Nanoparticle-Based Vaccines Against Respiratory Viruses

The respiratory mucosa is the primary portal of entry for numerous viruses such as the respiratory syncytial virus, the influenza virus and the parainfluenza virus. These pathogens initially infect the upper respiratory tract and then reach the lower respiratory tract, leading to diseases. Vaccination is an affordable way to control the pathogenicity of viruses and constitutes the strategy of choice to fight against infections, including those leading to pulmonary diseases. Conventional vaccines based on live-attenuated pathogens present a risk of reversion to pathogenic virulence while inactivated pathogen vaccines often lead to a weak immune response. Subunit vaccines were developed to overcome these issues. However, these vaccines may suffer from a limited immunogenicity and, in most cases, the protection induced is only partial. A new generation of vaccines based on nanoparticles has shown great potential to address most of the limitations of conventional and subunit vaccines. This is due to recent advances in chemical and biological engineering, which allow the design of nanoparticles with a precise control over the size, shape, functionality and surface properties, leading to enhanced antigen presentation and strong immunogenicity. This short review provides an overview of the advantages associated with the use of nanoparticles as vaccine delivery platforms to immunize against respiratory viruses and highlights relevant examples demonstrating their potential as safe, effective and affordable vaccines

Bottom up approach to the synthesis of polymers of peptides: synthesis of comb polypeptides via polymerization of NCA-peptides

Peptides are attracting considerable interest in the field of material science and can be view as highly functionalized and bioactive polyamides. The most economical and expedient process for synthesis of long polypeptide chains is the polymerization of α-amino N-carboxy-α-amino acid anhydrides (NCAs). Brush polypeptides can be obtained by this method and high molecular weight polymers can be prepared in both good yield and large quantity [1] [2] [3]. However, this approach is mostly limited to linear homopolypeptides (i.e. polymethionine [4] , polyglutamic acid [5], polyproline) and was never applied to the production of defined peptide sequence polymers. In this context, we developed a new and alternative strategy to generate peptide-based branched polymer. In parallel to our study, we also developed a convenient and straightforward methodology to generate the NCA activated species directly on the solid support. The activated peptide block was then released from the solid support to be engaged in the NCA/Ring Opening Polymerization (ROP) reaction.status: accepte

A new approach for the synthesis of peptide-based polymers

Peptides and polypeptides are attracting considerable interest in the field of biomaterials and biological sciences because of their biocompatibility and biodegradability properties. A common approach relies on post grafting of peptide sequences, using chemoselective reactions, on modified polymers. However, direct polymerization of large, synthetic peptides or macromolecules remains a challenge. In this context, we developed new strategies to polymerize well defined peptides. High molecular weight polymers can be prepared in both good yield and large quantity. The first one was the polymerization of α-amino N-carboxy-α-amino acid anhydrides (NCAs) which generated peptide-based branched polymers. For that, we developed a convenient and straightforward methodology to generate the NCA activated species directly on the solid support. The activated peptide block was then released from the solid support to be engaged in the NCA/Ring Opening Polymerization (ROP) reaction and gave comb polymer. The second strategy was to form Si-O-Si bond (siloxane) by poly-condensation of Si-OH (silanol). This method need to introduce two silanols functions at the C and N terminus of the peptide sequence or alternatively, on a N-ter Lysine. Polymerization was then carried out on a phosphate buffer to give linear or comb-like polypeptides.status: accepte

Synthesis of modified peptide to fight against Alopecia and Canities, and new methodology to polymerize peptide sequences

De part leurs nombreuses activités biologiques et leur propriétés physicochmiques et structurales, les peptides présentent un intérêt considérable pour la conception de molécules actives mais aussi pour l'élaboration de biomatériaux. Pour lutter contre l'alopécie (perte de cheveux) et la canitie (blanchiment des cheveux), nous avons axé nos travaux sur la recherche de peptides bioactifs. Pour cela, nous avons identifié des peptides têtes de série provenant soit de la littérature soit d'un criblage réalisé par l'institut européen de biologie (IEB). Ces peptides têtes de séries ont été modifiés afin d'améliorer leur activité et leur biodisponibilité tout en tenant compte du mode d'administration par voie topique. Lors de ce travail, nous avons également développé deux nouvelles méthodologies permettant la polymérisation de séquences peptidiques. En effet, les polymères à base de peptide présentent un intérêt majeur pour des applications en biotechnologie (tissus artificiels, implants), ou comme systèmes de transport ou de délivrance de principes actifs. Nous avons notamment mis au point la polymérisation de peptides hybrides présentant des fonctions dimethylsilanol ainsi que la polymérisation par ouverture du cycle de N-carboxyanhydrides portant une séquence peptidique. Ces deux stratégies ont permis d'obtenir des polymères linéaires ou en peigne.Because of their numerous biological activities and their structural and physico-chemical properties, peptides are of considerable interest for the design of active molecules but also for the development of biomaterials. To fight against alopecia (hair loss) and canities (whitning hair), we focused our attention on the research of bioactive peptides. In this context, we have identified leads peptides either from the literature or from a screening conducted by the European Institute of Biology (IEB). These Leads were modified to improve their activity and bioavailability knowing that they will be applied topically. In this work, we have also developed two new methodologies for the polymerization of peptide sequences. Indeed, peptide-based polymers are of major interest for applications in biotechnology (i.e. artificial tissue,implants), or as systems of transport and delivery of drug. The first methodology relies on the polymerization of the hybrid peptides displaying dimethyl hydroxysilane functions. The other one involves the ring opening polymerization of N-carboxyanhydrides bearing a peptide sequence. Both strategies were used to obtain linear or comb peptide-polymers

Molecularly engineered polymer-based systems in drug delivery and regenerative medicine

BACKGROUND: Polymer-based systems are attractive in drug delivery and regenerative medicine due to the possibility of tailoring their properties and functions to a specific application. METHODS: The present review provides several examples of molecularly engineered polymer systems, including stimuli responsive polymers and supramolecular polymers. RESULTS: The advent of controlled polymerization techniques has enabled the preparation of polymers with controlled molecular weight and well-defined architecture. By using these techniques coupled to orthogonal chemical modification reactions, polymers can be molecularly engineered to incorporate functional groups able to respond to small changes in the local environment or to a specific biological signal. This review highlights the properties and applications of stimuli-responsive systems and polymer therapeutics, such as polymer-drug conjugates, polymer-protein conjugates, polymersomes, and hyperbranched systems. The applications of polymeric membranes in regenerative medicine are also discussed. CONCLUSION: The examples presented in this review suggest that the combination of membranes with polymers that are molecularly engineered to respond to specific biological functions could be relevant in the field of regenerative medicine.status: publishe

Urea based gelator as a scaffold for cells in tissue engineering

During these last few decades the new endeavor of tissue engineering and regenerative medicine has developed.[1] Herein the regeneration or even full substitution of damaged tissue is contemplated. Recently a lot of interest has been invested in the use of hydrogels as scaffolds in the field of regenerative medicine.[2] The use of these scaffolds can be divided in three different categories: space filling agents, bioactive molecule delivery and cell\tissue delivery. Currently the hydrogels that are being used for these scaffolds are mainly polymer based, although a lot of research has been done on the use of self-assembling peptide hydrogels in the application.[3] When looking at the field of gelators in general the emergence of an interesting group of small molecules should be noted, the low molecular weight gelators (LMWG). Interest in these LMWG exploded in the beginning of the 90’s of last century.[4] The gels of some of these LMWG are considered to be smart materials, i.e. materials that are responsive to external stimuli. The link between tissue engineering and LMWG has often been made, but still most of the LMWG that have been used in tissue engineering are peptide based.[5] These peptide based gelators often have an elaborate synthesis, limiting the scalability. Because of the large potential market for these scaffolds, an easily scalable and cheap synthesis of scaffolds is highly desired. In this work we will describe the use of a new LMWG as a scaffold for cells and its use in tissue engineering. The gelator proposed in this work has been successfully synthesized using robust and easily scalable methodology. To empathize the green industrial potential the synthesis has been done in neat conditions in a ball milling reactor. The gelating ability of the compound was tested using standard gelation test procedures, which resulted in gel formation. The material properties of the gels were further characterized and the gels were tested on biocompatibility. [1] Berthiaume, F., Maguire, T. J., Yarmush, M. L., Annu. Rev. Chem. Biomol. Eng. 2 (2011) 403–30. [2] Drury, J. L., Mooney, D. J., Biomaterials. 24 (2003) 4337-4351. [3] Gazit, E., Chem. Soc. Rev., 36 (2007) 1263-1269. [4] Weiss, R. G., J. Am. Chem. Soc. 136 (2014) 7519-7530. [5] Hirst, A. R., Escuder, B., Miravet, J. F., Smith, D. K., Angew. Chem. Int. Ed. 47 (2008) 8002-8018.status: publishe

AN INDUSTRIALLY SCALABLE SMALL MOLECULE GELATOR WITH APPLICATIONS IN TISSUE ENGINEERING AND REGENERATIVE MEDICINE

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When giant vesicles mimic red blood cell's dynamics: swinging of two-phase vesicles in shear flow

International audienceRed blood cells under shear flow present a specific swinging motion superimposed to a fluid-like tanktreading motion. Swinging is hypothesized to originate from periodic storage of shear energy in the cell membrane. Here we designed giant unilamellar vesicles with two lipid phases separated by a contact line, which swing and tanktread like red cells. We propose a model that quantitatively fits our data, finds the value of the contact-line tension and shows that swinging is due to the storage of elastic energy associated with the periodic modulation of the contact-line length during tanktreading

An Industrially Scalable Small Molecule Gelator with Applications in Tissue Engineering and Regenerative Medicine

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An industrially scalable small molecule gelator with applications in tissue engineering and regenerative medicine

INTRODUCTION Recently, a lot of research has been invested in the use of hydrogels in the endeavour of tissue engineering and regenerative medicine (TERM) as scaffolds mimicking the extracellular matrix (ECM).1 Polymer based hydrogels are being extensively investigated in the field;2 however, in the class of low molecular weight gelators (LMWGs), mainly peptide based materials are used.3 These are very interesting because of the functionality of the peptides as well as the smart material capabilities, well-defined structure, and ability to form dynamic systems of the LMWGs. Because of the many advantages of LMWGs but the costly and elaborate synthesis of peptides, this work focuses on the development of non-peptide based low molecular weight hydrogelators with applications in TERM. EXPERIMENTAL METHODS The synthesis of the gelators was performed in batch and in a planetary ball milling setup. The compounds were analysed using 1H NMR, 13C NMR, FTIR, ESI, and DSC. The gelation ability of the compounds was assessed by dissolving the gelators in water or cell culture medium at 100 °C followed by cooling the supersaturated solution to room temperature under irradiation with ultrasound. The mechanical properties of the gels were determined by performing strain and frequency sweep measurements as well as a recoverability study on a rheometer. The morphology of the gelator network was studied using AFM and SEM. The cytocompatibility of the gels was assessed by encapsulating L929 cells at a concentration of 1x106 cells/mL in gels made with complete cell culture medium and culturing them for 72 hours at 37 °C in a humidified incubator. Cell proliferation was assessed by counting the cells at 1, 24, 48, and 72 hours, and cell morphology was evaluated by fixing the cells within the gels and staining them with phalloidin and DAPI. RESULTS AND DISCUSSION The gelators were synthesized in quantitative yields, and the scalability of the synthesis was shown using the green industrial technique of ball milling. The minimal gelation concentration was determined to be 0.3 wt. % in both water and cell culture medium. The maximum strain of 0.8 wt. % gels was determined to be between 3.16 – 3.98 %, and the G’ and G” values were 1.7x104 Pa and 3.7x103 Pa, respectively, at 0.08 % strain and an angular frequency of 6.28 rad/s. A recoverability study (Figure 1) showed that the material was thixotropic and thus suitable for delivery via injection. Figure 1 AFM and SEM imaging confirmed that the gelator network consisted of ribbon-like nanofibers, with average fiber heights of 2 nm and fiber lengths varying from 500 to 20000 nm. The cytocompatibility assays showed that cells remained viable in the hydrogels for several days and that the cells proliferated during the first 48 hours of the experiment. CONCLUSION In this work, a non-peptide based LMWG was developed for use in TERM. The compound was shown to have a robust and scalable synthesis. The thixotropic property of the material showed that the hydrogels would be injectable. The fiber morphology was studied, and ribbon-like nanofibers formed the gel network. Last but not least, cells could survive in the material for several days, and they further proliferated. Thus, we believe this material could provide a low cost and cytocompatible hydrogel scaffold for cell expansion and minimally invasive delivery. REFERENCES 1. Berthiaume, F., et al., Annu. Rev. Chem. Biomol. Eng. 2:403-430, 2011 2. Van Vlierberghe, S., et al., Biomacromolecules 12:1387-1408, 2011 3. Hirst, A. R., et al., Angew. Chem. Int. Ed. 47:8002-8018, 2008status: publishe