Dissolvable and Coated Microneedle Arrays: Design, Fabrication, Materials and Administration Methods
Boris Stoeber, Raja K Sivamani, Howard I. Maibach in Microneedling in Clinical Practice, 2020
Hybrid fabrication techniques can be utilized to create both coated and dissolvable MNAs. The general approach in hybrid fabrication techniques involves fabrication of a set of master molds using a direct technique, and subsequently using micromolding to create the final MNAs. The MNAs can be fabricated using micromolding either directly from the master molds or from production molds obtained from the master molds. Silicon, metals (e.g., aluminum), and thermoplastic polymers (e.g., poly(methyl methacrylate), PMMA) have been used as master mold materials [26, 45]. The molds (master or production) are filled with a molten, dissolved (solvent-based), multi-component (e.g., thermosets) or softened (above the glass-transition temperature) material to create solid polymer microneedles upon solidification (by cooling, solvent evaporation, or cross-linking). Similarly, ceramic microneedles have been fabricated by molding a ceramic-powder slurry (e.g., alumina) onto the MNA molds, and then sintering the molded slurry [47].
Synergistic Antimicrobial Activity of Silver and Chitosan
Huiliang Cao in Silver Nanoparticles for Antibacterial Devices, 2017
Employment of nanoparticles is a growing antimicrobial approach to overcoming drug resistance developed by microbes against antibiotics. By increasing the amount of drug uptake and by inhibiting the efflux of drugs from the microbial cells, nanoparticles can fight against biofilm development and could also conceivably combat intracellular bacteria. Moreover, nanoparticles may be able to guide antimicrobial agents to the spot of infection and improve aspects of drug delivery and controlled release, so that effective doses of drug are administered at the infected site, while reducing the overall doses necessary to the patient and thus mitigating the development of drug resistance (Pelgrift and Friedman 2013). Chitosan and silver nanoparticles have proved their effectiveness by studies carried out in vivo (Gaafar et al. 2014). A nanocomposite coating formed by attaching the polysaccharide 1-deoxylactit-1-yl chitosan (Chitlac) and AgNPs onto methacrylate thermosets was studied, and this system showed good antibacterial and antibiofilm activity (Marsich et al. 2013). CS/nHAp/nAg biocomposite scaffolds showed potential in controlling implant-associated bacterial infection during reconstructive surgery of bones (Saravanan et al. 2011).
Thermal Analysis of Herbal Drugs
Ravindra Kumar Pandey, Shiv Shankar Shukla, Amber Vyas, Vishal Jain, Parag Jain, Shailendra Saraf in Fingerprinting Analysis and Quality Control Methods of Herbal Medicines, 2018
TMA applications are, in many ways, the simplest of the thermal techniques. TMA merely measures the change in the height of the sample. The resultant information is useful in supplying information needed to design and process everything from chips to food products to motors. Because of the sensitivity of modern TMA, it is often used to measure Tgs that are difficult to obtain by DSC, for example, those of highly cross-linked thermosets.
Microencapsulation of reactive isocyanates for application in self-healing materials: a review
Published in Journal of Microencapsulation, 2021
Amanda N. B. Santos, Demetrio J. dos Santos, Danilo J. Carastan
The development of self-healing materials was inspired by natural biological systems which present a healing response after being damaged without the need of external intervention (Yuan et al.2008, Blaiszik et al.2010, Yang and Urban 2013). These smart materials emerge as a promise to increase durability and reliability of polymeric materials used in structural applications, such as in fiber-reinforced composites. Such polymers are often thermosets with a brittle behaviour and nano and microcracks appear inside them in long term applications. These flaws are hardly detectable and often evolve to material failure, increasing maintenance costs and restricting their use (Zhu et al.2015).
Understanding the basis of medical use of poly-lactide-based resorbable polymers and composites – a review of the clinical and metabolic impact
Published in Drug Metabolism Reviews, 2019
Sergiu Vacaras, Mihaela Baciut, Ondine Lucaciu, Cristian Dinu, Grigore Baciut, Liana Crisan, Mihaela Hedesiu, Bogdan Crisan, Florin Onisor, Gabriel Armencea, Ileana Mitre, Ioan Barbur, Winfried Kretschmer, Simion Bran
It has a melting temperature between 150–160 °C, it liquifies, does not burn, and can be cooled and reheated without major degradation – owing to its thermoplasticity. This property also confers its recyclability, as opposed to thermoset materials, which alter irreversibly upon heating and burn at the second heat exposure.
Determination of polycyclic aromatic hydrocarbons (PAHs) in carbon black-containing plastic consumer products from the Jordanian market
Published in Toxin Reviews, 2018
Mahmoud A. Alawi, Rana A. Abdullah, Ibrahim Tarawneh
Polymers are large molecules, which consist of a large number of small molecules that are linked together through a polymerization process. They are classified into two categories; thermosets and thermoplastics, the later is commonly called as plastics (Skoog et al. 1997).