Ursolic Acid: A Pentacyclic Triterpene from Plants in Nanomedicine
Mahfoozur Rahman, Sarwar Beg, Mazin A. Zamzami, Hani Choudhry, Aftab Ahmad, Khalid S. Alharbi in Biomarkers as Targeted Herbal Drug Discovery, 2022
Bioglass (BGs) was originally discovered in 1969 and now commonly used in bone tissue engineering because of its good biocompatibility and osteo-conductivity. After implanted in vivo, BGs can bond closely to host bones via the formation of carbonated hydroxyapatite (CHA) layer between them, however, their osteogenic capacity is not enough excellent to effectively heal bone defects especially for the patients with bone diseases (Hench, 2006; Park and Ha, 2018). Fortunately, empty mesoporous microspheres are mainly fit for the restorative scaffolds in which the controlled delivery of osteogenic drugs facilitates in vivo bone tissue formation (Kang et al., 2018). The empty interiors in hollow microspheres facilitate drug storage, and the mesoporous features provide the bigger surface areas for bone-like CHA deposition and drug delivery (Kang et al.. 2018; Moghaddam et al., 2018; Zhang et al., 2014; Logith et al.. 2016). Moreover. chitosan (CS) with 2-acetamido-2-deoxy-d-glucan and 2-amino-2-deoxy-d-glucan units possesses so excellent biocom-patibility, osteoconductivity, and biodegradability that it becomes a fascinating bone repair material (Gupta et al.. 2010). The functional groups such as -OH and -NH2 in CS can up-regulate drug loading (DL)-release behaviors via hydrogen-bonding interactions. Hence, it is inferred that hollow mesoporous bioglass (MBG)/CS scaffolds can serve as ideal therapeutic carriers for bone defect healing (Figure 4.7).
Calcium Phosphate and Bioactive Glasses
Vincenzo Guarino, Marco Antonio Alvarez-Pérez in Current Advances in Oral and Craniofacial Tissue Engineering, 2020
Bioglasses are mainly used in tissue bioengineering to promote bone regeneration by the ease with which they bind to the bone by forming a layer of hydroxyapatite substituted with carbonate or hydroxycarbonate apatite (HCA). There are three main types of bioglass that are, made of silicate, of phosphate and of borate, in addition to the combinations that occur between these and among other bioceramics (Rahaman et al. 2011; Fu et al. 2011; Jones 2015). Although the chemical mechanism by which the transformation of the bioglass into the HCA layer is well known, the process by which it joins the bone and favors the formation of new bone tissue is less studied. When placed in an organism, the bioglass will interact with physiological fluids, producing an ionic exchange that raises the pH of the medium, which dissolves the silicate and forms a silanol layer on which phosphate groups and calcium ions are added to form an amorphous calcium phosphate (APC), to which OH groups are attached, and CO, to finally form the HCA layer (Rahaman et al. 2011; Fu et al. 2011; Jones 2015). It is believed that the formed layer of HCA, as well as the ions released during its formation, has important roles in the regeneration of bone tissue, functioning as chemoattractants of stem cells and favoring their differentiation towards an osteoblastic phenotype.
Biomaterials
Manoj Ramachandran, Tom Nunn in Basic Orthopaedic Sciences, 2018
Osteoblasts covalently bond to bone when in contact with some ceramics, glass–ceramics, and calcium phosphates, and therefore they are osteoconductive. A hydroxyapatite layer (Ca10[PO4]6[OH]2) has enabled bone on-growth to uncemented prostheses and has been in clinical use for almost three decades. The thickness of coating and processing to attach the hydroxyapatite is debated. If the layer is too thick, it risks fracturing off due to its brittleness. If too thin, it can dissolve before bone on-growth. Hydroxyapatite and other bioglass materials are also used as an injectable bone filler. There is cross-over with tissue engineering as osteoinductive surface coatings are being designed. Impregnation with growth factors, bone morphogenetic proteins (BMPs) and antimicrobial agents is in development.
The era of biofunctional biomaterials in orthopedics: what does the future hold?
Published in Expert Review of Medical Devices, 2018
Mubashar Rehman, Asadullah Madni, Thomas J. Webster
Biofunctional materials interact with a biological environment to stimulate a desirable biological response or to enhance tissue bonding. Bioabsorable materials have been introduced that progressively degrade as new tissue is regenerated. Classical examples of biofunctional materials are HA and bioglass. HA has the ability to stimulate mineralization to form a strong bond with bone. Therefore, HA has been used with other biomaterials for the excellent fixation of prostheses. Bioglass is also considered as a biofunctional material due to its interaction with bone and other tissues. Different approaches have been used to functionalize traditional biomaterials. An enhanced understanding of the interaction between biomaterials and the biological environment has also lead to the discovery of many new biofunctional biomaterials.
Biomaterials for orthopedics: anti-biofilm activity of a new bioactive glass coating on titanium implants
Published in Biofouling, 2020
Daniella Maia Marques, Viviane de Cássia Oliveira, Marina Trevelin Souza, Edgar Dutra Zanotto, João Paulo Mardegan Issa, Evandro Watanabe
Since the first report of bioactive glass in 1969 (Bioglass®45S5) (Hench et al. 1971) different compositions have been proposed for various applications (Drago et al. 2018). The current scenario shows several clinical products, which have been used, mainly in orthopedics and dentistry (Baino et al. 2018). Additionally, soft tissue engineering applications, such as wound dressings, regeneration of cardiac, pulmonary and gastrointestinal tissues have been reported (Miguez-Pacheco et al. 2015; Kargozar et al. 2017). However, there is a plethora of new applications of bioactive glasses yet to be studied to find new answers to the challenges of biofilms associated with implants.
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