Nanoscale hydroxyapatite particles for bone tissue engineering

Synthesis methods for nanosized hydroxyapatite with diverse structures.

Calcium phosphate (CaP) bioceramics are widely used in the field of bone regeneration, both in orthopedics and in dentistry, due to their good biocompatibility, osseointegration and osteoconduction. The aim of this article is to review the history, structure, properties and clinical applications of these materials, whether they are in the form of bone cements, paste, scaffolds, or coatings. Major analytical techniques for characterization of CaPs, in vitro and in vivo tests, and the requirements of the US Food and Drug Administration (FDA) and international standards from CaP coatings on orthopedic and dental endosseous implants, are also summarized, along with the possible effect of sterilization on these materials. CaP coating technologies are summarized, with a focus on electrochemical processes. Theories on the formation of transient precursor phases in biomineralization, the dissolution and reprecipitation as bone of CaPs are discussed. A wide variety of CaPs are presented, from the individual phases to nano-CaP, biphasic and triphasic CaP formulations, composite CaP coatings and cements, functionally graded materials (FGMs), and antibacterial CaPs. We conclude by foreseeing the future of CaPs.

Calcium Phosphate Bioceramics: A Review of Their History, Structure, Properties, Coating Technologies and Biomedical Applications.

Healing of segmental bone defects remain a difficult problem in orthopedic and trauma surgery. One reason for this difficulty is the limited availability of bone material to fill the defect and promote bone growth. Hydroxyapatite (HA) is a synthetic biomaterial, which is chemically similar to the mineral component of bones and hard tissues in mammals and, therefore, it can be used as a filler to replace damaged bone or as a coating on implants to promote bone in-growth into prosthetic implants when used in orthopedic, dental, and maxillofacial applications. HA is a stoichiometric material with a chemical composition of Ca10(PO4)6(OH)2, while a mineral component of bone is a non-stoichiometric HA with trace amounts of ions such as Na+, Zn2+, Mg2+, K+, Si2+, Ba2+, F−, CO32−, etc. This review looks at the progress being made to extract HA and its precursors containing trace amount of beneficial ions from biological resources like animal bones, eggshells, wood, algae, etc. Properties, such as particle size, morphology, stoichiometry, thermal stability, and the presence of trace ions are studied with respect to the starting material and recovery method used. This review also highlights the importance of extracting HA from natural resources and gives future directions to the researcher so that HA extracted from biological resources can be used clinically as a valuable biomaterial.

Extracting hydroxyapatite and its precursors from natural resources

Bone tissue engineering has emerged as one of the most indispensable approaches to address bone trauma in the past few decades. This approach offers an efficient and a risk-free alternative to autografts and allografts by employing a combination of biomaterials and cells to promote bone regeneration. Hydroxyapatite (HA) is a ceramic biomaterial that mimics the mineral composition of bones and teeth in vertebrates. HA, commonly produced via several synthetic routes over the years has been found to exhibit good bioactivity, biocompatibility, and osteoconductivity under both in vitro and in vivo conditions. However, the brittle nature of HA restricts its usage for load bearing applications. To address this problem, HA has been used in combination with several polymers in the form of biocomposite implants to primarily improve its mechanical properties and also enhance the implants' overall performance by simultaneously exploiting the positive effects of both HA and the polymer involved in making the biocomposite. This review article summarizes the past and recent developments in the evolution of HA-polymer biocomposite implants as an "ideal" biomaterial scaffold for bone regeneration. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2046-2057, 2018.

Hydroxyapatite-polymer biocomposites for bone regeneration: A review of current trends.

Preparation and characterization of hydroxyapatite from eggshell

Effect of amine functionalization of spherical MCM-41 and SBA-15 on controlled drug release

Carboxylic modified spherical mesoporous silicas аs drug delivery carriers.

Controlled drug release on amine functionalized spherical MCM-41

Hydroxyapatite (HAp) was successfully produced from recycled eggshell, seashell and phosphoric acid. The phases obtained depended on the ratio of calcined eggshell/ seashell to phosphoric acid, the calcination temperature and the mechanochemical activation method (ball milling or attrition milling). The HAp structures were characterized by X-ray diffraction, scanning electron microsopy and infrared spectroscopy. Attrition milling was more effective than ball milling, yielding nanosize, homogenous and pure Hap.

Judit Mihály

Papers

Preparation and characterization of hydroxyapatite from eggshell

Effect of amine functionalization of spherical MCM-41 and SBA-15 on controlled drug release

Carboxylic modified spherical mesoporous silicas аs drug delivery carriers.

Controlled drug release on amine functionalized spherical MCM-41

Nano-hydroxyapatite preparation from biogenic raw materials