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Pulmonary exposure to some engineered nanomaterials can cause chronic lesions as a result of unresolved inflammation. Among two-dimensional (2D) nanomaterials and graphene, MoS2 have received tremendous attention in optoelectronics and nanomedicine. Here we propose an integrated approach to follow up the transformation of MoS2 nanosheets at the nanoscale and their impact on the lung inflammation status over one month after a single inhalation in mice. Analysis of immune cells, alveolar macrophages, extracellular vesicles, and cytokine profiling in bronchoalveolar lavage fluid (BALF) showed that MoS2 nanosheets induced initiation of lung inflammation that was rapidly resolved despite the persistence of various biotransformed molybdenum-containing nanostructures in alveolar macrophages and extracellular vesicles up to one month. Using in situ liquid phase transmission electron microscopy experiments, we could evidence the dynamics of MoS2 nanosheets transformation triggered by reactive oxygen species. Three main transformation mechanisms were observed directly at the nanoscale level: 1) scrolling of the dispersed sheets leading to the formation of nanoscrolls and folded patches, 2) etching releasing soluble MoO4-, and 3) oxidation generating oxidized sheet fragments. Extracellular vesicles released in BALF were also identified as a potential shuttle of MoS2 nanostructures and their degradation products and more importantly as mediators of inflammation resolution.

Resume Objectif Evaluation de la vectorisation par des vesicules extramembranaires issues de cellules souches mesenchymateuses (EVs) de la meta-tetra(hydroxyphenyl)chlorine (mTHPC) dans un modele murin de metastases peritoneales (MP) d’origine colique. Methodes Comparaison de l’effet de la vectorisation par des EVs de la mTHPC (EVs-mTHPC) par rapport a differentes formulations, sur sa biodistribution et sur l’efficacite de la therapie photodynamique (PDT) apres injection intraperitoneale (IP) de 5.104CT26. Resultats Les EVs permettaient une majoration de la selectivite intratumorale par rapport a la formulation libre ou liposomale de mTHPC (Foslip®) (ratio moyen tumeur/organes de 44 vs 1,4 et 12, respectivement). La PDT etait efficace des 48 h, avec induction par les EVs d’une reponse immunitaire antitumorale principalement pro-inflammatoire de type macrophages M1 et lymphocytaire T-CD8+. La proliferation intratumorale etait significativement diminuee (9,2 % ± 1,4) par rapport aux controles (47,9 % ± 2,3) et aux groupes traites par PDT avec mTHPC libre (26,2 % ± 4,5) ou Foslip® (17,9 % ± 3,1), p Conclusion La vectorisation par des EVs permettait une selectivite tumorale importante, a l’origine d’une diminution de la toxicite medicamenteuse, d’une regression de la proliferation tumorale et d’un prolongement de la survie des souris.

International audience; In this study, we investigated the combination of extracellular (nano) vesicles (EVs) from pig adipose tissue-derived stromal cells (ADSCs) and a thermoresponsive gel, Pluronic (R) F-127 (PF-127), to prevent stricture formation after endoscopic resection in a porcine model. ADSC EVs were produced at a liter scale by a high-yielding turbulence approach from ADSCs 3D cultured in bioreactors and characterized in terms of size, morphology and membrane markers. The thermoresponsive property of the PF-127 gel was assessed by rheology. The pro-regenerative potency of ADSC EVs was investigated ex vivo in esophageal biopsies under starvation. In vivo tests were performed in a porcine model after extended esophageal endoscopic mucosal dissection (ESD). Pigs were randomized into 3 groups: control (n = 6), gel (n = 6) or a combination of 1.45 x 10(12) EVs + gel (n = 6). Application of gel +/- EVs was performed just after ESD with a follow-up finalized on day 21 post-ESD. There was a trend towards less feeding disorder in the EV + gel group in comparison with the gel and the control groups (16.67% vs. 66.7% vs. 83.33%, respectively) but without reaching a statistically significant difference. A significant decrease in the esophageal stricture rate was confirmed by endoscopic, radiological and histological examination for the EV + gel group. A decrease in the mean fibrosis area and larger regenerated muscularis mucosae were observed for the EV + gel group. In summary, the application of EVs + gel after extended esophageal endoscopic resection succeeded in preventing stricture formation with an anti-fibrotic effect. This nano-therapy may be of interest to tackle an unmet medical need considering that esophageal stricture is the most challenging delayed complication after extended superficial cancer resection by endoscopy.

Extracellular vesicles (EVs), especially from stem/stromal cells (SCs), represent a cell-free alternative in regenerative medicine holding promises to promote tissue healing while providing safety and logistic advantages in comparison to cellular counterparts. Herein, we hypothesize that SC EVs, administered locally in a thermoresponsive gel, is a therapeutic strategy for managing post-surgical colo-cutaneous fistulas. This disease is a neglected and challenging condition associated to low remission rates and high refractoriness. Herein, EVs from a murine SC line were produced by a high-yield scalable method in bioreactors. The post-surgical intestinal fistula model was induced via a surgical cecostomy communicating the cecum and the skin in Wistar rats. Animals were treated just after cecostomy with PBS, thermoresponsive Pluronic F-127 hydrogel alone or containing SC EVs. A PET-monitored biodistribution investigation of SC EVs labelled with 89Zr was performed. Fistula external orifice and output assessment, probe-based confocal laser endomicroscopy, MRI and histology were carried out for therapy follow-up. The relevance of percutaneous EV administration embedded in the hydrogel vehicle was indicated by the PET-biodistribution study. Local administration of SC EVs in the hydrogel reduced colo-cutaneous fistula diameter, output, fibrosis and inflammation while increasing the density of neo-vessels when compared to the PBS and gel groups. This multi-modal investigation pointed-out the therapeutic potential of SC EVs administered locally and in a thermoresponsive hydrogel for the management of challenging post-surgical colon fistulas in a minimally-invasive cell-free strategy.

Extracellular vesicles, secreted spontaneously or in response to stress by all cell types, are proposed as alternative biotherapies to cellular therapies and to synthetic nanomedicines. Their logistical advantages (storage, stability, availability, tolerance), their ability to cross biological barriers, to deliver their contents (proteins, lipids and nucleic acids) in order to modify their target cells, as well as their immunomodulatory and regenerative activities, are of growing interest for a very wide spectrum of diseases. Here we review the challenges to bring these biotherapies to the clinic and discuss some promising applications in cancer and regenerative medicine.Applications thérapeutiques des vésicules extracellulaires.Les vésicules extracellulaires, sécrétées spontanément ou en réponse à un stress par tous les types cellulaires, sont proposés comme des biothérapies alternatives aux thérapies cellulaires et aux nanomédicaments synthétiques. Leurs atouts logistiques (stockage, stabilité, disponibilité, tolérance), leur capacité à franchir les barrières biologiques, à délivrer leurs contenus (protéines, lipides et acides nucléiques) pour modifier leurs cellules cibles, ainsi que leurs activités immunomodulatrice et régénérative, suscitent un intérêt grandissant pour un très large spectre de maladies. Cette synthèse présente les défis qui restent à relever pour appliquer ces biothérapies en clinique. Quelques applications prometteuses dans les domaines du cancer et de la médecine régénérative seront proposées.

International audience; Extracellular vesicles (EV) are emergent therapeutic effectors that have reached clinical trial investigation. To translate EV-based therapeutic to clinic, the challenge is to demonstrate quality, safety, and efficacy, as required for any medicinal product. EV research translation into medicinal products is an exciting and challenging perspective. Recent papers, provide important guidance on regulatory aspects of pharmaceutical development, defining EVs for therapeutic applications and critical considerations for the development of potency tests. In addition, the ISEV Task Force on Regulatory Affairs and Clinical Use of EV-based Therapeutics as well as the Exosomes Committee from the ISCT are expected to contribute in an active way to the development of EV-based medicinal products by providing update on the scientific progress in EVs field, information to patients and expert resource network for regulatory bodies. The contribution of our work group "Extracellular Vesicle translatiOn to clinicaL perspectiVEs - EVOLVE France", created in 2020, can be positioned in complement to all these important initiatives. Based on complementary scientific, technical, and medical expertise, we provide EV-specific recommendations for manufacturing, quality control, analytics, non-clinical development, and clinical trials, according to current European legislation. We especially focus on early phase clinical trials concerning immediate needs in the field. The main contents of the investigational medicinal product dossier, marketing authorization applications, and critical guideline information are outlined for the transition from research to clinical development and ultimate market authorization.

International audience; Extracellular vesicles (EVs) are 50–1000 nm vesicles secreted by virtually any cell type in the body. They are expected to transfer information from one cell or tissue to another in a short- or long-distance way. RNA-based transfer of information via EVs at long distances is an interesting well-worn hypothesis which is ~15 years old. We review from a quantitative point of view the different facets of this hypothesis, ranging from natural RNA loading in EVs, EV pharmacokinetic modeling, EV targeting, endosomal escape and RNA delivery efficiency. Despite the unique intracellular delivery properties endowed by EVs, we show that the transfer of RNA naturally present in EVs might be limited in a physiological context and discuss the lessons we can learn from this example to design efficient RNA-loaded engineered EVs for biotherapies. We also discuss other potential EV mediated information transfer mechanisms, among which are ligand–receptor mechanisms.

International audience

Extracellular vesicles (EVs) are becoming essential actors in bio-therapeutics, as much for their regenerative or immunomodulatory properties as for their potential as cargo delivery vehicles. To enable the democratization of these EV-based therapies, many challenges remain such as large-scale production which is necessary to reduce costs of treatment. Herein, we review some advanced works on high-yield EV manufacturing. One approach consists in developing large-scale cell culture platforms, while others focus on cell stimulation to increase particle yield per cell. This can be done by moderate physico-chemical stresses or by disrupting cell membrane towards autoassembled vesicle-like particles. We critically compare these different techniques, keeping in mind that the field still lacks shared characterization standards, underline the importance of therapeutic potency assessment and discuss mass production strategies that have been identified in current clinical trials.

The dissemination of tumor metastasis in the peritoneal cavity, also called peritoneal metastasis (PM) or carcinomatosis, represents a late stage of gastrointestinal and gynecological cancer with very poor prognosis, even when cytoreductive surgery is effective, due to residual microscopic disease. Photodynamic therapy (PDT) in the management of peritoneal metastasis has been clinically limited by the low tumor selectivity of photosensitizers (PS) and important adverse effects. Here, we propose extracellular nanovesicles (EVs) derived from mesenchymal stem/stromal cells (MSCs) as the fourth generation of immune active PS vectors that are able to target peritoneal metastasis with superior selectivity, potentiate PDT cytotoxicity at the tumor site without affecting healthy tissues, modulate the tumor microenvironment of immunocompetent colorectal and ovarian carcinomatosis models, and promote an antitumor immune response. A pioneering strategy was developed for high yield, large-scale production of MSC-EVs encapsulating the drug meta(tetrahydroxyphenyl)chlorin (mTHPC) (EVs-mTHPC) that is compatible with requirements of clinical translation and also preserves the topology and integrity of naturally produced EVs. Intraperitoneal injection of EVs-mTHPC showed an impressive enhancement of tumoral selectivity in comparison to the free drug and to the liposomal formulation Foslip (mean ratio of PS in tumors/organs of 40 for EVs-mTHPC versus 1.5 for the free PS and 5.5 for Foslip). PDT mediated by EVs-mTHPC permitted an important tumoral necrosis (55% of necrotic tumoral nodules versus 18% for Foslip (p < 0.0001)) and promoted antitumor immune cell infiltration, mainly proinflammatory M1-like CD80+ and CD8+ T cell effector. Intratumor proliferation was significantly decreased after PDT with EVs-mTHPC. Overall EVs vectorization of mTHPC afforded important tumoral selectivity while overcoming the PDT toxicity of the free drug and prolonged mice survival in the colorectal carcinomatosis model. MSC-EVs produced by our scalable manufacturing method appears like the clinically relevant fourth-generation PDT vehicle to overcome current limitations of PDT in the treatment of peritoneal metastasis and promote a hot tumor immune environment in PM.

Peritoneal metastasis (PM) is considered as the terminal stage of metastatic colon cancer, with still poor median survival rate even with the best recent chemotherapy treatment. The current PM treatment combines cytoreductive surgery, which consists of resecting all macroscopic tumors, with hyperthermic intraperitoneal chemotherapy (HIPEC), which uses mild hyperthermia to boost the diffusion and cytotoxic effect of chemotherapeutic drugs. As HIPEC is performed via a closed circulation of a hot liquid containing chemotherapy, it induces uncontrolled heating and drug distribution in the whole peritoneal cavity with important off-site toxicity and a high level of morbidity. Here, we propose a safer precision strategy using near-infrared (NIR) photoactivated gold nanoparticles (AuNPs) coupled to the chemotherapeutic drug 5-fluorouracil (5-FU) to enable a spatial and temporal control of mild chemo-hyperthermia targeted to the tumor nodules within the peritoneal cavity. Both the 16 nm AuNPs and the corresponding complex with 5-FU (AuNP-5-FU) were shown as efficient NIR photothermal agents in the microenvironment of subcutaneous colon tumors as well as PM in syngeneic mice. Noteworthy, NIR photothermia provided additional antitumor effects to 5-FU treatment. A single intraperitoneal administration of AuNP-5-FU resulted in their preferential accumulation in tumor nodules and peritoneal macrophages, allowing light-induced selective hyperthermia, extended tumor necrosis, and activation of a pro-inflammatory immune response while leaving healthy tissues without any damage. From a translational standpoint, the combined and tumor-targeted photothermal and chemotherapy mediated by the AuNP-drug complex has the potential to overcome the current off-target toxicity of HIPEC in clinical practice.

International audience; Despite current management strategies, digestive fistulae remain extremely debilitating complications associated with significant morbidity and mortality, generating a need to develop innovative therapies in these indications. A number of clinical trials and experimental studies have thus investigated the potential of stem/stromal cells (SCs) or SC-derived extracellular vesicles (EVs) administration for post-surgical and Crohn's-associated fistulae. This review summarizes the physiopathology and current standards-of-care for digestive fistulae, along with relevant evidence from animal and clinical studies regarding SC or EV treatment for post-surgical digestive fistulae. Additionally, existing preclinical models of fistulizing Crohn's disease and results of SC therapy trials in this indication will be presented. The optimal formulation and administration protocol of SC therapy products for gastrointestinal fistula treatment and the challenges for a widespread use of darvadstrocel (Alofisel) in clinical practice will be discussed. Finally, the potential advantages of EV therapy and the obstacles towards their clinical translation will be introduced.

Tissue engineering aims to repair or replace deficient tissue by delivering constructs that mimic the native in vivo structure. One challenge in cardiac tissue engineering approaches is to achieve ...

Background Despite the highly expected clinical application of nanoparticles (NPs), the translation of NPs from lab to the clinic has been relatively slow. Co-culture 3D spheroids account for the 3D arrangement of tumor cells and stromal components, e.g., cancer-associated fibroblasts (CAFs) and extracellular matrix, recapitulating microenvironment of head and neck squamous cell carcinoma (HNSCC). In the present study, we investigated how the stroma-rich tumor microenvironment affects the uptake, penetration, and photodynamic efficiency of three lipid-based nanoformulations of approved in EU photosensitizer temoporfin (mTHPC): Foslip® (mTHPC in conventional liposomes), drug-in-cyclodextrin-in-liposomes (mTHPC-DCL) and extracellular vesicles (mTHPC-EVs). Results Collagen expression in co-culture stroma-rich 3D HNSCC spheroids correlates with the amount of CAFs (MeWo cells) in individual spheroid. The assessment of mTHPC loading demonstrated that Foslip®, mTHPC-DCL and mTHPC-EVs encapsulated 0.05 × 10− 15 g, 0.07 × 10− 15 g, and 1.3 × 10− 15 g of mTHPC per nanovesicle, respectively. The mid-penetration depth of mTHPC NPs in spheroids was 47.8 µm (Foslip®), 87.8 µm (mTHPC-DCL), and 49.7 µm (mTHPC-EVs), irrespective of the percentage of stromal components. The cellular uptake of Foslip® and mTHPC-DCL was significantly higher in stroma-rich co-culture spheroids and was increasing upon the addition of serum in the culture medium. Importantly, we observed no significant difference between PDT effect in monoculture and co-culture spheroids treated with lipid-based NPs. Overall, in all types of spheroids mTHPC-EVs demonstrated outstanding total cellular uptake and PDT efficiency comparable to other NPs. Conclusions The stromal microenvironment strongly affects the uptake of NPs, while the penetration and PDT efficacy are less sensitive to the presence of stromal components. mTHPC-EVs outperform other lipid nanovesicles due to the extremely high loading capacity. The results of the present study enlarge our understanding of how stroma components affect the delivery of NPs into the tumors.

Summary This case report relates to the first-in-man use of a vessel occluder gel medical device as a fistula occluder in a repurposing strategy. A patient with chronic colocutaneous fistula received an off-label treatment with a thermoresponsive Poloxamer 407 gel (20%) via percutaneous administration and injected under endoscopic control. Treatment consisted in the association of esophageal stent placement and gel injection. The product was administered just after the stent placement at

Plasmodium falciparum gametocytes, the sexual stage responsible for malaria parasite transmission from humans to mosquitoes, are key targets for malaria elimination. Immature gametocytes develop in the human bone marrow parenchyma, where they accumulate around erythroblastic islands. Notably though, the interactions between gametocytes and this hematopoietic niche have not been investigated. Here, we identify late erythroblasts as a new host cell for P falciparum sexual stages and show that gametocytes can fully develop inside these nucleated cells in vitro and in vivo, leading to infectious mature gametocytes within reticulocytes. Strikingly, we found that infection of erythroblasts by gametocytes and parasite-derived extracellular vesicles delay erythroid differentiation, thereby allowing gametocyte maturation to coincide with the release of their host cell from the bone marrow. Taken together, our findings highlight new mechanisms that are pivotal for the maintenance of immature gametocytes in the bone marrow and provide further insights on how Plasmodium parasites interfere with erythropoiesis and contribute to anemia in malaria patients.

Extracellular vesicles (EVs) of endocytic origin are known as exosomes. These vesicles are released by cells and are found in biofluids, such as saliva, urine, and plasma. These vesicles are made up of small RNA, DNA, proteins, and play a vital role in many physiological processes. In the central nervous system (CNS), they participate in various physiological processes such as stress of nerve cells, communication between the cells, synaptic plasticity, and neurogenesis. The role of exosomes in depression needs to be explored further. It is known that exosomes can cross the blood brain barrier (BBB), which is made up of glial cells astrocytes. One of the advantages of these vesicles is that they are able to transfer macromolecules like DNA, protein, mRNAs, and miRNAs to recipient cells. This review focuses on the potential role of exosomes in depression and their utilization as a treatment option or diagnostic tool of depression.

Cell-derived extracellular vesicles (EVs) circulating in body fluids hold promises as bioactive therapeutic agents and as biomarkers to diagnose a wide range of diseases. However nano-imaging methods are needed to characterize these complex and heterogeneous soft materials in their native wet environment. Herein, we exploit liquid-cell transmission electron microscopy (LCTEM) to characterize the morphology and dynamic behavior of EVs in physiological media with nanometer resolution. The beam-induced controlled growth of Au nanoparticles on bilayer membranes is used as an original in situ staining method to improve the contrast of EVs and artificial liposomes. LCTEM provides information about the size distribution and concentration of EVs that are consistent with Cryo-TEM and nanoparticle tracking analysis measurements. Moreover, LCTEM gives a unique insight into the dynamics of EVs depending on their liquid environment. The size-dependent morphology of EVs is sensitive to osmotic stress which tends to transform their spherical shape to ellipsoidal, stomatocyte or discocyte morphologies. In the liquid-cell, EVs exhibit a sub-diffusive motion due to strong interactions between the Au nanoparticles and the liquid-cell windows. Finally, the high-resolution monitoring of EV aggregation and fusion illustrate that LCTEM opens up a new way to study cell-membrane dynamics.

Extracellular vesicles (EVs) have emerged as new drug delivery systems as well as a regenerative cell-free effectors going beyond academic research to reach industrial research and development (R&D). Many proof-of-concept studies are now published describing the delivery of drugs, nanoparticles or biologics among which nucleic acids, proteins, viruses, etc. Their main interests rely on their intrinsic biocompatibility, targeting capabilities and biological activities. The possibility of loading EVs with exogenous therapeutic drug/nanoparticles or imaging tracers opens up the perspectives to extend EV therapeutic properties and enable EV tracking. Clinical translation is still hampered by the difficulty to produce and load EVs with large scale, efficient and cGMP methods. In this review, we critically discuss important notions related to EV engineering and the methods available with a particular focus on technologies fitted for clinical translation. Besides, we provide a tentative data reporting frame in order to support comparability and standardization in the field.

The structural complexity and physical properties of the tumor microenvironment negatively affect the penetration and efficiency of conventional anticancer drugs. While previously underestimated, the tumor microenvironment now becomes a potential target for cancer treatment. This microenvironment can be modulated either systemically by pharmacological means, or locally, through physical effects mediated by certain nanoparticles. Some of them, such as magnetic, plasmonic or carbon-based nanoparticles, can generate heat on demand in a spatially and temporally controlled manner. In addition, the nanoparticles can be either activated by light or magnetic stimuli. The impact of the resulting local heating can be observed on the ultrastructural level, as it strongly affects the organization of collagen fibers, and on the macroscopic level, since the thermal damages alter the mechanical properties of the tumor. Nanoparticle-based hyperthermia thus improves the effect of conventional anticancer drugs, as it allows their better penetration through the altered extracellular matrix. Here we suggest the use of nanoparticle-generated hyperthermia, obtained after magnetic or light activation, as an adjuvant treatment to prime the tumor microenvironment and improve the efficacy of chemotherapy.

International audience; Photoacoustic imaging (PAI) is an emerging noninvasive and inexpensive bioimaging modality, which has stimulated a wide interest in recent years for cancer theranostics. Hybrid nano-and microgels have been designed as protective carriers to incorporate PAI contrast agents due to their biocompatibility and biodegradability, high loading capacity, versatile surface chemistry, and stimuliresponsive properties. These key features offer unprecedented opportunities for the design of innovative multifunctional cancer theranostic agents. This review focuses on the recent development of photoacoustic active nano-and microgels for biomedical applications in cancer theranostics and cancer hallmark imaging. The various chemical natures of gels and PAI contrast agents and the elaboration methods of hybrid matrices are summarized and discussed. Their applications in multimodal cancer theranostics and cancer hallmark imaging are presented, highlighting their merits and potential in treatment and diagnosis.

International audience; Stimulus-responsive systems have demonstrated for some time now significant advantages for the therapeutic and imaging fields. Nevertheless, this last decade was marked by the emergence of innovative concepts, opening new avenues of investigation. Since the field's inception, the driving force for the development of responsive materials has been motivated by the potential to modulate remotely a therapeutic or diagnostic action, with precise spatial and temporal control via externally-applied physical stimuli, such as light, temperature, electric or magnetic fields. It became possible to actuate materials on-demand, by altering at distance molecular interactions at critical onset points, and to provide controlled and sustained drug delivery, drug activation, heat triggering and contrast enhancement. This special issue covers the latest achievements and prospects related to physically-triggered nanosystems for therapy and diagnosis. Notably, important progress has been achieved for precision nanomedicine in nucleic acid delivery and theranostics, described by Do et al [1] and Mohamed et al [2], respectively. Also, recent developments on nano/micro-motors as well as electric field-responsive nanosystems for controlled drug release deserve special attention, being overviewed by Srivastava et al [3] and Kolosnjaj-Tabi [4], respectively. We have also witnessed a new momentum in the field of physically-triggered nanosystems mainly due to the fast-forward progress in nanosystem design. Roca et al [5] shows how innovative synthesis routes revolutionized material combination, modular designs and shape possibilities. Dimers or multimers, multi-layered designs and exquisite shape control resulted in a new generation of materials featuring

Innovative synthesis routes revolutionized nanomaterial combination and design possibilities resulting in a new generation of fine-tuned nanoparticles featuring exquisite shape and constitution control. However, there is still room for improvement when it comes to the development of multi-functional nanoparticle agents merging a plurality of therapeutic functions to tackle tumors simultaneously by synergic mechanisms. Herein, we report the design of an optimized nanohybrid for cancer tri-therapy featuring a maghemite (γ-Fe2O3) nanoflower-like multicore nanoparticle conceived for efficient magnetic hyperthermia (MHT) and a spiky copper sulfide shell (IONF@CuS) with a high near-infrared (NIR) absorption coefficient suitable for photothermal (PTT) and photodynamic therapy (PDT). Methods: Spiky-like IONF@CuS nanohybrids were obtained through a straightforward and scalable water-based template sacrificial synthesis, which allows the shell shape control by tuning polyvinylpyrrolidone (PVP) concentration. A comprehensive characterization of nanohybrid size, shape and structural properties was carried out by combining complementary TEM, SEM, HR-TEM, EELS, XRD and NTA. The all-in-one therapeutic multi-functionality was assessed on cancer cells and on tumor-bearing nude mice. Results: Tests carried out on IONF@CuS nanohybrid aqueous dispersion demonstrated their impressive efficiency to convert light (conversion coefficient = 42 ± 6 %) and magnetic stimulation (SAR ~ 350 W g-1) into heat as well as to induce concurrent reactive oxygen species (ROS) formation upon laser irradiation. Such capabilities were further confirmed in cellular environment by in vitro tests and at the organism level by in vivo tests in a murine tumor model. Notably, complete tumor regression was obtained for the PTT mode at low Cu concentration. Overall, these results allowed determining windows of applicability for each therapy individually or in combination. Conclusions: Altogether, the obtained data evidence the successful synthesis of a unique tri-therapeutic nanoparticle featuring highly relevant assets for clinical translation such as reduced nanoparticle administered dose, reduced laser power exposure, reduced magnetic field frequency, and the possibility of serial heating cycles and therapy monitoring by photoacoustic (PA) and magnetic resonance imaging (MRI). Furthermore, the integration of the dual heating capability (MHT + PTT) with the PDT insult offers a unique asset to tackle tumors by multiple cytotoxic strategies in order to improve the therapeutic outcome in a broader spectrum of clinical conditions.

International audience; Emerging advances in extracellular vesicle (EV) research brings along new promises for tailoring clinical treatments in order to meet specific disease features of each patient in a personalized medicine concept. EVs may act as regenerative effectors conveying endogenous therapeutic factors from parent cells or constitute a bio-camouflaged delivery system for exogenous therapeutic agents. Physical stimulation may be an important tool in the field of EVs for personalized therapy by powering EV production, loading and therapeutic properties. Physically-triggered EV production is inspired by naturally occurring EV release by shear stress in blood vessels. Bioinspired physically-triggered EV production technologies may bring along high yield advantages combined to scalability assets. Physical stimulation may also provide new prospects for high-efficient EV loading. Additionally, physically-triggered EV theranostic properties brings new hopes for spatio-temporal controlled therapy combined to tracking. Technological considerations related to EV-based personalized medicine and the input of physical stimulation on EV production, loading and theranostic properties will be overviewed herein.

Cell sheet technology opens new perspectives in tissue regeneration therapy by providing readily implantable, scaffold-free 3D tissue constructs. Many studies have focused on the therapeutic effects of cell sheet implantation while relatively little attention has concerned the fate of the implanted cells in vivo. The aim of the present study was to track longitudinally the cells implanted in the cell sheets in vivo in target tissues. To this end we (i) endowed bone marrow-derived mesenchymal stem cells (BMMSCs) with imaging properties by double labeling with fluorescent and magnetic tracers, (ii) applied BMMSC cell sheets to a digestive fistula model in mice, (iii) tracked the BMMSC fate in vivo by MRI and probe-based confocal laser endomicroscopy (pCLE), and (iv) quantified healing of the fistula. We show that image-guided longitudinal follow-up can document both the fate of the cell sheet-derived BMMSCs and their healing capacity. Moreover, our theranostic approach informs on the mechanism of action, either directly by integration of cell sheet-derived BMMSCs into the host tissue or indirectly through the release of signaling molecules in the host tissue. Multimodal imaging and clinical evaluation converged to attest that cell sheet grafting resulted in minimal clinical inflammation, improved fistula healing, reduced tissue fibrosis and enhanced microvasculature density. At the molecular level, cell sheet transplantation induced an increase in the expression of anti-inflammatory cytokines (TGF-s2 and IL-10) and host intestinal growth factors involved in tissue repair (EGF and VEGF). Multimodal imaging is useful for tracking cell sheets and for noninvasive follow-up of their regenerative properties.

We report the construct of a nanosystem based on multi-walled carbon nanotubes (MWCNT) and the photosensitizer m-tetrahydroxyphenylchlorin (mTHPC) for cancer treatment by combination of photodynamic (PDT) and photothermal (PTT) therapy. The photoactivity of the complex mTHPC/MWCNT was studied revealing quenching of the photosensitizer associated to CNT and almost total release of the photosensitizer into the cell cytoplasm after uptake by SKOV3 ovarian cancer cells. The photothermal and photodynamic cytotoxicity of these mTHPC/MWCNT on/off complexes was assessed at the cell level by viability test, imaging flow cytometry, confocal microscopy and transmission electron microscopy and at the molecular level by a proteomic analysis of apoptosis-related proteins and genomic analysis of 84 genes involved in oxidative stress. Cytotoxicity correlated at the cell level to the uptake of mTHPC/MWCNT, while PDT and PTT treatment induced different signaling pathways leading to cell apoptosis. For the first time, the mechanisms of PDT/PTT synergy in eradication of cancer cells were studied revealing that distinct cell responses to PDT and PTT defeat the cell defense to oxidative stress.

Background & Aim Extracellular vesicles (EVs) are membrane-delimited particles between 30nm and 500nm, released by all cells, which are biological actors of far-reaching intercellular communication. As EVs can recapitulate the properties of their mother cells, they offer a promising alternative to cell therapies, mitigating the risks of cell injection while presenting storage advantages. However, poor yield and scalability issues of EV manufacturing are major bottlenecks hindering the translation of EV-based therapies to clinics. In a groundbreaking strategy, our lab developed a high yield and scalable production method for EVs, increasing the classical agitation speed of an impeller to create a turbulent flow in a bioreactor. Adherent cells cultured on microcarriers were subjected to shear stress which triggered an active and massive EV shedding. These turbulence EVs from mesenchymal stem cells demonstrated the same regenerative potency as classical EVs produced by starvation in an in vivo model of chronic heart failure and featured anti-apoptotic and immunomodulatory properties in vitro. However, some cells, mostly derived from blood, are anchorage independent, our aim was thus to decipher if this method could also increase the EV release of non-adherent suspension cells. Methods, Results & Conclusion In a proof of concept, we have shown that THP-1, a human monocytic cell line, can produce 20 000 EVs/cell or more in three hours given that the size of the smallest vortices in the flow – calculated via the Kolmogorov equation – is below 30µm. This represents a tenfold increase compared to cells in starvation which produce up to 2000 EV/cell in 72h. By monitoring cell viability and cell lysis during production for three cell lines, we have shown that cells such as THP-1, HeLa and Raji react differently to shear stress and that a trade-off can be made between cellular damage and high EV yield. Isolated EVs were analyzed by flow cytometry and Exoview, exhibiting EV markers such as CD63 and CD81, as well as markers reflecting the nature of their mother cells. Our scalable and high yield approach extends EV manufacturing perspectives to suspension cell-derived EVs, in particular from immune cells derived from blood.

Extracellular vesicles (EVs) are increasingly envisioned as the next generation of biological pro-regenerative nanotherapeutic agents, as has already been demonstrated for heart, kidney, liver, and brain tissues; lung injury repair; and skin regeneration. Herein, we explore another potential EV therapeutic application, fistula healing, together with a local minimally invasive delivery strategy. Allogenic extracellular vesicles (EVs) from adipose tissue-derived stromal cells (ASCs) are administered in a porcine fistula model through a thermoresponsive Pluronic F-127 (PF-127) gel, injected locally at 4 °C and gelling at body temperature to retain EVs in the entire fistula tract. Complete fistula healing is reported to be 100% for the gel plus EVs group, 67% for the gel group, and 0% for the control, supporting the therapeutic use of Pluronic F-127 gel alone or combined with EVs. However, only the combination of gel and EVs results in a statistically significant (i) reduction of fibrosis, (ii) decline of inflammatory response, (iii) decrease in the density of myofibroblasts, and (iv) increase of angiogenesis. Overall, we demonstrate that ASC-EV delivery into a PF-127 gel represents a successful local minimally invasive strategy to induce a therapeutic effect in a swine fistula model. Our study presents prospects for EV administration strategies and for the management of post-operative fistulas.

Magnetic hyperthermia (MHT) and photothermal therapy (PTT) are emergent state‐of‐the‐art modalities for thermal treatment of cancer. While their mechanisms of action have distinct physical bases, both approaches rely on nanoparticle‐mediated remote onset of thermotherapy. Yet, are the two heating techniques interchangeable? Here, the heating obtained either with MHT or with PTT is compared. The heating is assessed in distinct environments and involves a set of nanomaterials differing in shape (spheres, cubes, stars, shells, and rods) as well as in composition (maghemite, magnetite, cobalt ferrite, and gold). The nanoparticle's heating efficacy in an aqueous medium is first evaluated. Subsequently, the heating efficiency within the cellular environment, where intracellular processing markedly decreases MHT, is compared. Conversely, endosomal sequestration could have a positive effect on PTT. Finally, iron oxide nanocubes and gold nanostars are compared in MHT and PTT in vivo within the heterogeneous intratumoral environment. Overall, two distinct therapeutic approaches, related to high dosage allowing MHT and low dosage associated with PTT, are identified. It is also demonstrated that PTT mediated by magnetic nanoparticles has an efficacy that is comparable to that of plasmonic nanoparticles, but only at significant nanoparticle dosages. At low concentrations, only plasmonic nanoparticles can deliver a therapeutic heating.

Providing appropriate means for heat generation by low intratumoral nanoparticle concentrations is a major challenge for cancer nanotherapy. Here we propose RGD-tagged magnetosomes (magnetosomes@RGD) as a biogenic, genetically engineered, inorganic platform for multivalent thermal cancer treatment. Magnetosomes@RGD are biomagnetite nanoparticles synthesized by genetically modified magnetotactic bacteria thanks to a translational fusion of the RGD peptide with the magnetosomal protein MamC. Magnetosomes@RGD thus combine the high crystallinity of their magnetite core with efficient surface functionalization. The specific affinity of RGD was first quantified by single-cell magnetophoresis with a variety of cell types, including immune, muscle, endothelial, stem and cancer cells. The highest affinity and cellular uptake was observed with PC3 prostatic and HeLa uterine cancer cells. The efficiency of photothermia and magnetic hyperthermia was then compared on PC3 cells. Unexpectedly, photothermia was far more efficient than magnetic hyperthermia, which was almost totally inhibited by the cellular environment. RGD targeting was then assessed in vivo at tumor site, in mice bearing PC3 tumors. As a result, we demonstrate that targeted magnetic nanoparticles could generate heat on a therapeutic level after systemic administration, but only under laser excitation, and successfully inhibit tumor progression.

International audience; Extracellular vesicles (EVs) are recognized as nature's own carriers to transport macromolecules throughout the body. Hijacking this endogenous communication system represents an attractive strategy for advanced drug delivery. However, efficient and reproducible loading of EVs with therapeutic or imaging agents still represents a bottleneck for their use as a drug delivery system. Here, we developed a method for modifying cell-derived EVs through their fusion with liposomes containing both membrane and soluble cargoes. The fusion of EVs with functionalized liposomes was triggered by polyethylene glycol (PEG) to create smart biosynthetic hybrid vectors. This versatile method proved to be efficient to enrich EVs with exogenous lipophilic or hydrophilic compounds , while preserving their intrinsic content and biological properties. Hybrid EVs improved cellular delivery efficiency of a chemotherapeutic compound by a factor of 3−4, as compared to the free drug or the drug-loaded liposome precursor. On one side, this method allows the biocamouflage of liposomes by enriching their lipid bilayer and inner compartment with biogenic molecules. On the other side, the proposed fusion strategy enables efficient EV loading, and the pharmaceutical development of EVs with adaptable activity and drug delivery property.

Polysaccharides are abundant biomolecules in nature presenting important roles in a wide variety of living systems processes. Considering the structural and biological functions of polysaccharides, their properties have raised interest for tissue engineering. Herein, we described the latest advances in cardiac tissue engineering mediated by polysaccharides. We reviewed the data already obtained in vitro and in vivo in this field with several types of polysaccharides. Cardiac injection, intramyocardial in situ polymerization strategies, and scaffold-based approaches involving polysaccharides for heart tissue engineering are thus discussed.

Extracellular vesicles (EVs) are multifaceted subcellular entities that act as a far-reaching intercellular communication pathway controlling cell signaling. Such unique properties stem from the extraordinary ability of EVs to transfer biomolecules between neighbor and distal cells. The possibility of engineering EVs for imaging or therapeutic purposes is now an active research field. On the one side, EV engineering with an image tracer aims to enable biodistribution investigation, which is fundamental for deciphering the complex fate of EV in the organism. On the other side, vesicle engineering with drug or heating nanoparticles attempts to translate such cell communication effectors into an intrinsically biocompatible bio-inspired vector for therapy. Herein we provide an overview of critical steps in EV engineering such as production, loading, isolation, and characterization. We also focus on recent studies evidencing that EVs may be tracked by imaging approaches or harnessed for the delivery of therapeutic agents via the introduction of exogenous cargoes such as nanoparticles, fluorescent dyes, nucleic acids, or drugs. Future investigations may bring along ultimate proofs to ensure the safety and efficacy of EVs loaded with exogenous cargoes including reproducible and scalable production, loading and isolation techniques, rigorous characterization, as well as thorough pharmacokinetic and toxicological studies. The advances in perspectives are expected to overcome current challenges in the field and move engineered EVs to the clinical practice.

International audience; We investigated emulsions of water and toluene stabilized by (co) polymers consisting of styrene (S) and 2-(dimethylamino) ethyl methacrylate (DMAEMA) monomer units with different compositions and structures such as a PDMAEMA homopolymer, a P(S-co-DMAEMA) random copolymer and various PS-b-PDMAEMA and PS-b-(S-co-DMAEMA) block copolymers. The model system is used to study the fundamental conditions under which the different kinds of polymer-stabilized emulsions (direct oil in water, inverse water in oil and multiple emulsions) are stabilized or destabilized by pH change (at constant temperature). Polymer properties like chain conformation at the toluene-water interface as probed by SANS and neutron reflectivity at the liquid-liquid interface, the oil-water partitioning of the polymer chains (Bancroft's rule of thumb) as determined by UV spectroscopy and interfacial tensions measured by the rising and spinning drop techniques are determined. Overall, results evidence that the curvature sign, as defined by positive and negative values as the chain segments occupy preferentially the water and toluene sides of the interface respectively, reliably predicts the emulsion kind. In contrast, the Bancroft rule failed at foreseeing the emulsion type. In the region of near zero curvature the crossover from direct to inverse emulsions occurs through the formation of either unstable coexisting direct and inverse emulsions (i) or multiple emulsions (ii). The high compact adsorption of the chains at the interface as shown by low interfacial tension values does not allow to discriminate between both cases. However, the toluene-water partitioning of the polymeric emulsifier is still a key factor driving the formation of (i) or (ii) emulsions. Interestingly, the stabilization of the multiple emulsions can be tuned to a large extent as the toluene-water polymer partitioning can be adjusted using quite a large number of physico-chemical parameters linked to polymer architecture like diblock length ratio or polymer total molar mass, for example. Moreover, we show that monitoring the oil-water partitioning aspect of the emulsion system can also be used to lower the interfacial tension at low pH to values slightly higher than 0.01 mN m(-1), irrespective of the curvature sign.