scholarly journals Antimicrobial peptide coatings for hydroxyapatite: electrostatic and covalent attachment of antimicrobial peptides to surfaces

2017 ◽  
Vol 14 (126) ◽  
pp. 20160657 ◽  
Author(s):  
Leigh Townsend ◽  
Richard L. Williams ◽  
Olachi Anuforom ◽  
Matthew R. Berwick ◽  
Fenella Halstead ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Cell Attachment ◽  
Bacterial Colonization ◽  
Covalent Attachment ◽  
Dual Approach ◽  
Covalently Bonded ◽  
Novel Method ◽  
Tissue Interface ◽  
Peptide Coatings ◽  
Implanted Devices

The interface between implanted devices and their host tissue is complex and is often optimized for maximal integration and cell adhesion. However, this also gives a surface suitable for bacterial colonization. We have developed a novel method of modifying the surface at the material–tissue interface with an antimicrobial peptide (AMP) coating to allow cell attachment while inhibiting bacterial colonization. The technology reported here is a dual AMP coating. The dual coating consists of AMPs covalently bonded to the hydroxyapatite surface, followed by deposition of electrostatically bound AMPs. The dual approach gives an efficacious coating which is stable for over 12 months and can prevent colonization of the surface by both Gram-positive and Gram-negative bacteria.

scholarly journals Developmental switch of intestinal antimicrobial peptide expression

2008 ◽  
Vol 205 (1) ◽  
pp. 183-193 ◽  
Author(s):  
Sandrine Ménard ◽  
Valentina Förster ◽  
Michael Lotz ◽  
Dominique Gütle ◽  
Claudia U. Duerr ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
High Performance ◽  
Bacterial Colonization ◽  
Paneth Cell ◽  
Active Form ◽  
Constitutive Expression ◽  
Postnatal Period ◽  
Enteric Infection ◽  
Immune Effector ◽  
Developmental Switch

Paneth cell–derived enteric antimicrobial peptides provide protection from intestinal infection and maintenance of enteric homeostasis. Paneth cells, however, evolve only after the neonatal period, and the antimicrobial mechanisms that protect the newborn intestine are ill defined. Using quantitative reverse transcription–polymerase chain reaction, immunohistology, reverse-phase high-performance liquid chromatography, and mass spectrometry, we analyzed the antimicrobial repertoire in intestinal epithelial cells during postnatal development. Surprisingly, constitutive expression of the cathelin-related antimicrobial peptide (CRAMP) was observed, and the processed, antimicrobially active form was identified in neonatal epithelium. Peptide synthesis was limited to the first two weeks after birth and gradually disappeared with the onset of increased stem cell proliferation and epithelial cell migration along the crypt–villus axis. CRAMP conferred significant protection from intestinal bacterial growth of the newborn enteric pathogen Listeria monocytogenes. Thus, we describe the first example of a complete developmental switch in innate immune effector expression and anatomical distribution. Epithelial CRAMP expression might contribute to bacterial colonization and the establishment of gut homeostasis, and provide protection from enteric infection during the postnatal period.

scholarly journals RELATION BETWEEN BACTERIAL COLONIZATION IN LUNGS AND LEVELS OF 25-HYDROXYVITAMIN D AND ANTIMICROBIAL PEPTIDE LL-37 IN CHILDREN WITH CYSTIC FIBROSIS

InterConf ◽  
2021 ◽  
pp. 278-282
Author(s):  
Veronika Dudnyk ◽  
Valeriia Demianyshyna
Keyword(s):  
Cystic Fibrosis ◽  
Antimicrobial Peptide ◽  
Bacterial Colonization ◽  
Hydroxyvitamin D ◽  
25 Hydroxyvitamin D ◽  
25 Hydroxycholecalciferol

The aim of the study was to assess the bacterial colonization in lungs of children with cystic fibrosis based on the antimicrobial peptide cathelicidin and 25-hydroxycholecalciferol in the serum. Study showed significant correlation between P. aeruginosa infection and cathelicidin and 25-hydroxycholecalciferol levels.

scholarly journals Multilayer Polyelectrolyte Films Functionalized by Insertion of Defensin: a New Approach to Protection of Implants from Bacterial Colonization

2004 ◽  
Vol 48 (10) ◽  
pp. 3662-3669 ◽  
Author(s):  
O. Etienne ◽  
C. Picart ◽  
C. Taddei ◽  
Y. Haikel ◽  
J. L. Dimarcq ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Micrococcus Luteus ◽  
Bacterial Colonization ◽  
Streaming Potential ◽  
Multilayer Films ◽  
Microbial Infection ◽  
Host Protection ◽  
New Strategy ◽  
Local Host ◽  
Positively Charged

ABSTRACT Infection of implanted materials by bacteria constitutes one of the most serious complications following prosthetic surgery. In the present study, we developed a new strategy based on the insertion of an antimicrobial peptide (defensin from Anopheles gambiae mosquitoes) into polyelectrolyte multilayer films built by the alternate deposition of polyanions and polycations. Quartz crystal microbalance and streaming potential measurements were used to follow step by step the construction of the multilayer films and embedding of the defensin within the films. Antimicrobial assays were performed with two strains: Micrococcus luteus (a gram-positive bacterium) and Escherichia coli D22 (a gram-negative bacterium). The inhibition of E. coli D22 growth at the surface of defensin-functionalized films was found to be 98% when 10 antimicrobial peptide layers were inserted in the film architecture. Noticeably, the biofunctionalization could be achieved only when positively charged poly(l-lysine) was the outermost layer of the film. On the basis of the results of bacterial adhesion experiments observed by confocal or electron microscopy, these observations could result from the close interaction of the bacteria with the positively charged ends of the films, which allows defensin to interact with the bacterial membrane structure. These results open new possibilities for the use of such easily built and functionalized architectures onto any type of implantable biomaterial. The modified surfaces are active against microbial infection and represent a novel means of local host protection.

scholarly journals The biological seal of the implant–soft tissue interface evaluated in a tissue-engineered oral mucosal model

2012 ◽  
Vol 9 (77) ◽  
pp. 3528-3538 ◽  
Author(s):  
Wen L. Chai ◽  
Ian M. Brook ◽  
Anders Palmquist ◽  
Richard van Noort ◽  
Keyvan Moharamzadeh
Keyword(s):  
Soft Tissue ◽  
Cell Attachment ◽  
Tritiated Water ◽  
Three Dimensional ◽  
Permeability Test ◽  
Significant Difference ◽  
Surface Topographies ◽  
Tissue Interface

For dental implants, it is vital that an initial soft tissue seal is achieved as this helps to stabilize and preserve the peri-implant tissues during the restorative stages following placement. The study of the implant–soft tissue interface is usually undertaken in animal models. We have developed an in vitro three-dimensional tissue-engineered oral mucosal model (3D OMM), which lends itself to the study of the implant–soft tissue interface as it has been shown that cells from the three-dimensional OMM attach onto titanium (Ti) surfaces forming a biological seal (BS). This study compares the quality of the BS achieved using the three-dimensional OMM for four types of Ti surfaces: polished, machined, sandblasted and anodized (TiUnite). The BS was evaluated quantitatively by permeability and cell attachment tests. Tritiated water (HTO) was used as the tracing agent for the permeability test. At the end of the permeability test, the Ti discs were removed from the three-dimensional OMM and an Alamar Blue assay was used for the measurement of residual cells attached to the Ti discs. The penetration of the HTO through the BS for the four types of Ti surfaces was not significantly different, and there was no significant difference in the viability of residual cells that attached to the Ti surfaces. The BS of the tissue-engineered oral mucosa around the four types of Ti surface topographies was not significantly different.

Strategies for antimicrobial peptide coatings on medical devices: a review and regulatory science perspective

2020 ◽  
Vol 41 (1) ◽  
pp. 94-120 ◽  
Author(s):  
Mehdi Kazemzadeh-Narbat ◽  
Hao Cheng ◽  
Rosa Chabok ◽  
Mario Moisés Alvarez ◽  
Cesar de la Fuente-Nunez ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Medical Devices ◽  
Regulatory Science ◽  
Peptide Coatings

A Detailed and Fast Model of Extracellular Recordings

2013 ◽  
Vol 25 (5) ◽  
pp. 1191-1212 ◽  
Author(s):  
Luis A. Camuñas-Mesa ◽  
Rodrigo Quian Quiroga
Keyword(s):  
Action Potentials ◽  
Finite Size ◽  
Real Data ◽  
Recording Electrode ◽  
Electrode Diameter ◽  
Extracellular Recordings ◽  
Novel Method ◽  
Tissue Interface ◽  
Tetrode Recordings

We present a novel method to generate realistic simulations of extracellular recordings. The simulations were obtained by superimposing the activity of neurons placed randomly in a cube of brain tissue. Detailed models of individual neurons were used to reproduce the extracellular action potentials of close-by neurons. To reduce the computational load, the contributions of neurons further away were simulated using previously recorded spikes with their amplitude normalized by the distance to the recording electrode. For making the simulations more realistic, we also considered a model of a finite-size electrode by averaging the potential along the electrode surface and modeling the electrode-tissue interface with a capacitive filter. This model allowed studying the effect of the electrode diameter on the quality of the recordings and how it affects the number of identified neurons after spike sorting. Given that not all neurons are active at a time, we also generated simulations with different ratios of active neurons and estimated the ratio that matches the signal-to-noise values observed in real data. Finally, we used the model to simulate tetrode recordings.

Novel Method for Construction of a Metal–Organic Monolayer–Si Structure Utilizing Thiol-terminated Monolayer Covalently Bonded to the Surface through Si–C Bonds

2010 ◽  
Vol 39 (7) ◽  
pp. 768-770 ◽  
Author(s):  
Hitoshi Fukumitsu ◽  
Takuya Masuda ◽  
Deyu Qu ◽  
Yusuke Waki ◽  
Hidenori Noguchi ◽  
...  
Keyword(s):  
Organic Monolayer ◽  
Covalently Bonded ◽  
Metal Organic ◽  
Novel Method

Surface Modifications of Titanium With Covalently-Bonded Silver Nanoparticles for Antimicrobial Applications

2019 ◽  
Author(s):  
Shahrima Maharubin ◽  
Xiaomei Shu ◽  
Manavi Singh ◽  
Benildo De los Reyes ◽  
George Tan
Keyword(s):  
Silver Nanoparticles ◽  
Film Structure ◽  
Bacterial Attachment ◽  
Covalent Attachment ◽  
Implant Surface ◽  
Covalent Bonds ◽  
Surface Profiling ◽  
Short Term Exposure ◽  
Covalently Bonded ◽  
Effective Remedy

Abstract Formation of biofilm on implant surface is one of the major causes for port-operative infection. Incorporation of antimicrobial silver nanoparticles (AgNPs) on implant surface has been studied as an effective remedy in recent decades. This paper presents a novel AgNPs-titanium composite foil manufactured through covalent attachment of AgNPs for biofilm control. This composite foil was fabricated by a series of chemical reactions including thiol-derivatization and formation of Ag-S covalent bonds. The film structure and properties were characterized through scanning electron microscopy (SEM), Energy dispersive X-ray Spectroscopy (EDS) and surface profiling. The antimicrobial performance was examined against gram positive bacterial strain Staphylococcus aureus. Results indicate that the prepared composite foil effectively reduced bacterial attachment in short term exposure and possess high stability against the release of nanoparticles. This novel antimicrobial composite material has a great potential to be used in the future biomedical instrumentation.

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