Polymeric micelles for enhanced Photofrin II ® delivery, cytotoxicity and pro-apoptotic activity in human breast and ovarian cancer cells

Nanoparticles drug delivery for 5-aminolevulinic acid (5-ALA) in photodynamic therapy (PDT) for multiple cancer treatment: a critical review on biosynthesis, detection, and therapeutic applications

Photodynamic therapy (PDT) is a promising cancer treatment that kills cancer cells selectively by stimulating reactive oxygen species generation with photosensitizers exposed to specific light wavelengths. 5-aminolevulinic acid (5-ALA) is a widely used photosensitizer. However, its limited tumour penetration and targeting reduce its therapeutic efficacy. Scholars have investigated nano-delivery techniques to improve 5-ALA administration and efficacy in PDT. This review summarises recent advances in biological host biosynthetic pathways and regulatory mechanisms for 5-ALA production. The review also highlights the potential therapeutic efficacy of various 5-ALA nano-delivery modalities, such as nanoparticles, liposomes, and gels, in treating various cancers. Although promising, 5-ALA nano-delivery methods face challenges that could impair targeting and efficacy. To determine their safety and biocompatibility, extensive preclinical and clinical studies are required. This study highlights the potential of 5-ALA-NDSs to improve PDT for cancer treatment, as well as the need for additional research to overcome barriers and improve medical outcomes.

The Application of Nanoparticle-Based Imaging and Phototherapy for Female Reproductive Organs Diseases

Various female reproductive disorders affect millions of women worldwide and bring many troubles to women's daily life. Let alone, gynecological cancer (such as ovarian cancer and cervical cancer) is a severe threat to most women's lives. Endometriosis, pelvic inflammatory disease, and other chronic diseases-induced pain have significantly harmed women's physical and mental health. Despite recent advances in the female reproductive field, the existing challenges are still enormous such as personalization of disease, difficulty in diagnosing early cancers, antibiotic resistance in infectious diseases, etc. To confront such challenges, nanoparticle-based imaging tools and phototherapies that offer minimally invasive detection and treatment of reproductive tract-associated pathologies are indispensable and innovative. Of late, several clinical trials have also been conducted using nanoparticles for the early detection of female reproductive tract infections and cancers, targeted drug delivery, and cellular therapeutics. However, these nanoparticle trials are still nascent due to the body's delicate and complex female reproductive system. The present review comprehensively focuses on emerging nanoparticle-based imaging and phototherapies applications, which hold enormous promise for improved early diagnosis and effective treatments of various female reproductive organ diseases.

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.

Photodynamic inactivation of pathogenic Gram-negative and Gram-positive bacteria mediated by Si(IV) phthalocyanines bearing axial ammonium units

The photodynamic inactivation (PDI) of microorganisms has gained interest as an efficient option for conventional antibiotic treatments. Recently, Si(IV) phthalocyanines (SiPcs) have been highlighted as promising photosensitizers (PSs) to the PDI of microorganisms due to their remarkable absorption and emission features. To increase the potential of cationic SiPcs as PS drugs, one novel (1a) and two previously described (2a and 3a) axially substituted PSs with di-, tetra-, and hexa-ammonium units, respectively, were synthesized and characterized. Their PDI effect was evaluated for the first time against Escherichia coli and Staphylococcus aureus, a Gram-negative and a Gram-positive bacterium, respectively. The photodynamic treatments were conducted with PS concentrations of 3.0 and 6.0 μM under 60 min of white light irradiation (150 mW.cm^-2). The biological results show high photodynamic efficiency for di- and tetra-cationic PSs 1a and 2a (6.0 μM), reducing the E. coli viability in 5.2 and 3.9 log, respectively (after 15 min of dark incubation before irradiation). For PS 3a, a similar bacterial reduction (3.6 log) was achieved but only with an extended dark incubation period (30 min). Under the same experimental conditions, the photodynamic effect of cationic PSs 1a-3a on S. aureus was even more promising, with abundance reductions of ca. 8.0 log after 45-60 min of PDI treatment. These results reveal the high PDI efficiency of PSs bearing ammonium groups and suggest their promising application as a broad-spectrum antimicrobial to control infections caused by Gram-negative and Gram-positive bacteria.

Necroptosis-associated long noncoding RNAs can predict prognosis and differentiate between cold and hot tumors in ovarian cancer

Objective

The mortality rate of ovarian cancer (OC) is the highest among all gynecologic cancers. To predict the prognosis and the efficacy of immunotherapy, we identified new biomarkers.

Methods

The Cancer Genome Atlas (TCGA) and the Genotype-Tissue Expression Project (GTEx) databases were used to extract ovarian cancer transcriptomes. By performing the co-expression analysis, we identified necroptosis-associated long noncoding RNAs (lncRNAs). We used the least absolute shrinkage and selection operator (LASSO) to build the risk model. The qRT-PCR assay was conducted to confirm the differential expression of lncRNAs in the ovarian cancer cell line SK-OV-3. Gene Set Enrichment Analysis, Kaplan-Meier analysis, and the nomogram were used to determine the lncRNAs model. Additionally, the risk model was estimated to evaluate the efficacy of immunotherapy and chemotherapy. We classified necroptosis-associated IncRNAs into two clusters to distinguish between cold and hot tumors.

Results

The model was constructed using six necroptosis-associated lncRNAs. The calibration plots from the model showed good consistency with the prognostic predictions. The overall survival of one, three, and five-year areas under the ROC curve (AUC) was 0.691, 0.678, and 0.691, respectively. There were significant differences in the IC50 between the risk groups, which could serve as a guide to systemic treatment. The results of the qRT-PCR assay showed that AL928654.1, AL133371.2, AC007991.4, and LINC00996 were significantly higher in the SK-OV-3 cell line than in the Iose-80 cell line (P < 0.05). The clusters could be applied to differentiate between cold and hot tumors more accurately and assist in accurate mediation. Cluster 2 was more vulnerable to immunotherapies and was identified as the hot tumor.

Conclusion

Necroptosis-associated lncRNAs are reliable predictors of prognosis and can provide a treatment strategy by screening for hot tumors.

Rational Mitomycin Nanocarriers Based on Hydrophobically Functionalized Polyelectrolytes and Poly(lactide-co-glycolide)

Encapsulation of hydrophilic and amphiphilic drugs in appropriate colloidal carrier systems for sustained release is an emerging problem. In general, hydrophobic bioactive substances tend to accumulate in water-immiscible polymeric domains, and the release process is controlled by their low aqueous solubility and limited diffusion from the nanocarrier matrix. Conversely, hydrophilic/amphiphilic drugs are typically water-soluble and insoluble in numerous polymers. Therefore, a core-shell approach─nanocarriers comprising an internal core and external shell microenvironments of different properties─can be exploited for hydrophilic/amphiphilic drugs. To produce colloidally stable poly(lactic-co-glycolic) (PLGA) nanoparticles for mitomycin C (MMC) delivery and controlled release, a unique class of amphiphilic polymers─hydrophobically functionalized polyelectrolytes─were utilized as shell-forming materials, comprising both stabilization via electrostatic repulsive forces and anchoring to the core via hydrophobic interactions. Undoubtedly, the use of these polymeric building blocks for the core-shell approach contributes to the enhancement of the payload chemical stability and sustained release profiles. The studied nanoparticles were prepared via nanoprecipitation of the PLGA polymer and were dissolved in acetone as a good solvent and in an aqueous solution containing hydrophobically functionalized poly(4-styrenesulfonic-co-maleic acid) and poly(acrylic acid) of differing hydrophilic-lipophilic balance values. The type of the hydrophobically functionalized polyelectrolyte (HF-PE) was crucial for the chemical stability of the payload─derivatives of poly(acrylic acid) were found to cause very rapid degradation (hydrolysis) of MMC, in contrast to poly(4-styrenesulfonic-co-maleic acid). The present contribution allowed us to gain crucial information about novel colloidal nanocarrier systems for MMC delivery, especially in the fields of optimal HF-PE concentrations, appropriate core and shell building materials, and the colloidal and chemical stability of the system.

Biocompatible Nanocarriers for Enhanced Cancer Photodynamic Therapy Applications

In recent years, the role of nanotechnology in drug delivery has become increasingly important, and this field of research holds many potential benefits for cancer treatment, particularly, in achieving cancer cell targeting and reducing the side effects of anticancer drugs. Biocompatible and biodegradable properties have been essential for using a novel material as a carrier molecule in drug delivery applications. Biocompatible nanocarriers are easy to synthesize, and their surface chemistry often enables them to load different types of photosensitizers (PS) to use targeted photodynamic therapy (PDT) for cancer treatment. This review article explores recent studies on the use of different biocompatible nanocarriers, their potential applications in PDT, including PS-loaded biocompatible nanocarriers, and the effective targeting therapy of PS-loaded biocompatible nanocarriers in PDT for cancer treatment. Furthermore, the review briefly recaps the global clinical trials of PDT and its applications in cancer treatment.

Photodynamic therapy of prostate cancer using porphyrinic formulations

Prostate cancer (PCa) is the second most frequent cancer diagnosed in men worldwide. Among the common treatment options, photodynamic therapy (PDT) is being considered a promising local therapy to treat this cancer. Although PDT is an established treatment modality approved for several types of cancer, the low solubility, the reduced tumor selectivity, the absorption in the therapeutic window and the poor clearance from the body of the currently approved photosensitizers (PS) hampers its wide clinical application. In this regard, herein we synthesized three fluorinated porphyrinoid derivatives and entrapped them into polyvinylpyrrolidone (PVP) to prevent their aggregation and preserve their desirable photophysical properties under the physiological environment. In vitro studies revealed the negligible dark cytotoxicity of all PVP formulations (PS1@PVP, PS2@PVP and PS3@PVP) at the tested concentrations (5.0 to 20 μM), but also confirmed the significant photodynamic effect of PS2@PVP and PS3@PVP towards the PCa cell line PC-3, upon red light irradiation at an irradiance of 17.6 mW.cm^-2. To provide insight into the underlying mechanisms of cell death under PDT treatment induced by PS2@PVP and PS3@PVP, their intracellular localization in PC-3 cells was firstly investigated by confocal microscopy. Since both PS2@PVP and PS3@PVP nanoparticles were mainly localized in mitochondria, the involvement of this organelle in PDT-induced apoptosis mediated by both formulations was further explored. Western blot analysis revealed that PDT treatment of PC-3 cells with either PS2@PVP or PS3@PVP resulted in the reduction of the expression level of the anti-apoptotic protein Bcl-2. As the photodamage to Bcl-2 after PDT with PS2@PVP and PS3@PVP was accompanied by the further activation of pro-caspase-3, we assumed that upon irradiation the photogenerated reactive oxygen species (ROS) were able to activate a caspase-dependent apoptotic response as a consequence of a post-mitochondrial event. Taken together, these findings demonstrate that among the tested fluorinated porphyrinoids, PS2@PVP and, particularly, PS3@PVP, are significantly more effective in overall PC-3 cell killing than PS1@PVP, thus highlighting their great potential as therapeutic agents for PCa.

Smart Stimuli-Responsive and Mitochondria Targeting Delivery in Cancer Therapy

Dysfunction in the mitochondria (Mc) contributes to tumor progression. It is a major challenge to deliver therapeutic agents specifically to the Mc for precise treatment. Smart drug delivery systems are based on stimuli-responsiveness and active targeting. Here, we give a whole list of documented pathways to achieve smart stimuli-responsive (St-) and Mc-targeted DDSs (St-Mc-DDSs) by combining St and Mc targeting strategies. We present the formulations, targeting characteristics of St-Mc-DDSs and clarify their anti-cancer mechanisms as well as improvement in efficacy and safety. St-Mc-DDSs usually not only have Mc-targeting groups, molecules (lipophilic cations, peptides, and aptamers) or materials but also sense the surrounding environment and correspondingly respond to internal biostimulators such as pH, redox changes, enzyme and glucose, and/or externally applied triggers such as light, magnet, temperature and ultrasound. St-Mc-DDSs exquisitely control the action site, increase therapeutic efficacy and decrease side effects of the drug. We summarize the clinical research progress and propose suggestions for follow-up research. St-Mc-DDSs may be an innovative and sensitive precision medicine for cancer treatment.

The Therapeutic Efficacy of Dendrimer and Micelle Formulations for Breast Cancer Treatment

Breast cancer is among the most common types of cancer in women and it is the cause of a high rate of mortality globally. The use of anticancer drugs is the standard treatment approach used for this type of cancer. However, most of these drugs are limited by multi-drug resistance, drug toxicity, poor drug bioavailability, low water solubility, poor pharmacokinetics, etc. To overcome multi-drug resistance, combinations of two or more anticancer drugs are used. However, the combination of two or more anticancer drugs produce toxic side effects. Micelles and dendrimers are promising drug delivery systems that can overcome the limitations associated with the currently used anticancer drugs. They have the capability to overcome drug resistance, reduce drug toxicity, improve the drug solubility and bioavailability. Different classes of anticancer drugs have been loaded into micelles and dendrimers, resulting in targeted drug delivery, sustained drug release mechanism, increased cellular uptake, reduced toxic side effects of the loaded drugs with enhanced anticancer activity in vitro and in vivo. This review article reports the biological outcomes of dendrimers and micelles loaded with different known anticancer agents on breast cancer in vitro and in vivo.

Co-delivery of IR-768 and daunorubicin using mPEG-b-PLGA micelles for synergistic enhancement of combination therapy of melanoma

Malignant melanoma is an emerging problem worldwide due to the high degree of lethalness. Its aggressiveness and the ability to metastasize along with the heterogeneity at the molecular and cellular levels, limit the overall therapeutic efficacy. Despite significant advances in melanoma treatment over the last decade, there is still a need for improved therapeutic modalities. Thus, we demonstrate here a combinatorial approach that targets multiple independent therapeutic pathways, in which polymeric micelles (PMs) were used as efficacious colloidal nanocarriers loaded with both daunorubicin (DRB) as a cytotoxic drug and IR-768 as a photosensitizer. This afforded the dual drug loaded delivery system IR-768 + DRB in PMs. The fabricated mPEG-b-PLGA micelles (hydrodynamic diameters ≈ 25 nm) had a relatively narrow size distribution (PdI > ca. 0.3) with uniform spherical shapes. CLSM study showed that mPEG-b-PLGA micelles were uptaken by mitochondria, which further contributed to excellent singlet oxygen generation capacity for PDT in A375 melanoma cells. Furthermore, the PMs were efficiently internalized by tested cells through endocytosis, resulting in much higher cellular uptake comparing to the free drug. As a result of these properties, IR-768 + DRB in PMs exhibited very potent and synergistically enhanced anticancer activity against A375 cells. Additionally, this combination approach allowed to reduce drug doses and provided low side effects towards normal HaCaT. This study indicates excellent properties of mPEG-b-PLGA micelles resulting in great therapeutic potential possessed by the developed nanoscale drug delivery system for combined chemo-photodynamic therapy of melanoma.

Viriditoxin Stabilizes Microtubule Polymers in SK-OV-3 Cells and Exhibits Antimitotic and Antimetastatic Potential

Microtubules play a crucial role in mitosis and are attractive targets for cancer therapy. Recently, we isolated viriditoxin, a cytotoxic and antibacterial compound, from a marine fungus Paecilomyces variotii. Viriditoxin has been reported to inhibit the polymerization of bacterial FtsZ, a tubulin-like GTPase that plays an essential role in bacterial cell division. Given the close structural homology between FtsZ and tubulin, we investigated the potential antimitotic effects of viriditoxin on human cancer cells. Viriditoxin, like paclitaxel, enhanced tubulin polymerization and stabilized microtubule polymers, thereby perturbing mitosis in the SK-OV-3 cell line. However, the morphology of the stabilized microtubules was different from that induced by paclitaxel, indicating subtle differences in the mode of action of these compounds. Microtubule dynamics are also essential in cell movement, and viriditoxin repressed migration and colony formation ability of SK-OV-3 cells. Based on these results, we propose that viriditoxin interrupts microtubule dynamics, thus leading to antimitotic and antimetastatic activities.

A clioquinol-containing Pluronic® F127 polymeric micelle system is effective in the treatment of visceral leishmaniasis in a murine model

A clioquinol (ICHQ)-containing Pluronic^® F127 polymeric micelle system (ICHQ/Mic) was recently shown to be effective against Leishmania amazonensis infection in a murine model. In the present study, ICHQ/Mic was tested against L. infantum infection. BALB/c mice (n = 12 per group) were infected with L. infantum stationary promastigotes through subcutaneous injection and, 45 days after challenge, received saline or were treated via the subcutaneous route with empty micelles, ICHQ or ICHQ/Mic. In addition, animals were treated with miltefosine by the oral route, as a drug control. Half of the animals were euthanized 1 and 15 days after treatment, aiming to evaluate two endpoints after therapy, when parasitological and immunological parameters were investigated. Results showed that the treatment using miltefosine, ICHQ or ICHQ/Mic induced significantly higher anti-parasite IFN-γ, IL-12, GM-CSF, nitrite and IgG2a isotype antibody levels, which were associated with low IL-4 and IL-10 production. In addition, a higher frequency of IFN-γ and TNF-α-producing CD4⁺ and CD8⁺ T-cells was found in these animals. The parasite load was evaluated in distinct organs, and results showed that the treatment using miltefosine, ICHQ or ICHQ/Mic induced significant reductions in organic parasitism in the treated and infected mice. A comparison between the treatments suggested that ICHQ/Mic was the most effective in inducing a highly polarized Th1-type response, as well as reducing the parasite load in significant levels in the treated and infected animals. Data obtained 15 days after treatment suggested maintenance of the immunological and parasitological responses. In conclusion, ICHQ/Mic could be considered in future studies for the treatment of visceral leishmaniasis.

Porphyrin Derivative Nanoformulations for Therapy and Antiparasitic Agents

Porphyrins and analogous macrocycles exhibit interesting photochemical, catalytic, and luminescence properties demonstrating high potential in the treatment of several diseases. Among them can be highlighted the possibility of application in photodynamic therapy and antimicrobial/antiparasitic PDT, for example, of malaria parasite. However, the low efficiency generally associated with their low solubility in water and bioavailability have precluded biomedical applications. Nanotechnology can provide efficient strategies to enhance bioavailability and incorporate targeted delivery properties to conventional pharmaceuticals, enhancing the effectiveness and reducing the toxicity, thus improving the adhesion to the treatment. In this way, those limitations can be overcome by using two main strategies: (1) Incorporation of hydrophilic substituents into the macrocycle ring while controlling the interaction with biological systems and (2) by including them in nanocarriers and delivery nanosystems. This review will focus on antiparasitic drugs based on porphyrin derivatives developed according to these two strategies, considering their vast and increasing applications befitting the multiple roles of these compounds in nature.

PTS micelles for the delivery of hydrophobic methotrexate

Polyoxyethanyl-α-tocopheryl sebacate (PTS) is an amphiphilic compound with self-emulsifying properties known to form micelles. In this work, we report the production of PTS micelles for the encapsulation and delivery of a hydrophobic derivative of methotrexate, MTX di-ethylated (MTX-OEt). We optimized the micelles production by testing two different techniques: auxiliary solvent and sonication. Small and homogeneous micelles (≈40 nm) were obtained through the auxiliary solvent method performed at 30 °C and using 15 mg/mL of PTS. The produced micelles with the most promising physicochemical properties did not induce cytotoxicity when tested in normal human cells (BJ5ta cells), being considered for the encapsulation of MTX-OEt. This prodrug was achieved by Fisher esterification using ethanol, being isolated in good yield (η = 68%). MTX-OEt was efficiently encapsulated onto the produced micelles which preserved their physicochemical properties. The PTS micelles loaded with MTX-OEt, free MTX-OEt and free unmodified MTX revealed similar biological effect against cancer cells (Caco-2 cells). These results demonstrated that the biological activity of MTX is not altered after modification. The developed PTS micelles revealed a promising intracellular delivery performance with potentiality for cancer therapy.

Recent progress in the engineering of multifunctional colloidal nanoparticles for enhanced photodynamic therapy and bioimaging

This up-to-date review summarizes the design and current fabrication strategies that have been employed in the area of mono- and multifunctional colloidal nanoparticles - nanocarriers well suited for photodynamic therapy (PDT) and diagnostic purposes. Rationally engineered photosensitizer (PS)-loaded nanoparticles may be achieved via either noncovalent (i.e., self-aggregation, interfacial deposition, interfacial polymerization, or core-shell entrapment along with physical adsorption) or covalent (chemical immobilization or conjugation) processes. These PS loading approaches should provide chemical and physical stability to PS payloads. Their hydrophilic surfaces, capable of appreciable surface interactions with biological systems, can be further modified using functional groups (stealth effect) to achieve prolonged circulation in the body after administration and/or grafted by targeting agents (such as ligands, which bind to specific receptors uniquely expressed on the cell surface) or stimuli (e.g., pH, temperature, and light)-responsive moieties to improve their action and targeting efficiency. These attempts may in principle permit efficacious PDT, combination therapies, molecular diagnosis, and - in the case of nanotheranostics - simultaneous monitoring and treatment. Nanophotosensitizers (nano-PSs) should possess appropriate morphologies, sizes, unimodal distributions and surface processes to be successfully delivered to the place of action after systemic administration and should be accumulated in certain tumors by passive and/or active targeting. Additionally, physically facilitating drug delivery systems emerge as a promising approach to enhancing drug delivery, especially for the non-invasive treatment of deep-seated malignant tissues. Recent advances in nano-PSs are scrutinized, with an emphasis on design principles, via the promising use of colloid chemistry and nanotechnology.

An insight on the role of photosensitizer nanocarriers for Photodynamic Therapy

Photodynamic therapy (PDT) is a modality of cancer treatment in which tumor cells are destroyed by reactive oxygen species (ROS) produced by photosensitizers following its activation with visible or near infrared light. The PDT success is dependent on different factors namely on the efficiency of the photosensitizer deliver and targeting ability. In this review a special attention will be given to the role of some drug delivery systems to improve the efficiency of tetrapyrrolic photosensitizers to this type of treatment.

Comparing the therapeutic efficacy of different amphotericin B-carrying delivery systems against visceral leishmaniasis

Amphotericin B (Amp) has been well-successfully used to treat against Leishmania infection, although high toxicity has been found in patients. In the present study, Amp was administered in Leishmania infantum-infected BALB/c mice by three distinct delivery systems aiming to compare their efficacy against challenge infection, as well as their side effects in a murine visceral leishmaniasis (VL) model. This product was administered in a Poloxamer P407 (Pluronic^® F127)-based polymeric micelle system (Amp/M), in the Ambisome^® formulation (Lip-Amp) or in a free format (free Amp). Glucantime^® (Gluc) was used as a comparative drug. Aiming to evaluate different endpoints of the treatments, the efficacy of the compounds was investigated one and 15-days after the therapeutic regimens, determining the parasite load by a limiting dilution assay and a quantitative PCR (qPCR) technique, as well as evaluating the immune response generated in the infected and treated animals. In the results, Amp/M or Lip-Amp-treated mice presented the best outcomes, since significant parasite load reductions were found in the evaluated organs, as well as a parasite-specific Th1 immune response was observed in the animals. In addition, no hepatic or renal damage was found in these mice. On the other hand, free Amp or Gluc induced toxicity in the animals, which was associated with a low Th1 immune response. Comparatively, Amp/M was the most effective drug in our experimental model, and results showed that the Amp-carrying system could be considered as a future alternative in studies against VL.

Polymeric micelles: Basic research to clinical practice

Rapidly developing polymeric micelles as potential targeting carriers has intensified the need for better understanding of the underlying principles related to the selection of suitable delivery materials for designing, characterizing, drug loading, improving stability, targetability, biosafety and efficacy. The emergence of advanced analytical tools such as fluorescence resonance energy transfer and dissipative particle dynamics has identified new dimensions of these nanostructures and their behavior in much greater details. This review summarizes recent efforts in the development of polymeric micelles with respect to their architecture, formulation strategy and targeting possibilities along with their preclinical and clinical aspects. Literature of the past decade is discussed critically with special reference to the chemistry involved in the formation and clinical applications of these versatile materials. Thus, our main objective is to provide a timely update on the current status of polymeric micelles highlighting their applications and the important parameters that have led to successful delivery of drugs to the site of action.

Porphyrin photosensitizers in photodynamic therapy and its applications

In 1841, the extraction of hematoporphyrin from dried blood by removing iron marked the birth of the photosensitizer. The last twenty years has witnessed extensive research in the application of photodynamic therapy (PDT) in tumor-bearing (or other diseases) animal models and patients. The period has seen development of photosensitizers from the first to the third generation, and their evolution from simple to more complex entities. This review focuses on porphyrin photosensitizers and their effect on tumors, mediated via several pathways involved in cell necrosis, apoptosis or autophagic cell death, and the preventive and therapeutic application of PDT against atherosclerosis.

Location of Varying Hydrophobicity Zinc(II) Phthalocyanine-Type Photosensitizers in Methoxy Poly(ethylene oxide) and Poly(l-lactide) Block Copolymer Micelles Using 1H NMR and XPS Techniques

Hydrophobic zinc(II) phthalocyanine-type derivatives, solubilized in polymeric micelles (PMs), provide a befitting group of so-called nanophotosensitizers, suitable for a variety of photodynamic therapy (PDT) protocols. The factors that influence the success of such products in PDT are the location of the active cargo in the PMs and the nanocarrier-enhanced ability to safely interact with biological systems and fulfill their therapeutic functions. Therefore, the aim of this work was to determine the solubilization loci of three phthalocyanines of varying hydrophobicity, i.e., zinc(II) phthalocyanine (ZnPc), along with its tetrasulfonic acid (ZnPc-sulfo₄) and perfluorinated (ZnPcF₁₆) derivatives, loaded in polymeric micelles of methoxy poly(ethylene oxide)-b-poly(l-lactide) (mPEG-b-PLLA), by means of ¹H nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) combined with ion sputtering. Furthermore, the microenvironment influence upon the chemical and physical status of the solubilized cargo in PMs, expressed by photobleaching and reactive oxygen species (ROS) generation comparing to the same properties of native cargoes in solution, was also evaluated and discussed in regards to the probing location data. The studied phthalocyanine-loaded PMs exhibited good physical stability, high drug-loading efficiency, and a size of less than ca. 150 nm with low polydispersity indices. The formation of polymeric micelles and the solubilization locus were investigated by ¹H NMR and XPS. ZnPc localized within the PM core, whereas both ZnPcF₁₆ and ZnPc-sulfo₄ - in the corona of PMs. We proved that the cargo locus is crucial for the photochemical properties of the studied phthalocyanines; the increase in photostability and ability to generate ROS in micellar solution compared to free photosensitizer was most significant for the photosensitizer in the PM core. Our results indicate the role of the cargo location in the PM microenvironment and demonstrate that such attempts are fundamental for improving the properties of photosensitizers and their assumed efficiency as nanophotosensitizers in PDT.

Design of Pluronic-Based Formulation for Enhanced Redaporfin-Photodynamic Therapy against Pigmented Melanoma

The therapeutic outcome of photodynamic therapy (PDT) with redaporfin (a fluorinated sulfonamide bacteriochlorin, F2BMet or LUZ11) was improved using Pluronic-based (P123, F127) formulations. Neither redaporfin encapsulated in Pluronic nor micelles alone exhibited cytotoxicity in a broad concentration range. Comprehensive in vitro studies against B16F10 melanoma cells showed that redaporfin-P123 micelles enhanced cellular uptake and increased oxidative stress compared with redaporfin-F127 or photosensitizer alone after short incubation times. ROS-sensitive fluorescent probes showed that the increased oxidative stress is due, at least in part, to a more efficient formation of hydroxyl radicals, and causes strong light-dose dependent apoptosis and necrosis. Tissue distribution and pharmacokinetic studies in tumor-bearing mice show that the Pluronic P123 formulation of redaporfin increases its bioavailability as well as the tumor-to-muscle and tumor-to-skin ratios, in comparison with Cremophor EL and Pluronic F127 formulations. Redaporfin in P123 was most successful in the PDT of C57BL/6J mice bearing subcutaneously implanted B16F10 melanoma tumors. Vascular-targeted PDT combining 1.5 mg kg(-1) redaporfin in P123 with a light dose of 74 J cm(-2) led to 100% complete cures (i.e., no tumor regrowth over one year post-treatment). This remarkable result reveals that modification of redaporfin with Pluronic block copolymers overcomes the resistance of melanoma cells to PDT possibly via increased tumor selectivity and enhanced ROS generation.

Poloxamer 407 (Pluronic(®) F127)-based polymeric micelles for amphotericin B: In vitro biological activity, toxicity and in vivo therapeutic efficacy against murine tegumentary leishmaniasis

In the present study, a Poloxamer 407-based amphotericin B (AmpB)-containing polymeric micelles system (AmpB/M) was employed in the treatment of Leishmania amazonensis-infected BALB/c mice. Initially, the in vitro antileishmanial activity (IC50 value) of AmpB/M and B-AmpB/M (empty micelles) against stationary promastigotes and amastigotes-like forms of the parasites was determined, and results were of 1.83 ± 0.4 and 22.1 ± 0.7 μM, respectively, for the promastigotes, and of 2.27 ± 0.5 and 33.98 ± 2.6 μM, respectively, for the amastigotes-like. The cytotoxic concentration (CC50) values of these products were also evaluated, and we found the results of 119.5 ± 9.6 and 134.7 ± 10.3 μM, respectively. With these values, the selectivity index (SI) was calculated and results were of 65.3 and 5.4, respectively, for the promastigotes, and of 59.3 and 3.96, respectively, for the amastigotes-like of the parasites. Free AmpB showed IC50 values of 1.2 ± 0.3 and 2.5 ± 0.5 μM for the promastigotes and amastigotes-like, respectively, whereas the CC50 value was of 9.5 ± 0.4 μM. The SI values of this drug were of 7.9 and 3.8, respectively, for the promastigote and amastigote-like stages of the parasites. After, animals were infected and received saline or were treated subcutaneously with free AmpB, AmpB/M or B-AmpB/M. In the results, free AmpB-treated and infected mice showed reductions in their body weight, which were associated with hepatic and renal damage; however, no organic alteration was observed in the AmpB/M-treated animals. In addition, these animals showed significant reductions in their lesion average size and in the parasite burden in all evaluated infected tissue and organs, when compared to the other groups; as well as significantly higher levels of antileishmanial IFN-γ, IL-12, GM-CSF and nitrite, which were associated with low production of IL-4, IL-10 and IgG1 isotype antibodies. In conclusion, this AmpB/M system could be considered as an alternative for future studies in the treatment of tegumentary leishmaniasis.

Treatment of murine visceral leishmaniasis using an 8-hydroxyquinoline-containing polymeric micelle system

New therapeutics are urgently needed to treat visceral leishmaniasis (VL). Due to the fact that drug discovery is a long and expensive process, the development of delivery systems to carry old and toxic drugs could be considered, as well as the evaluation of new molecules that have already shown to present biological activity. In this context, the present study evaluated the in vitro and in vivo antileishmanial activity of an 8-hydroxyquinoline (8-HQN)-containing polymeric micelle (8-HQN/M) system against Leishmania infantum, the main causative agent of VL in the Americas. The experimental strategy used was based on the evaluation of the parasite load by a limiting-dilution technique in the spleen, liver, bone marrow and draining lymph nodes of the infected and treated animals, as well as by a quantitative PCR (qPCR) technique to also assess the splenic parasite load. The immune response developed was evaluated by the production of IFN-γ, IL-4, IL-10, IL-12 and GM-CSF cytokines, as well as by antileishmanial nitrite dosage and antibodies production. Hepatic and renal enzymes were also investigated to verify cellular injury as a result of treatments toxicity. In the results, 8-HQN/M-treated mice, when compared to the other groups: saline, free amphotericin B (AmpB, as a drug control), 8-HQN and B-8-HQN/M (as a micelle control) showed more significant reductions in their parasite burden in all evaluated organs. These animals also showed an antileishmanial Th1 immunity, which was represented by high levels of IFN-γ, IL-12, GM-CSF and nitrite, associated with a low production of IL-4 and IL-10 and anti-Leishmania IgG1 isotype antibodies. In addition, any hepatic or renal damage was found in these treated animals. In conclusion, 8-HQN/M was effective in treating L. infantum-infected BALB/c mice, and can be considered alone, or combined with other drugs, as an alternative treatment for VL.

Polymeric nanocapsules with up-converting nanocrystals cargo make ideal fluorescent bioprobes

An innovative approach for up-converting nanoparticles adaptation for bio-related and theranostic applications is presented. We have successfully encapsulated multiple, ~8 nm in size NaYF₄ nanoparticles inside the polymeric nanocarriers with average size of ~150 nm. The initial coating of nanoparticles surfaces was preserved due to the hydrophobic environment inside the nanocapsules, and thus no single nanoparticle surface functionalization was necessary. The selection of biodegradable and sugar-based polyelectrolyte shells ensured biocompatibility of the nanostructures, while the choice of Tm³⁺ and Yb³⁺ NaYF₄ nanoparticles co-doping allowed for near-infrared to near-infrared bioimaging of healthy and cancerous cell lines. The protective role of organic shell resulted in not only preserved high up-converted emission intensity and long luminescence lifetimes, without quenching from water environment, but also ensured low cytotoxicity and high cellular uptake of the engineered nanocapsules. The multifunctionality of the proposed nanocarriers is a consequence of both the organic exterior part that is accessible for conjugation with biologically important molecules, and the hydrophobic interior, which in future application may be used as a container for co-encapsulation of inorganic nanoparticles and anticancer drug cargo.

An 8-hydroxyquinoline-containing polymeric micelle system is effective for the treatment of murine tegumentary leishmaniasis

The current treatment of leishmaniasis has been hampered due to the high toxicity of the available drugs and long duration protocols, which often lead to its abandonment. In the present study, a poloxamer 407-based delivery system was developed, and a molecule, 8-hydroxyquinoline (8-HQN), was incorporated with it, leading to an 8-HQN/micelle (8-HQN/M) composition. Assays were performed to evaluate the in vitro antileishmanial activity of 8-HQN/M against Leishmania amazonensis stationary promastigotes. The cytotoxicity in murine macrophages and in human red cells, as well as the efficacy of the treatment in macrophages infected by parasites, was also assessed. This product was also evaluated for the treatment of murine tegumentary leishmaniasis, using L. amazonensis-infected BALB/c mice. To evaluate the in vivo efficacy of the treatment, the average lesion diameter (area) in the infected tissue, as well as the parasite load at the site of infection (skin), spleen, liver and draining lymph nodes were examined. Non-incorporated micelle (B-8-HQN/M) and the free molecule (8-HQN) were used as controls, besides animals that received only saline. The parasite burden was evaluated by limiting dilution and quantitative real-time PCR (qPCR) techniques, and immunological parameters associated with the treatments were also investigated. In the results, the 8-HQN/M group, when compared to the others, presented more significant reductions in the average lesion diameter and in the parasite burden in the skin and all evaluated organs. These animals also showed significantly higher levels of parasite-specific IFN-γ, IL-12, and GM-CSF, associated with low levels of IL-4 and IL-10, when compared to the saline, 8-HQN/M, and B-8-HQN groups. A predominant IL-12-driven IFN-γ production, against parasite proteins, mainly produced by CD4⁺ T cells, was observed in the treated animals, post-infection. In conclusion, 8-HQN/M was highly effective in treating L. amazonensis-infected BALB/c mice and can be considered alone, or combined with other drugs, as an alternative treatment for tegumentary leishmaniasis. Graphical Abstract Therapeutic scheme and immunological and parasitological parameters developed in the present study.

The Effect of Millisecond Pulsed Electric Fields (msPEF) on Intracellular Drug Transport with Negatively Charged Large Nanocarriers Made of Solid Lipid Nanoparticles (SLN): In Vitro Study

Drug delivery technology is still a dynamically developing field of medicine. The main direction in nanotechnology research (nanocarriers, nanovehicles, etc.) is efficient drug delivery to target cells with simultaneous drug reduction concentration. However, nanotechnology trends in reducing the carrier sizes to several nanometers limit the volume of the loaded substance and may pose a danger of uncontrolled access into the cells. On the other hand, nanoparticles larger than 200 nm in diameter have difficulties to undergo rapid diffusional transport through cell membranes. The main advantage of large nanoparticles is higher drug encapsulation efficiency and the ability to deliver a wider array of drugs. Our present study contributes a new approach with large Tween 80 solid lipid nanoparticles SLN (i.e., hydrodynamic GM-SLN-glycerol monostearate, GM, as the lipid and ATO5-SLNs-glyceryl palmitostearate, ATO5, as the lipid) with diameters DH of 379.4 nm and 547 nm, respectively. They are used as drug carriers alone and in combination with electroporation (EP) induced by millisecond pulsed electric fields. We evaluate if EP can support the transport of large nanocarriers into cells. The study was performed with two cell lines: human colon adenocarcinoma LoVo and hamster ovarian fibroblastoid CHO-K1 with coumarin 6 (C6) as a fluorescent marker for encapsulation. The biological safety of the potential treatment procedure was evaluated with cell viability after their exposure to nanoparticles and EP. The EP efficacy was evaluated by FACS method. The impact on intracellular structure organization of cytoskeleton was visualized by CLSM method with alpha-actin and beta-tubulin. The obtained results indicate low cytotoxicity of both carrier types, free and loaded with C6. The evaluation of cytoskeleton proteins indicated no intracellular structure damage. The intracellular uptake and accumulation show that SLNs do not support transport of C6 coumarin. Only application of electroporation improved the transport of encapsulated and free C6 into both treated cell lines.

Polymeric Nanoparticles for Cancer Photodynamic Therapy

In chemotherapy a fine balance between therapeutic and toxic effects needs to be found for each patient, adapting standard combination protocols each time. Nanotherapeutics has been introduced into clinical practice for treating tumors with the aim of improving the therapeutic outcome of conventional therapies and of alleviating their toxicity and overcoming multidrug resistance. Photodynamic therapy (PDT) is a clinically approved, minimally invasive procedure emerging in cancer treatment. It involves the administration of a photosensitizer (PS) which, under light irradiation and in the presence of molecular oxygen, produces cytotoxic species. Unfortunately, most PSs lack specificity for tumor cells and are poorly soluble in aqueous media, where they can form aggregates with low photoactivity. Nanotechnological approaches in PDT (nanoPDT) can offer a valid option to deliver PSs in the body and to solve at least some of these issues. Currently, polymeric nanoparticles (NPs) are emerging as nanoPDT system because their features (size, surface properties, and release rate) can be readily manipulated by selecting appropriate materials in a vast range of possible candidates commercially available and by synthesizing novel tailor-made materials. Delivery of PSs through NPs offers a great opportunity to overcome PDT drawbacks based on the concept that a nanocarrier can drive therapeutic concentrations of PS to the tumor cells without generating any harmful effect in non-target tissues. Furthermore, carriers for nanoPDT can surmount solubility issues and the tendency of PS to aggregate, which can severely affect photophysical, chemical, and biological properties. Finally, multimodal NPs carrying different drugs/bioactive species with complementary mechanisms of cancer cell killing and incorporating an imaging agent can be developed. In the following, we describe the principles of PDT use in cancer and the pillars of rational design of nanoPDT carriers dictated by tumor and PS features. Then we illustrate the main nanoPDT systems demonstrating potential in preclinical models together with emerging concepts for their advanced design.

Redox-sensitive cross-linking enhances albumin nanoparticle function as delivery system for photodynamic cancer therapy

Photodynamic cancer therapy is still limited in its efficiency because of a lack of targeted methods avoiding non-specific toxicity. To overcome this we developed a system that is solely effective upon cellular uptake and intracellular activation by incorporating redox-sensitive chemistry. We used a nanoprecipitation method to obtain human serum albumin nanoparticles (HSA NP) with a diameter of 295 ± 5 nm and decorated them with the photosensitizer (PS) chlorin e6 (Ce6). The NP were stabilized using a redox-sensitive cross-linker to create a smart drug delivery system that is activated only upon NP disintegration in the reducing intracellular environment. Indeed, our drug delivery NP broke down in an environment emulating the reducing intracellular environment with 10 mM glutathione, but not under extracellular conditions. In contrast, the control cross-linked with glutaraldehyde did not break down in the reducing environment. Upon NP disintegration Ce6 fluorescence doubled as the result of diminished self-quenching. While the Ce6-HSA NP did not produce a significant amount of singlet oxygen upon irradiation, NP disintegration restored singlet oxygen production to about half of the value generated by the free Ce6. In vitro experiments with HeLa cells showed that the smart system was able to kill up to 81% of the cells while the glutaraldehyde cross-linked control only killed 56% of them at a drug concentration of 10 ng/ml. Also, Ce6 immobilization in HSA NP prevented dark toxicity in three different cell lines. For the first time, we demonstrate that it is possible to design a smart NP drug delivery system delivering a PS drug to cancer cells while avoiding toxicity prior to the uptake and irradiation. This finding may provide a means of designing more efficient PDT in cancer treatment.