Bioceramic Nanoparticles for Tissue Engineering
Harishkumar Madhyastha, Durgesh Nandini Chauhan in Nanopharmaceuticals in Regenerative Medicine, 2022
Nanosized bioceramic particles of calcium phosphates (CaPs) like nano-hydroxyapatite (nHAp) and nano-tricalcium phosphates (nTCP) have obtained specific interest in the development of biomaterials used for clinical applications specifically as restorative dental and orthopaedic implants. Different compounds of calcium phosphates such as hydroxyapatite (HAp), calcium tetraphosphate (Ca4P2O9), tricalcium phosphate (TCP) Ca3(PO4)2, and calcium hydroxyapatite Ca10(PO4)6(OH)2 can be produced by varying the atomic ratio of Ca/P from 1.5 to 2 (Ramay and Zhang 2004). Since the structure of calcium phosphate resembles the inorganic component of natural hard tissue, i.e. bone and teeth, and also they have typical biological responses such as good bioaffinity and enhancement of osseo-integration as well as successful clinical history, these ceramics are in high demand in the clinical field (Ebrahimi et al. 2019). However, the biological performance such as protein adsorption, angiogenesis, and vascularisation will totally depend on CaP particle composition, structure, morphology, and crystallite sizes (Zhou et al. 2013). Also, calcium phosphates are soluble under aqueous solution below pH 4.2, the property which makes it exploited during resorption of bone mineral by osteoclasts (bone remodelling) leading to the conditions of lysosomal degradation. Therefore, calcium phosphate nanoceramics are often applied for making scaffolds for solid bone tissue engineering (Ebrahimi et al. 2019).
Biology of Acinetobacter spp.
E. Bergogne-Bénézin, M.L. Joly-Guillou, K.J. Towner in Acinetobacter, 2020
Phosphate removal from wastewater is an important feature of sewage treatment plants in order to minimise the problem of eutrophication. Although the addition of various inorganic compounds (e.g., calcium, iron or aluminium salts) to activated sewage sludge, followed by settlement, can be used to remove phosphates, the ingredients for the process are expensive, and large quantities of chemical waste are generated. Examination of activated sludge samples from sewage treatment plants has shown that acinetobacters form a significant part of the constituent microflora. Although their precise role, and its importance, remains a matter of some debate, it can be shown in the laboratory that such strains can accumulate polyphosphates, thereby forming the potential basis of an inexpensive biological method for the direct removal of phosphate from wastewaters.
Computed Tomography
Stanton H. Cohn in Non-Invasive Measurements of Bone Mass and Their Clinical Application, 2020
For preliminary evaluation, the EMI head unit was used to study phantoms constructed to simulate mineral, soft tissue, and fat, either separately or in composite form. A dipotassium hydrogen phosphate (K2HPO4) solution was chosen for standardization, since it has absorption properties11 similar to calcium hydroxyapatite (Ca10[PO4]6[OH]2). Water was used to simulate soft tissue and ethyl alcohol (C2H5OH) to simulate fat.12-14 Single chamber cylinders (16 mm diameter) were filled with combinations of these solutions. Coaxial dual chamber cylinders were constructed with the outer circumferential chamber (42 or 33 mm diameters) containing high concentrations of phosphate solution and the inner chamber (31 or 22 mm diameters) containing lower concentrations, to simulate cancellous bone. Variable amounts of alcohol were added to the central chamber to simulate marrow fat. Monitor displays of single and coaxial phantoms and the corresponding digital print-outs were used for quantification.
Stimulus-responsive peptide hydrogels: a safe and least invasive administration approach for tumor treatment
Published in Journal of Drug Targeting, 2023
Yuchen Hu, Ying Fan, Ban Chen, Hong Li, Gang Zhang, Jiangtao Su
Ionic bonds and hydrophobic interactions work together to promote the self-assembly process of peptides [33]. Hydrophilic amino acid residues such as histidine (H), lysine (K), arginine (R), aspartic acid (D) and glutamic acid (E) typically form ionic bonds [47]. These bonds are usually formed between residues with opposite charges, such as E and K, D and R, D and K, and K and phosphate ions (PO43-). For instance, the ionic self-complementary peptide EKA16, consisting of hydrophobic alanine and oppositely charged K and E, is thought to form nanofibrous hydrogels through electrostatic interactions [48]. In addition, metal iron also contributes to the formation of hydrogels (Figure 2(D)). For example, oligopeptides with unique forky structures are self-assembled into hydrogels under high concentrations of zinc ions [49].
Toxic uranium contamination in groundwater of Thoothukudi district, India: Evaluation of health risks using the geochemical and statistical approach
Published in Toxin Reviews, 2023
Velayutham Raja, Mallanpillai Ananthakrishnan Neelakantan
Factor 3 has positive values (>0.5) for the parameters F−, SO42−, HCO3− and U in the collected samples in both seasons, representing the groundwater’s geogenic impact. Factor 4 has positive values (>0.5) for the parameters NO3− and PO43− during pre-monsoon and NO3−, PO43−, Ca2+ and Mg2+ in post-monsoon. It represents the anthropogenic activities such as phosphate fertilizers used in the agriculture activities in the study area. During the post-monsoon the increase in the concentrations of Ca2+ (mean − 196 ppm) and Mg2+ (mean − 96 ppm) than the pre-monsoon (mean Ca2+ − 145 ppm, mean Mg2+ - 86 ppm) is observed. It may be due to the influence of the anthropogenic impact of NO3− and PO43−. The factor analysis confirms that Ca2+ and Mg2+ have positive values along with NO3− and PO43−.
Pirfenidone as a potential antifibrotic injectable for Dupuytren’s disease
Published in Pharmaceutical Development and Technology, 2022
Suchitra Panigrahi, Amanda Barry, Scott Multner, Gerald B. Kasting, Julio A. Landero Figueroa, Latha Satish, Harshita Kumari
SC injection doses usually have small volumes; hence, we aimed to use an injection volume of 0.4 mL for safety studies in animals, which is within the generally accepted range (≤1.5 mL). The clear homogenous solution could lead to pain at the injection site if factors, such as the tonicity, pH, buffer type, and viscosity are not controlled during formulation. As the PFD solution was prepared in an aqueous medium, the viscosity was not investigated. Benzyl alcohol was added as a preservative to prevent the growth of microorganisms (typically in multidose injections). Benzyl alcohol is considered safe up to 2% w/v for small-molecule injectable formulations (Usach et al. 2019) and has been used in many approved injectable preparations (U.S. Food and Drug Administration). Buffers are added to maintain the pH of the overall formulation close to physiological pH. Most buffering agents in injectable products are used at concentrations of 10–100 mM (Usach et al. 2019) depending on the amount of active ingredient in the final product. Citric acid, which is commonly used as a buffer in approved parenteral products (Nash et al. 2016), induced more pain than other buffers. Therefore, phosphate, which is the second most common buffering agent, was used at the recommended concentration to maintain the pH of the prepared formulation close to physiological pH during storage (pH of the formulation without buffer observed to be ∼5).
Related Knowledge Centers
- Chemistry
- Ester
- Functional Group
- Phosphoric Acid
- Trisodium Phosphate
- Ion
- Salt
- Phosphoric Acids & Phosphates
- Ammonium Dihydrogen Phosphate
- Dihydrogen Phosphate