A tumor-targeted Ganetespib-zinc phthalocyanine conjugate for synergistic chemo-photodynamic therapy

Developing Chlorin/Arylaminoquinazoline Conjugates with Nanomolar Activity for Targeted Photodynamic Therapy: Design, Synthesis, SAR, and Biological Evaluation

In this report, we developed novel chlorin/arylaminoquinazoline conjugates for targeted photodynamic therapy of cancer. The synthesized photosensitizers consisted of chlorin-e6 metallocomplexes (Zn, In, or Pd) conjugated with arylaminoquinazoline ligands with high affinity for epidermal growth factor receptors (EGFR). Additionally, the selectivity and antitumor properties of the conjugates were investigated in the EGFR-expressing A431 human tumor cell line in vitro. Among the tested molecules, the In-containing conjugate effectively inhibited tumor cell proliferation at nanomolar concentrations, a rare property for conventional photosensitizers. In in vivo experiments, the conjugates rapidly accumulated at the tumor site in nude mice bearing A431 xenograft tumors. Subsequent distribution analysis among different tissues was carried out using fluorescence imaging and elemental analysis. Finally, we demonstrated that the most promising In-containing conjugate was capable of inhibiting xenograft tumor growth in mice through combinational therapy. This therapeutic approach, combined with the conjugate's confirmed safety profile, highlights its potential for effective and safe cancer treatment.

Targeting HSP90 for Cancer Therapy: Current Progress and Emerging Prospects

Heat shock protein 90 (HSP90), a highly conserved member of the heat shock protein family, regulates various proteins and signaling pathways involved in cancer, making it a promising target for cancer therapy. Traditional HSP90 inhibitors have demonstrated significant antitumor potential in preclinical trials, with over 20 compounds advancing to clinical trials and showing promising results. However, the limited clinical efficacy and shared toxicity of these inhibitors restrict their further clinical use. Encouragingly, developing novel inhibitors using conventional medicinal chemistry approaches─such as selective inhibitors, dual inhibitors, protein-protein interaction inhibitors, and proteolysis-targeting chimeras─is expected to address these challenges. Notably, the selective inhibitor TAS-116 has already been successfully marketed. In this Perspective, we summarize the structure, biological functions, and roles of HSP90 in cancer, analyze the clinical status of HSP90 inhibitors, and highlight the latest advancements in novel strategies, offering insights into their future development.

"NIR-triggered ROS storage" photodynamic intraocular implant for high-efficient and safe posterior capsular opacification prevention

Posterior capsular opacification (PCO) is the leading cause of vision loss after cataract, mainly caused by the adhesion, proliferation and trans-differentiation of post-operative residual lens epithelial cells (LECs). Effective PCO prevention remains a huge challenge to ophthalmologists and researches for decades. Herein, we developed a "NIR-triggered ROS storage" intraocular implant (CTR-Py-PpIX) based on capsular tension ring (CTR), which is concurrently linked with photosensitizer protophorphyrin IX (PpIX) and energy storage 2-pyridone derivative (Py), to guarantee instantaneous and sustainable ROS generation for LECs killing, aiming to achieve more efficient and safer photodynamic therapy (PDT) to effectively prevent PCO. The silylated PpIX-Si and Py-Si were covalently conjugated to the plasma activated CTR surface to obtain CTR-Py-PpIX. Results demonstrated that CTR-Py-PpIX had dual functions of PDT and battery, in which PpIX could generate ROS extracellularly under irradiation, with one part directly inhibiting LECs by lipid peroxidation (LPO) induction of cell membranes. Meanwhile, the excess ROS stored in Py could be continuously released to amplify LPO levels after the irradiation was removed. Ultimately, the proliferation of LECs in capsular bag was completely inhibited under mild irradiation conditions, achieving a sustainable and controlled PDT effect for effective PCO prevention with good biocompatibility. This NIR-triggered ROS storage intraocular implant would provide a more efficient and safer approach for long-term PCO prevention.

Targeted cancer phototherapy using phthalocyanine-anticancer drug conjugates

Phototherapy, the use of light to selectively ablate cancerous tissue, is a compelling prospect. Phototherapy is divided into two major domains: photodynamic and photothermal, whereby photosensitizer irradiation generates reactive oxygen species or heat, respectively, to disrupt the cancer microenvironment. Phthalocyanines (Pcs) are prominent phototherapeutics due to their desirable optical properties and structural versatility. Targeting of Pc photosensitizers historically relied on the enhanced permeation and retention effect, but the weak specificity engendered by this approach has hindered bench-to-clinic translation. To improve specificity, antibody and peptide active-targeting groups have been employed to some effect. An alternative targeting method exploits the binding of anticancer drugs to direct the photosensitizer close to essential cellular components, allowing for precise, synergistic phototherapy. This Perspective explores the use of Pc-drug conjugates as targeted anticancer phototherapeutic systems with examples of Pc-platin, Pc-kinase, and Pc-anthracycline conjugates discussed in detail.

Porphyrin-Based Nanoparticles: A Promising Phototherapy Platform

Phototherapy, including photodynamic therapy and photothermal therapy, is an emerging form of non-invasive treatment. The combination of imaging technology and phototherapy is becoming an attractive development in the treatment of cancer, as it allows for highly effective therapeutic results through image-guided phototherapy. Porphyrins have attracted significant interest in the treatment and diagnosis of cancer due to their excellent phototherapeutic effects in phototherapy and their remarkable imaging capabilities in fluorescence imaging, magnetic resonance imaging and photoacoustic imaging. However, porphyrins suffer from poor water solubility, low near-infrared absorption and insufficient tumor accumulation. The development of nanotechnology provides an effective way to improve the bioavailability, phototherapeutic effect and imaging capability of porphyrins. This review highlights the research results of porphyrin-based small molecule nanoparticles in phototherapy and image-guided phototherapy in the last decade and discusses the challenges and directions for the development of porphyrin-based small molecule nanoparticles in phototherapy.

Histopathological Analysis of the Effect of Photodynamic Action on Post-Chemotherapy Excised Breast Cancer Tissue

Background and objectives: Breast cancer is the most commonly diagnosed cancer in women and its mortality is increasing. Therefore, research to improve treatment is of paramount importance. One method of treatment is photodynamic therapy. Photodynamic therapy selectively stimulates apoptosis in photosensitizer-treated neoplastic breast cells as a result of cytotoxic singlet oxygen generation via collisions between triplet excited state photosensitizer and triplet ground state oxygen upon tissue irradiation. The aim of this study was to evaluate the effects of photodynamic action on cancerous breast tissue samples as a model of photodynamic therapy. Materials and Methods: Breast cancer tissue samples were obtained from post-operative material and the patterns of histopathological changes in breast cancer tissue before and after photodynamic action on post-chemotherapy tissue were evaluated. Excised tissue samples were obtained from 48 female breast cancer patients who had previously undergone chemotherapy. Breast cancer tissues for this study were taken from macroscopically visible tumors larger than 10 mm. Histopathological analysis was performed to evaluate any morphological changes prior to and after photodynamic action on the post-chemotherapy tissue samples. Eighteen breast cancer tissue samples were analyzed before chemotherapy, fifteen after chemotherapy, and fifteen samples were analyzed after chemotherapy and application of photodynamic action. The photosensitizer Rose Bengal was applied to the samples subjected to photodynamic action. Results: Photodynamic action on post-chemotherapy neoplastic tissue showed histological changes under a light microscope. The results showed that morphological changes in breast cancer tissues after chemotherapy and photodynamic action were dependent on the concentration of Rose Bengal. In all cases, follow-up imaging showed tumor shrinkage of an average of 35% from baseline size. Conclusions: Histopathological examination revealed photosensitizer-concentration-dependent changes after photodynamic action in excised post-chemotherapy tissue. The effects of photodynamic action observed in this study suggest that the application of photodynamic therapy after chemotherapy can aid in breast cancer cell eradication.

Synergic Antitumor Effect of Photodynamic Therapy and Chemotherapy Mediated by Nano Drug Delivery Systems

This review provides a summary of recent progress in the development of different nano-platforms for the efficient synergistic effect between photodynamic therapy and chemotherapy. In particular, this review focuses on various methods in which photosensitizers and chemotherapeutic agents are co-delivered to the targeted tumor site. In many cases, the photosensitizers act as drug carriers, but this review, also covers different types of appropriate nanocarriers that aid in the delivery of photosensitizers to the tumor site. These nanocarriers include transition metal, silica and graphene-based materials, liposomes, dendrimers, polymers, metal–organic frameworks, nano emulsions, and biologically derived nanocarriers. Many studies have demonstrated various benefits from using these nanocarriers including enhanced water solubility, stability, longer circulation times, and higher accumulation of therapeutic agents/photosensitizers at tumor sites. This review also describes novel approaches from different research groups that utilize various targeting strategies to increase treatment efficacy through simultaneous photodynamic therapy and chemotherapy.

Liposomal cyanine dyes with enhanced nonradiative transition for synergistic phototherapy of tumor

Organic photosensitizers are of great interest in cancer diagnose and treatment such as fluorescence imaging, photodynamic therapy (PDT), and photothermal therapy (PTT). However, their poor aqueous solubility, inadequate photostability and...

Synthesis of pH-responsive cyclometalated iridium(III) complex and its application in the selective killing of cancerous cells

Cyclometalated iridium(III) complexes are promising candidates as photosensitizers (PSs) in photodynamic therapy (PDT). The challenge in PDT is the selective killing of cancerous cells over the neighboring normal cells. In this work, a pH-responsive cyclometalated iridium(III) complex (probe 1) was designed and synthesized as an effective PS to selectively kill cancerous cells, with 3-(2-pyridyl)benzaldehyde used as the main ligand and 1-(2-pyridyl)-β-carboline used as an ancillary ligand. Probe 1 shows enhanced photoluminescence emission and higher ¹O₂ quantum yield in an acidic environment compared to a neutral solution, which led to remarkable phototoxicity toward cancerous cells and high selectivity for killing cancerous cells over normal cells within 10 min. This work demonstrates that the cyclometalated iridium(III) complex with acidic pH-responsive photoluminescence emission and high ¹O₂ generation is an effective alternative PS for selectively killing cancerous cells.

Photodynamic Therapy with Zinc Phthalocyanine Inhibits the Stemness and Development of Colorectal Cancer: Time to Overcome the Challenging Barriers?

Photodynamic therapy (PDT) is a light-based cancer therapy approach that has shown promising results in treating various malignancies. Growing evidence indicates that cancer stem cells (CSCs) are implicated in tumor recurrence, metastasis, and cancer therapy resistance in colorectal cancer (CRC); thus, targeting these cells can ameliorate the prognosis of affected patients. Based on our bioinformatics results, SOX2 overexpression is significantly associated with inferior disease-specific survival and worsened the progression-free interval of CRC patients. Our results demonstrate that zinc phthalocyanine (ZnPc)-PDT with 12 J/cm2 or 24 J/cm2 irradiation can substantially decrease tumor migration via downregulating MMP9 and ROCK1 and inhibit the clonogenicity of SW480 cells via downregulating CD44 and SOX2. Despite inhibiting clonogenicity, ZnPc-PDT with 12 J/cm2 irradiation fails to downregulate CD44 expression in SW480 cells. Our results indicate that ZnPc-PDT with 12 J/cm2 or 24 J/cm2 irradiation can substantially reduce the cell viability of SW480 cells and stimulate autophagy in the tumoral cells. Moreover, our results show that ZnPc-PDT with 12 J/cm2 or 24 J/cm2 irradiation can substantially arrest the cell cycle at the sub-G1 level, stimulate the intrinsic apoptosis pathway via upregulating caspase-3 and caspase-9 and downregulating Bcl-2. Indeed, our bioinformatics results show considerable interactions between the studied CSC-related genes with the studied migration- and apoptosis-related genes. Collectively, the current study highlights the potential role of ZnPc-PDT in inhibiting stemness and CRC development, which can ameliorate the prognosis of CRC patients.

Mitochondrial heat shock protein mortalin as potential target for therapies based on oxidative stress

BACKGROUND

Treatments based on production of reactive oxygen species for bladder cancer such as photodynamic therapy (PDT) have been marginalized due to low specificity and the existence of resistance mainly associated with the up-regulation of Heat Shock Proteins (HSPs). To overcome these barriers, the establishment of strategies combining PDTs with HSP inhibitors may be promising and the identification of HSPs involved with oxidative stress from bladder tumors in animal models represents a key step in this direction.

MATERIALS

Thus, the present study aims to identify cytosolic and mitochondrial HSPs up expressed in murine bladder tumors and in the urothelial carcinoma cell line MB49 by qRT-PCR screening, and to analyze the importance of the activity of the HSPs associated with oxidative stress protection in the survival of the MB49 using strategy of inhibition in vitro.

RESULTS

Results showed that both tumor tissues and MB49 cells in culture had significant overexpression of the mitochondrial HSPA9 (mortalin) and HSP60 mRNAs, while the cytosolic HSP90 was overexpressed only in the tumor. The effect of mortalin in the MB49 cells survival under oxidative stress was evaluated in vitro in presence of the specific inhibitor MKT-077 and H₂O₂. The findings showed that MB49 viability was permanently reduced by the MKT-077 in a dose-dependent manner by inducing apoptosis or necrosis, mainly under oxidative stress conditions.

CONCLUSION

Results suggest that mortalin is preferentially expressed in the MB49 cancer model and plays a key role in tumoral survival, especially under oxidative stress, making this HSP a potential target for an alternative treatment combining PDT with HSP inhibitors.

Recent progress in photosensitizers for overcoming the challenges of photodynamic therapy: from molecular design to application

Photodynamic therapy (PDT), a therapeutic mode involving light triggering, has been recognized as an attractive oncotherapy treatment. However, nonnegligible challenges remain for its further clinical use, including finite tumor suppression, poor tumor targeting, and limited therapeutic depth. The photosensitizer (PS), being the most important element of PDT, plays a decisive role in PDT treatment. This review summarizes recent progress made in the development of PSs for overcoming the above challenges. This progress has included PSs developed to display enhanced tolerance of the tumor microenvironment, improved tumor-specific selectivity, and feasibility of use in deep tissue. Based on their molecular photophysical properties and design directions, the PSs are classified by parent structures, which are discussed in detail from the molecular design to application. Finally, a brief summary of current strategies for designing PSs and future perspectives are also presented. We expect the information provided in this review to spur the further design of PSs and the clinical development of PDT-mediated cancer treatments.

Functional titanium dioxide nanoparticle conjugated with phthalocyanine and folic acid as a promising photosensitizer for targeted photodynamic therapy in vitro and in vivo

Photodynamic therapy (PDT) is a promising cancer treatment that can be implemented using various agents. The conventional photosensitizer Al (III) phthalocyanine chloride tetrasulfonic acid (Pc) has limitations of selectivity in tumor targeting, low affinity to cancer cells, and low two-photon absorption. This study presents a novel photosensitizer FA-TiO₂-Pc, which has the TiO₂ nanoparticle conjugated with a tumor targeting agent of folic acid (FA), and Pc. FA-TiO₂-Pc possessed high targeted photodynamic therapeutic activity and excellent biocompatibility. This promising photosensitizer showed high therapeutic drug efficiency in vitro at a low concentration dose and short incubation time under one-photon excitation (OPE). In vivo, when treated with a low dose of FA-TiO₂-Pc and low light irradiation, the tumor growth was depressed in mice bearing HeLa xenograft tumors with minimal side effects. In addition, the two-photon absorption of FA-TiO₂-Pc was also enhanced compared to Pc, proving that FA-TiO₂-Pc system has a great potential to be used for the therapy of the folate receptor positive cancer cells in both OPE-PDT and two-photon excitation (TPE)-PDT agents.

Application of a polyelectrolyte complex based on biocompatible polysaccharides for colorectal cancer inhibition

Strategies for incorporating water-insoluble photosensitisers (PS) in drug delivery systems have been extensively studied. In this work, we evaluate the formation, characterisation, drug sorption studies, and cytotoxicity of chitosan (CHT)/chondroitin sulphate (CS) polyelectrolyte complexes (PECs) coated with polystyrene-block-poly(acrylic acid) (PS-b-PAA) nanoparticles (NPs) loaded with chloroaluminum phthalocyanine (AlClPc). The PECs were characterised by infrared spectroscopy (FTIR), differential scanning calorimetric (DSC), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The PS-b-PAA NPs on the PEC surface was confirmed by scanning electron microscopy (SEM). Additionally, optical images distinguished the PEC structures containing PS-b-PAA or PS-b-PAA/AlClPc from the unloaded PEC. Kinetic and equilibrium studies investigate the sorption capacity of the PEC/PS-b-PAA toward AlClPc. The encapsulation efficiency reached 95% at 190 μg mL^-1 AlClPc after only 15 min. The Brunauer-Emmett-Teller (BET) isotherm and pseudo-second-order kinetic fitted well to the experimental data. The PS-b-PAA NPs on the PEC surfaces increase the AlClPc bioavailability and the PEC structure stabilizes the PS-b-PAA/AlClPc nanostructures. The materials were cytocompatible upon healthy VERO (kidney epithelial cells), and cytotoxic against colorectal cancerous cells (HT-29 cells). For the first time, we associate PS-b-PAA/AlClPc with a hydrophilic and cytocompatible polysaccharide matrix. We suggest the use of these materials in strategies to treat cancer by using photodynamic therapy.

In Vitro Photodynamic Therapy of Mononuclear and Dinuclear Iridium(III) Bis(terpyridine) Complexes

Three mononuclear or dinuclear bis(terpyridine) (tpy) iridium(III) complexes bearing pyren-1-yl (pyr) group(s) were synthesized. Their photophysical properties in water and in vitro photodynamic therapy (PDT) effects toward the human lung epithelial cancer cell line A549 and the human epidermal skin cancer cell line A431 were investigated to evaluate the effects of dinuclear versus mononuclear complexes and the impact of the oligoether substituent at the ligand. All complexes possessed pyr-tpy ligand-associated charge transfer (¹CT)/¹π,π* absorption bands at 350-550 nm, with the dinuclear complex Ir3 showing the much enhanced absorptivity of this band. These complexes exhibited dual emission upon excitation at >430 nm in most cases, with the emitting states being ascribed to ¹ILCT (intraligand charge transfer) and ³π,π*/³CT states, respectively. All complexes exhibited relatively weak to moderate cytotoxicity in the dark but high photocytotoxicity upon broadband visible light irradiation. Among them, the dinuclear complex Ir3 showed the highest intracellular reactive oxygen species (ROS) generation and PDT efficiency compared to its mononuclear counterpart Ir1. Introducing an oligoether substituent on one of the tpy ligands in Ir2 also improved its intracellular ROS generation and PDT efficacy compared to those induced by Ir1. Ir3 induced both mitochondrial dysfunction and lysosomal damage upon light activation toward both cell lines, whereas Ir1 and Ir2 caused both mitochondrial dysfunction and lysosomal damage in A431 cells but only lysosomal damage in A549 cells. The dominant cell death pathway induced by Ir1-Ir3 PDT is apoptosis.

Optimized HSP90 mediated fluorescent probes for cancer-specific bioimaging

Cancer-specific bioimaging has been correlated with fluorescence-guided tumor therapy, garnering extensive interest from researchers. Herein, a highly efficient tumor-targeting fluorescent probe (NP-001), which is integrated with 4-hydroxy-1,8-naphthalimide and NVP-AUY922, for tumor imaging has been established. 4-Hydroxy-1,8-naphthalimide is a fluorescent molecule with remarkable imaging compatibility. NVP-AUY922 is a heat shock protein 90 (HSP90) inhibitor with preferential tumor selectivity that is conjugated to 4-hydroxy-1,8-naphthalimide as a tumor-targeting ligand. NP-002, a resorcinol-blocked probe which prevented binding with an amino acid residue of the HSP90 ATP binding pocket, was also synthesized as a control. In vitro and ex vivo assays showed that NP-001 could arrest cell proliferation, induce apoptosis and accumulate to inhibit HSP90. Confocal laser scanning microscopy (CLSM) also confirmed that NP-001 could be selectively internalized by tumor cells for cancer-specific bioimaging. Moreover, pharmacokinetic studies and histological analysis also indicated that NP-001 had a relatively longer retention time and showed no major organ-related toxicities. Overall, these encouraging data suggest that NP-001 is a promising new candidate for the early diagnosis of metastatic disease as well as targeted tumor imaging.

Zn phthalocyanines loaded into liposomes: Characterization and enhanced performance of photodynamic activity on glioblastoma cells

Photodynamic therapy (PDT) is considered a promising strategy for cancer treatment. PDT utilizes light in combination with a photosensitizer (PS) to induce several phototoxic reactions. Phthalocyanines (Pcs), a second generation of photosensitizers, have been studied in several cancer models. Among these, Pcs, have become of interest for the treatment of glioblastomas which are one of the most common and aggressive forms of tumors of the central nervous system. Due to the lipophilic nature of Pcs and their limited solubility in water, Pcs can be loaded in liposomes. In this work, we characterized liposomes of ZnPc and TAZnPc and their effectiveness to photoinactivate glioblastoma cells, was evaluated. Both Pcs show an increase in their photosensitizing activity when they were administrated in Dipalmitoylphosphatidylcholine-cholesterol liposomes compared to Pcs administrated in dimethylformamide.

The unique features and promises of phthalocyanines as advanced photosensitisers for photodynamic therapy of cancer

Phthalocyanines exhibit superior photoproperties that make them a surely attractive class of photosensitisers for photodynamic therapy of cancer. Several derivatives are at various phases of clinical trials, and efforts have been put continuously to improve their photodynamic efficacy. To this end, various strategies have been applied to develop advanced phthalocyanines with optimised photoproperties, dual therapeutic actions, tumour-targeting properties and/or specific activation at tumour sites. The advantageous properties and potential of phthalocyanines as advanced photosensitisers for photodynamic therapy of cancer are highlighted in this tutorial review.

Synthesis and evaluation of novel chlorophyll a derivatives as potent photosensitizers for photodynamic therapy

Chlorophyll a exhibits excellent photosensitive activity in photosynthesis. The unstability limited its application as photoensitizer drug in photodynamic therapy. Here a series of novel chlorophyll a degradation products pyropheophorbide-a derivatives were synthesized and evaluated for lung cancer in PDT. These compounds have strong absorption in 660-670 nm with high molar extinction coefficient, and fluorescence emission in 660-675 nm upon excitation with 410-415 nm light. They all have much higher ROS yields than pyropheophorbide-a, and compound 10 was even higher than [3-(1-hexyloxyethyl)]-pyrophoeophorbide a (HPPH). Distinctive phototoxicity was observed in vitro and the inhibition effect was in light dose-dependent and drug dose-dependent style. They can effectively inhibit the growth of lung tumor in vivo. Among them, compound 8 and 11 have outstanding photodynamic anti-tumor effects without obvious skin photo-toxicity, so they can act as new drug candidates for photodynamic therapy.

The photodynamic activities of dimethyl 131-[2-(guanidinyl)ethylamino] chlorin e6 photosensitizers in A549 tumor

Effective photosensitizers are particularly important factor in clinical photodynamic therapy (PDT). However, there is a scarcity of photosensitizers for simultaneous cancer photo-diagnosis and targeted PDT. Herein, two novel dimethyl 2-(guanidinyl)ethylamino chlorin e₆ photosensitizers were synthesized and their efficacy in PDT in A549 tumor was investigated. It was shown that compounds 3 and 4 have a long absorption wavelength in the near infrared region and strong fluorescence emission with slow photo-bleaching rate and markedly strong ability of ¹O₂ generation. They exhibited lower cytotoxicity and higher photo-cytotoxicity in vitro compared to the known anticancer drug m-THPC in MTT assay in A549 lung cancer cell lines. Compound 4 exhibit better inhibition effect than compound 3 and the IC₅₀ value of compound 4 was 0.197 μM/L under 2 J/cm² laser irradiation, while compound 3 showed better anti-tumor effects compared to compound 4 in vivo. Intracellular ROS generation was found to be responsible for apoptotic cell death in DCFDA assay. Subcellular localization confirmed the damage site of compounds 3 and 4 in PDT. These findings suggest that the two novel photosensitizers might serve as potential photosensitizers for improved therapeutic efficiency of PDT.

Advances in nanocarriers as drug delivery systems in Chagas disease

Chagas disease is one of the most important public health problems in Latin America due to its high mortality and morbidity levels. There is no effective treatment for this disease since drugs are usually toxic with low bioavailability. Serious efforts to achieve disease control and eventual eradication have been unsuccessful to date, emphasizing the need for rapid diagnosis, drug development, and a reliable vaccine. Novel systems for drug and vaccine administration based on nanocarriers represent a promising avenue for Chagas disease treatment. Nanoparticulate systems can reduce toxicity, and increase the efficacy and bioavailability of active compounds by prolonging release, and therefore improve the therapeutic index. Moreover, nanoparticles are able to interact with the host's immune system, modulating the immune response to favour the elimination of pathogenic microorganisms. In addition, new advances in diagnostic assays, such as nanobiosensors, are beneficial in that they enable precise identification of the pathogen. In this review, we provide an overview of the strategies and nanocarrier-based delivery systems for antichagasic agents, such as liposomes, micelles, nanoemulsions, polymeric and non-polymeric nanoparticles. We address recent progress, with a particular focus on the advances of nanovaccines and nanodiagnostics, exploring new perspectives on Chagas disease treatment.

Hypericin photodynamic activity. Part III: in vitro evaluation in different nanocarriers against trypomastigotes of Trypanosoma cruzi

Chagas is a parasitic endemic disease caused by the protozoan Trypanosoma cruzi. It represents a strong threat to public health due to its strong resistance against commonly available drugs. We studied the in vitro ability to inactivate the trypomastigote form of this parasite using photodynamic inactivation of microorganisms (or antimicrobial Photodynamic Therapy, aPDT). For this, we chose to use the photosensitizer hypericin (Hyp) formulated in ethanol/water (1% v/v) and Hyp loaded in the dispersion of different aqueous nanocarrier systems. These included polymeric micelles of F-127 and P-123 (both Pluronic™ surfactants), and liposomal vesicles of phospholipid 2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). These systems with Hyp had their activity compared against trypomastigote forms under light and in the dark. Hyp revealed a high level of effectiveness to eradicate protozoa in vitro. Samples at concentrations higher than 0.8 μmol L-1 of Hyp in Pluronic micelles showed efficacy even in the dark, with the EC50 around (6-8) μmol L-1. Therefore, Hyp/Pluronics can be used also as a chemotherapeutic agent. The best result for EC50 is at approximately 0.31 μmol L-1 for illuminated systems of Hyp in F-127 micelles. For Hyp in P-123 micelles under light, the results also led to a low EC50 value of 0.36 μmol L-1. The highest value of EC50 was 2.22 μmol L-1, which was found for Hyp/DPPC liposomes under light. For the Hyp-free (ethanol/water, 1% v/v)/illuminated group, the EC50 value was 0.37 μmol L-1, which also is a value that shows effectiveness. However, in free-form, Hyp is not protected against blood components, unlike when Hyp is loaded into the nanocarriers.

Biotin-conjugated PEGylated porphyrin self-assembled nanoparticles co-targeting mitochondria and lysosomes for advanced chemo-photodynamic combination therapy

In this study, the chemo-drug doxorubicin (DOX) was successfully encapsulated in PEG–biotin conjugated porphyrin SANs (DOX@TPP–PEG–biotin) and had synergistic effects after PDT action.