In vitro and in vivo characterization of temoporfin-loaded PEGylated PLGA nanoparticles for use in photodynamic therapy

Nanoemulsion applications in photodynamic therapy

Nanoemulsion, or nanoscaled-size emulsions, is a thermodynamically stable system formed by blending two immiscible liquids, blended with an emulsifying agent to produce a single phase. Nanoemulsion science has advanced rapidly in recent years, and it has opened up new opportunities in a variety of fields, including pharmaceuticals, biotechnology, food, and cosmetics. Nanoemulsion has been recognized as a potential drug delivery technology for various drugs, such as photosensitizing agents (PS). In photodynamic therapy (PDT), PSs produce cytotoxic reactive oxygen species under specific light irradiation, which oxidize the surrounding tissues. Over the past decades, the idea of PS-loaded nanoemulsions has received researchers' attention due to their ability to overcome several limitations of common PSs, such as limited permeability, non-specific phototoxicity, hydrophobicity, low bioavailability, and self-aggregation tendency. This review aims to provide fundamental knowledge of nanoemulsion formulations and the principles of PDT. It also discusses nanoemulsion-based PDT strategies and examines nanoemulsion advantages for PDT, highlighting future possibilities for nanoemulsion use.

Secure transplantation by tissue purging using photodynamic therapy to eradicate malignant cells

The field of photodynamic therapy (PDT) for treating various malignant neoplasms has been given researchers' attention due to its ability to be a selective and minimally invasive cancer therapy strategy. The possibility of tumor cell infection and hence high recurrence rates in cancer patients tends to restrict autologous transplantation. So, the photodynamic tissue purging process, which consists of selective photoinactivation of the malignant cells in the graft, is defined as a compromising strategy to purify contaminated tissues before transplantation. In this strategy, the direct malignant cells' death results from the reactive oxygen species (ROS) generation through the activation of a photosensitizer (PS) by light exposure in the presence of oxygen. Since new PS generations can effectively penetrate the tissue, PDT could be an ideal ex vivo tissue purging protocol that eradicates cancer cells derived from various malignancies. The challenge is that the applied pharmacologic ex vivo tissue purging should efficiently induce tumor cells with minor influence on normal tissue cells. This review aims to provide an overview of the current status of the most effective PDT strategies and PS development concerning their potential application in ex vivo purging before hematopoietic stem cell or ovarian tissue transplantation.

Photodynamic cancer therapy using liposomes as an advanced vesicular photosensitizer delivery system

The multidisciplinary field of photodynamic therapy (PDT) is a combination of photochemistry and photophysics sciences, which has shown tremendous potential for cancer therapy application. PDT employs a photosensitizing agent (PS) and light to form cytotoxic reactive oxygen species and subsequently oxidize light-exposed tissue. Despite numerous advantages of PDT and enormous progress in this field, common PSs are still far from ideal treatment because of their poor permeability, non-specific phototoxicity, side effects, hydrophobicity, weak bioavailability, and tendency to self-aggregation. To circumvent these limitations, PS can be encapsulated in liposomes, an advanced drug delivery system that has demonstrated the ability to enhance drug permeability into biological membranes and loading both hydrophobic and lipophilic agents. Moreover, liposomes can also be coated by targeting agents to improve delivery efficiency. The present review aims to summarize the principles of PDT, various PS generations, PS-loaded nanoparticles, liposomes, and their impact on PDT, then discuss recent photodynamic cancer therapy strategies using liposomes as PS-loaded vectors, and highlight future possibilities and perspectives.

Nanotechnology in cardiac stem cell therapy: cell modulation, imaging and gene delivery

The wide arena of applications opened by nanotechnology is multidimensional. It is already been proven that its prominence can continuously influence human life. The role of stem cells in curing degenerative diseases is another major area of research. Cardiovascular diseases are one of the major causes of death globally. Nanotechnology-assisted stem cell therapy could be used to tackle the challenges faced in the management of cardiovascular diseases. In spite of the positive indications and proven potential of stem cells to differentiate into cardiomyocytes for cardiac repair and regeneration during myocardial infarction, this therapeutic approach still remains in its infancy due to several factors such as non-specificity of injected cells, insignificant survival rate, and low cell retention. Attempts to improve stem cell therapy using nanoparticles have shown some interest among researchers. This review focuses on the major hurdles associated with cardiac stem cell therapy and the role of nanoparticles to overcome the major challenges in this field, including cell modulation, imaging, tracking and gene delivery.

This review summarizes the potential challenges present in cardiac stem cell therapy and the major role of nanotechnology to overcome these challenges including cell modulation, tracking and imaging of stem cells.

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

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

Augmented cytotoxicity using the physical adsorption of Poloxamer 188 on allicin-loaded gelatin nanoparticles

OBJECTIVES

The aim of this work was to study the effect of the physically adsorbed Poloxamer 188 coating polymer on the cytotoxic activity of allicin-loaded gelatin nanoparticles.

METHODS

The double desolvation method was utilised to prepare the nanoparticles which were characterised for particle size (PS), polydispersity index (PDI) and zeta potential and visualised using transmission electron microscopy. The coating density of the used polymer was determined using 1H-nuclear magnetic resonance (1H-NMR); 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to evaluate the cytotoxicity on HepG-2 cell lines.

KEY FINDINGS

The particles were spherical possessing a PS of 714 ± 25.21 nm and a PDI of 0.663 ± 0.143. These results together with the 1H-NMR results analysis confirmed the efficient coating of Poloxamer 188. The coating of particles rendered them more cytotoxic, scoring an IC50 of 6.736 µm (2-folds lower than the uncoated counter parts and 4-folds lesser than the allicin solution), and apt for cancer-targeting. Moreover, the prepared nanoparticles were stable to gamma-sterilisation and to a storage of 12 months.

CONCLUSIONS

Augmented cytotoxicity on HepG-2 cell lines was obtained using the physical adsorption of an abundant and relatively cheap material, Poloxamer 188, on allicin-loaded gelatin nanoparticles.

The challenges and applications of nanotechnology against bacterial resistance

Bacterial resistance to the antibiotics develops rapidly and is increasingly serious health concern in the world. It is an insoluble topic due to the multiple resistant mechanisms. The overexpression of relative activities of the efflux pump has proven to be a frequent and important source of bacterial resistance. Efflux transporters in the membrane from the resistant bacteria could play a key role to inhibit the intracellular drug intake and impede the drug activities. However, nanoparticles (NPs), one of the most frequently used encapsulation materials, could increase the intracellular accumulation of the drug and inhibit the transporter activity effectively. The rational and successful application of nanotechnology is a key factor in overcoming bacterial resistance. Furthermore, nanoparticles such as metallic, carbon nanotubes and so on, may prevent the development of drug resistance and be associated with antibiotic agents, inhibiting biofilm formation or increasing the access into the target cell and exterminating the bacteria eventually. In the current study, the mechanisms of bacterial resistance are discussed and summarized. Additionally, the opportunities and challenges in the use of nanoparticles against bacterial resistance are also illuminated. At the same time, the use of nanoparticles to combat multidrug-resistant bacteria is also investigated by coupling natural antimicrobials or other alternatives. In short, we have provided a new perspective for the application of nanoparticles against multidrug-resistant bacteria.

PLGA-Based Drug Delivery Systems for Remotely Triggered Cancer Therapeutic and Diagnostic Applications

Intelligent drug delivery systems based on nanotechnology have been widely developed and investigated in the field of nanomedicine since they were able to maximize the therapeutic efficacy and minimize the undesirable adverse effects. Among a variety of organic or inorganic nanomaterials available to fabricate drug delivery systems (DDSs) for cancer therapy and diagnosis, poly(D,L-lactic-co-glycolic acid) (PLGA) has been extensively employed due to its biocompatibility and biodegradability. In this paper, we review the recent status of research on the application of PLGA-based drug delivery systems (DDSs) in remotely triggered cancer therapy and the strategies for tumor imaging provided by PLGA-based DDSs. We firstly discuss the employment of PLGA-based DDSs for remotely triggered cancer therapy, including photo-triggered, ultrasound-triggered, magnetic field-triggered, and radiofrequency-triggered cancer therapy. Photo-triggered cancer therapy involves photodynamic therapy (PDT), photothermal therapy (PTT), and photo-triggered chemotherapeutics release. Ultrasound-triggered cancer therapy involves high intensity focused ultrasound (HIFU) treatment, ultrasound-triggered chemotherapeutics release, and ultrasound-enhanced efficiency of gene transfection. The strategies which endows PLGA-based DDSs with imaging properties and the PLGA-based cancer theranostics are further discussed. Additionally, we also discuss the targeting strategies which provide PLGA-based DDSs with passive, active or magnetic tumor-targeting abilities. Numerous studies cited in our review demonstrate the great potential of PLGA-based DDSs as effective theranostic agent for cancer therapy and diagnosis.

Multifunctional, CD44v6-Targeted ORMOSIL Nanoparticles Enhance Drugs Toxicity in Cancer Cells

Drug-loaded, PEGylated, organic-modified silica (ORMOSIL) nanoparticles prepared by microemulsion condensation of vinyltriethoxysilane (VTES) were investigated as potential nanovectors for cancer therapy. To target cancer stem cells, anti-CD44v6 antibody and hyaluronic acid (HA) were conjugated to amine-functionalized PEGylated ORMOSIL nanoparticles through thiol-maleimide and amide coupling chemistries, respectively. Specific binding and uptake of conjugated nanoparticles were studied on cells overexpressing the CD44v6 receptor. Cytotoxicity was subsequently evaluated in the same cells after the uptake of the nanoparticles. Internalization of nanocarriers loaded with the anticancer drug 3N-cyclopropylmethyl-7-phenyl-pyrrolo- quinolinone (MG2477) into cells resulted in a substantial increase of the cytotoxicity with respect to the free formulation. Targeting with anti-CD44v6 antibodies or HA yielded nanoparticles with similar effectiveness, in their optimized formulation.

Current state of the nanoscale delivery systems for temoporfin-based photodynamic therapy: Advanced delivery strategies

Enthusiasm for photodynamic therapy (PDT) as a promising technique to eradicate various cancers has increased exponentially in recent decades. The majority of clinically approved photosensitizers are hydrophobic in nature, thus, the effective delivery of photosensitizers at the targeted site is the main hurdle associated with PDT. Temoporfin (mTHPC, medicinal product name: Foscan®), is one of the most potent clinically approved photosensitizers, is not an exception. Successful temoporfin-PDT requires nanoscale delivery systems for selective delivery of photosensitizer. Over the last 25 years, the number of papers on nanoplatforms developed for mTHPC delivery such as conjugates, host-guest inclusion complexes, lipid-and polymer-based nanoparticles and carbon nanotubes is burgeoning. However, none of them appeared to be "ultimate". The present review offers the description of different challenges and achievements in nanoparticle-based mTHPC delivery focusing on the synergetic combination of various nano-platforms to improve temoporfin delivery at all stages of biodistribution. Furthermore, the association of different nanoparticles in one nanoplatform might be considered as an advanced strategy allowing the combination of several treatment modalities.

Evaluation of mTHPC-loaded PLGA nanoparticles for in vitro photodynamic therapy on C6 glioma cell line

Photodynamic therapy (PDT) is a very attractive strategy to complement or replace common cancer treatments such as radiotherapy, surgery, and chemotherapy. Some molecules have shown their efficiency as photosensitizers (PS), still many issues have to be solved such as the inherent cytotoxicity of the PS or its hydrophobic properties causing limitation in their solubility, leading to side effects. In this study, the encapsulation of an approved PS, the meso-tetra hydroxyphenylchlorine (mTHPC, Foscan®) within biocompatible and biodegradable poly(D, l-lactide-co-glycolide) acid (PLGA) NPs prepared by the nanoprecipitation method was studied. The mTHPC-loaded NPs (mTHPC ⊂ PLGA NPs) were analyzed by UV-vis spectroscopy to determine the efficiency of mTHPC encapsulation, and by dynamic light scattering (DLS) and atomic force microscopy (AFM) to determine mTHPC ⊂ PLGA NPs sizes, morphologies and surface charges. The longitudinal follow-up of mTHPC release from the NPs indicated that 50% of the encapsulated PS was retained within the NP matrix after a period of five days. Finally, the cytotoxicity and the phototoxicity of the mTHPC ⊂ PLGA NPs were determined in murine C6 glioma cell lines and compared to the ones of mTHPC alone. The studies showed a strong decrease of mTHPC cytotoxicity and an increase of mTHPC photo-cytotoxicity when mTHPC was encapsulated. In order to have a better insight of the underlying cellular mechanisms that governed cell death after mTHPC ⊂ PLGA NPs incubation and irradiation, annexin V staining tests were performed. The results indicated that apoptosis was the main cell death mechanism.

Pre-Conditioning Stem Cells in a Biomimetic Environment for Enhanced Cardiac Tissue Repair: In Vitro and In Vivo Analysis

Introduction

Stem cell-based therapies represent a valid approach to restore cardiac function due to their beneficial effect in reducing scar area formation and promoting angiogenesis. However, their translation into the clinic is limited by the poor differentiation and inability to secrete sufficient therapeutic factors. To address this issue, several strategies such as genetic modification and biophysical preconditioning have been used to enhance the efficacy of stem cells for cardiac tissue repair.

Methods

In this study, a biomimetic approach was used to mimic the natural mechanical stimulation of the myocardium tissue. Specifically, human adipose-derived stem cells (hASCs) were cultured on a thin gelatin methacrylamide (GelMA) hydrogel disc and placed on top of a beating cardiomyocyte layer. qPCR studies and metatranscriptomic analysis of hASCs gene expression were investigated to confirm the correlation between mechanical stimuli and cardiomyogenic differentiation. In vivo intramyocardial delivery of pre-conditioned hASCs was carried out to evaluate their efficacy to restore cardiac function in mice hearts post-myocardial infarction.

Results

The cyclic strain generated by cardiomyocytes significantly upregulated the expression of both mechanotransduction and cardiomyogenic genes in hASCs as compared to the static control group. The inherent angiogenic secretion profile of hASCs was not hindered by the mechanical stimulation provided by the designed biomimetic system. Finally, in vivo analysis confirmed the regenerative potential of the pre-conditioned hASCs by displaying a significant improvement in cardiac function and enhanced angiogenesis in the peri-infarct region.

Conclusion

Overall, these findings indicate that cyclic strain provided by the designed biomimetic system is an essential stimulant for hASCs cardiomyogenic differentiation, and therefore can be a potential solution to improve stem-cell based efficacy for cardiovascular repair.

meso-Tetrahydroxyphenylchlorin-Conjugated Gold Nanoparticles as a Tool To Improve Photodynamic Therapy

Photodynamic therapy (PDT) is a promising therapeutic modality for cancer. However, current protocols using bare drugs suffer from several limitations that impede its beneficial clinical effects. Here, we introduce a new approach for an efficient PDT treatment. It involves conjugating a PDT agent, meso-tetrahydroxyphenylchlorin (mTHPC) photosensitizer, to gold nanoparticles (AuNPs) that serve as carriers for the drug. AuNPs have a number of characteristics that make them highly suitable to function as drug carriers: they are biocompatible, serve as biomarkers, and function as contrast agents in vitro and in vivo. We synthesized AuNPs and covalently conjugated the mTHPC drug molecules through a linker. The resultant functional complex, AuNP-mTHPC, is a stable, soluble compound. SH-SY5Y human neuroblastoma cells were incubated with the complex, showing possible administration of higher doses of drug when conjugated to the AuNPs. Then cells were irradiated with a laser beam at 650 nm to mimic the PDT procedure. Our study shows higher rates of cell death in cells incubated with the AuNP-mTHPC complex compared to the incubation with the free drug. Using the new complex may form the basis for a better PDT strategy for a wide range of cancers.

Polymer-Based Nanomaterials and Applications for Vaccines and Drugs

Nanotechnology plays a significant role in drug development. As carriers, polymeric nanoparticles can deliver vaccine antigens, proteins, and drugs to the desired site of action. Polymeric nanoparticles with lower cytotoxicity can protect the delivered antigens or drugs from degradation under unfavorable conditions via a mucosal administration route; further, the uptake of nanoparticles by antigen-presenting cells can increase and induce potent immune responses. Additionally, nanomaterials are widely used in vaccine delivery systems because nanomaterials can make the vaccine antigen long-acting. This review focuses on some biodegradable polymer materials such as natural polymeric nanomaterials, chemically synthesized polymer materials, and biosynthesized polymeric materials, and points out the advantages and the direction of research on degradable polymeric materials. The application and future perspectives of polymeric materials as delivery carriers and vaccine adjuvants in the field of drugs and vaccines are presented. With the increase of knowledge and fundamental understandings of polymer-based nanomaterials, means of integrating some other attractive properties, such as slow release, target delivery, and alternative administration methods and delivery pathways are feasible. Polymer-based nanomaterials have great potential for the development of novel vaccines and drug systems for certain needs, including single-dose and needle-free deliveries of vaccine antigens and drugs in the future.

Silica-based nanoparticles are efficient delivery systems for temoporfin

BACKGROUND

Drug targeting using functionalized nanoparticles to advance their transport to the dedicated site became a new standard in novel anticancer methods Anticancer photodynamic therapy also takes benefit from using nanoparticles by means of increasing targeting efficiency and decreased side effect. With this in mind, the silica-based nanoparticles, as drug delivery systems for the second-generation photosensitizer 5,10,15,20-tetrakis(m-hydroxyphenyl) chlorin (temoporfin) were developed.

METHODS

In order to determine the stability and therapeutic performance of the selected nanomaterials in physiological fluids, their physicochemical properties (i.e. size, polydispersity, zeta potential) were measured by dynamic light scattering technique and the diameter and the morphology of the individual particles were visualized by a transmission electron microscopy. Their efficacy was compared with commercial temoporfin formulation in terms of in vitro phototoxicity in 4T1 (murine mammary carcinoma) and of in vivo anticancer effect in Nu/Nu mice bearing MDA-MB-231 tumors.

RESULTS AND CONCLUSIONS

The two types of silica nanoparticles, porous and non-porous and with different surface chemical modification, were involved and critically compared within the study. Their efficacy was successfully demonstrated and was shown to be superior in comparison with commercial temoporfin formulation in terms of in vitro phototoxicity and cellular uptake as well as in terms of in vivo anticancer effect on human breast cancer model. Temoporfin-loaded silica nanoparticles also passed through the blood-brain barrier showing potential for the treatment of brain metastases.

Strategies for optimizing the delivery to tumors of macrocyclic photosensitizers used in photodynamic therapy (PDT)

This review briefly summaries the principles and mechanisms of action of photodynamic therapy (PDT) as concerns its application in the oncological field, highlighting its drawbacks and some of the strategies that have been or are being explored to overcome them. The major aim is to increase the efficiency and selectivity of the photosensitizer (PS) uptake in the cancer cells for optimizing the PDT effects on tumors while sparing normal cells. Some attempts to achieve this are based on the conjugation of the PS to biomolecules (small ligands, peptides) functioning as carriers with the ability to efficiently penetrate cells and/or specifically recognize and bind proteins/receptors overexpressed on the surface of cancer cells. Alternatively, the PS can be entrapped in nanocarriers derived from various types of materials that can target the tumor by exploiting the enhanced permeability and retention (EPR) effects. The use of nanocarriers is particularly attractive because it allows the simultaneous delivery of more than one drug with the possibility of combining PDT with other therapeutic modalities.

Studying the effect of physically-adsorbed coating polymers on the cytotoxic activity of optimized bisdemethoxycurcumin loaded-PLGA nanoparticles

The aim of this work was to study the effect of different physically-adsorbed coating polymers on the cytotoxic activity of optimized bisdemethoxycurcumin (BDMC) loaded-PLGA nanoparticles. BDMC-loaded poly(DL-lactide-co-glycolide) (PLGA) nanoparticles were prepared adopting the nanoprecipitation technique according to a full factorial study design. The effects of three independent variables each at two levels, namely: the polymer type, polymer concentration, and poly vinyl alcohol concentration were studied. The particles were optimized regarding particle size and entrapment efficiency where sizes <200 nm and entrapment efficiencies reaching ∼98% were obtained. The particles were further characterized using x-ray diffraction, transmission electron microscopy, and in-vitro release studies. A selected formulation was subjected to physical coating using various coating moieties, namely: PEG 4000, Tween 80 and Pluronic F68, to impart a hydrophilic stealth character to the surface. The surface hydrophobicity was assessed using the Rose Bengal dye test where the hydrophilicity character followed the following order: Tween 80 > PEG 4000 > Pluronic F68. The particles coating rendered the particles suitable for cancer-targeting regarding particle size measurements, morphology, release kinetics, and stability studies. Moreover, cytotoxicity testing was performed using HepG-2 cells. Coated NPs showed the highest inhibition of malignant cells viability compared to the uncoated NPs and free BDMC where the IC₅₀ of Pluronic-F68 coated NPs was 0.54 ± 0.01 µg/mL. The augmented effect against malignant cells poses these particles as a successful cancer remedy. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1433-1445, 2017.

Nano-encapsulation of a novel anti-Ran-GTPase peptide for blockade of regulator of chromosome condensation 1 (RCC1) function in MDA-MB-231 breast cancer cells

Ran is a small ras-related GTPase and is highly expressed in aggressive breast carcinoma. Overexpression induces malignant transformation and drives metastatic growth. We have designed a novel series of anti-Ran-GTPase peptides, which prevents Ran hydrolysis and activation, and although they display effectiveness in silico, peptide activity is suboptimal in vitro due to reduced bioavailability and poor delivery. To overcome this drawback, we delivered an anti-Ran-GTPase peptide using encapsulation in PLGA-based nanoparticles (NP). Formulation variables within a double emulsion solvent evaporation technique were controlled to optimise physicochemical properties. NP were spherical and negatively charged with a mean diameter of 182-277nm. Peptide integrity and stability were maintained after encapsulation and release kinetics followed a sustained profile. We were interested in the relationship between cellular uptake and poly(ethylene glycol) (PEG) in the NP matrix, with results showing enhanced in vitro uptake with increasing PEG content. Peptide-loaded, pegylated (10% PEG)-PLGA NP induced significant cytotoxic and apoptotic effects in MDA-MB-231 breast cancer cells, with no evidence of similar effects in cells pulsed with free peptide. Western blot analysis showed that encapsulated peptide interfered with the proposed signal transduction pathway of the Ran gene. Our novel blockade peptide prevented Ran activation by blockage of regulator of chromosome condensation 1 (RCC1) following peptide release directly in the cytoplasm once endocytosis of the peptide-loaded nanoparticle has occurred. RCC1 blockage was effective only when a nanoparticulate delivery approach was adopted.

Photo-Cross-Linkable Polymer Dots with Stable Sensitizer Loading and Amplified Singlet Oxygen Generation for Photodynamic Therapy

Photodynamic therapy (PDT) is a promising treatment modality for clinical cancer therapy. However, the therapeutic effect of PDT is strongly dependent on the property of photosensitizer. Here, we developed photo-cross-linkable semiconductor polymer dots doped with photosensitizer Chlorin e6 (Ce6) to construct a nanoparticle platform for photodynamic therapy. Photoreactive oxetane groups were attached to the side chains of the semiconductor polymer. After photo-cross-linking reaction, the Ce6-doped Pdots formed an interpenetrated structure to prevent Ce6 leaching out from the Pdot matrix. Spectroscopic characterizations revealed an efficient energy transfer from the polymer to Ce6 molecules, resulting in amplified generation of singlet oxygen. We evaluated the cellular uptake, cytotoxicity, and photodynamic effect of the Pdots in gastric adenocarcinoma cells. In vitro photodynamic experiments indicated that the Ce6-doped Pdots (∼10 μg/mL) effectively killed the cancer cells under low dose of light irradiation (∼60 J/cm²). Furthermore, in vivo photodynamic experiments were carried out in tumor-bearing nude mice, which indicated that the Pdot photosensitizer apparently suppressed the growth of solid tumors. Our results demonstrate that the photo-cross-linkable Pdots doped with photosensitizer are promising for photodynamic cancer treatment.

Angiopoietin-1 Modified Human Umbilical Cord Mesenchymal Stem Cell Therapy for Endotoxin-Induced Acute Lung Injury in Rats

PURPOSE

Angiopoietin-1 (Ang1) is a critical factor for vascular stabilization and endothelial survival via inhibition of endothelial permeability and leukocyte- endothelium interactions. Hence, we hypothesized that treatment with umbilical cord mesenchymal stem cells (UCMSCs) carrying the Ang1 gene (UCMSCs-Ang1) might be a potential approach for acute lung injury (ALI) induced by lipopolysaccharide (LPS).

MATERIALS AND METHODS

UCMSCs with or without transfection with the human Ang1 gene were delivered intravenously into rats one hour after intra-abdominal instillation of LPS to induce ALI. After the rats were sacrificed at 6 hours, 24 hours, 48 hours, 8 days, and 15 days post-injection of LPS, the serum, the lung tissues, and bronchoalveolar lavage fluid (BALF) were harvested for analysis, respectively.

RESULTS

Administration of fluorescence microscope confirmed the increased presence of UCMSCs in the injured lungs. The evaluation of UCMSCs and UCMSCs-Ang1 actions revealed that Ang1 overexpression further decreased the levels of the pro-inflammatory cytokines TNF-α, TGF-β₁, and IL-6 and increased the expression of the anti-inflammatory cytokine IL-10 in the injured lungs. This synergy caused a substantial decrease in lung airspace inflammation and vascular leakage, characterized by significant reductions in wet/dry ratio, differential neutrophil counts, myeloperoxidase activity, and BALF. The rats treated by UCMSCs-Ang1 showed improved survival and lower ALI scores.

CONCLUSION

UCMSCs-Ang1 could improve both systemic inflammation and alveolar permeability in ALI. UC-derived MSCs-based Ang1 gene therapy may be developed as a potential novel strategy for the treatment of ALI.

Poly-(D,L-lactide-co-glycolide) nanoparticles with covalently-bound porphyrins for efficient singlet oxygen photosensitization

With the aim of assessing the role of the chemical structure of the photosensitizer on the photophysical and photochemical properties of the final nanoparticle suspension, we have investigated a series of poly-(ethylene glycol)-poly-([Formula: see text]-lactide-co-glycolide) nanoparticles containing a hydrophobic or a hydrophilic porphyrin covalently conjugated to the nanoparticle. Covalent conjugation responded to the objective of trying to improve photosensitizer loading in these nanoparticles, especially for hydrophilic photosensitizers, but also enabled the porphyrins to remain attached to the nanoparticle without necessarily being inside the poly-([Formula: see text]-lactide-co-glycolide) core. This strategy has provided valuable information about the dependence of the photophysical and singlet oxygen photosensitizing properties of the suspensions on the nature of the photosensitizer. It is concluded that poly-([Formula: see text]-lactide-co-glycolide) nanoparticles with covalently-bound hydrophilic porphyrins show superior singlet oxygen photosensitizing ability.

Lipid nanoemulsions and liposomes improve photodynamic treatment efficacy and tolerance in CAL-33 tumor bearing nude mice

Background

Photodynamic therapy (PDT) as promising alternative to conventional cancer treatments works by irradiation of a photosensitizer (PS) with light, which creates reactive oxygen species and singlet oxygen (¹O₂), that damage the tumor. However, a routine use is hindered by the PS’s poor water solubility and extended cutaneous photosensitivity of patients after treatment. In our study we sought to overcome these limitations by encapsulation of the PS m-tetrahydroxyphenylchlorin (mTHPC) into a biocompatible nanoemulsion (Lipidots).

Results

In CAL-33 tumor bearing nude mice we compared the Lipidots to the existing liposomal mTHPC nanoformulation Foslip and the approved mTHPC formulation Foscan. We established biodistribution profiles via fluorescence measurements in vivo and high performance liquid chromatography (HPLC) analysis. All formulations accumulated in the tumors and we could determine the optimum treatment time point for each substance (8 h for mTHPC, 24 h for Foslip and 72 h for the Lipidots). We used two different light doses (10  and 20 J/cm²) and evaluated immediate PDT effects 48 h after treatment and long term effects 14 days later. We also analyzed tumors by histological analysis and performing reverse transcription real-time PCR with RNA extracts. Concerning tumor destruction Foslip was superior to Lipidots and Foscan while with regard to tolerance and side effects Lipidots were giving the best results.

Conclusions

We could demonstrate in our study that nanoformulations are superior to the free PS mTHPC. The development of a potent nanoformulation is of major importance because the free PS is related to several issues such as poor bioavailability, solubility and increased photosensibility of patients. We could show in this study that Foslip is very potent in destroying the tumors itself. However, because the Lipidots' biocompatibility is outstanding and superior to the liposomes we plan to carry out further investigations and protocol optimization. Both nanoformulations show great potential to revolutionize PDT in the future.

Electronic supplementary material

The online version of this article (doi:10.1186/s12951-016-0223-8) contains supplementary material, which is available to authorized users.

In vitro IFN-α release from IFN-α- and pegylated IFN-α-loaded poly(lactic-co-glycolic acid) and pegylated poly(lactic-co-glycolic acid) nanoparticles

Aim: Interferon alpha (IFN-α) controlled release of nanoparticles was investigated under in vitro conditions. Materials & methods: IFN-α and pegylated IFN-α (PEG-IFN-α) were encapsulated by poly(lactic-co-glycolic acid) (PLGA) and pegylated PLGA (PEG-PLGA) copolymers using double emulsion solvent evaporation method. Results: The size of resulting four nanoparticles (IFN-α in poly(lactic-co-glycolic acids), IFN-α in poly(lactic-co-glycolic acid)-polyethylene glycol, PEG-IFN-α in poly(lactic-co-glycolic acids) and PEG-IFN-α in poly(lactic-co-glycolic acid)-polyethylene glycol) was below 130 nm diameter. IFN-α encapsulation efficiency of the nanoparticles was between 78 and 91%. Conclusion: The in vitro drug release studies conducted in phosphate-buffered saline and human plasma highlighted the role of incubation medium on the IFN release from the nanoparticles. The PEG-IFN-α in poly(lactic-co-glycolic acid)-polyethylene glycol was the most promising nanoparticle among the four formulations because of its remarkably constant release in both phosphate-buffered saline and plasma.

Polymeric Nanohybrids as a New Class of Therapeutic Biotransporters

A possible solution to enhance existing drug and gene therapies is to develop hybrid nanocarriers capable of delivering therapeutic agents in a controlled and targeted manner. This goal can be achieved by designing nanohybrid systems, which combine organic or inorganic nanomaterials with biomacromolecules into a single composite. The unique combination of properties along with their facile fabrication enables the design of smart carriers for both drug and gene delivery. These hybrids can be further modified with cell targeting motifs to enhance their biological interactivity. In this Talents and Trends article, an overview of emerging nanohybrid-based technologies will be provided to highlight their potential use as innovative platforms for improved cancer therapies and new strategies in regenerative medicine. The clinical relevance of these systems will be reviewed to define the current challenges which still need to be addressed to allow these therapies to move from bench to bedside.

Nanoparticle drug delivery systems and their use in cardiac tissue therapy

Cardiovascular diseases make up one of the main causes of death today, with myocardial infarction and ischemic heart disease contributing a large share of the deaths reported. With mainstream clinical therapy focusing on palliative medicine following myocardial infarction, the structural changes that occur in the diseased heart will eventually lead to end-stage heart failure. Heart transplantation remains the only gold standard of cure but a shortage in donor organs pose a major problem that led to clinicians and researchers looking into alternative strategies for cardiac repair. This review will examine some alternative methods of treatment using chemokines and drugs carried by nanoparticles as drug delivering agents for the purposes of treating myocardial infarction through the promotion of revascularization. We will also provide an overview of existing studies involving such nanoparticulate drug delivery systems, their reported efficacy and the challenges facing their translation into ubiquitous clinical use.

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.

Poly(D, L-lactide-co-glycolide) nanoparticles as delivery agents for photodynamic therapy: enhancing singlet oxygen release and photototoxicity by surface PEG coating

Poly(D, L-lactide-co-glycolide) (PLGA) nanoparticles (NPs) are being considered as nanodelivery systems for photodynamic therapy. The physico-chemical and biological aspects of their use remain largely unknown. Herein we report the results of a study of PLGA NPs for the delivery of the model hydrophobic photosensitizer ZnTPP to HeLa cells. ZnTPP was encapsulated in PLGA with high efficiency and the NPs showed negative zeta potentials and diameters close to 110 nm. Poly(ethylene glycol) (PEG) coating, introduced to prevent opsonization and clearance by macrophages, decreased the size and zeta potential of the NPs by roughly a factor of two and improved their stability in the presence of serum proteins. Photophysical studies revealed two and three populations of ZnTPP and singlet oxygen in uncoated and PEGylated NPs, respectively. Singlet oxygen is confined within the NPs in bare PLGA while it is more easily released into the external medium after PEG coating, which contributes to a higher photocytotoxicity towards HeLa cells in vitro. PLGA NPs are internalized by endocytosis, deliver their cargo to lysosomes and induce cell death by apoptosis upon exposure to light. In conclusion, PLGA NPs coated with PEG show high potential as delivery systems for photodynamic applications.

Nanocarriers for photodynamic therapy-rational formulation design and medium-scale manufacture

The development and manufacture of novel nanocarriers for drug delivery has proved challenging with regards to scale-up and pharmaceutical quality. Polymeric nanocarriers composed of poly(lactic-co-glycolic acid)-b-poly(ethylene glycol) (PLGA-PEG) were prepared and the photosensitizer meso-tetrakis(3-hydroxyphenyl) chlorin (mTHPC) was effectively encapsulated. Furthermore, the interplay of various process and formulation parameters and their impact on the most important product specifications were investigated by using a factorial design and a central composite design in a microfluidic manufacturing process. These nanoparticles for intravenous administration with a size of 97 ± 0.13 nm, narrow size distribution, and an encapsulation efficiency of more than 80% were produced at high throughput. In vitro stability and in vitro drug release testing were applied for quality control purposes. Finally, the toxicity of the photosensitizer was tested in vitro. The cytotoxicity was successfully reduced while the efficacy of the formulation was maintained. First observations using in vivo imaging suggest effective distribution of the nanocarrier system after injection into rodents. Thus, further in vivo testing of the beneficial effects of nanoencapsulation into the matrix system and its formulation will be considered for the delivery of mTHPC to tumor tissues during photodynamic therapy.

Baculovirus-mediated gene delivery and RNAi applications

Baculoviruses are widely encountered in nature and a great deal of data is available about their safety and biology. Recently, these versatile, insect-specific viruses have demonstrated their usefulness in various biotechnological applications including protein production and gene transfer. Multiple in vitro and in vivo studies exist and support their use as gene delivery vehicles in vertebrate cells. Recently, baculoviruses have also demonstrated high potential in RNAi applications in which several advantages of the virus make it a promising tool for RNA gene transfer with high safety and wide tropism.

Targeted photodynamic therapy in head and neck squamous cell carcinoma: heading into the future

The aim of this article is to give an insight into the future of photodynamic therapy (PDT) in head and neck squamous cell carcinoma (HNSCC). Through the combination of a photosensitizing agent with light and oxygen, PDT produces highly cytotoxic reactive oxygen species leading to selective tumor eradication. PDT is an attractive treatment for focal therapy of localized tumors, especially in the case of unresectable tumors. In HNSCC, over 1500 patients have been treated by PDT, and the majority of them responded quite favorably to this treatment. However, the non-negligible photosensitization of healthy tissue is a major limitation for the clinical application of PDT. Improvement in tumor selectivity is the main challenge that can be taken up by the use of a new generation of photosensitizing nanoparticles. Passive targeting, by using functionalised nanocarriers to target to overexpressed transmembrane receptors afford attractive solutions. To this day, epidermal growth factor receptor (EGFR) remains the only validated molecular target for HNSCC, and photosensitizer immunoconjugates to EGFR have been developed for the intracellular delivery of photosensitizing agents. Depending on coordinated research between biomarkers, specific ligands, and photosensitizers, similar approaches could be rapidly developed. In addition, some photosensitizers hold high fluorescence yield and therefore could emerge as theranostic agents.

Therapeutic application of adipose derived stem cells in acute myocardial infarction: lessons from animal models

The majority of patients survive an acute myocardial infarction (AMI). Their outcome is negatively influenced by post-AMI events, such as loss of viable cardiomyocytes due to a post-AMI inflammatory response, eventually resulting in heart failure and/or death. Recent pre-clinical animal studies indicate that mesenchymal stem cells derived from adipose tissue (ASC) are new promising candidates that may facilitate cardiovascular regeneration in the infarcted myocardium. In this review we have compared all animal studies in which ASC were used as a therapy post-AMI and have focused on aspects that might be important for future successful clinical application of ASC.

π-π Stacking induced enhanced molecular solubilization, singlet oxygen production, and retention of a photosensitizer loaded in thermosensitive polymeric micelles

Cancer photodynamic therapy (PDT) by photosensitizers (PS)-loaded polymeric micelles (PM) is hampered by the tendency of PS to aggregate in PM and/or by premature release of PS in the blood circulation. In the present study, aromatic thermosensitive PM, characterized by π-π stacking interaction, are used to encapsulate an axially solketal-substituted silicon phthalocyanine (Si(sol)2 Pc) with enhanced loading capacity, smaller size, and significantly improved retention of Si(sol)2 Pc compared with systems based on thermosensitive PM lacking aromatic groups. Interestingly, Si(sol)2 Pc is much less prone to aggregation in the aromatic PM, i.e., the amount of Si(sol)2 Pc that could be encapsulated without aggregation is 330 times higher in the aromatic PM than in the nonaromatic PM. Furthermore, Si(sol)2 Pc in the aromatic PM in a molecularly dissolved (non-aggregated) form displays three times more efficient singlet oxygen production than Si(sol)2 Pc aggregated in the non-aromatic PM. As a result, the photocytotoxicity of Si(sol)2 Pc-loaded aromatic PM to B16F10 cells is increased, compared with that of the non-aromatic PM, while no significant cytotoxicity is observed in the dark. Fluorescence-activated cell sorting (FACS) and confocal laser scanning microscopy (CLSM) analysis shows cell uptake of Si(sol)2 Pc loaded in the aromatic PM, and the Si(sol)2 Pc is taken up by the cells together with the micelles. The efficient singlet oxygen production of Si(sol)2 Pc dissolved in the aromatic PM makes it an interesting formulation for cancer PDT.

A new magnetic resonance imaging contrast agent loaded into poly(lacide-co-glycolide) nanoparticles for long-term detection of tumors

The incorporation of a lipophilic Gd chelate (GdDO3A-C12) in biocompatible PLGA poly(D, L-lactide-co-glycolide) nanoparticles was explored as an approach to increase the relaxivity of contrast agents for magnetic resonance imaging. By nanoprecipitation, it was possible to obtain PEGylated gadolinium nanoparticles (mean diameter of 155 nm) with high Gd loading (1.1 × 10(4) Gd centers per nanoparticle). The corresponding GdDO3AC12 ⊂ NPs nanoparticles exhibited an enhanced relaxivity (up to sixfold greater than DOTAREM® at 40 MHz) because the nanoparticle framework constrained the lipophilic Gd chelate motion and favorably impacted the Gd chelate rotational correlation time. T1-weighted imaging at 3 T on phantoms showed enhanced contrast for the GdDO3AC12 ⊂ NPs. Importantly, Gd chelate leakage was almost nonexistent, which suggested that these GdDO3AC12 ⊂ NPs could be useful for long-term MRI detection.

Application of adipose-derived stem cells in heart disease

Therapy with mesenchymal stem cells is one of the promising tools to improve outcomes after myocardial infarction. Adipose-derived stem cells (ASCs) are an ideal source of mesenchymal stem cells due to their abundance and ease of preparation. Studies in animal models of myocardial infarction have demonstrated the ability of injected ASCs to engraft and differentiate into cardiomyocytes and vasculature cells. ASCs secrete a wide array of angiogenic and anti-apoptotic paracrine factors such as vascular endothelial growth factor, hepatocyte growth factor, and insulin-like growth factor 1. ASCs are capable of enhancing heart function, reducing myocardial infarction, promoting vascularization, and reversing remodeling in the ischemically injured hearts. Furthermore, several ongoing clinical trials using ASCs are producing promising results for heart diseases. This article reviews the isolation, differentiation, immunoregulatory properties, mechanisms of action, animal models, and ongoing clinical trials of ASCs for cardiac disease.

Protein synthesis and secretion in human mesenchymal cells derived from bone marrow, adipose tissue and Wharton's jelly

Introduction

Different mesenchymal stromal cells (MSC) have been successfully isolated and expanded in vitro and nowadays they are tested in clinical trials for a wide variety of diseases. Whether all MSC express the same cell surface markers or have a similar secretion profile is still controversial, making it difficult to decide which stromal cell may be better for a particular application.

Methods

We isolated human mesenchymal stromal cells from bone marrow (BM), adipose tissue (AT) and Wharton’s jelly (WJ) and cultured them in fetal bovine serum supplemented media. We evaluated proliferation, in vitro differentiation (osteogenic, adipogenic and chondrogenic potential), expression of cell surface markers and protein secretion using Luminex and ELISA assays.

Results

Cell proliferation was higher for WJ-MSC, followed by AT-MSC. Differences in surface expression markers were observed only for CD54 and CD146. WJ-MSC secreted higher concentrations of chemokines, pro-inflammatory proteins and growth factors. AT-MSC showed a better pro-angiogenic profile and secreted higher amounts of extracellular matrix components and metalloproteinases.

Conclusions

Mesenchymal stromal cells purified from different tissues have different angiogenic, inflammatory and matrix remodeling potential properties. These abilities should be further characterized in order to choose the best protocols for their therapeutic use.

Bioactive baculovirus nanohybrids for stent based rapid vascular re-endothelialization

Present study, for the first time, reports the development of a nanohybridized baculovirus based stent that can locally promote vascular re-endothelialization by efficient delivery of pro-angiogenic vascular endothelial growth factor (Vegf) genes. In vitro data demonstrated rapid expression of functionally active Vegf by the bioactive stent-transduced vascular cells. In vivo site-specific transgene expression was observed at the stented regions of balloon-denuded canine femoral artery, which eventually lead to significant endothelial recovery at the injured sites. A significant reduction in neointima formation (2.23 ± 0.56 mm² vs 2.78 ± 0.49 mm² and 3.11 ± 0.23 mm², p < 0.05; n = 8) and percent stenosis was observed in treated stent group compared to negative control and bare metal stent groups. These findings collectively implicate the potential of this newly developed baculovirus based biotherapeutic stent to ameliorate damaged vascular biology and attenuate re-narrowing of stented artery by inhibiting neointima formation.

Stimulating the neurotrophic and angiogenic properties of human adipose-derived stem cells enhances nerve repair

In future, adipose-derived stem cells (ASC) might be used to treat neurological disorders. In this study, the neurotrophic and angiogenic properties of human ASC were evaluated, and their effects in a peripheral nerve injury model were determined. In vitro growth factor stimulation of the cells resulted in increased secretion of brain-derived neurotrophic factor (BDNF), glial cell-derived neurotrophic factor (GDNF), vascular endothelial growth factor-A (VEGF-A), and angiopoietin-1 proteins. Conditioned medium from stimulated cells increased neurite outgrowth of dorsal root ganglia (DRG) neurons. Similarly, stimulated cells showed an enhanced ability to induce capillary-like tube formation in an in vitro angiogenesis assay. ASC were seeded into a fibrin conduit that was used to bridge a 10 mm rat nerve gap. After 2 weeks, the animals treated with control or stimulated ASC showed an enhanced axon regeneration distance. Stimulated cells evoked more total axon growth. Analysis of regeneration and apoptosis-related gene expression showed that both ASC and stimulated ASC enhanced GAP-43 and activating transcription factor 3 (ATF-3) expression in the spinal cord and reduced c-jun expression in the DRG. Caspase-3 expression in the DRG was reduced by stimulated ASC. Both ASC and stimulated ASC also increased the vascularity of the fibrin nerve conduits. Thus, ASC produce functional neurotrophic and angiogenic factors, creating a more desirable microenvironment for nerve regeneration.

Angiogenic nanodelivery systems for myocardial therapy

Despite outstanding progress in the area of cardiovascular diseases, significant challenges remain in designing efficient delivery systems for myocardial therapy. Nanotechnology provides the tools to explore such frontiers of biomedical science at cellular level and thus offers unique features for potential application in the field of cardiac therapy. This chapter focuses on the methodology, based on the work done in our lab, to prepare and investigate two kinds of biocompatible nanoparticles (NPs) that can be useful for sustained delivery of single or multiple angiogenic growth factors to damaged sites, such as in myocardially infarcted heart to promote myocardial angiogenesis and reduce scar area.

Paclitaxel-loaded poly(glycolide-co-ε-caprolactone)-b-D-α-tocopheryl polyethylene glycol 2000 succinate nanoparticles for lung cancer therapy

In order to improve the therapeutic efficacy and minimize the side effects of lung cancer chemotherapy, the formulation of paclitaxel-loaded poly(glycolide-co-ε-caprolactone)-b-D-α-tocopheryl polyethylene glycol 2000 succinate nanoparticles (PTX-loaded [PGA-co-PCL]-b-TPGS_2k NPs) was prepared. The novel amphiphilic copolymer (PGA-co-PCL)-b-TPGS_2k was synthesized by ring-opening polymerization and characterized by proton nuclear magnetic resonance spectroscopy and gel permeation chromatography. The PTX-loaded (PGA-co-PCL)-b-TPGS_2k NPs were characterized in terms of size, size distribution, zeta potential, drug encapsulation, surface morphology, and drug release. In vitro cellular uptakes of NPs were investigated with confocal laser scanning microscopy, indicating the coumarin 6-loaded (PGA-co-PCL)-b-TPGS_2k NPs could be internalized by human lung cancer A-549 cells. The antitumor effect of PTX-loaded NPs was evaluated, both in vitro and in vivo, on an A-549 cell tumor-bearing mouse model via intratumoral injection. The commercial PTX formulation Taxol was chosen as the reference. Experimental results showed that the PTX-loaded NPs possessed higher cytotoxicity and could effectively inhibit the growth of tumor. All the results suggested that amphiphilic copolymer (PGA-co-PCL)-b-TPGS_2k could act as a potential biological material for nanoformulation in the treatment of lung cancer.