Intraperitoneal photodynamic therapy mediated by a fullerene in a mouse model of abdominal dissemination of colon adenocarcinoma

Phonozen-mediated photodynamic therapy comparing two wavelengths in a mouse model of peritoneal carcinomatosis

BACKGROUND

This study assessed the therapeutic efficacy of intraperitoneal photodynamic therapy (PDT) using photosensitizer activation at two different wavelengths, 405 and 664 nm, in a mouse model of peritoneal carcinomatosis.

METHODS

The dark and light cytotoxicity of chlorin e6-polyvinylpyrrolidone (Phonozen) were measured in vitro under 402 ± 14 and 670 ± 18 nm LED activation in bioluminescent human gastric cancer cells, MKN45-luc. Cell viability was measured at 6 h after irradiation using the PrestoBlue assay. Corresponding in vivo studies were performed in athymic nude mice by intraperitoneal injection of 1 × 106 MKN45-luc cells. PDT was performed 10 d after tumor induction and comprised intraperitoneal injection of Phonozen followed by light irradiation at 3 h, delivered by a diffusing-tip optical fiber placed in the peritoneal cavity and coupled to a 405 or 664 nm diode laser to deliver a total energy of 50 J (20 mice per cohort). Whole-body bioluminescence imaging was used to track the tumor burden after PDT out to 130 days, and 5 mice in each cohort were sacrificed at 4 h post treatment to measure the acute tumor necrosis.

RESULTS

Photosensitizer dose-dependent photocytotoxicity was higher in vitro at 405 than 664 nm. In vivo, PDT reduced the tumor growth rate at both wavelengths, with no statistically significant difference. There was substantial necrosis, and median survival was significantly prolonged at both wavelengths compared with controls (46 and 46 vs. 34 days).

CONCLUSIONS

Phonozen-mediated PDT results in significant cytotoxicity in vitro as well as tumor necrosis and prolonged survival in vivo following intraperitoneal light irradiation. Blue light was more photocytotoxic than red in vitro and had marginally higher efficacy in vivo.

Carbon nanomaterials for phototherapy

Phototherapy attracts increasing interest for broad bio-applications due to its noninvasive and highly selective nature. Owing to their good biocompatibility, unique optoelectronic properties and size/surface effects, carbon nanomaterials show great promise for phototherapy. Various carbon nanomaterials have been demonstrated as efficient phototherapy agents for a large variety of phototherapeutic applications, including cancer treatment, anti-bacteria, and Alzheimer's disease. This review summarizes the recent progress of carbon nanomaterials for phototherapy. Current challenges and future perspectives are also discussed.

New Generation of Photosensitizers Based on Inorganic Nanomaterials

Advance of nanomaterials and nanotechnology has offered new possibilities for photodynamic therapy (PDT). Large amount of different kinds of sensitizers and targeting moieties can now be loaded in nanometer's volume, which not only results in the improvement of the efficacy of PDT, but also enables the control of image-guided PDT with unprecedented precision and variation. This chapter shall overview the recently most studied inorganic nanomaterials for PDT.

Symphony of nanomaterials and immunotherapy based on the cancer-immunity cycle

The immune system is involved in the initiation and progression of cancer. Research on cancer and immunity has contributed to the development of several clinically successful immunotherapies. These immunotherapies often act on a single step of the cancer–immunity cycle. In recent years, the discovery of new nanomaterials has dramatically expanded the functions and potential applications of nanomaterials. In addition to acting as drug-delivery platforms, some nanomaterials can induce the immunogenic cell death (ICD) of cancer cells or regulate the profile and strength of the immune response as immunomodulators. Based on their versatility, nanomaterials may serve as an integrated platform for multiple drugs or therapeutic strategies, simultaneously targeting several steps of the cancer–immunity cycle to enhance the outcome of anticancer immune response. To illustrate the critical roles of nanomaterials in cancer immunotherapies based on cancer–immunity cycle, this review will comprehensively describe the crosstalk between the immune system and cancer, and the current applications of nanomaterials, including drug carriers, ICD inducers, and immunomodulators. Moreover, this review will provide a detailed discussion of the knowledge regarding developing combinational cancer immunotherapies based on the cancer–immunity cycle, hoping to maximize the efficacy of these treatments assisted by nanomaterials.

Antimicrobial photodynamic therapeutic effects of cationic amino acid-porphyrin conjugate 4i on Porphyromonas gingivalis in vitro

BACKGROUND

Porphyromonas gingivalis (P. gingivalis) is considered to be among the principal pathogens in periodontal disease. The present study aimed to investigate the effect of antimicrobial photodynamic therapy (aPDT) mediated by cationic amino acid-porphyrin conjugate 4i on P. gingivalis METHODS: The uptake of 4i by P. gingivalis over different times of incubation was evaluated by optical density using a microplate reader. Laser radiation at λ=650nm-660nm with I =50 mW/cm² at doses of 0, 3.0, 6.0, 9.0, and 12 J/cm² was used for aPDT. A colony-counting method and confocal laser scanning microscopy (CLSM) were used to observe the neutralization of P. gingivalis. The fluorescent molecular probe 3'(p-hydroxyphenyl)-fluorescein and the reagent Singlet Oxygen Sensor Green were used to measure the quantities of •OH and ¹O₂ produced by 4i after irradiation with different light energies.

RESULTS

The 4i conjugate was absorbed gradually by P. gingivalis, reaching a maximum at 30 min. A clear cytotoxic effect on P. gingivalis was observed with aPDT using 62.5 µM 4i, with colony counts dropping by a factor of 3.35 log₁₀, indicating a sterilization rate of 99.95%. Light irradiation resulted principally in the production of • OHby 4i. A live/dead viability assay demonstrated substantial red fluorescence in P. gingivalis treated with aPDT.

CONCLUSIONS

The results suggest that 4i-aPDT caused substantial cytotoxicity in P. gingivalis.

Gynecologic cancers and non-coding RNAs: Epigenetic regulators with emerging roles

Gynecologic cancers involve the female genital organs, such as the vulva, vagina, cervix, endometrium, ovaries, and fallopian tubes. The occurrence and frequency of gynecologic cancer depends on personal lifestyle, history of exposure to viruses or carcinogens, genetics, body shape, and geographical habitat. For a long time, research into the molecular biology of cancer was broadly restricted to protein-coding genes. Recently it has been realized that non-coding RNAs (ncRNA), including long noncoding RNAs (LncRNAs), microRNAs, circular RNAs and piRNAs (PIWI-interacting RNAs), can all play a role in the regulation of cellular function within gynecological cancer. It is now known that ncRNAs are able to play dual roles, i.e. can exert both oncogenic or tumor suppressive functions in gynecological cancer. Moreover, several clinical trials are underway looking at the biomarker and therapeutic roles of ncRNAs. These efforts may provide a new horizon for the diagnosis and treatment of gynecological cancer. Herein, we summarize some of the ncRNAs that have been shown to be important in gynecological cancers.

Photodynamic Diagnosis and Therapy for Peritoneal Carcinomatosis from Gastrointestinal Cancers: Status, Opportunities, and Challenges

Selective accumulation of a photosensitizer and the subsequent response in only the light-irradiated target are advantages of photodynamic diagnosis and therapy. The limited depth of the therapeutic effect is a positive characteristic when treating surface malignancies, such as peritoneal carcinomatosis. For photodynamic diagnosis (PDD), adjunctive use of aminolevulinic acid- protoporphyrin IX-guided fluorescence imaging detects cancer nodules, which would have been missed during assessment using white light visualization only. Furthermore, since few side effects have been reported, this has the potential to become a vital component of diagnostic laparoscopy. A variety of photosensitizers have been examined for photodynamic therapy (PDT), and treatment protocols are heterogeneous in terms of photosensitizer type and dose, photosensitizer-light time interval, and light source wavelength, dose, and dose rate. Although several studies have suggested that PDT has favorable effects in peritoneal carcinomatosis, clinical trials in more homogenous patient groups are required to identify the true benefits. In addition, major complications, such as bowel perforation and capillary leak syndrome, need to be reduced. In the long term, PDD and PDT are likely to be successful therapeutic options for patients with peritoneal carcinomatosis, with several options to optimize the photosensitizer and light delivery parameters to improve safety and efficacy.

Photodynamic Nanophotosensitizers: Promising Materials for Tumor Theranostics

Photodynamic theranostics/therapy (PDT) is a potential strategy for selectively imaging malignant sites and treating cancer via a non-invasive therapeutic method. Photosensitizers, the crucial components of PDT, enable colocalization of photons and light, and photon/light therapy in the therapeutic window of 400-900 nm exhibits photocytotoxicity to tumor cells. Due to their high biostability and photocytotoxicity, nanophotosensitizers (NPSs) are of much interest for malignant tumor theranostics at present. NPS-activated photons transfer energy through the absorption of a photon and convert molecular oxygen to the singlet reactive oxygen species, which leads to apoptosis and necrosis. Moreover, NPSs modified by polymers, including PLGA, PEG-PLA, PDLLA, PVCL-g-PLA, and P(VCL-co-VIM)-g-PLA, exhibit excellent biocompatibility, and a tumor-targeting molecule linked on the nanoparticle surface can precisely deliver NPSs into the tumor region. The development of NPSs will accelerate the progress in tumor theranostics through the photon/light pathway.

Evaluation of the Biodistribution of Serinolamide-Derivatized C60 Fullerene

Carbon nanoparticles have consistently been of great interest in medicine. However, there are currently no clinical materials based on carbon nanoparticles, due to inconsistent biodistribution and excretion data. In this work, we have synthesized a novel C60 derivative with a metal chelating agent (1,4,7-Triazacyclononane-1,4,7-triacetic acid; NOTA) covalently bound to the C60 cage and radiolabeled with copper-64 (t1/2 = 12.7 h). Biodistribution of the material was assessed in vivo using positron emission tomography (PET). Bingel-Hirsch chemistry was employed to functionalize the fullerene cage with highly water-soluble serinolamide groups allowing this new C60 conjugate to clear quickly from mice almost exclusively through the kidneys. Comparing the present results to the larger context of reports of biocompatible fullerene derivatives, this work offers an important evaluation of the in vivo biodistribution, using experimental evidence to establish functionalization guidelines for future C60-based biomedical platforms.

The pharmaceutical multi-activity of metallofullerenol invigorates cancer therapy

Currently, cancer continues to afflict humanity. The direct destruction and killing of tumor cells by surgery, radiation and chemotherapy gives rise to many side effects and compromised efficacy. Encouragingly, the rapid development of nanotechnology offers attractive opportunities to revolutionize the current situation of cancer therapy. Metallofullerenol Gd@C82(OH)22, in contrast to chemotherapeutics that directly kill tumor cells, demonstrates anti-tumor behavior with high efficiency and low toxicity by modulating the tumor microenvironment. Furthermore, Gd@C82(OH)22 has been recently reported to specifically target cancer stem cells. In this review, we give a concise introduction to the development of the fullerene family and then report the anti-tumor activity of Gd@C82(OH)22 based on its unique physicochemical characteristics, followed by a comprehensive summary of the anti-tumor biological mechanisms which target different components of the tumor microenvironment as well as the biodistribution and toxicity of Gd@C82(OH)22. Finally, we describe Gd@C82(OH)22 as a "particulate medicine" to highlight its distinctions from conventional "molecular medicine", with considerable emphasis on the advantages of nanomedicine. The in-depth investigation of Gd@C82(OH)22 undoubtedly provides a constructive reference for the development of other nanomedicines, especially in the fullerene family. The application of nanotechnology in the medical field definitely provides a promising and favorable future for improving the current status of cancer therapy.

Phototoxicity Generated by Silicon Quantum Dot Nanoparticles on Zebrafish Embryos

We demonstrate phototoxicity generated by silicon quantum dot nanoparticles (SiQDNPs) using zebrafish as an animal model. Having long exciton lifetime, the SiQDNPs can function as photosensitizers which absorb incident optical light and transfer the energy to oxygen molecules in close proximity, generating cytotoxic singlet oxygens. First, the zebrafish embryos were soaked in the SiQDNP suspension in E3 medium, while being illuminated under blue light or kept in the dark for 6 h. Through neutral red staining immediately afterward, the illuminated embryos showed more prominent injuries at their head, yolk sac and tail parts than those in the dark. Furthermore, prolonged observation after the treatment revealed that the illuminated embryos had mortality rates significantly higher than those without illumination, clearly showing the phototoxicity effect generated by the SiQDNPs. However, adverse effect due to the immersion of whole embryos in the SiQDNP suspension was also observed. To alleviate this issue, minute amounts of the SiQDNPs were microinjected to the embryos, followed by blue light illumination. By acridine orange staining subsequently, cell apoptosis localized near the microinjection site was revealed, whereas no apoptosis was found for those also microinjected with the SiQDNPs but without illumination. The phototoxicity effect demonstrated on zebrafish embryos in this work manifests the potential of using the SiQDNPs as a photosensitizer for photodynamic therapy.

Microgels in biomaterials and nanomedicines

Microgels are colloidal particles with crosslinked polymer networks and dimensions ranging from tens of nanometers to micrometers. Specifically, smart microgels are fascinating capable of responding to biological signals in vivo or remote triggers and making the possible for applications in biomaterials and biomedicines. Therefore, how to fundamentally design microgels is an urgent problem to be solved. In this review, we put forward our important fundamental opinions on how to devise the intelligent microgels for cancer therapy, biosensing and biological lubrication. We focus on the design ideas instead of specific implementation process by employing reverse synthesis analysis to programme the microgels at the original stage. Moreover, special insights will be, for the first time, as far as we know, dedicated to the particles completely composed of DNA or proteins into microgel systems. These are discussed in detail in this review. We expect to give readers a broad overview of the design criteria and practical methodologies of microgels according to the application fields, as well as to propel the further developments of highly interesting concepts and materials.

Recent Advances in Carbon Nanomaterials for Cancer Phototherapy

Carbon nanomaterials have received great attention from the scientific community over the past few decades because of their unique physical and chemical properties. In this minireview, we will summarize the recent progress of the use of various carbon nanomaterials in the field of cancer phototherapy. The structural characteristics of each category and the surface functionalization strategies of these nanomaterials will be briefly introduced before focusing on their therapeutic applications. Recent advances on their use in photothermal therapy, photodynamic therapy, and combined phototherapies are presented. Moreover, a few challenges and perspectives on the development of carbon nanomaterials for future theranostics are also discussed.

Photodynamic therapy and photothermal therapy for the treatment of peritoneal metastasis: a systematic review

Background

The aim of this review was to analyze preclinical studies and clinical trials evaluating photodynamic therapy (PDT), and photothermal therapy (PTT) in peritoneal metastasis (PM) treatment.

Content

Systematic review according PRISMA guidelines. Electronic searches using PubMed and Clinical Trials.

Summary

A total of 19 preclinical studies analyzing PDT in PM treatment were included. Each new generations of photosensitizers (PS) permitted to improve tumoral targeting. Phase III preclinical studies showed an important tumoral biodistribution (ratio 9.6 vs normal tissue) and significant survival advantage (35.5 vs 52.5 days for cytoreductive surgery vs cytoreductive surgery+PDT, p<0.005). Height clinical trials showed important side effects (capillary leak syndrome and bowel perforation), mainly explained by low tumor-selectivity of the PS used (first generation mainly).

Peritoneal mesothelioma apparition with carbon nanotubes first limited the development of PTT. But gold nanoparticles, with a good tolerance, permitted a limitation of tumoral growth (reduction of bioluminescence to 37 % 20 days after PTT), and survival benefit (35, 32, and 26 days for PTT with cisplatine, PTT alone and laser alone, respectively).

Outlook

Recent improvement in tumor-selectivity and light delivery systems is promising but further development would be necessary before PDT and PTT routinely applied for peritoneal carcinomatosis.

Fullerenes as photosensitizers in photodynamic therapy: pros and cons

One class of carbon nanomaterials is the closed cages known as fullerenes. The first member to be discovered in 1985 was C60, called "buckminsterfullerene" as its cage structure resembled a geodesic dome. Due to their extended π-conjugation they absorb visible light, possess a high triplet yield and can generate reactive oxygen species upon illumination, suggesting a possible role of fullerenes in photodynamic therapy (PDT). Pristine C60 is highly hydrophobic and prone to aggregation, necessitating functionalization to provide aqueous solubility and biocompatibility. The most common functional groups attached are anionic (carboxylic or sulfonic acids) or cationic (various quaternary ammonium groups). Depending on the functionalization, these fullerenes can be designed to be taken up into cancer cells, or to bind to microbial cells (Gram-positive, Gram-negative bacteria, fungi). Fullerenes can be excited with a wide range of wavelengths, UVA, blue, green or white light. We have reported a series of functionalized fullerenes (C60, C70, C82) with attached polycationic chains and additional light-harvesting antennae that can be used in vitro and in animal models of localized infections. Advantages of fullerenes as photosensitizers are: (a) versatile functionalization; (b) light-harvesting antennae; (c) ability to undergo Type 1, 2, and 3 photochemistry; (d) electron transfer can lead to oxygen-independent photokilling; (e) antimicrobial activity can be potentiated by inorganic salts; (f) can self-assemble into supramolecular fullerosomes; (g) components of theranostic nanoparticles; (h) high resistance to photobleaching. Disadvantages include: (a) highly hydrophobic and prone to aggregation; (b) overall short wavelength absorption; (c) relatively high molecular weight; (d) paradoxically can be anti-oxidants; (e) lack of fluorescence emission for imaging.

C60 fullerene accumulation in human leukemic cells and perspectives of LED-mediated photodynamic therapy

Recent progress in nanobiotechnology has attracted interest to a biomedical application of the carbon nanostructure C₆₀ fullerene since it possesses a unique structure and versatile biological activity. C₆₀ fullerene potential application in the frame of cancer photodynamic therapy (PDT) relies on rapid development of new light sources as well as on better understanding of the fullerene interaction with cells. The aim of this study was to analyze C₆₀ fullerene effects on human leukemic cells (CCRF-CEM) in combination with high power single chip light-emitting diodes (LEDs) light irradiation of different wavelengths: ultraviolet (UV, 365 nm), violet (405 nm), green (515 nm) and red (632 nm). The time-dependent accumulation of fullerene C₆₀ in CCRF-CEM cells up to 250 ng/10⁶ cells at 24 h with predominant localization within mitochondria was demonstrated with immunocytochemical staining and liquid chromatography mass spectrometry. In a cell viability assay we studied photoexcitation of the accumulated C₆₀ nanostructures with ultraviolet or violet LEDs and could prove that significant phototoxic effects did arise. A less pronounced C₆₀ fullerene phototoxic effect was observed after irradiation with green, and no effect was detected with red light. A C₆₀ fullerene photoactivation with violet light induced substantial ROS generation and apoptotic cell death, confirmed by caspase3/7 activation and plasma membrane phosphatidylserine externalization. Our work proved C₆₀ fullerene ability to induce apoptosis of leukemic cells after photoexcitation with high power single chip 405 nm LED as a light source. This underlined the potential for application of C₆₀ nanostructure as a photosensitizer for anticancer therapy.

Treatment of peritoneal carcinomatosis with photodynamic therapy: Systematic review of current evidence

BACKGROUND

Peritoneal carcinomatosis results when tumour cells implant and grow within the peritoneal cavity. Treatment and prognosis vary based on the primary cancer. Although therapy with intention-to-cure is offered to selective patients using cytoreductive surgery with chemotherapy, the prognosis remains poor for most of the patients. Photodynamic therapy (PDT) is a cancer-therapeutic modality where a photosensitiser is administered to patients and exerts a cytotoxic effect on cancer cells when excited by light of a specific wavelength. It has potential application in the treatment of peritoneal carcinomatosis.

METHODS

We systematically reviewed the evidence of using PDT to treat peritoneal carcinomatosis in both animals and humans (Medline/EMBASE searched in June 2017).

RESULTS

Three human and 25 animal studies were included. Phase I and II human trials using first-generation photosensitisers showed that applying PDT after surgical debulking in patients with peritoneal carcinomatosis is feasible with some clinical benefits. The low tumour-selectivity of the photosensitisers led to significant toxicities mainly capillary leak syndrome and bowel perforation. In animal studies, PDT improved survival by 15-300%, compared to control groups. PDT led to higher tumour necrosis values (categorical values 0-4 [4=highest]: PDT 3.4±1.0 vs. control 0.4±0.6, p<0.05) and reduced tumour size (residual tumour size is 10% of untreated controls, p<0.001).

CONCLUSION

PDT has potential in treating peritoneal carcinomatosis, but is limited by its narrow therapeutic window and possible serious side effects. Recent improvement in tumour-selectivity and light delivery systems is promising, but further development is needed before PDT can be routinely applied for peritoneal carcinomatosis.

Green Processing of Carbon Nanomaterials

Carbon nanomaterials (CNMs) from fullerenes, carbon nanotubes, and graphene are promising carbon allotropes for various applications such as energy-conversion devices and biosensors. Because pristine CNMs show substantial van der Waals interactions and a hydrophobic nature, precipitation is observed immediately in most organic solvents and water. This inevitable aggregation leads to poor processability and diminishes the intrinsic properties of the CNMs. Highly toxic and hazardous chemicals are used for chemical and physical modification of CNMs, even though efficient dispersed solutions are obtained. The development of an environmentally friendly dispersion method for both safe and practical processing is a great challenge. Recent green processing approaches for the manipulation of CNMs using chemical and physical modification are highlighted. A summary of the current research progress on: i) energy-efficient and less-toxic chemical modification of CNMs using covalent-bonding functionality and ii) non-covalent-bonding methodologies through physical modification using green solvents and dispersants, and chemical-free mechanical stimuli is provided. Based on these experimental studies, recent advances and challenges for the potential application of green-processable energy-conversion and biological devices are provided. Finally, a conclusion section is provided summarizing the insights from the present studies as well as some future perspectives.

Recent advances in carbon based nanosystems for cancer theranostics

This review deals with four different types of carbon allotrope based nanosystems and summarizes the results of recent studies that are likely to have applications in cancer theranostics. We discuss the applications of these nanosystems for cancer imaging, drug delivery, hyperthermia, and PDT/TA/PA.

C60@lysozyme: a new photosensitizing agent for photodynamic therapy

C₆₀@lysozyme showed significant visible light-induced singlet oxygen generation in a physiological environment, indicating the potential of this hybrid as an agent for photodynamic therapy.

Carbon-Based Materials for Photo-Triggered Theranostic Applications

Carbon-based nanomaterials serve as a type of smart material for photo-triggered disease theranostics. The inherent physicochemical properties of these nanomaterials facilitate their use for less invasive treatments. This review summarizes the properties and applications of materials including fullerene, nanotubes, nanohorns, nanodots and nanographenes for photodynamic nanomedicine in cancer and antimicrobial therapies. Carbon nanomaterials themselves do not usually act as photodynamic therapy (PDT) agents owing to the high hydrophobicity, however, when the surface is passivated or functionalized, these materials become great vehicles for PDT. Moreover, conjugation of carbonaceous nanomaterials with the photosensitizer (PS) and relevant targeting ligands enhances properties such as selectivity, stability, and high quantum yield, making them readily available for versatile biomedical applications.

Targeted and effective photodynamic therapy for cancer using functionalized nanomaterials

Photodynamic therapy (PDT) is an emerging, non-invasive therapeutic strategy that involves photosensitizer (PS) drugs and external light for the treatment of diseases. Despite the great progress in PS-mediated PDT, their clinical applications are still hampered by poor water solubility and tissue/cell specificity of conventional PS drugs. Therefore, great efforts have been made towards the development of nanomaterials that can tackle fundamental challenges in conventional PS drug-mediated PDT for cancer treatment. This review highlights recent advances in the development of nano-platforms, in which various functionalized organic and inorganic nanomaterials are integrated with PS drugs, for significantly enhanced efficacy and tumor-selectivity of PDT.

New photosensitizers for photodynamic therapy

Photodynamic therapy (PDT) was discovered more than 100 years ago, and has since become a well-studied therapy for cancer and various non-malignant diseases including infections. PDT uses photosensitizers (PSs, non-toxic dyes) that are activated by absorption of visible light to initially form the excited singlet state, followed by transition to the long-lived excited triplet state. This triplet state can undergo photochemical reactions in the presence of oxygen to form reactive oxygen species (including singlet oxygen) that can destroy cancer cells, pathogenic microbes and unwanted tissue. The dual-specificity of PDT relies on accumulation of the PS in diseased tissue and also on localized light delivery. Tetrapyrrole structures such as porphyrins, chlorins, bacteriochlorins and phthalocyanines with appropriate functionalization have been widely investigated in PDT, and several compounds have received clinical approval. Other molecular structures including the synthetic dyes classes as phenothiazinium, squaraine and BODIPY (boron-dipyrromethene), transition metal complexes, and natural products such as hypericin, riboflavin and curcumin have been investigated. Targeted PDT uses PSs conjugated to antibodies, peptides, proteins and other ligands with specific cellular receptors. Nanotechnology has made a significant contribution to PDT, giving rise to approaches such as nanoparticle delivery, fullerene-based PSs, titania photocatalysis, and the use of upconverting nanoparticles to increase light penetration into tissue. Future directions include photochemical internalization, genetically encoded protein PSs, theranostics, two-photon absorption PDT, and sonodynamic therapy using ultrasound.

Stimuli-responsive nanogel composites and their application in nanomedicine

Nanogels are nanosized crosslinked polymer networks capable of absorbing large quantities of water. Specifically, smart nanogels are interesting because of their ability to respond to biomedically relevant changes like pH, temperature, etc. In the last few decades, hybrid nanogels or composites have been developed to overcome the ever increasing demand for new materials in this field. In this context, a hybrid refers to nanogels combined with different polymers and/or with nanoparticles such as plasmonic, magnetic, and carbonaceous nanoparticles, among others. Research activities are focused nowadays on using multifunctional hybrid nanogels in nanomedicine, not only as drug carriers but also as imaging and theranostic agents. In this review, we will describe nanogels, particularly in the form of composites or hybrids applied in nanomedicine.

Photodynamic Therapy with Hexa(sulfo-n-butyl)[60]Fullerene Against Sarcoma In Vitro and In Vivo

The hydrophilic molecular micellar hexa(sulfo-n-butyl)[60]fullerene (FC₄S), first synthesized in 1998 as a photosensitizer (PS) has been reported to exhibit high efficacy for singlet oxygen generation and antimicrobial photodynamic inactivation. The purpose of this study was to investigate the effects of photoactivated FC₄S for free radical generation and to mediate photodynamic therapy (PDT) of cancer in vitro and in vivo. The results demonstrated that following light irradiation, FC4S produced singlet oxygen, but after addition of electron donors such as ferrocytochrome c or NADH, FC4S also produced superoxide. The combination of FC4S with light irradiation was able to induce cytotoxicity to human fibrosarcoma cells and murine sarcoma 180 cells in vitro. Cell-killing was proportional to fluence as well as FC4S concentration. Photoirradiation by argon-ion laser after intraperitoneal injection of FC4S also resulted in inhibition of S180 tumor growth in vivo (up to 80% reduction of tumor volume). Hematological and blood biochemistry parameters of the cancer-bearing mice were improved by PDT. Based on these findings, we conclude that FC₄S has a great potential as a nanomedicine in PDT for cancer.

Nanotechnology for photodynamic therapy: a perspective from the Laboratory of Dr. Michael R. Hamblin in the Wellman Center for Photomedicine at Massachusetts General Hospital and Harvard Medical School

The research interests of the Hamblin Laboratory are broadly centered on the use of different kinds of light to treat many different diseases. Photodynamic therapy (PDT) uses the combination of dyes with visible light to produce reactive oxygen species and kill bacteria, cancer cells and destroy unwanted tissue. Likewise, UV light is also good at killing especially pathogens. By contrast, red or near-infrared light can have the opposite effect, to act to preserve tissue from dying and can stimulate healing and regeneration. In all these applications, nanotechnology is having an ever-growing impact. In PDT, self-assembled nano-drug carriers (micelles, liposomes, etc.) play a great role in solubilizing the photosensitizers, metal nanoparticles can carry out plasmon resonance enhancement, and fullerenes can act as photosensitizers, themselves. In the realm of healing, single-walled carbon nanotubes can be electrofocused to produce nano-electonic biomedical devices, and nanomaterials will play a great role in restorative dentistry.

Enhanced effect of photodynamic therapy in ovarian cancer using a nanoparticle drug delivery system

Nanoparticles are promising novel drug delivery carriers that allow tumor targeting and controlled drug release. In the present study, we prepared poly butyl-cyanoacrylate nanoparticles (PBCA-NP) entrapped with hypocrellin B (HB) to improve the effect of photodynamic therapy (PDT) in ovarian cancer. An ovarian cancer ascites model using Fischer 344 rats and PBCA-NP entrapped with HB (HB-PBCA-NP) were formed successfully. The pharmacodynamic characteristics and biodistribution of the HB-PBCA-NP system were evaluated by comparison with HB dimethyl sulfoxide (HB-DMSO) and testing at various time-points following intraperitoneal drug administration. HB-PBCA-NP-based PDT combined with cytoreductive surgery was then administrated to the tumor-bearing animals. Kaplan-Meier survival analysis was performed to assess the therapeutic effect of the nanoparticle system. The serum HB concentration peaked 4 h after drug administration in the nanoparticle system, and 1 h with HB-DMSO. The peak exposure time of tumor tissues was also extended (4 vs. 2 h), and PBCA-NP remained present for much longer than HB-DMSO. Although PDT combined with surgery prolonged the survival time significantly compared with surgery alone (84 days, P<0.05), there was no significant difference in the survival time of animals that received either HB-PBCA-NP- or HB-DMSO-based PDT after cytoreductive surgery (99 vs. 95 days, P=0.293). PBCA-NP exhibited potential advantages in controlled drug release and tumor targeting, which was beneficial for HB-based PDT. PDT combined with surgery prolonged the survival time, suggesting that this might be an alternative treatment option for ovarian cancer.

Functionalized fullerenes in photodynamic therapy

Since the discovery of C60 fullerene in 1985, scientists have been searching for biomedical applications of this most fascinating of molecules. The unique photophysical and photochemical properties of C60 suggested that the molecule would function well as a photosensitizer in photodynamic therapy (PDT). PDT uses the combination of non-toxic dyes and harmless visible light to produce reactive oxygen species that kill unwanted cells. However the extreme insolubility and hydrophobicity of pristine CO60, mandated that the cage be functionalized with chemical groups that provided water solubility and biological targeting ability. It has been found that cationic quaternary ammonium groups provide both these features, and this review covers work on the use of cationic fullerenes to mediate destruction of cancer cells and pathogenic microorganisms in vitro and describes the treatment of tumors and microbial infections in mouse models. The design, synthesis, and use of simple pyrrolidinium salts, more complex decacationic chains, and light-harvesting antennae that can be attached to C60, C70 and C84 cages are covered. In the case of bacterial wound infections mice can be saved from certain death by fullerene-mediated PDT.

In vivo studies of nanostructure-based photosensitizers for photodynamic cancer therapy

Animal models, particularly rodents, are major translational models for evaluating novel anticancer therapeutics. In this review, different types of nanostructure-based photosensitizers that have advanced into the in vivo evaluation stage for the photodynamic therapy (PDT) of cancer are described. This article focuses on the in vivo efficacies of the nanostructures as delivery agents and as energy transducers for photosensitizers in animal models. These materials are useful in overcoming solubility issues, lack of tumor specificity, and access to tumors deep in healthy tissue. At the end of this article, the opportunities made possible by these multiplexed nanostructure-based systems are summarized, as well as the considerable challenges associated with obtaining regulatory approval for such materials. The following questions are also addressed: (1) Is there a pressing demand for more nanoparticle materials? (2) What is the prognosis for regulatory approval of nanoparticles to be used in the clinic?

Development of nanoscale approaches for ovarian cancer therapeutics and diagnostics

Ovarian cancer is the deadliest of all gynecological cancers and the fifth leading cause of death due to cancer in women. This is largely due to late-stage diagnosis, poor prognosis related to advanced-stage disease, and the high recurrence rate associated with development of chemoresistance. Survival statistics have not improved significantly over the last three decades, highlighting the fact that improved therapeutic strategies and early detection require substantial improvements. Here, we review and highlight nanotechnology-based approaches that seek to address this need. The success of Doxil, a PEGylated liposomal nanoencapsulation of doxorubicin, which was approved by the FDA for use on recurrent ovarian cancer, has paved the way for the current wave of nanoparticle formulations in drug discovery and clinical trials. We discuss and summarize new nanoformulations that are currently moving into clinical trials and highlight novel nanotherapeutic strategies that have shown promising results in preclinical in vivo studies. Further, the potential for nanomaterials in diagnostic imaging techniques and the ability to leverage nanotechnology for early detection of ovarian cancer are also discussed.

Cytoreductive surgery under aminolevulinic acid-mediated photodynamic diagnosis plus hyperthermic intraperitoneal chemotherapy in patients with peritoneal carcinomatosis from ovarian cancer and primary peritoneal carcinoma: results of a phase I trial

Background

We conducted a phase I clinical trial to evaluate the sensitivity, specificity, and safety of cytoreductive surgery (CRS) under aminolevulinic acid-mediated photodynamic diagnosis (ALA-PDD) plus hyperthermic intraperitoneal chemotherapy (HIPEC) on 20 patients with peritoneal carcinomatosis (PC) from ovarian cancer and primary peritoneal carcinoma (PPC).

Patients and Methods

Patients took 5-aminolevulinic acid (5-ALA) at a dose of 20 mg/kg orally with 50 mL of water 2 h before surgery. During surgery, the abdominal cavity was observed under blue light (wavelength of 440 nm) before and after CRS plus HIPEC. Specimens were excised and submitted for pathological examination to evaluate the specificity of ALA-PDD. Postoperative course was closely monitored and detailed information was recorded.

Results

CRS under ALA-PDD plus HIPEC was performed 21 times in 20 patients with PC (16 ovarian cancer, 4 PPC) between June 2011 and October 2013. With the exception of 1 (5 %) patient, strong red fluorescence was detected in 19 patients with ovarian cancer, with a sensitivity of 95 %. All specimens from red fluorescent lesions were invaded by cancer cells, with a specificity of 100 %. No severe adverse events occurred during the perioperative period, with the exception of some abnormal laboratory results and mild complications. All patients were alive until the last follow-up.

Conclusion

ALA-PDD provided a high sensitivity and specificity in detecting peritoneal metastasis in patients with PC from ovarian serous carcinoma and PPC. CRS under ALA-PDD plus HIPEC was a feasible and safe treatment option for patients with PC from ovarian cancer and PPC.

Photodynamic therapy with decacationic [60]fullerene monoadducts: effect of a light absorbing electron-donor antenna and micellar formulation

We report the synthesis and anticancer photodynamic properties of two new decacationic fullerene (LC14) and red light-harvesting antenna-fullerene conjugated monoadduct (LC15) derivatives. The antenna of LC15 was attached covalently to C60>with distance of only <3.0 Ǻ to facilitate ultrafast intramolecular photoinduced-electron-transfer (for type-I photochemistry) and photon absorption at longer wavelengths. Because LC15 was hydrophobic we compared formulation in Cremophor EL micelles with direct dilution from dimethylacetamide. LC14 produced more (1)O2 than LC15, while LC15 produced much more HO·than LC14 as measured by specific fluorescent probes. When delivered by DMA, LC14 killed more HeLa cells than LC15 when excited by UVA light, while LC15 killed more cells when excited by white light consistent with the antenna effect. However LC15 was more effective than LC14 when delivered by micelles regardless of the excitation light. Micellar delivery produced earlier apoptosis and damage to the endoplasmic reticulum as well as to lysosomes and mitochondria.

FROM THE CLINICAL EDITOR

This team of authors report the synthesis and the photodynamic properties of two new derivatives for cancer treatment; one is a decacationic fullerene (LC14) and the other is a red light-harvesting antenna-fullerene conjugated monoadduct (LC15) utilizing a HeLa cell model.

Shining light on nanotechnology to help repair and regeneration

Phototherapy can be used in two completely different but complementary therapeutic applications. While low level laser (or light) therapy (LLLT) uses red or near-infrared light alone to reduce inflammation, pain and stimulate tissue repair and regeneration, photodynamic therapy (PDT) uses the combination of light plus non-toxic dyes (called photosensitizers) to produce reactive oxygen species that can kill infectious microorganisms and cancer cells or destroy unwanted tissue (neo-vascularization in the choroid, atherosclerotic plaques in the arteries). The recent development of nanotechnology applied to medicine (nanomedicine) has opened a new front of advancement in the field of phototherapy and has provided hope for the development of nanoscale drug delivery platforms for effective killing of pathological cells and to promote repair and regeneration. Despite the well-known beneficial effects of phototherapy and nanomaterials in producing the killing of unwanted cells and promoting repair and regeneration, there are few reports that combine all three elements i.e. phototherapy, nanotechnology and, tissue repair and regeneration. However, these areas in all possible binary combinations have been addressed by many workers. The present review aims at highlighting the combined multi-model applications of phototherapy, nanotechnology and, reparative and regeneration medicine and outlines current strategies, future applications and limitations of nanoscale-assisted phototherapy for the management of cancers, microbial infections and other diseases, and to promote tissue repair and regeneration.

Type I and Type II mechanisms of antimicrobial photodynamic therapy: an in vitro study on gram-negative and gram-positive bacteria

BACKGROUND AND OBJECTIVES

Antimicrobial photodynamic therapy (APDT) employs a non-toxic photosensitizer (PS) and visible light, which in the presence of oxygen produce reactive oxygen species (ROS), such as singlet oxygen ((1) O(2), produced via Type II mechanism) and hydroxyl radical (HO(.), produced via Type I mechanism). This study examined the relative contributions of (1) O(2) and HO(.) to APDT killing of Gram-positive and Gram-negative bacteria.

STUDY DESIGN/MATERIALS AND METHODS

Fluorescence probes, 3'-(p-hydroxyphenyl)-fluorescein (HPF) and singlet oxygen sensor green reagent (SOSG) were used to determine HO(.) and (1) O(2) produced by illumination of two PS: tris-cationic-buckminsterfullerene (BB6) and a conjugate between polyethylenimine and chlorin(e6) (PEI-ce6). Dimethylthiourea is a HO(.) scavenger, while sodium azide (NaN(3)) is a quencher of (1) O(2). Both APDT and killing by Fenton reaction (chemical generation of HO(.)) were carried out on Gram-positive bacteria (Staphylococcus aureus and Enterococcus faecalis) and Gram-negative bacteria (Escherichia coli, Proteus mirabilis, and Pseudomonas aeruginosa).

RESULTS

Conjugate PEI-ce6 mainly produced (1) O(2) (quenched by NaN(3)), while BB6 produced HO(.) in addition to (1) O(2) when NaN(3) potentiated probe activation. NaN(3) also potentiated HPF activation by Fenton reagent. All bacteria were killed by Fenton reagent but Gram-positive bacteria needed a higher concentration than Gram-negatives. NaN(3) potentiated Fenton-mediated killing of all bacteria. The ratio of APDT killing between Gram-positive and Gram-negative bacteria was 2 or 4:1 for BB6 and 25:1 for conjugate PEI-ce6. There was a NaN(3) dose-dependent inhibition of APDT killing using both PEI-ce6 and BB6 against Gram-negative bacteria while NaN(3) almost failed to inhibit killing of Gram-positive bacteria.

CONCLUSION

Azidyl radicals may be formed from NaN(3) and HO(.). It may be that Gram-negative bacteria are more susceptible to HO(.) while Gram-positive bacteria are more susceptible to (1) O(2). The differences in NaN(3) inhibition may reflect differences in the extent of PS binding to bacteria (microenvironment) or differences in penetration of NaN(3) into cell walls of bacteria.

Synthesis and photodynamic effect of new highly photostable decacationically armed [60]- and [70]fullerene decaiodide monoadducts to target pathogenic bacteria and cancer cells

Novel water-soluble decacationically armed C(60) and C(70) decaiodide monoadducts, C(60)- and C(70)[>M(C(3)N(6)(+)C(3))(2)], were synthesized, characterized, and applied as photosensitizers and potential nano-PDT agents against pathogenic bacteria and cancer cells. A high number of cationic charges per fullerene cage and H-bonding moieties were designed for rapid binding to the anionic residues displayed on the outer parts of bacterial cell walls. In the presence of a high number of electron-donating iodide anions as parts of quaternary ammonium salts in the arm region, we found that C(70)[>M(C(3)N(6)(+)C(3))(2)] produced more HO(•) than C(60)[>M(C(3)N(6)(+)C(3))(2)], in addition to (1)O(2). This finding offers an explanation of the preferential killing of Gram-positive and Gram-negative bacteria by C(60)[>M(C(3)N(6)(+)C(3))(2)] and C(70)[>M(C(3)N(6)(+)C(3))(2)], respectively. The hypothesis is that (1)O(2) can diffuse more easily into porous cell walls of Gram-positive bacteria to reach sensitive sites, while the less permeable Gram-negative bacterial cell wall needs the more reactive HO(•) to cause real damage.

Photodynamic therapy with fullerenes in vivo: reality or a dream?

Photodynamic therapy (PDT) employs the combination of nontoxic photosensitizers and visible light that is absorbed by the chromophore to produce long-lived triplet states that can carry out photochemistry in the presence of oxygen to kill cells. The closed carbon-cage structure found in fullerenes can act as a photosensitizer, especially when functionalized to impart water solubility. Although there are reports of the use of fullerenes to carry out light-mediated destruction of viruses, microorganisms and cancer cells in vitro, the use of fullerenes to mediate PDT of diseases such as cancer and infections in animal models is less well developed. It has recently been shown that fullerene PDT can be used to save the life of mice with wounds infected with pathogenic Gram-negative bacteria. Fullerene PDT has also been used to treat mouse models of various cancers including disseminated metastatic cancer in the peritoneal cavity. In vivo PDT with fullerenes represents a new application in nanomedicine.

Can nanotechnology potentiate photodynamic therapy?

Photodynamic therapy (PDT) uses the combination of non-toxic dyes and harmless visible light to produce reactive oxygen species that can kill cancer cells and infectious microorganisms. Due to the tendency of most photosensitizers (PS) to be poorly soluble and to form nonphotoactive aggregates, drug-delivery vehicles have become of high importance. The nanotechnology revolution has provided many examples of nanoscale drug-delivery platforms that have been applied to PDT. These include liposomes, lipoplexes, nanoemulsions, micelles, polymer nanoparticles (degradable and nondegradable), and silica nanoparticles. In some cases (fullerenes and quantum dots), the actual nanoparticle itself is the PS. Targeting ligands such as antibodies and peptides can be used to increase specificity. Gold and silver nanoparticles can provide plasmonic enhancement of PDT. Two-photon excitation or optical upconversion can be used instead of one-photon excitation to increase tissue penetration at longer wavelengths. Finally, after sections on in vivo studies and nanotoxicology, we attempt to answer the title question, "can nano-technology potentiate PDT?"

Applications of functionalized fullerenes in tumor theranostics

Functionalized fullerenes with specific physicochemical properties have been developed for cancer diagnosis and therapy. Notably, metallofullerene is a new class of magnetic resonance imaging (MRI) contrast-enhancing agent, and may have promising applications for clinical diagnosis. Polyhydroxylated and carboxyl fullerenes have been applied to photoacoustic imaging. Moreover, in recent years, functionalized fullerenes have shown potential in tumor therapies, such as photodynamic therapy, photothermal treatment, radiotherapy and chemotherapeutics. Their antitumor effects may be associated with the modulation of oxidative stress, anti-angiogenesis, and immunostimulatory activity. While various types of novel nanoparticle agents have been exploited in tumor theranostics, their distribution, metabolism and toxicity in organisms have also been a source of concern among researchers. The present review summarizes the potential of fullerenes as tumor theranostics agents and their possible underlying mechanisms are discussed.