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Ursolic Acid: A Pentacyclic Triterpene from Plants in Nanomedicine
Published in Mahfoozur Rahman, Sarwar Beg, Mazin A. Zamzami, Hani Choudhry, Aftab Ahmad, Khalid S. Alharbi, Biomarkers as Targeted Herbal Drug Discovery, 2022
Monalisha Sen Gupta, Md. Adil Shaharyar, Mahfoozur Rahman, Kumar Anand, Imran Kazmi, Muhammad Afzal, Sanmoy Karmakar
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).
An Introduction to Bioactivity via Restorative Dental Materials
Published in Mary Anne S. Melo, Designing Bioactive Polymeric Materials for Restorative Dentistry, 2020
Mary Anne S. Melo, Ashley Reid, Abdulrahman A. Balhaddad
The concept of “bioactive” was established in the late 1960s when a young professor in the Department of Materials Science and Engineering at the University of Florida, Larry Hench, invented the material we know as Bioglass. He created an entirely new paradigm for how biomaterials research viewed the interactions between synthetic materials and the human body (Greenspan 2016). The discovered Bioglass 45S5 or calcium sodium phosphosilicate material was able to replace the defective bone by the deposition of hydroxyapatite to bind the existing bone without any signs of rejection or complications (Hench et al. 1971). In the first stage of Bioglass placement, the alkali ions on the glass surface interact with the hydrogen ions from the surrounding tissue causing hydrolysis of the silica groups and an increased pH. As a result, the silanol group formation occurs and forms a silica-gel layer at the surface of the Bioglass. The calcium and phosphate ions transferred at the silica-rich layer making the structure of the Bioglass similar to the hydroxyapatite layer, which attracts the surrounding growth factors to promote the remineralization and regeneration process (Rabiee et al. 2015; Hench 2006).
Calcium Phosphate and Bioactive Glasses
Published in Vincenzo Guarino, Marco Antonio Alvarez-Pérez, Current Advances in Oral and Craniofacial Tissue Engineering, 2020
Osmar A. Chanes-Cuevas, José L. Barrera-Bernai, Iñigo Gaitán-S., David Masuoka
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.
Eye Socket Regeneration and Reconstruction
Published in Current Eye Research, 2020
M. Borrelli, G. Geerling, K. Spaniol, J. Witt
Composite implants combining a non-integrated posterior methyl methacrylate with an integrated hydroxyapatite material aim to improve prosthesis motility. Guthoff et al.89 compared 30 full HA with 25 composite implants consisting of HA in its anterior surface to guarantee safe tissue integration while the posterior part was manufactured from silicon rubber. Only one implant was extruded among the full HA implant group, while motility of the prosthesis was reported as “moderate to good” in both the full HA and in the composite implants groups. Ma et al.90 retrospectively reviewed the results of 170 composite implants made of PP and bioglass. With a follow-up ranging from 1 to 74 months, they found implant exposure in 7 (4%) cases. Five patients required ectropion repair (2.9%) and 3 volume augmentation (1.7%). One patient (0.6%) developed an implant infection. Motility was not quantified. Finally, injectable calcium hydroxyapatite has been suggested as a well-tolerated, simple and cost-effective alternative to treat volume deficiency in the anophthalmic orbit91, but has gained little acceptance so far.
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.