Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 17 de 17
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Biofouling ; 39(1): 47-63, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36856008

RESUMO

This study aimed to characterize the immobilization of the novel JIChis-2 peptide on the Ti-6Al-4V alloy, widely used in the biomedical sector. The antimicrobial activity of JIChis-2 was evaluated in the Gram-negative bacterium E. coli. Its immobilization occurred by inducing the formation of covalent bonds between the N-terminus of the peptides and the surface previously submitted to acrylic acid polymerization via the PECVD technique. Coated and uncoated surfaces were characterized by FTIR, AFM, SEM and EDX. Studies of global and localized corrosion were carried out, seeking to explore the effects triggered by surface treatment in an aggressive environment. Additionally, the ability of the functionalized material to prevent E. coli biofilm formation evidenced that the strategy to immobilize JIChis-2 in the Ti-6Al-4V alloy via PECVD of acrylic acid resulted in the development of a functional material with antibiofilm properties.


Assuntos
Peptídeos Antimicrobianos , Escherichia coli , Teste de Materiais , Polimerização , Biofilmes , Titânio/farmacologia , Titânio/química , Ligas/farmacologia , Ligas/química
2.
Int J Mol Sci ; 23(17)2022 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-36077561

RESUMO

Wnt signaling plays an important role in embryogenesis and adult stem cell homeostasis. Its diminished activation is implicated in osteoporosis and degenerative neural diseases. However, systematic administration of Wnt-signaling agonists carries risk, as aberrantly activated Wnt/ß-catenin signaling is linked to cancer. Therefore, technologies for local modulation and control of Wnt signaling targeted to specific sites of disease or degeneration have potential therapeutic value in the treatment of degenerative diseases. We reported a facile approach to locally activate the canonical Wnt signaling cascade using nanomagnetic actuation or ligand immobilized platforms. Using a human embryonic kidney (HEK293) Luc-TCF/LEF reporter cell line, we demonstrated that targeting the cell membrane Wnt receptor, Frizzled 2, with peptide-tagged magnetic nanoparticles (MNPs) triggered canonical Wnt signaling transduction when exposed to a high-gradient, time-varying magnetic field, and the induced TCF/LEF signal transduction was shown to be avidity-dependent. We also demonstrated that the peptide retained signaling activity after functionalization onto glass surfaces, providing a versatile platform for drug discovery or recreation of the cell niche. In conclusion, these results showed that peptide-mediated Wnt signaling kinetics depended not only on ligand concentration but also on the presentation method of the ligand, which may be further modulated by magnetic actuation. This has important implications when designing future therapeutic platforms involving Wnt mimetics.


Assuntos
Nanopartículas de Magnetita , Via de Sinalização Wnt , Células HEK293 , Humanos , Ligantes , Peptídeos/farmacologia , Proteínas Wnt/metabolismo , beta Catenina/metabolismo
3.
Small ; 17(13): e2007551, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33690981

RESUMO

Biointerface engineering is a wide-spread strategy to improve the healing process and subsequent tissue integration of biomaterials. Especially the integration of specific peptides is one promising strategy to promote the regenerative capacity of implants and 3D scaffolds. In vivo, these tailored interfaces are, however, first confronted with the innate immune response. Neutrophils are cells with pronounced proteolytic potential and the first recruited immune cells at the implant site; nonetheless, they have so far been underappreciated in the design of biomaterial interfaces. Herein, an in vitro approach is introduced to model and analyze the neutrophil interaction with bioactivated materials at the example of nano-bioinspired electrospun surfaces that reveals the vulnerability of a given biointerface design to the contact with neutrophils. A sacrificial, transient hydrogel coating that demonstrates optimal protection for peptide-modified surfaces and thus alleviates the immediate cleavage by neutrophil elastase is further introduced.


Assuntos
Materiais Biocompatíveis , Elastase de Leucócito , Humanos , Hidrogéis , Imunidade Inata , Neutrófilos
4.
J Pept Sci ; 23(10): 777-789, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28707817

RESUMO

The prevention of implant-associated infection, one the most feared complications in orthopaedic surgery, remains a major clinical challenge and urges development of effective methods to prevent bacterial colonization of implanted devices. Alpha-helical antimicrobial peptides (AMPs) may be promising candidates in this respect due to their potent and broad-spectrum antimicrobial activity, their low tendency to elicit resistance and possible retention of efficacy in the immobilized state. The aim of this study was to evaluate the potential of five different helical AMPs, the cathelicidins BMAP-27 and BMAP-28, their (1-18) fragments and the rationally designed, artificial P19(9/G7) peptide, for the prevention of orthopaedic implant infections. Peptides were effective at micromolar concentrations against 22 Staphylococcus and Streptococcus isolates from orthopaedic infections, while only BMAP-28 and to a lesser extent BMAP-27 were active against Enterococcus faecalis. Peptides in solution showed activities comparable to those of cefazolin and linezolid, on a molar basis, and also a variable capacity to neutralize bacterial lipopolysaccharide, while devoid of adverse effects on MG-63 osteoblast cells at concentrations corresponding to the MIC. The (1-18) BMAP fragments and P19(9/G7) were selected for further examination, based on better selectivity indices, and showed effectiveness in the presence of hyaluronic acid and in synovial fluid, while human serum affected their activity to variable extents, with BMAP-27(1-18) best retaining activity. This peptide was immobilized on streptavidin-resin beads and retained activity against reference Staphylococcus epidermidis and Staphylococcus aureus strains, with negligible toxicity towards osteoblasts, underlining its potential for the development of infection-resistant biomaterials for orthopaedic application. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.


Assuntos
Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Antibacterianos/química , Anti-Infecciosos/química , Peptídeos Catiônicos Antimicrobianos/química , Humanos , Testes de Sensibilidade Microbiana , Proteínas/química , Proteínas/farmacologia , Staphylococcus/efeitos dos fármacos
5.
Biofouling ; 33(7): 544-555, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28675109

RESUMO

Infections on implanted medical devices are a challenging problem, especially when bacteria form difficult-to-treat biofilms. Antimicrobial peptides are considered to be a solution due to their potency against antibiotic-resistant superbugs. Previously, the authors' laboratory demonstrated the prevention of staphylococcal biofilm formation in an animal catheter model by injecting merecidin (formerly known as 17BIPHE2), a peptide engineered based on the only human cathelicidin. This study documents an alternative solution via covalent immobilization of FK-16, amino acid sequence FKRIVQRIKDFLRNLV-amide, which corresponds to the major antimicrobial region (residues 17-32) of LL-37. FK-16 is superior to the longer peptide LL-37 in terms of synthesis cost and the shorter peptide KR-12 in terms of activity spectrum. Indeed, the FK16-coated titanium surface showed a broad-spectrum activity against the ESKAPE pathogens, including Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species. It also demonstrated anti-adhesion and biofilm inhibition capabilities against both S. aureus and E. coli.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Biofilmes/efeitos dos fármacos , Fragmentos de Peptídeos/farmacologia , Titânio/química , Acinetobacter baumannii/efeitos dos fármacos , Sequência de Aminoácidos , Animais , Antibacterianos/química , Antibacterianos/toxicidade , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/toxicidade , Aderência Bacteriana/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Catéteres/microbiologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Eritrócitos/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Humanos , Queratinócitos/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/toxicidade , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Propriedades de Superfície , Catelicidinas
6.
Chembiochem ; 16(5): 782-91, 2015 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-25737226

RESUMO

Stable primary functionalization of metal surfaces plays a significant role in reliable secondary attachment of complex functional molecules used for the interfacing of metal objects and nanomaterials with biological systems. In principle, this can be achieved through chemical reactions either in the vapor or liquid phase. In this work, we compared these two methods for oxidized silicon surfaces and thoroughly characterized the functionalization steps by tagging and fluorescence imaging. We demonstrate that the vapor-phase functionalization only provided transient surface modification that was lost on extensive washing. For stable surface modification, a liquid-phase method was developed. In this method, silicon wafers were decorated with azides, either by silanization with (3-azidopropyl)triethoxysilane or by conversion of the amine groups of an aminopropylated surface by means of the azido-transfer reaction. Subsequently, D-amino acid adhesion peptides could be immobilized on the surface by use of Cu(I)-catalyzed click chemistry. This enabled the study of cell adhesion to the metal surface. In contrast to unmodified surfaces, the peptide-modified surfaces were able to maintain cell adhesion during significant flow velocities in a microflow reactor.


Assuntos
Alcinos/química , Azidas/química , Cobre/química , Silício/química , Catálise , Adesão Celular , Ciclização , Fluorescência , Células HEK293 , Humanos , Estrutura Molecular , Propriedades de Superfície
7.
Mater Today Bio ; 25: 101017, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38495914

RESUMO

The limited osteointegration often leads to the failure of implant, which can be improved by fixing bioactive molecules onto the surface, such as arginyl-glycyl-aspartic acid (RGD): a cell adhesion motif. Metal-Phenolic Networks (MPNs) have garnered increasing attention from different disciplines in recent years due to their simple and rapid process for depositing on various substrates or particles with different shapes. However, the lack of cellular binding sites on MPNs greatly blocks its application in tissue engineering. In this study, we present a facile and efficient approach for producing PC/Fe@c(RGDfc) composite coatings through the conjugation of c(RGDfc) peptides onto the surface of PC/Fe-MPNs utilizing thiol-click reaction. By combined various techniques (ellipsometry, X-ray photoelectron spectroscopy, Liquid Chromatography-Mass Spectrometry, water contact angle, scanning electronic microscopy, atomic force microscopy) the physicochemical properties (composition, coating mechanism and process, modulus and hydrophilicity) of PC/Fe@c(RGDfc) surface were characterized in detail. In addition, the PC/Fe@c(RGDfc) coating exhibits the remarkable ability to positively modulate cellular attachment, proliferation, migration and promoted bone-implant integration in vivo, maintaining the inherent features of MPNs: anti-inflammatory, anti-oxidative properties, as well as multiple substrate deposition. This work contributes to engineering MPNs-based coatings with bioactive molecules by a facile and efficient thiol-click reaction, as an innovative perspective for future development of surface modification of implant materials.

8.
J Adv Res ; 2023 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-37777063

RESUMO

INTRODUCTION: The stem cell microenvironment has been evidenced to robustly affect its biological functions and clinical grade. Natural or synthetic growth factors, especially, are essential for modulating stem cell proliferation, metabolism, and differentiation via the interaction with specific extracellular receptors. Fibroblast growth factor-2 (FGF-2) possesses pleiotropic functions in various tissues and organs. It interacts with the FGF receptor (FGFR) and activates FGFR signaling pathways, which involve numerous biological functions, such as angiogenesis, wound healing, cell proliferation, and differentiation. OBJECTIVES: Here, we aim to explore the molecular functions, mode of action, and therapeutic activity of yet undetermined function, FGF-2-derived peptide, FP2 (44-ERGVVSIKGV-53) in promoting the proliferation, differentiation, and therapeutic application of human Wharton's jelly mesenchymal stem cells (hWJ-MSCs) in comparison to other test peptides, canofin1 (FP1), hexafin2 (FP3), and canofin3 (FP4) with known functions. METHODS: The immobilization of test peptides that are fused with mussel adhesive proteins (MAP) on the culture plate was carried out via EDC/NHS chemistry. Cell Proliferation assay, colony-forming unit, western blotting analysis, gene expression analysis, RNA-Seq. analysis, osteogenic, and chondrogenic differentiation capacity were applied to test the activity of the test peptides. We additionally utilized three-dimensional (3D) structural analysis and artificial intelligence (AI)-based AlphaFold2 and CABS-dock programs for receptor interaction prediction of the peptide receptor. We also verified the in vivo therapeutic capacity of FP2-cultured hWJ-MSCs using an osteoarthritis mice model. RESULTS: Culture of hWJ-MSC onto an FP2-immobilized culture plate showed a significant increase in cell proliferation (n = 3; *p < 0.05, **p < 0.01) and the colony-forming unit (n = 3; *p < 0.05, **p < 0.01) compared with the test peptides. FP2 showed a significantly upregulated phosphorylation of FRS2α and FGFR1 and activated the AKT and ERK signaling pathways (n = 3; *p < 0.05, **p < 0.01, ***p < 0.001). Interestingly, we detected efficient FP2 receptor binding that was predicted using AI-based tools. Treatment with an AKT inhibitor significantly abrogated the FP2-mediated enhancement of cell differentiation (n = 3; *p < 0.05, **p < 0.01, ***p < 0.001). Intra-articular injection of FP2-cultured MSCs significantly mitigated arthritis symptoms in an osteoarthritis mouse model, as shown through the functional tests (n = 10; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001), modulation of the expression level of the pro-inflammatory and anti-inflammatory genes, and improved osteochondral regeneration as demonstrated by tissue sections. CONCLUSION: Our study identified the FGF-2-derived peptide FP2 as a promising candidate peptide to improve the therapeutic potential of hWJ-MSCs, especially in bone and cartilage regeneration.

9.
Front Bioeng Biotechnol ; 11: 1154986, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37101749

RESUMO

Combining synthetic polymers and biomacromolecules prevents the occurrence of thrombogenicity and intimal hyperplasia in small-diameter vascular grafts (SDVGs). In the present study, an electrospinning poly (L)-lactic acid (PLLA) bilayered scaffold is developed to prevent thrombosis after implantation by promoting the capture and differentiation of endothelial colony-forming cells (ECFCs). The scaffold consists of an outer PLLA scaffold and an inner porous PLLA biomimetic membrane combined with heparin (Hep), peptide Gly-Gly-Gly-Arg-Glu-Asp-Val (GGG-REDV), and vascular endothelial growth factor (VEGF). Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and contact angle goniometry were performed to determine successful synthesis. The tensile strength of the outer layer was obtained using the recorded stress/strain curves, and hemocompatibility was evaluated using the blood clotting test. The proliferation, function, and differentiation properties of ECFCs were measured on various surfaces. Scanning electronic microscopy (SEM) was used to observe the morphology of ECFCs on the surface. The outer layer of scaffolds exhibited a similar strain and stress performance as the human saphenous vein via the tensile experiment. The contact angle decreased continuously until it reached 56° after REDV/VEGF modification, and SEM images of platelet adhesion showed a better hemocompatibility surface after modification. The ECFCs were captured using the REDV + VEGF + surface successfully under flow conditions. The expression of mature ECs was constantly increased with the culture of ECFCs on REDV + VEGF + surfaces. SEM images showed that the ECFCs captured by the REDV + VEGF + surface formed capillary-like structures after 4 weeks of culture. The SDVGs modified by REDV combined with VEGF promoted ECFC capture and rapid differentiation into ECs, forming capillary-like structures in vitro. The bilayered SDVGs could be used as vascular devices that achieved a high patency rate and rapid re-endothelialization.

10.
ACS Appl Mater Interfaces ; 15(20): 24186-24196, 2023 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-37167266

RESUMO

This work combines the wound-healing-related properties of the host defense peptide KR-12 with wood-derived cellulose nanofibrils (CNFs) to obtain bioactive materials, foreseen as a promising solution to treat chronic wounds. Amine coupling through carbodiimide chemistry, thiol-ene click chemistry, and Cu(I)-catalyzed azide-alkyne cycloaddition were investigated as methods to covalently immobilize KR-12 derivatives onto CNFs. The effects of different coupling chemistries on the bioactivity of the KR12-CNF conjugates were evaluated by assessing their antibacterial activities against Escherichia coli and Staphylococcus aureus. Potential cytotoxic effects and the capacity of the materials to modulate the inflammatory response of lipopolysaccharide (LPS)-stimulated RAW 245.6 macrophages were also investigated. The results show that KR-12 endowed CNFs with antibacterial activity against E. coli and exhibited anti-inflammatory properties and those conjugated by thiol-ene chemistry were the most bioactive. This finding is attributed to a favorable peptide conformation and accessibility (as shown by molecular dynamics simulations), driven by the selective chemistry and length of the linker in the conjugate. The results represent an advancement in the development of CNF-based materials for chronic wound care. This study provides new insights into the effect of the conjugation chemistry on the bioactivity of immobilized host defense peptides, which we believe to be of great value for the use of host defense peptides as therapeutic agents.


Assuntos
Antibacterianos , Escherichia coli , Antibacterianos/química , Peptídeos Catiônicos Antimicrobianos/química , Staphylococcus aureus , Fenômenos Químicos
11.
Pharmaceutics ; 13(11)2021 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-34834333

RESUMO

Prevention of orthopedic implant-related infections is a major medical challenge, particularly due to the involvement of biofilm-encased and multidrug-resistant bacteria. Current therapies, based on antibiotic administration, have proven to be insufficient, and infection prevalence may rise due to the dissemination of antibiotic resistance. Antimicrobial peptides (AMPs) have attracted attention as promising substitutes of conventional antibiotics, owing to their broad-spectrum of activity, high efficacy at very low concentrations, and, importantly, low propensity for inducing resistance. The aim of this review is to offer an updated perspective of the development of AMPs-based preventive strategies for orthopedic and dental implant-related infections. In this regard, two major research strategies are herein addressed, namely (i) AMP-releasing systems from titanium-modified surfaces and from bone cements or beads; and (ii) AMP immobilization strategies used to graft AMPs onto titanium or other model surfaces with potential translation as coatings. In overview, releasing strategies have evolved to guarantee higher loadings, prolonged and targeted delivery periods upon infection. In addition, avant-garde self-assembling strategies or polymer brushes allowed higher immobilized peptide surface densities, overcoming bioavailability issues. Future research efforts should focus on the regulatory demands for pre-clinical and clinical validation towards clinical translation.

12.
Methods Mol Biol ; 2178: 251-284, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33128755

RESUMO

Nowadays, monolithic stationary phases, because of their special morphology and enormous permeability, are widely used for the development and realization of fast dynamic and static processes based on the mass transition between liquid and solid phases. These are liquid chromatography, solid-phase synthesis, microarrays, flow-through enzyme reactors, etc. High-performance liquid chromatography on monoliths, including the bioaffinity mode, represents unique technique appropriate for fast and efficient separation of biological (macro)molecules of different sizes and shapes (proteins, nucleic acids, peptides), as well as such supramolecular systems as viruses.In the edited chapter, the examples of the application of commercially available macroporous monoliths for modern affinity processing are presented. In particular, the original methods developed for efficient isolation and fractionation of monospecific antibodies from rabbit blood sera, the possibility of simultaneous affinity separation of protein G and serum albumin from human serum, the isolation of recombinant products, such as protein G and tissue plasminogen activator, respectively, are described in detail. The suggested and realized multifunctional fractionation of polyclonal pools of antibodies by the combination of several short monolithic columns (disks) with different affinity functionalities stacked in the same cartridge represents the original and practically valuable method that can be used in biotechnology. In addition, macroporous monoliths were adapted to the immobilization of such different enzymes as polynucleotide phosphorylase, ribonuclease A, α-chymotrypsin, chitinolytic biocatalysts, ß-xylosidase, and ß-xylanase. The possibility of use of immobilized enzyme reactors based on monoliths for different purposes is demonstrated.


Assuntos
Anticorpos , Ácidos Nucleicos , Peptídeos , Vírus , Anticorpos/química , Anticorpos/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Ácidos Nucleicos/química , Ácidos Nucleicos/isolamento & purificação , Peptídeos/química , Peptídeos/isolamento & purificação , Vírus/química , Vírus/isolamento & purificação
13.
Biomed Phys Eng Express ; 6(6)2020 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-35065538

RESUMO

The surface modification of polyvinylidene difluoride (PVDF) for various biomedical uses is notoriously hampered by the chemical inertness of the polymer. A wet chemical approach aiming at covalently grafting biomolecules was demonstrated by means of an elimination reaction of fluorine from the polymer backbone followed by subsequent modification steps. Exemplified as a possible biological application, the coupling of the peptide REDV rendered the material adhesive for endothelial cells while adhesion of thrombocytes was dramatically reduced.


Assuntos
Células Endoteliais , Polivinil , Polímeros de Fluorcarboneto , Polímeros
14.
Colloids Surf B Biointerfaces ; 193: 111113, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32447201

RESUMO

We recently reported in vitro suppression of platelet adhesion on expanded polytetrafluoroethylene (ePTFE) by surface grafting of poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC). However, this may be inadequate for long-term hemocompatibility of blood-contacting biomaterials, and it has led us to develop a strategy of circulating mononuclear cell-capture. ePTFE was treated with argon (Ar) plasma, and grafted with 2-methacryloyloxyethyl phosphorylcholine (MPC) and methacrylic acid (MAA), by glycidyl methacrylate (GMA)-anchored graft polymerization. Next, it was immobilized with integrin α4ß1-positive circulating blood cell-specific peptides, i.e., the traditional arginine-glutamic acid-aspartic acid-valine (REDV), and our original hemocompatible peptide-1 (HCP-1). Both the surfaces retained the anti-platelet property just like the PMPC-grafted surface, and revealed considerable affinity to human umbilical vein endothelial cells (HUVEC), which is a well-known in vitro integrin α4ß1-positive model. Better HUVEC spreading and proliferation was also confirmed, in terms of the cell extension property. Since coagulation and endothelialization on the materials compete in the body, they cannot be properly evaluated separately, in vitro. They were assessed by using an in situ porcine closed-circuit system for 18 h in the present study. Our findings suggest that poly(MPC-co-MAA) is a great ePTFE surface modifier, exhibiting good hemocompatibility in association with REDV/HCP-1 immobilization, which suppresses anti-platelet adhesion and enhances circulating cell capture simultaneously.


Assuntos
Materiais Biocompatíveis/farmacologia , Células Progenitoras Endoteliais/efeitos dos fármacos , Peptídeos/farmacologia , Fosforilcolina/análogos & derivados , Ácidos Polimetacrílicos/farmacologia , Animais , Materiais Biocompatíveis/química , Células Cultivadas , Humanos , Teste de Materiais , Estrutura Molecular , Tamanho da Partícula , Peptídeos/química , Fosforilcolina/química , Fosforilcolina/farmacologia , Adesividade Plaquetária/efeitos dos fármacos , Ácidos Polimetacrílicos/química , Politetrafluoretileno , Propriedades de Superfície , Suínos
15.
ACS Appl Mater Interfaces ; 10(23): 20170-20181, 2018 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-29767501

RESUMO

Resistance to antibiotics has posed a high demand for novel strategies to fight bacterial infections. Antimicrobial peptides (AMPs) are a promising alternative to conventional antibiotics. However, their poor solubility in water and sensitivity to degradation has limited their application. Here, we report the design of a smart, pH-responsive antimicrobial nanobiocomposite material based on the AMP nisin and 2,2,6,6-tetramethyl-1-piperidinyloxyl-oxidized nanofibrillated cellulose (TONFC). Morphological transformations of the nanoscale structure of nisin functionalized-TONFC fibrils were discovered at pH values between 5.8 and 8.0 using small-angle X-ray scattering. Complementary ζ potential measurements indicate that electrostatic attractions between the negatively charged TONFC surface and the positively charged nisin molecules are responsible for the integration of nisin. Modification of the pH level or increasing the ionic strength reduces the nisin binding capacity of TONFC. Biological evaluation studies using a bioluminescence-based reporter strain of Bacillus subtilis and a clinically relevant strain of Staphylococcus aureus indicated a significantly higher antimicrobial activity of the TONFC-nisin biocomposite compared to the pure nisin against both strains under physiological pH and ionic strength conditions. The in-depth characterization of this new class of antimicrobial biocomposite material based on nanocellulose and nisin may guide the rational design of sustainable antimicrobial materials.

16.
Acta Biomater ; 59: 243-256, 2017 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-28694236

RESUMO

To enhance fibrin hydrogel affinity towards pluripotent stem cell-derived neural stem/progenitor cells (NSPCs) and its capacity to support NSPC migration and neurite extension, we explored the tethering of synthetic peptides engaging integrin α6ß1, a cell receptor enriched in NSPCs. Six α6ß1 integrin ligands were tested for their ability to support integrin α6ß1-mediated adhesion of embryonic stem cell-derived NSPCs (ES-NSPs) and sustain ES-NSPC viability, migration, and neuronal differentiation. Due to their better performance, peptides T1, HYD1, and A5G81 were immobilized into fibrin and functionalized gels characterized in terms of peptide binding efficiency, structure and viscoelastic properties. Tethering of T1 or HYD1 successfully enhanced cell outgrowth from ES-NSPC neurospheres (up to 2.4-fold increase), which exhibited a biphasic response to peptide concentration. Inhibition assays evidenced the involvement of α6ß1 and α3ß1 integrins in mediating radial outgrowth on T1-/HYD1-functionalized gels. Fibrin functionalization also promoted neurite extension of single ES-NSPCs in fibrin, without affecting cell proliferation and neuronal differentiation. Finally, HYD1-functionalized gels were found to provide a permissive environment for axonal regeneration, leading up to a 2.0-fold increase in neurite extension from rat dorsal root ganglia explants as compared to unmodified fibrin, and to significant improved locomotor function after spinal cord injury (complete transection), along with a trend toward a higher area positive for growth associated protein 43 (marker for axonal growth cone formation). Our results suggest that conjugation of α6ß1 integrin-binding motifs is of interest to increase the biofunctionality of hydrogels used in 3D platforms for ES-NSPC culture and potentially, in matrix-assisted ES-NSPC transplantation. STATEMENT OF SIGNIFICANCE: Impact statement: The transplantation of NSPCs derived from pluripotent stem cells holds much promise for the treatment of central nervous system disorders. Moreover, the combinatorial use of biodegradable hydrogels with NSPCs was shown to contribute to the establishment of a more permissive environment for survival and integration of transplanted cells. In this study, fibrin hydrogels functionalized with a synthetic peptide engaging integrin α6ß1 (HYD1) were shown to promote neurite extension of ES-NSPCs, which is fundamental for the formation of functional neuronal relay circuits after NSPC transplantation. Notably, HYD1-functionalized fibrin per se led to enhanced axonal growth ex vivo and to an improvement in locomotor function after implantation in a rat model of spinal cord injury. Conjugation of α6ß1 integrin-binding motifs may therefore be of interest to confer bioactivity to NSPC hydrogel vehicles.


Assuntos
Células-Tronco Embrionárias/metabolismo , Fibrina/química , Integrina alfa6beta1/metabolismo , Células-Tronco Neurais/metabolismo , Neuritos/metabolismo , Animais , Linhagem Celular Tumoral , Células-Tronco Embrionárias/citologia , Humanos , Ligantes , Camundongos , Células-Tronco Neurais/citologia , Ratos , Ratos Wistar
17.
Acta Biomater ; 15: 127-38, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25541344

RESUMO

Catheter-associated urinary tract infections (CAUTIs) are the most common hospital-acquired infections worldwide, aggravating the problem of antimicrobial resistance and patient morbidity. There is a need for a potent and robust antimicrobial coating for catheters to prevent these infections. An ideal coating agent should possess high antimicrobial efficacy and be easily and economically conjugated to the catheter surface. In this study, we report a simple yet effective immobilization strategy to tether a potent synthetic antimicrobial peptide, CWR11, onto catheter-relevant surfaces. Polydopamine (PD) was deposited as a thin adherent film onto a polydimethylsiloxane (PDMS) surface to facilitate attachment of CWR11 onto the PD-functionalized polymer. Surface characterization of the CWR11-tethered surfaces confirmed the successful immobilization of peptides onto the PD-coated PDMS. The CWR11-immobilized PDMS slides displayed excellent antimicrobial (significant inhibition of 5×10(4) colony-forming units of CAUTI-relevant microbes) and antibiofilm (∼92% enhanced antibacterial adherence) properties. To assess its clinical relevance, the PD-based immobilization platform was translated onto commercial silicone-coated Foley catheters. The CWR11-impregnated catheter displayed potent bactericidal properties against both Gram-positive and Gram-negative bacteria, and retained its antimicrobial functionality for at least 21days, showing negligible cytotoxicity against human erythrocyte and uroepithelial cells. The outcome of this study demonstrates the proof-of-concept potential of a polydopamine-CWR11-functionalized catheter to combat CAUTIs.


Assuntos
Anti-Infecciosos/farmacologia , Biofilmes/efeitos dos fármacos , Catéteres/microbiologia , Materiais Revestidos Biocompatíveis/farmacologia , Indóis/farmacologia , Peptídeos/farmacologia , Polímeros/farmacologia , Células 3T3 , Albuminas/metabolismo , Animais , Incrustação Biológica , Morte Celular/efeitos dos fármacos , Linhagem Celular , Humanos , Concentração de Íons de Hidrogênio , Camundongos , Testes de Sensibilidade Microbiana , Concentração Osmolar , Propriedades de Superfície
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA