Peptide-based polymers and materials

Peptide-based polymers and materials

With their outstanding range of structures, structural and biological activities, peptides are highly attractive molecules to give a tailored function to an existing material but also to design innovative materials with unprecedented properties. Existing approaches to functionalise materials with biomolecules mostly relies on post-modification using conjugation chemistry (e.g. click reactions, activated esters). On the contrary, we envisioned innovative bottom-up approaches based on peptide building-blocks bearing functions for polymerisation or condensation. We investigated organic polymerisation using peptides bearing N-carboxyanhydride (NCA) moieties or lactame rings but also inorganic polymerisation methods, using sol-gel process relying on hydroxysilane-derivatized peptides.

Applications are numerous and some of them are currently investigated thought founded programs and collaborations :

• The functionalization of medical devices and dressing with wound-healing and/or antibacterial peptides and the design of smart ‘communicant’ dressings using RFID technology.
• The synthesis of multi-ligands nanoparticles for cancer treatment and imaging.
• The synthesis of polymers for cell targeting and vectorization.
• The design of biomimetic hydrogels for cell-based therapies that can be printed as 3D scaffolds.
From a fundamental point of view, the self-assembly of hybrid peptides is also studied for the design of new nanostructured materials.

ORALCANCERPRINT

ORALCANCERPRINT
Biofabrication of an oral squamous cell carcinoma model by 3D bioprinting

Funding : Emergence, Cancéropôle Grand Sud-Ouest

June 2018 – June 2019

 

Nowadays, treatments of oral squamous cell carcinoma is principally based on excision surgery and can be associated with radiotherapy and chemotherapy. It is really important to have a better understanding of the neoplastic oral mucous membrane to develop less aggressive treatment. This project is a multidisciplinary project aiming at designing an oral squamous cell carcinoma model by 3D bioprinting, to help the development of cancer treatments.

The aim of the project is to develop an in vitro 3D organotipic model of oral mucous membrane with the help of 3D-bioprinting of cellularized layers. The use of two different 3D bioprinting technologies will allow to reproduce the architecture of cancer tissues at a macroscopic and a microscopic scale. Layers of hybrid collagenous peptide based hydrogel encapsulating gingival fibroblasts will be 3D printed by extrusion with layers of endothelial cells in the same hydrogel but 3D printed by a laser-assisted technology, to create a vascularized tissue. Finally, a layer of cancerous keratinocytes embedded into the hydrogel, printed by laser, will cover the model. The complexity of the model will give a better understanding of cellular communication in oral cancer and will be a platform for drug screening.

 

This project is developed in collaboration with BioTis Team ( Dr. Adrien Naveau and Dr. Raphael Devillar), Inserm 1026 : Tissular Bio-engineering team, Bordeaux.

THE TEAM

Gilles Subra
raphael devillard
RAPHAEL DEVILLAR (BioTis)
adrien naveau
ADRIEN NAVEAU (BioTis)
Ahmad Mehdi
AHMAD MEHDI
Laurine Valot
LAURINE VALOT
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E-dressing

E-dressing
The e-dressing project aims at developing a smart wound dressing able to detect an enzymatic activity and to transmit information by passive RFID (radio frequency identification)

Funding: MUSE research founding
Mar 2018- Feb 2021

E-dressing project

The e-dressing project aims at developing a smart wound dressing able to detect an enzymatic activity and to transmit information by passive RFID (radio frequency identification).

The cost of ineffective treatment of chronic wounds (diabetic foot, leg ulcers…) is estimated to be $20-25 billion annually. Efficient and simple wound diagnostic devices could reduce the complications associated with infection or excessive inflammation being able to target the right therapy, at the right time.

We chose to focus on the design of the RFID device which will be included into the dressing, in contact with the wound exudates. The antenna of RFID device, constituted of porous aluminum oxide, will be grafted by a layer of hybrid material, sensitive to the degradation by bacterial enzymes, virulence markers, or by enzymes related to the inflammation of wounds.

Hybrid material will be composed of hybrid silylated peptides whose sequences will be chosen to be enzyme substrates. Material will be synthesized by sol-gel process and will be degraded specifically by these chosen enzymes.

The first part of the work consists in the design and synthesis of hybrid peptides that will be modified by alkoxysilane groups. They will allow their immobilization by sol-gel process on aluminium oxide substrates.

The second part of the work aims the characterization of the hybrid material (AFM, XPS, SEM…) layer during its degradation. In vitro assays in the presence of isolated enzymes and with relevant bacterial strains will be performed.

The aim of the third part of project is to demonstrate that the degradation of hybrid material by enzymes will generate a detectable modification of electrical signal. Indeed, this electrical variation will impact on the RFID reading and the putative quantification of the targeted enzymes.

At last, the system will be assayed on infected exsudates of patients, collected at Montpellier University Hospital.

E-dressing is multidisciplinary project supported by Montpellier University Site of Excellence which also involves the Institute of Electronics and Systems (IES-team Brice Sorli), the University Hospital of Montpellier (CHU-teams Eric Renard and Luc Teot), Institute Charles Gerhart of Montpellier (ICG-team Ahmad Mehdi) and the Ecole des Mines d’Ales (EAM, team Ingrid Bazin)

THE TEAM

Gilles Subra
Ahmad Mehdi
AHMAD MEHDI
Amandine Sandoval
AMANDINE SANDOVAL
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LEGOGEL

LEGOGEL
A 'Lego'-like method to access multifunctional hydrogels for mesenchymal stem cell-based cartilage repair

Funding: ANR-16-CE18-0003-01
October 2016- September 2019

The LEGOGEL multidisciplinary project combines peptide chemistry and sol-gel inorganic polymerization to provide multifunctional hydrogels for full-thickness cartilage lesion repair using mesenchymal stem cells (MSC).

Treatment of cartilage injuries remains one of the most difficult challenges in regenerative medicine. Mesenchymal stem cell (MSC)-based therapies represent one possible innovative strategy. It is highly important that MSC will be associated with a support, to put the cells directly into the lesion to be repaired but also to avoid dissemination at the time of implantation. The support can be a scaffold shaped to fit the cartilage defect or a liquid that can be injected and can rapidly turn into a gel to fill the lesion. LEGOGEL is a multidisciplinary project aiming at designing cell therapy strategies for osteo-articular diseases.

Legogel Project

LEGOGEL aims at establishing a ground-breaking method to build modular and multifunctional hydrogels whose synthesis was too complex to be envisioned by existing methods. LEGOGEL relies on original ‘hybrid’ bioorganic-inorganic building blocks (peptides, biopolymers, dyes…) bearing alcoxysilane groups. Hydrolysis and condensation of these groups lead to the formation of a covalent hydrogel network. Interestingly, this sol-gel process occurs in water in physiological conditions, without the use of chemical cross-linkers, toxic reagents or catalysts. It is thus compatible with biomolecules (ligands, growth factors…) and the presence of cells. Moreover, the mixture of blocks is first obtained as a colloidal solution that can be either injected, or 3D-printed before complete gelation to get porous scaffolds. Taking advantage of this innovative ‘lego-like’ bottom-up approach, the complexity of extracellular matrices (ECM) composed of a huge variety of biological components, could be mimicked. Any type of bioactive peptide, biopolymer, dye or contrast agent can be combined in appropriate ratio to yield covalent hydrogel. Of course, any other component (as growth factors) can be added during the gel formation, in a non-covalent way.

Specific objectives of LEGOGEL project

  1. The first goal will be the synthesis of the different hybrid blocks (i.e. the ‘lego parts’). Bioactive peptide promoting cell migration and colonization, biopolymers (growth factors) and contrast agents will be specifically silylated. The synthesis of hybrid bioactive peptides is already mastered by the partners but the introduction of silyl groups on proteins is a challenge that will be tackled.
  2. The second objective will be to obtain multifunctional hydrogels whose biological and physicochemical properties (stiffness, porosity, degradability…) will be suitable for cell-based engineering. The obtainment of hydrogel substrates from liquid solution will be studied. The most challenging work will be the control of gelation conditions to transfer the soft polymerization method on the 3D printer for the biofabrication of cell-seeded porous scaffolds. If required, Peptide sequences sensitives to ECM degradation enzymes will be incorporated to tune the degradation rate of the matrix and to release the differentiation factors to induce the lineage commitment.

    3D printer used for the project
  3. The third objective will be to obtain optimized hydrogel substrates promoting in vitro and in vivo MSC colonization and differentiation into chondrocytes or osteoblasts. Different composition of hydrogels, containing differentiation factors tailored to mimic specific cartilage and subchondral bone environments will be assayed to obtain the ‘ideal’ substrate. It will be either 3D-printed as a scaffold or used as an injectable hydrogel. Ultimately, the scaffold will present a bilayer membrane composed of TGFβ3- hyaluronic acid upper layer to induce differentiation of MSCs into chondrocytes and secretion of the cartilage ECM; and BMP2-hydroxyapatite-collagen lower layer to favor the differentiation of MSC into osteoblasts.

THE TEAM

Gilles Subra
Ahmad Mehdi
AHMAD MEHDI
Laurine Valot
LAURINE VALOT
MM
MARIE MAUMUS
Luc Brunel
LUC BRUNEL
DANIÈLE NOËL
DANIÈLE NOËL
Pascal Verdier

PASCAL VERDIÉ

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CONTACT

Gilles Subra
Gilles Subra
Pascal Verdier
Pascal Verdier
Jean Martinez
Jean Martinez
Muriel Amblard
Muriel Amblard
Lubomir Vezenkov portrait
Lubomir Vezenkov

Site-specific grafting on titanium surfaces with hybrid temporin antibacterial peptides

J. Mater. Chem. B, 2018,6, 1782-1790. doi 10.1039/C8TB00051D

Abstract

Relying on a membrane-disturbing mechanism of action and not on any intracellular target, antimicrobial peptides (AMP) are attractive compounds to be grafted on the surface of implantable materials such as silicone catheters or titanium surgical implants. AMP sequences often display numerous reactive functions (e.g. amine, carboxylic acid) on their side chains and straightforward conjugation chemistries could lead to uncontrolled covalent grafting, random orientation, and non-homogenous density. To achieve an easy and site specific covalent attachment of unprotected peptides on titanium surfaces, we designed hybrid silylated biomolecules based on the temporin-SHa amphipathic helical antimicrobial sequence. With the grafting reaction being chemoselective, we designed five analogues displaying the silane anchoring function at the N-ter, C-ter or at different positions inside the sequence to get an accurate control of the orientation. Grafting density calculations were performed by XPS and the influence of the orientation of the peptide on the surface was clearly demonstrated by the measure of antimicrobial activity. Temporin amphipathic helices are described to permeabilize the bacterial membrane by interacting in a parallel orientation with it. Our results move in the direction of this mechanism as the selective grafting of hybrid temporin 2 through a lysine placed at the center of the peptide sequence, resulted in better biofilm growth inhibition of E. coli and S. epidermis than substrates in which temporins were grafted via their C- or N-terminus.

Inorganic polymerization: an attractive route to biocompatible hybrid hydrogels

J. Mater. Chem. B, 2018,6, 3434-3448,  doi 10.1039/C8TB00456K

T

Abstract

As an intermediate state between liquid and solid materials, hydrogels display unique properties, opening a wide scope of applications, especially in the biomedical field. Organic hydrogels are composed of an organic network cross-linked via chemical or physical reticulation nodes. In contrast, hybrid hydrogels are defined by the coexistence of organic and inorganic moieties in water. Inorganic polymerization, i.e. the sol–gel process, is one of the main techniques leading to hybrid hydrogels. The chemoselectivity of this method proceeds through hydrolysis and condensation reactions of metal oxide moieties. In addition, the mild reaction conditions make this process very promising for the preparation of water-containing materials and their bio-applications.

Heteromultivalent targeting of integrin αvβ3 and neuropilin 1 promotes cell survival via the activation of the IGF-1/insulin receptors

Biomaterials 2018 Feb;155:64-79. doi: 10.1016/j.biomaterials.2017.10.042. Epub 2017 Oct 29.

Jia T, Choi J, Ciccione J, Henry M, Mehdi A, Martinez J, Eymin B, Subra G, Coll JL.

Abstract

Angiogenesis strongly depends on the activation of integrins, especially integrin αvβ3, and of neuropilin-1 (NRP-1), a co-receptor of VEGFR2. Dual-targeted molecules that simultaneously block both of them are expected have increased anti-angiogenic and antitumor activity. Toward this goal, we generated bifunctional 40 nm-sized silica nanoparticles (NPs) coated with controlled amounts of cRGD and ATWLPPR peptides and studied their affinity, selectivity and biological activity in HUVECs. Sub-nanomolar concentrations of NPs grafted either with ATWLPPR alone or in combination with cRGD exhibit potent and specific antagonist activity against VEGFR2/AKT signaling. However, a 1 nM concentration of the cRGD/ATWLPPR-heteromultivalent particles (RGD/ATW-NPs) also blocks the phosphorylation of VEGFR2 while co-inducing an unexpected long-lasting activation of AKT via IGF-1R/IR-AKT/GSK3β/eNOS signaling that stimulates cell survival and abrogates the intrinsic toxicity of silica-NPs to serum-starved HUVECs. We also showed that their repeated intravenous administration was associated with the proliferation of human U87MG tumor cells engrafted in nude mice and a dilatation of the tumor blood vessels. We present biochemical evidence for the complex cross-talk generated by the binding of the heteromultivalent NPs with αvβ3-integrin and with NRP1. In particular, we show for the first time that such heteromultivalent NPs can trans-activate IGF-1/insulin receptors and exert dose-dependent pro-survival activity. This study demonstrates the difficulties in designing targeted silica-based NPs for antiangiogenic therapies and the possible risks posed by undesirable side effects.

Sol-gel synthesis of collagen-inspired peptide hydrogel

 Materials Today , Pages: Ahead of Print, Journal, 2017,  DOI: 10.1016/j.mattod.2017.02.001

C. Echalier, S. Jebors, G. Laconde, B. Guillaume, V. Luc, C. Pascal, B. Lea, A. Bethry, B. Legrand, H. Van Den Berghe, X. Garric, D. Noel, J. Martinez, A. Mehdi, G. Subra

Abstract

Conceiving biomaterials able to mimic the specific environments of extracellular matrixes are a prerequisite for tissue engineering applications. Numerous types of polymers (PEG, PLA, etc.) have been used for the design of biocompatible scaffolds, but they are still less efficient than natural biopolymers such as collagen exts. Chem. modified and loaded with different bioactive factors, biopolymers afford an environment favorable to cell proliferation and differentiation. Unfortunately, they present several drawbacks, such as weak batch-to-batch reproducibility, potential immunogenicity and high cost of prodn. Herein we propose a fully synthetic covalent hydrogel obtained by sol-gel polymn. of a silylated peptide. We selected a short and low mol. building-block derived from the consensus collagen sequence [Pro-Hyp-Gly]. Interestingly, the sol-gel process occurs in physiol. buffer, enabling the embedment of stem cells. This collagen-inspired hydrogel provides a cell-friendly environment comparable to natural collagen substrates, demonstrating its potency as a biomimetic scaffold.

-Modular bioink for 3D printing of biocompatible hydrogels: sol-gel polymerization of hybrid peptides and polymers

RSC Advances, 2017, Volume: 7, Issue: 20, Pages: 12231-12235, DOI: 10.1039/C6RA28540F

C. Echalier, R. Levato, M. A. Mateos-Timoneda, O. Castano, S. Dejean, X. Garric, C. Pinese, D. Noel, E. Engel, J. Martinez, A. Mehdi, G.Subra

RCS materials

Abstract

An unprecedented generic system allowing the 3D printing of peptide-functionalized hydrogels by soft sol-gel inorg. polymn. is presented. Hybrid silylated inorg./bioorg. blocks are mixed in biol. buffer in an appropriate ratio, to yield a multicomponent bioink that can be printed as a hydrogel without using any photochem. or org. reagent. Hydrolysis and condensation of the silylated precursors occur during the printing process and result in a covalent network in which mols. are linked through siloxane bonds. The viscosity of the colloidal soln. used as bioink was monitored in order to set up the optimal conditions for extrusion printing. Grid-patterned hydrogel scaffolds contg. a hybrid integrin ligand were printed using a pressure-driven rapid prototyping machine. Finally, they were seeded with mesenchymal stem cells, demonstrating their suitability for cell culture. The versatility of the sol-gel process and its biocompatibility makes this approach highly promising for the prepn. of tailor-made cell-laden scaffolds.

Unambiguous and Controlled One-Pot Synthesis of Multifunctional Silica Nanoparticles

Chemistry of Materials, 2016, Volume: 28, Issue: 3, Pages: 885-889, DOI: 10.1021/acs.chemmater.5b04398

J. Ciccione, T. Jia, J .L. Coll, K. Parra, M. Amblard, S. Jebors, J. Martinez, A. Mehdi, G. Subra 

Abstract

A method for obtaining in a single step well-defined tunable multifunctional fluorescent particles having their surface functionalized with multiple covalently linked ligands is reported.  The strategy relies on the synthesis of hybrid bioorg.-inorg. peptide ligands, greatly simplifying the design of multifunctional nanoparticles.  It was possible to tune the ratio of two grafted ligands on the surface of the SiNPs simply by adjusting the relative concn. of hybrid species in the starting soln.  An original fluorine NMR method was applied to the dissolved SiNPs to demonstrate our hypothesis.

Easy Synthesis of Tunable Hybrid Bioactive Hydrogels

Chemistry of Materials, 2016, Volume: 28, Issue: 5, Pages: 1261-1265,  DOI: 10.1021/acs.chemmater.5b04881

C. Echalier, C. Pinese, X. Garric, H. Van Den Berghe, E. Jumas Bilak, J. Martinez, A. Mehdi, G. Subra 

Abstract

Hydrogels are raising an increasing interest in the biomedical field and have found applications in tissue engineering and regenerative medicine.  In order to mimic the complexity of natural tissues, functionalization of hydrogels with bioactive mols. is of first importance.  In this context, we developed a bottom-up approach based on the synthesis of hybrid silylated blocks that can be combined to obtain covalently functionalized gels.  In this study, hybrid silylated PEG and hybrid silylated bioactive peptides were synthesized and mixed in desired ratio before being simply dissolved in phosphate buff-er at physiol. pH to form a gel.  The soln. turns quickly into a covalent functional gel at 37 °C.  Mech. properties of these hydrogels were studied and their biocompatibility was demonstrated.  Depending on the type of bioactive peptides introduced within the gels, they exhibited either antibacterial or cell adhesion properties demonstrating the potency of this sol-gel modular strategy for fine tuning of gel properties.

Selective homodimerization of unprotected peptides using hybrid hydroxydimethylsilane derivatives

RSC Advances, 2016, Volume: 6, Issue: 39, Pages: 32905-32914, DOI: 10.1039/C6RA06075G

C. Echalier, A. Kalistratova, J. Ciccione, A. Lebrun, B. Legrand, E. Naydenova, D. Gagne, J. A. Fehrentz , J. Marie, M. Amblard, A. Mehdi, J. Martinez, G. Subra 

Abstract

We developed a simple and straightforward way to dimerize unprotected peptide sequences that relies on a chemoselective condensation of hybrid peptides bearing a hydroxydimethylsilyl group at a chosen position (either C-ter, N-ter or side-chain linked) to generate siloxane bonds upon freeze-drying. Interestingly, the siloxane bond sensitivity to hydrolysis is strongly pH-dependent. Thus, we investigated the stability of siloxane dimers in different exptl. conditions. For that purpose, 29Si, 13C and 1H NMR spectra were recorded to accurately quantify the ratio of dimer/monomer. More interestingly, we showed that 1H resonances of the methylene and Me groups connected to the Si can be used as sensitive probes to monitor siloxane hydrolysis and to det. the half-lives of the dimers. Importantly, we showed that the dimers were rather stable at pH 7.4 (t1/2 ≈ 400 h) and we applied the dimerization strategy to bioactive sequences. Once optimized, three dimers of the growth hormone releasing hexapeptide (GHRP-6) were prepd. Interestingly, their pharmacol. evaluation revealed that the activity of the dimeric ligands could be switched from agonist to inverse agonist depending on the position of dimerization.

A new way to silicone-based peptide polymers

Angewandte Chemie, 2015, Volume: 54, Issue: 12, Pages: 3778-3782,  DOI: 10.1002/anie.201411065

S. Jebors, J. Ciccione, S. Al-Halifa, B. Nottelet, C. Enjalbal, C. M’Kadmi,  M. Amblard, A. Mehdi, J. Martinez, G. Subra

Abstract

We describe a new class of silicone-contg. peptide polymers obtained by a straightforward polymn. in water using tailored chlorodimethylsilyl peptide blocks as monomeric units.  This general strategy is applicable to any type of peptide sequences, yielding linear or branched polymer chains composed of well-defined peptide sequences.

Engineered Adhesion Peptides for Improved Silicon Adsorption

Langmuir, 2015, Volume: 31, Issue: 43, Pages: 11868-11874,  DOI: 10.1021/acs.langmuir.5b02857

S. R.  Kumar; S. Jebors, M. Martin, T. Cloitre,  V. Agarwal, A. Mehdi, J. Martinez, G. Subra, C. Gergely 

Abstract

Engineering peptides that present selective recognition and high affinity for a material is a major challenge for assembly-driven elaboration of complex systems with wide applications in the field of biomaterials, hard-tissue regeneration, and functional materials for therapeutics.  Peptide-material interactions are of vital importance in natural processes but less exploited for the design of novel systems for practical applications because of our poor understanding of mechanisms underlying these interactions.  Here, we present an approach based on the synthesis of several truncated peptides issued from a silicon-specific peptide recovered via phage display technol.  We use the photonic response provided by porous silicon microcavities to evaluate the binding efficiency of 14 different peptide derivs.  We identify and engineer a short peptide sequence (SLVSHMQT), revealing the highest affinity for p+-Si.  The mol. recognition behavior of the obtained peptide fragment can be revealed through mutations allowing identification of the preferential affinity of certain amino acids toward silicon.  These results constitute an advance in both the engineering of peptides that reveal recognition properties for silicon and the understanding of biomol.-material interactions.