scholarly journals Nonthermal plasma treatment of polymers modulates biological fouling but can cause material embrittlement

2019 ◽  
Author(s):  
Greg D. Learn ◽  
Emerson J. Lai ◽  
Emily J. Wilson ◽  
Horst A. von Recum
Keyword(s):  
Structural Characteristics ◽  
Biological Response ◽  
Nonthermal Plasma ◽  
Polymeric Materials ◽  
Exposure Limits ◽  
Plasma Exposure ◽  
Bulk Properties ◽  
Surgical Meshes ◽  
Fibroblast Attachment ◽  
Polymeric Implants

AbstractPlasma-based treatment is a prevalent strategy to alter biological response and enhance biomaterial coating quality at the surfaces of biomedical devices and implants, especially polymeric materials. Plasma, an ionized gas, is often thought to have negligible effects on the bulk properties of prosthetic substrates given that it alters the surface chemistry on only the outermost few nanometers of material. However, no studies to date have systematically explored the effects of plasma exposure on both the surface and bulk properties of a biomaterial. This work examines the time-dependent effects of a nonthermal plasma on the surface and bulk properties of polymeric implants, specifically polypropylene surgical meshes and sutures. Findings suggest that plasma exposure improved resistance to fibrinogen adsorption and Escherichia coli attachment, and promoted mammalian fibroblast attachment, although increased duration of exposure resulted in a state of diminishing returns. At the same time, it was observed that plasma exposure can be detrimental to the material properties of individual filaments (i.e. sutures), as well as the structural characteristics of knitted meshes, with longer exposures resulting in further embrittlement and larger changes in anisotropic qualities. Though there are few guidelines regarding appropriate mechanical properties of surgical textiles, the results from this investigation imply that there are ultimate exposure limits for plasma-based treatments of polymeric implant materials when structural properties must be preserved, and that the effects of a plasma on a given biomaterial should be examined carefully before translation to a clinical scenario.

scholarly journals A Middle-Aged Enzyme Still in Its Prime: Recent Advances in the Field of Cutinases

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 612 ◽  
Author(s):  
Efstratios Nikolaivits ◽  
Maria Kanelli ◽  
Maria Dimarogona ◽  
Evangelos Topakas
Keyword(s):  
Structure Function ◽  
Present Article ◽  
Food Processing ◽  
Structural Characteristics ◽  
Polymeric Materials ◽  
Ester Synthesis ◽  
Middle Aged ◽  
Natural Function ◽  
Phytopathogenic Microorganisms ◽  
Hydrolysis Of

Cutinases are α/β hydrolases, and their role in nature is the degradation of cutin. Such enzymes are usually produced by phytopathogenic microorganisms in order to penetrate their hosts. The first focused studies on cutinases started around 50 years ago. Since then, numerous cutinases have been isolated and characterized, aiming at the elucidation of their structure–function relations. Our deeper understanding of cutinases determines the applications by which they could be utilized; from food processing and detergents, to ester synthesis and polymerizations. However, cutinases are mainly efficient in the degradation of polyesters, a natural function. Therefore, these enzymes have been successfully applied for the biodegradation of plastics, as well as for the delicate superficial hydrolysis of polymeric materials prior to their functionalization. Even though research on this family of enzymes essentially began five decades ago, they are still involved in many reports; novel enzymes are being discovered, and new fields of applications arise, leading to numerous related publications per year. Perhaps the future of cutinases lies in their evolved descendants, such as polyesterases, and particularly PETases. The present article reviews the biochemical and structural characteristics of cutinases and cutinase-like hydrolases, and their applications in the field of bioremediation and biocatalysis.

Relationship between Biomaterials Structure Used in Hernia Mesh Fixation and Chronic Infection

2015 ◽  
Vol 1114 ◽  
pp. 278-282 ◽  
Author(s):  
Carmen Iuliana Mavrodin ◽  
Vasile Iulian Antoniac ◽  
George Pariza
Keyword(s):  
Structural Characteristics ◽  
Mesh Fixation ◽  
Polymeric Materials ◽  
Abdominal Hernia ◽  
Prosthetic Material ◽  
Hernia Surgery ◽  
Septic Complications ◽  
Wall Structures ◽  
Increased Risk ◽  
Negative Effect

Broad introduction and development of polymeric materials in abdominal hernia surgery led to the emergence and identification of secondary complications due to interaction between prosthetic material and human tissue. Whether identification of these reactions has led to the placement instructions of the prostheses into the wall structures of adbomen, there is no clear rule on fixation materials of these prosthesis; they generally follow the recommendations of the prosthesis materials.There are some situations in which the faulty choice of fixing materials can compromise such surgery, followed by chronic septic complications and negative effect on quality of life of these patients and increased risk of recurrence.The choice of fixing materials considering the structural characteristics of polymeric threads can prevent chronic suppuration secondary to this type of surgery.

Structural characteristics defining high barrier properties in polymeric materials

2004 ◽  
Vol 20 (1) ◽  
pp. 1-7 ◽  
Author(s):  
J. M. Lagaron ◽  
R. Catalá ◽  
R. Gavara
Keyword(s):  
Structural Characteristics ◽  
Polymeric Materials ◽  
Barrier Properties

Application of Auxetic Polymeric Structures for Body Protection

2016 ◽  
Author(s):  
Chulho Yang ◽  
Hitesh D. Vora ◽  
Young B. Chang
Keyword(s):  
Structural Characteristics ◽  
Polymeric Materials ◽  
The Body ◽  
Material Structure ◽  
Light Weight ◽  
Body Parts ◽  
Shock Absorption ◽  
Element Analysis ◽  
Auxetic Materials ◽  
Polymeric Structures

Negative Poisson’s ratio (NPR) materials, also known as auxetic materials, have many promising application areas. In recent years, various auxetic material structures have been designed and fabricated for diverse applications that utilized normal materials which follow Hooke’s law but still show the properties of negative Poisson’s ratios. In light of this, efforts are made to apply auxetic material structures to body protection pads that are comfortable to wear and effective in protecting body parts by reducing impact force and preventing injuries in high-risk individuals such as elderly people, industry workers, law enforcement and military personnel, and sport players. For those people, blunt impacts such as falls, bullets, and blast wave may reduce quality of life, increase the possibility of early death and generate an extremely high medical costs. Therefore, it is important to develop new body protectors that best combine each individual’s requirements of wearing comfort (flexible, light weight), ease of fitting (customized), ensured protection, and cost-effectiveness. The developed protection pad would be made from multilayer materials with an adaptive structure to achieve a unique multifunctional properties such as high hardness, impact toughness, light weight, excellent shock absorption, self-assembly suitable for the needs. Particularly, an integrated computational (finite element analysis) approach is used to investigate the effect of three material structures (honeycomb or flexin structure, re-entrant hexagonal cells or reflexin structure, and arrowhead structure) in combination with three polymeric materials (Polylactic acid (PLA) and two thermoplastic polyurethane (TPU) materials). Efforts are made to relate the individual and/or combined effect of auxetic structure and materials to the overall stiffness and shock-absorption performance of the body protection pads. Initially, parametric 3D CAD models of auxetic polymeric structures are developed. Later, key structural characteristics of protectors are evaluated through static analyses of FEA models. Impact/shock analyses are conducted to validate the results obtained from the static analyses. The mechanism for ideal input force distribution or shunting is suggested for designing protectors using various shapes, thicknesses, and materials of auxetic materials to reduce the risk of injury. The results show that the auxetic material can be considered as an effective material structure for body protection pads.

scholarly journals COMPARATIVE ANALYSIS OF DIELECTRIC AND STRUCTURAL CHARACTERISTICS OF THE SAMPLES BASED ON POLYETHYLENETEREPHTALATE

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Dragana Cerović ◽  
Jablan Dojčilović ◽  
Ivan Petronijević ◽  
Dušan Popović
Keyword(s):  
Comparative Analysis ◽  
Dielectric Spectroscopy ◽  
Structural Characteristics ◽  
Polymeric Materials ◽  
Detailed Examination ◽  
Medical Applications ◽  
Dielectric Parameters ◽  
External Influences ◽  
Woven Structures ◽  
Β Relaxation

Widespread use of polymeric materials from the items for daily use to electrical engineering, electronics and medical applications causes a need for their detailed examination under various external influences. Dielectric spectroscopy allows monitoring changes in the structure of polymers under various external influences. In this paper we analyzed β relaxation recorded in polymer woven structures and meshes based on polyethyleneterephtalate. Based on the results obtained, a comparative analysis of dielectric parameters and structural characteristics of the samples was done.

scholarly journals Using nonthermal plasma treatment to improve quality and durability of hydrophilic coatings on hydrophobic polymer surfaces

2019 ◽  
Author(s):  
Greg D. Learn ◽  
Emerson J. Lai ◽  
Horst A. von Recum
Keyword(s):  
Plasma Treatment ◽  
Biological Response ◽  
Covalent Bond ◽  
Nonthermal Plasma ◽  
Consumer Products ◽  
Improve Quality ◽  
Polymeric Substrates ◽  
Substrate Surfaces ◽  
Hydrophilic Coatings

AbstractLow surface energy substrates, which include many polymers in medicine/industry, present challenges toward achieving uniform, adherent, durable coatings, thus limiting intended coating function. Examples include hydrophobic polymers such as polypropylene, polyethylene, polytetrafluoroethylene, and polydimethylsiloxane. These inert materials are used in various biomedical implants due to favorable bulk properties despite perhaps unfavorable surface properties. The capability to coat such materials holds great value as the surface heavily influences biological response and implant function in vivo. Likewise, paint/ink coatings are often necessary on these same plastics, as their final appearance can be critical for automotive, packaging, and consumer products. Substrate exposure to nonthermal plasma was explored here as a means to improve quality of coatings, specifically cyclodextrin-based polyurethanes previously explored for biomedical applications such as controlled drug delivery and anti-biofouling, upon otherwise incompatible polypropylene substrates. Plasma treatment was found to increase wettability and oxygen content on substrate surfaces. These plasma-induced surface alterations were associated with enhanced coating uniformity, and improved coating/substrate adherence – determined to derive partly from interfacial covalent bond formation. Findings demonstrate the utility of plasma-based surface activation as a strategy to improve coating quality on polymeric substrates, and reveal insights regarding mechanisms by which plasma improves polymer coating adherence.

scholarly journals STUDIES OF KINETICS AND STRUCTURAL CHARACTERISTICS OF ELECTROBAROMEMBRANE PURIFICATION OF RINSING WATERS OF PRODUCTION OF 2,2'-DIBENZOTHIAZOLILEDISULPHIDE

2018 ◽  
Vol 59 (2) ◽  
pp. 34 ◽  
Author(s):  
Sergeiy I. Lazarev ◽  
Sergeiy V. Kovalev ◽  
Vadim G. Kazakov
Keyword(s):  
Pore Radius ◽  
Structural Characteristics ◽  
Experimental Studies ◽  
Polymeric Materials ◽  
Hindrance Factor ◽  
Radius Of Gyration ◽  
Chemical Additives ◽  
Specific Flow ◽  
X Ray Scattering ◽  
Kinetic Coefficients

The results of experimental studies are presented for the kinetic characteristics of the membranes of electrobaromembrane  purification  of rinsing waters of electrochemical synthesis of 2,2' - dibenzothiazoliledisulphide used as a corrosion inhibitor and chemical additives for the production of polymeric materials. The experimental studies for the determination the pore radius of the membranes were carried out by the method of low-angle X-ray scattering. The data obtained on the hindrance factor, specific flow, pore radius and radius of gyration allow to predict and to calculate the kinetic coefficients of electrobaromembrane process of purification of rinsing waters of 2,2' -2,2'- dibenzothiazoliledisulphide production.

scholarly journals Current Challenges and Innovative Developments in Hydroxyapatite-Based Coatings on Metallic Materials for Bone Implantation: A Review

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1249
Author(s):  
Bilal Beig ◽  
Usman Liaqat ◽  
Muhammad Farooq Khan Niazi ◽  
Inamullah Douna ◽  
Muhammad Zahoor ◽  
...  
Keyword(s):  
Structural Characteristics ◽  
Polymeric Materials ◽  
Extensive Study ◽  
Human Bone ◽  
Metallic Materials ◽  
Corrosion Properties ◽  
Similar Chemical ◽  
Calcium Magnesium ◽  
Normal Human ◽  
Future Direction

Biomaterials are in use for the replacement and reconstruction of several tissues and organs as treatment and enhancement. Metallic, organic, and composites are some of the common materials currently in practice. Metallic materials contribute a big share of their mechanical strength and resistance to corrosion properties, while organic polymeric materials stand high due to their biocompatibility, biodegradability, and natural availability. To enhance the biocompatibility of these metals and alloys, coatings are frequently applied. Organic polymeric materials and ceramics are extensively utilized for this purpose due to their outstanding characteristics of biocompatibility and biodegradability. Hydroxyapatite (HAp) is the material from the ceramic class which is an ultimate candidate for coating on these metals for biomedical applications. HAp possesses similar chemical and structural characteristics to normal human bone. Due to the bioactivity and biocompatibility of HAp, it is used for bone implants for regenerating bone tissues. This review covers an extensive study of the development of HAp coatings specifically for the orthopaedic applications that include different coating techniques and the process parameters of these coating techniques. Additionally, the future direction and challenges have been also discussed briefly in this review, including the coating of HAp in combination with other calcium magnesium phosphates that occur naturally in human bone.

APPLICATION OF COMBINED DATA-DRIVEN COMPUTATIONAL CHEMISTRY AND CHEMINFORMATICS APPROACHES TO PREDICT PROPERTIES OF MATERIALS

2021 ◽  
Author(s):  
Bakhtiyor Rasulev ◽  
Keyword(s):  
Biological Activity ◽  
Computational Chemistry ◽  
Materials Science ◽  
Structural Characteristics ◽  
Chemical Properties ◽  
Polymeric Materials ◽  
Data Driven ◽  
Ligand Docking ◽  
New Materials ◽  
And Performance

For the last two decades, breakthrough research has been going on in all aspects of materials science at accelerated pace. New materials of unprecedented functionality and performance are being developed and characterized. Moreover, the new materials with improved functionality are in high demand in the marketplace and this need increases in an exponential way for the new materials of desired functionality and performance. Here we show the application of combined computational and cheminformatics methods in various materials properties prediction, including organometallic materials, polymeric materials and nanomaterials. Since most of the materials are complex entities from a chemical point of view, the investigation of them requires an interdisciplinary approach, involving multiple aspects ranging from physics and chemistry to biology and informatics. In this report we show how the combination of computational chemistry, available experimental data, machine learning and cheminformatics approaches can help in materials research and properties assessment, such as physico-chemical properties, toxicity, and biological activity. We discuss here a few case studies where data-driven models developed to reveal the relationships between the physicochemical properties, biological activity and structural characteristics, by application quantum chemical, protein-ligand docking, cheminformatics approaches and developed nanodescriptors.

scholarly journals An Open, Randomized, Single-Center, Crossover Pharmacokinetic Study of Meropenem after Intraperitoneal and Intravenous Administration in Patients Receiving Automated Peritoneal Dialysis

2016 ◽  
Vol 60 (5) ◽  
pp. 2790-2797 ◽  
Author(s):  
Martin Wiesholzer ◽  
Petra Pichler ◽  
Gottfried Reznicek ◽  
Michaela Wimmer ◽  
Manuel Kussmann ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
High Performance ◽  
Pharmacokinetic Profile ◽  
Liquid Chromatography Mass Spectrometry ◽  
Automated Peritoneal Dialysis ◽  
Single Center ◽  
Exposure Limits ◽  
Plasma Exposure ◽  
The Mean ◽  
Systemic Infections

ABSTRACTThe objective of this study was to determine the pharmacokinetic profile of meropenem in automated peritoneal dialysis (APD) patients. In 6 patients without peritonitis, a single dose of 0.5 g of meropenem was applied intraperitoneally (i.p.) or intravenously (i.v.) and concentrations in serum and dialysate were measured at specified intervals over 24 h with high-performance liquid chromatography-mass spectrometry. The mean maximum concentrations of meropenem in serum (Cmax) were 27.2 mg/liter (standard deviation [SD], ±6.9) and 10.1 mg/liter (SD, ±2.5) and in dialysate were 3.6 mg/liter (SD, ±2.3) and 185.8 mg/liter (SD, ±18.7) after i.v. and i.p. administrations, respectively. The mean areas under the curve from 0 to 24 (AUC0–24) of meropenem in serum were 173.5 mg · h/liter (SD, ±29.7) and 141.4 mg · h/liter (SD, ±37.5) (P= 0.046) and in dialysate were 42.6 mg · h/liter (SD, ±20.0) and 623.4 mg · h/liter (SD, ±84.1) (P= 0.028) after i.v. and i.p. administrations, respectively. The ratios for dialysate exposure over plasma exposure after i.v. and i.p. treatments were 0.2 (SD, ±0.1) and 4.6 (SD, ±0.9), respectively (P= 0.031). A mean target value of 40%T>MIC (time for which the free meropenem concentration exceeds the MIC) for clinically relevant pathogens with EUCAST susceptibility breakpoints of 2 mg/liter was reached in serum after i.p. and i.v. administrations and in dialysate after i.p. but not after i.v. administration. The present data indicate that low i.p. exposure limits the i.v. use of meropenem for PD-associated peritonitis. In contrast, i.p. administration not only results in superior concentrations in dialysate but also might be used to treat systemic infections.

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