China
Africa
Explore chapters and articles related to this topic
Lactic acid-based polymers in depth
Published in Yoshinobu Onuma, Patrick W.J.C. Serruys, Bioresorbable Scaffolds, 2017
As for exploitation-related properties, PLA-type polymers, especially amorphous ones, can absorb water slowly from a humid atmosphere which can cause slow hydrolytic degradation that results in undesired aging. Rearrangements of more or less oriented chain conformation, a phenomenon referred to as chain relaxation, can occur very slowly below Tg to affect dimensions and stability on storage. Sterilization is also a source of problems because there is a risk of fast deformation (above Tg) and thermal degradation if heat is used. In the case of radiation-based sterilization, severe decreases of molecular mass are observed and cross-linking has been suggested. Sterilization by cold plasma seems to be the best characteristic-respecting process with very small molecular weight decreases although some surface functionalization may change protein adsorption.
Human Noroviruses
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
G. Sanchez, W. Randazzo, D.H. D'Souza
Atmospheric pressure plasma (APP) uses a neutral ionized gas that comprises highly reactive species including positive and negative ions, free radicals, electrons, excited or nonexcited molecules, and photons.161 Some information is available about effect of nonthermal plasma against viral pathogen including norovirus (reviewed by Pradeep and Chulkyoon162). Recently, Ahlfeld et al.163 investigated the impact of cold APP (CAPP) on HNoVGII.4 inactivation showing that increased plasma treatment times led to decreased copy numbers of HNoV in inoculated surfaces. Similarly, Aboubakr et al.164 investigated the virucidal activity of cold atmospheric gaseous plasma (CGP) against FCV-F9, reporting that factors such as the plasma generation power, the exposure time and distance, the plasma feed gas mixture, and the virus suspension medium deeply affect the inactivation results. They also reported that virus titer reduction increased with increasing exposure time and decreasing exposure distance. They postulated that the production of reactive oxygen and nitrogen species in the solution appeared to oxidize the viral capsid proteins and thus inactivate the virus.165 Alshraiedeh et al.166 investigated an atmospheric pressure, nonthermal plasma jet operating at varying helium/oxygen feed gas concentrations that exhibited a rapid virucidal activity against MS2 bacteriophage (reduction of 3 log after 3 minutes and more than 7 log after 9 minutes). A comparative study with FCV-F9, MNV-1, and bacteriophage MS2 was performed by treating with nonthermal plasma on stainless steel surfaces, with a sensitivity range as FCV-F9 > MS2 > MNV-1.167 The effect of APP jets against MNV-1 in fresh meats was recently reported by Bae et al.168 showing that 5 minutes of APP jet treatment was effective in >99% reduction of virus titer without changes in meat quality. Dielectric barrier discharge atmospheric cold plasma was reported to inhibit only 0.7 log of TV in packaged lettuce, with a decreased inactivation effect in reduced-oxygen MAP conditions.169
Exploring the functionalization of Ti-6Al-4V alloy with the novel antimicrobial peptide JIChis-2 via plasma polymerization
Published in Biofouling, 2023
Gabriella Teresinha Lima Teixeira, Rogério Valentim Gelamo, Malu Mateus Santos Obata, Leonardo Eurípedes de Andrade Silva, Marcos Vinícius da Silva, Carlo José Freire de Oliveira, Brunela Pereira da Silva, Idalina Vieira Aoki, Jeferson Aparecido Moreto, Natália Bueno Leite Slade
This work aims to immobilize the JI-2 peptide, analogous to the antimicrobial peptide Jelleine in the Ti-6Al-4V alloy surfaces. This strategy was used to develop a material with good potential for applications in the dentistry and orthodontic sectors. The peptide was immobilized on the surfaces after the deposition of AA via PECVD. This method consists of using cold plasma discharge to fragment volatile precursor molecules and place them over solid substrates. Thus, polymeric thin films with a structure consisting of a high degree of crosslinking are obtained. The polymerized AA are biocompatible and the presence of carboxyl groups allows the functionalization of materials with different biomolecules (de Giglio et al. 2007), such as peptides (Lopez et al. 2005; Seo et al. 2010), proteins (Ulbricht and Riedel 1998) and heparin loaded liposomes (Kastellorizios et al. 2012). In addition, PAA coating has excellent anti-corrosion properties (de Giglio et al. 2007), acting as a protective barrier on metal surfaces.
Efficacy of cavity liners with/without atmospheric cold helium plasma jet for dentin remineralization
Published in Biomaterial Investigations in Dentistry, 2020
Hamid Kermanshah, Reza Saeedi, Elham Ahmadi, Ladan Ranjbar Omrani
Plasma is the 4th state of matters that forms at very high temperatures. This ionized gas includes photons, electrons, positive and negative ions, atoms, free radicals, and excited and non-excited molecules that constantly interact with each other [11]. Plasma has different types including hot, warm and cold plasma. The cold plasma is a type of plasma created by electrical discharge [12]. Of different methods of production of cold plasma, plasma jet has gained attention since it is portable, can be charged on spot and has low energy consumption. The ACPJ has low temperature (room temperature) and therefore, has several medical applications [13]. Researchers have shown that plasma surface modification is a clean and effective method [10]. Its effect is related to plasma reactive species. According to the plasma type, the plasma gas reacts with the surface of substrates and creates new surface characteristics [10]. Increased wettability, as well as permeability, is among the modifications caused by argon and helium plasma in dental substrates [10].
Topical negative-pressure wound therapy: emerging devices and techniques
Published in Expert Review of Medical Devices, 2020
Raymund E. Horch, Ingo Ludolph, Wibke Müller-Seubert, Katharina Zetzmann, Theresa Hauck, Andreas Arkudas, Alexander Geierlehner
Cold plasma, one of the four fundamental states of matter, was recently introduced as a promising application to enhance wound healing. Especially in chronic and heavily contaminated wounds, the combination of cold plasma with sub-atmospheric pressure could be beneficial to the wound healing process. An increasing number of drug-resistant bacteria and the lack of new antibiotics make further optimization of NPWT as a delivery vehicle worthy. The delivery of adjunct therapies such as saline irrigation or instillation with antimicrobial solutions is increasingly used in the clinical wound management [116,122]. Wound instillation possesses the ability to deliver wound dependent and wound-specific substances. Cell suspensions containing prefabricated stem cells derived from the affected patient might also be able to promote wound healing. However, this is highly dependent on the type of tissue involved. Furthermore, substances known to have an impact on the physiological wound healing process could be applied in combination with NPWT in future studies. The combination with later techniques of tissue regeneration, such as tissue engineering and bioprinting in conjunction with biomolecular insights seems desirable, yet is not in the stage of clinical application [1]. Different vascular and collagen related growth factors might be of high interest [123]. Also applying perioperative analgesia or antibiotics using substances that interact directly at the foam–wound interface is a possible modification in the overall treatment concept of NPTW. Basic research for the detailed understanding of cell signaling mechanism is essential in this context.