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Biomimetic Approaches for the Design and Development of Multifunctional Bioresorbable Layered Scaffolds for Dental Regeneration
Published in Vincenzo Guarino, Marco Antonio Alvarez-Pérez, Current Advances in Oral and Craniofacial Tissue Engineering, 2020
Campodoni Elisabetta, Dozio Samuele Maria, Mulazzi Manuela, Montanari Margherita, Montesi Monica, Panseri Silvia, Sprio Simone, Tampieri Anna, Sandri Monica
Focusing on 3D biomaterials design, there are two main features by which they can interact with cultured cells directing their fate. One is their 3D structure, ranging from nano to macroscale hierarchy. A well-designed 3D structure is much more instructive than its chemical composition. Starting from the nanometric scale of a biomaterial hierarchy, its degree of surface rugosity impact on cell attachment ability, fundamental for avoiding anoikis, a form of apoptosis cell-surface anchoring dependent, and essential for biomaterial colonization after implantation (Valentijn et al. 2004). Increasing the micrometric and macrometric levels, the overall biomaterial porosity and resulting 3D structure play an important role in cell-colonization capacity and cell development (Loh and Choong 2013). If hierarchically organized, the pores could resemble the dentin aligned channels serving as a way for deep cell colonization and spatial orientation (Fig. 8.4G—J) (Pansen et al. 2016). Or it could be shaped in a multilayer biomaterial with differential porosity which, combined with differential chemical compositions, mimic the different tissues composing the periodontium. By adding different instructor layers, the biomaterial could direct the cell fate in a refined fashion, also diminishing external infection occurrence through a protective layer with reduced porosity composed by FeHA plus cellulose acetate, fundamental for dental applications (Fig. 8.4A—F) (Li et al. 2003; Sprio et al. 2018).
Microdialysis Techniques for Epilepsy Research
Published in Steven L. Peterson, Timothy E. Albertson, Neuropharmacology Methods in Epilepsy Research, 2019
John W. Dailey, Pravin K. Mishra
Many fiber-shaped dialysis materials have been successfully used in fabrication of microdialysis probes. Popular ones are regenerated cellulose, cellulose acetate, cellulose ester, polysulfone, etc.28 These membranes vary in their permeability limits, diameter, wall thickness, etc. When choosing a dialysis membrane, the primary consideration should be the permeability limit and its performance in vivo. Certain membrane materials (such as polysulfone) offer excellent in vitro recovery numbers for a given surface area, but may perform poorly in vivo, and others are vice versa. The regenerated cellulose membranes are usually rugged enough to sustain the handling required under common laboratory conditions. If the membrane must be wet in order to stay patent, threading it inside the plumbing tubes and gluing it can be tricky. Flaccidity and handling of the membrane in dry and wet conditions should be considered. The membrane should be firm enough that it can be conveniently placed inside the target tissue. Also important factors are availability of diameters that are suitable for the target tissue, and their ability to withhold internal fluid pressures. Such information is usually available from the membrane manufacturer.
Formaldehyde
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 4, 2017
William J. Rea, Kalpana D. Patel
Acetic acid is one of the simplest carboxylic acids. It is an important chemical reagent and industrial chemical, mainly used in the production of cellulose acetate, especially for photographic film and polyvinyl acetate for wood glue, as well as synthetic fibers and fabrics. In households, diluted acetic acid is often used in descaling agents. In the food industry, acetic acid is used under the food additive code E260 as an acidity regulator and as a condiment. As a food additive, it is approved for usage in the EU,3 the United States,4 Australia, and New Zealand.5
Preparation and functional evaluation of electrospun polymeric nanofibers as a new system for sustained topical ocular delivery of itraconazole
Published in Pharmaceutical Development and Technology, 2022
Saba Mehrandish, Ghobad Mohammadi, Shahla Mirzaeei
Prepared CA-PVA, PCL8, and PCL6 nanofibers are represented in Figures 1(C–E). Cellulose acetate is one of the most common biopolymers used in the development of polymeric nanofibers which can be used as drug carriers or in tissue engineering (Tan et al. 2020). This polymer can be dissolved in pure acetone but when dissolved in a mixture of acetone with another organic solvent like dimethylformamide or dimethylacetamide, fewer beads, and finer fibers may be obtained (Son et al. 2006; Taepaiboon et al. 2007). Because of the poor physicochemical properties of pure CA nanofibers like the low flexibility and tensile strength, the addition of PVA blend was considered to enhance the prepared nanofibers. After the electrospinning process, a uniform, and flexible CA-PVA nanofiber with an acceptable strength was obtained.
Recent advancements in cellulose-based biomaterials for management of infected wounds
Published in Expert Opinion on Drug Delivery, 2021
Munira Momin, Varsha Mishra, Sankalp Gharat, Abdelwahab Omri
Various wound dressings based on cellulose composites have been studied for an improved wound healing effect. In composite dressing, cellulose plays the function of an efficient carrier for the active agent and also provides ease of fabrication. A study by Samadian et al. explored the use of cellulose acetate/gelatin nanofiber loaded with berberine for the treatment of diabetic foot ulcer. In-vivo analysis showed enhanced wound healing in diabetic rats. The histopathological examination after 16 days of treatment showed that the groups with placebo dressing and berberine loaded dressing had complete epithelialization and fewer inflammatory cells as compared to the negative control group (Figure 4). The berberine-loaded group presented most resemblance to healthy skin (Positive control) and showed evident epidermal proliferation and the epidermal layer enlargement. Various other assessments confirmed that the fabricated dressing was suitable for wound management [142]. Some other examples are cellulose acetate incorporated with gallic acid to form a bio-hybrid nanofiber with high potential for wound healing [143] and composite mats of zein and cellulose acetate for diabetic wound healing [144]. Tissue scaffolds made of cellulose and its derivatives have been used in recent complementary approaches [145]. Altogether, various studies have determined that 3D scaffolds made of cellulose are easy to produce biocompatible, and they can successfully integrate in the healthy tissue [145,146]
Coated colloidosomes as novel drug delivery carriers
Published in Expert Opinion on Drug Delivery, 2019
Qian Sun, Jian-Feng Chen, Alexander F. Routh
To make colloidosomes, an aqueous phase containing the active material as well as colloidal particles, which are typically polymeric, is prepared. This mixture is emulsified in an oil phase to give a water-in-oil emulsion. The size of the emulsion droplets is the size of the resulting microcapsules. The colloidal particles are self-assembled at the interface of emulsion droplets forming a stable structure called a Pickering emulsion [9]. The particles are then locked in place to give a stable microcapsule which can be transferred to a continuous aqueous phase. The locking step can involve sintering above the glass transition temperature (Tg), using salt to create a colloidal instability and aggregation of the Pickering particles, using an oppositely charged polyelectrolyte to coat the shell or even using a gelling agent to fix the colloidal particles into robust shells. An advantage of the colloidosome method is that the emulsion formation and shell locking steps can be very gentle and biocompatible. Figure 1(a) schematically shows the preparation method and some SEM images of typical colloidosomes [10,11]. A wide variety of shell materials have been demonstrated from biodegradable polymers such as poly(lactic acid), poly(amino acid) and polylactone; non-degradable polymers such as poly(methyl methacrylate), polystyrene and polyvinyl chloride; cellulosic polymers such as poly(methyl cellulose), poly(hexyl cellulose) and poly(cellulose acetate) and polyscaccharides such as alginate, starch and chitosan [10–12]. Inorganic materials, commonly silica, have also been used for the shell.