploring new nanomaterial-based tumor immunotherapy strategies.

A Sulfur-Bridging Sulfonate-Modified Zinc(II) Phthalocyanine Nanoliposome Possessing Hybrid Type I and Type II Photoreactions with Efficient Photodynamic Anticancer Effects

Phthalocyanines are potentially promising photosensitizers (PSs) for photodynamic therapy (PDT), but the inherent defects such as aggregation-caused quenching effects and non-specific toxicity severely hinder their further application in PDT. Herein, we synthesized two zinc(II) phthalocyanines (PcSA and PcOA) monosubstituted with a sulphonate group in the alpha position with "O bridge" and "S bridge" as bonds and prepared a liposomal nanophotosensitizer (PcSA@Lip) by thin-film hydration method to regulate the aggregation of PcSA in the aqueous solution and enhance its tumor targeting ability. PcSA@Lip exhibited highly efficient production of superoxide radical (O₂^∙-) and singlet oxygen (¹O₂) in water under light irradiation, which were 2.6-fold and 15.4-fold higher than those of free PcSA, respectively. Furthermore, PcSA@Lip was able to accumulate selectively in tumors after intravenous injection with the fluorescence intensity ratio of tumors to livers was 4.1:1. The significant tumor inhibition effects resulted in a 98% tumor inhibition rate after PcSA@Lip was injected intravenously at an ultra-low PcSA@Lip dose (0.8 nmol g^-1 PcSA) and light dose (30 J cm^-2). Therefore, the liposomal PcSA@Lip is a prospective nanophotosensitizer possessing hybrid type I and type II photoreactions with efficient photodynamic anticancer effects.

Insight on nano drug delivery systems with targeted therapy in treatment of oral cancer

Oral cancer is a type of cancer that develops in the mouth and is one of the deadliest malignancies in the world. Currently surgical, radiation therapy, and chemotherapy are most common treatments. Better treatment and early detection strategies are required. Chemotherapeutic drugs fail frequently due to toxicity and poor tumor targeting. There are high chances of failure of chemotherapeutic drugs due to toxicity. Active, passive, and immunity-targeting techniques are devised for tumor-specific activity. Nanotechnology-based drug delivery systems are the best available solution and important for precise targeting. Nanoparticles, liposomes, exosomes, and cyclodextrins are nano-based carriers for drug delivery. Nanotechnology is being used to develop new techniques such as intratumoral injections, microbubble mediated ultrasonic therapy, phototherapies, and site-specific delivery. This systematic review delves into the details of such targeted and nano-based drug delivery systems in order to improve patient health and survival rates in oral cancer.

Synthesis, Cellular Uptake, and Photodynamic Activity of Oligogalactosyl Zinc(II) Phthalocyanines

A series of di-α-substituted zinc(II) phthalocyanines with different number of galactose moieties, ranging from 1 to 8, namely Pc-gal_n (n=1, 2, 4, and 8) were designed and synthesized. The synthesis involved the copper-catalyzed azide-alkyne cycloaddition reaction of a mono- or dialkynyl zinc(II) phthalocyanine with an acetyl-protected galactosyl azide or its dendritic derivative with four acetyl-protected galactosyl groups, followed by removal of the acetyl protecting groups via alkaline hydrolysis. In N,N-dimethylformamide, these oligogalactosyl phthalocyanines were non-aggregated as shown by the strong Q-band absorption and fluorescence emission. Owing to the di-α-substitution, they also behaved as efficient singlet oxygen generators upon light irradiation with a singlet oxygen quantum yield of 0.84. The spectroscopic and photophysical properties were not affected by the number of galactosyl units. In contrast, the compounds became significantly aggregated and quenched in phosphate-buffered saline. Their cellular uptake was then studied using a range of cell lines, which generally followed the order Pc-gal₁ >Pc-gal₂ ≈Pc-gal₄ >Pc-gal₈ . Interestingly, the di-galactosyl analogue exhibited selective uptake against HeLa human cervical carcinoma cells through an energy-dependent pathway instead of the expected asialoglycoprotein receptor. Upon light irradiation, it could effectively kill the cells with a half-maximal inhibitory concentration of 0.58 μM.

Rose bengal-decorated rice husk-derived silica nanoparticles enhanced singlet oxygen generation for antimicrobial photodynamic inactivation

Rice husks are well known for their high silica content, and the RH-derived silica nanoparticles (RH NPs) are amorphous and biocompatible; therefore, they are suitable raw materials for biomedical applications. In this study, rose bengal-impregnated rice husk nanoparticles (RB-RH NPs) were prepared for their potential photosensitization and ¹O₂ generation as antimicrobial photodynamic inactivation. RB is a halogen-xanthene type's photosensitizer showing high singlet oxygen efficiency, and the superior photophysical properties are desirable for RB in the antimicrobial photodynamic inactivation of bacteria. To enhance the binding of anionic RB to RH NPs, we conducted cationization for the RH NPs using polyethyleneimine (PEI). The control of the RB adsorption state on cationic PEI-modified RH NPs was essential for RB RH-NP photosensitizers to obtain efficient ¹O₂ generation. Minimizing RB aggregation allowed highly efficient ¹O₂ production from RB-RH NPs at the molar ratio of RB with the PEI, X_RB/PEI. = 0.1. The RB-RH NPs have significant antimicrobial activity against Streptococcus mutans compared to free RB after white light irradiation. The RB-RH NP-based antimicrobial photodynamic inactivation can be employed effectively in treating Streptococcus mutans for dental applications.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10853-023-08194-z.

Comparative Analysis of Tetra(2-naphthyl)tetracyano-porphyrazine and Its Iron Complex as Photosensitizers for Anticancer Photodynamic Therapy

Photodynamic therapy (PDT) is a rapidly developing modality of primary and adjuvant anticancer treatment. The main trends today are the search for new effective photodynamic agents and the creation of targeted delivery systems with the function of controlling the release of the agent in the tumor. Recently, the new group of cyanoarylporphyrazine dyes was reported, which combine the properties of photosensitizers and sensors of the local microenvironment. Such unique characteristics allow the release of the photosensitizer from the transport carrier to be assessed in real time in vivo. The aim of the present work was to compare the photophysical and photobiological properties of tetra(2-naphthyl)tetracyanoporphyrazine and its newly synthesized Fe(II) complex. We have shown that the chelation of the Fe(II) cation with the porphyrazine macrocycle leads to a decrease in molar extinction and an increase in the quantum yield of fluorescence and photostability. We demonstrate that the iron cation significantly affects the rate of dye accumulation in cells, the dark toxicity and photodynamic activity, and the direction of the changes depends on the particular cell line. However, in all the cases, the photodynamic index of a metal complex was higher than that of a metal-free base. In general, both of the compounds were found to be very promising for PDT, including for the use with transport delivery systems, and can be recommended for further in vivo studies.

Nanomaterials-mediated photodynamic therapy and its applications in treating oral diseases

Oral diseases, such as dental caries, periodontitis and oral cancer, have a very high morbidity over the world. Basically, many oral diseases are commonly related to bacterial infections or cell malignant proliferation, and usually located on the superficial positions. These features allow the convenient and efficient application of photodynamic therapy (PDT) for oral diseases, since PDT is ideally suitable for the diseases on superficial sites and has been widely used for antimicrobial and anticancer therapy. Photosensitizers (PSs) are an essential element in PDT, which induce the generation of a large number of reactive oxygen species (ROS) upon absorption of specific lights. Almost all the PSs are small molecules and commonly suffered from various problems in the PDT environment, such as low solubility and poor stability. Recently, reports on the nanomedicine-based PDT have been well documented. Various functionalized nanomaterials can serve either as the PSs carriers or the direct PSs, thus enhancing the PDT efficacy. Herein, we aim to provide a comprehensive understanding of the features of different oral diseases and discuss the potential applications of nanomedicine-based PDT in the treatment of some common oral diseases. Also, the concerns and possible solutions for nanomaterials-mediated PDT are discussed.

Development of Biotechnological Photosensitizers for Photodynamic Therapy: Cancer Research and Treatment-From Benchtop to Clinical Practice

Photodynamic therapy (PDT) is a noninvasive therapeutic approach that has been applied in studies for the treatment of various diseases. In this context, PDT has been suggested as a new therapy or adjuvant therapy to traditional cancer therapy. The mode of action of PDT consists of the generation of singlet oxygen (¹O₂) and reactive oxygen species (ROS) through the administration of a compound called photosensitizer (PS), a light source, and molecular oxygen (³O₂). This combination generates controlled photochemical reactions (photodynamic mechanisms) that produce ROS, such as singlet oxygen (¹O₂), which can induce apoptosis and/or cell death induced by necrosis, degeneration of the tumor vasculature, stimulation of the antitumor immune response, and induction of inflammatory reactions in the illuminated region. However, the traditional compounds used in PDT limit its application. In this context, compounds of biotechnological origin with photosensitizing activity in association with nanotechnology are being used in PDT, aiming at its application in several types of cancer but with less toxicity toward neighboring tissues and better absorption of light for more aggressive types of cancer. In this review, we present studies involving innovatively developed PS that aimed to improve the efficiency of PDT in cancer treatment. Specifically, we focused on the clinical translation and application of PS of natural origin on cancer.