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Ferrari CR, de Oliveira TE, Buzalaf MAR, Netz PA. Interaction of Statherin-Derived Peptide with the Surface of Hydroxyapatite: Perspectives Based on Molecular Dynamics Simulations. Caries Res 2024; 58:431-443. [PMID: 38763135 DOI: 10.1159/000539064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Accepted: 04/20/2024] [Indexed: 05/21/2024] Open
Abstract
INTRODUCTION Statherin-derived peptide (StatpSpS) has shown promise against erosive tooth wear. To elucidate its interaction with the hydroxyapatite (HAP) surface, the mechanism related to adsorption of this peptide with HAP was investigated through nanosecond-long all-atom molecular dynamics simulations. METHODS StatpSpS was positioned parallel to the HAP surface in 2 orientations: 1 - neutral and negative residues facing the surface and 2 - positive residues facing the surface. A system containing StatpSpS without HAP was also simulated as control. In the case of systems with HAP, both partially restrained surface and unrestrained surface were constructed. Structural analysis, interaction pattern, and binding-free energy were calculated. RESULTS In the peptide system without the HAP, there were some conformational changes during the simulation. In the presence of the surface, only moderate changes were observed. Many residues exhibited short and stable distances to the surface, indicating strong interaction. Specially, the residues ASP1 and SER2 have an important role to anchor the peptide to the surface, with positively charged residues, mainly arginine, playing a major role in the further stabilization of the peptide in an extended conformation, with close contacts to the HAP surface. CONCLUSION The interaction between StatpSpS and HAP is strong, and the negative charged residues are important to the anchoring of the peptide in the surface, but after the initial placement the peptide rearranges itself to maximize the interactions between positive charged residues.
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Affiliation(s)
- Carolina Ruis Ferrari
- Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, Brazil,
| | - Tiago Espinosa de Oliveira
- Department of Pharmacosciences, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brazil
| | | | - Paulo Augusto Netz
- Department of Physical Chemistry, Institute of Chemistry, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
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Xing H, Yang F, Sun S, Pan P, Wang H, Wang Y, Chen J. Green efficient ultrasonic-assisted extraction of abalone nacre water-soluble organic matrix for bioinspired enamel remineralization. Colloids Surf B Biointerfaces 2022; 212:112336. [PMID: 35051793 DOI: 10.1016/j.colsurfb.2022.112336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 12/31/2021] [Accepted: 01/12/2022] [Indexed: 11/25/2022]
Abstract
Reconstructing enamel-like hydroxyapatite structures on damaged teeth remains a great challenge in the materials science and dentistry due to its highly ordered hierarchical microstructure. Inspired by the mineralization of mollusk nacre in nature, abalone nacre water-soluble organic matrix (WSM) was isolated successfully though an ultrasonic-assisted water extraction (UWE) strategy with nondestructive activity and high-quality extraction for simulating the process of tooth hard tissue mineralization. Results showed that the UWE strategy significantly increased the protein yield from 7.60% to 9.60% and improved the polysaccharide yield from 2.59% to 3.34%, respectively, indicating its excellent extraction efficiency of WSM. Noteworthily, the smallest averaged particle size (~155 nm) of WSM were obtained at an ultrasound time of 6 h, whereas the highest absolute values (~ -32 mV) of zeta potential was produced. Moreover, it was proved that WSM could induce the growth of enamel-like hydroxyapatite crystals to further facilitate biomimetic remineralization of the demineralized enamel and restore its continuous and smooth surface structure in vitro. Besides, the hardness (4.37 ± 0.07 GPa) and modulus of elasticity (84.80 ± 1.49 GPa) of the WSM-repaired enamel was similar to that of native enamel, indicating superior mechanical properties after repair. Herein, it provides a promising green, efficient strategy for the remineralization of damaged enamel and high value utilization of waste abalone shells.
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Affiliation(s)
- Huaran Xing
- Marine College, Shandong University, Weihai 264209, China
| | - Faming Yang
- Marine College, Shandong University, Weihai 264209, China
| | - Shengjun Sun
- Shandong Provincial Key Laboratory of Oral Biomedicine, College of Stomatology, Shandong University, Jinan 250021, China.
| | - Panpan Pan
- Marine College, Shandong University, Weihai 264209, China; Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan 430022, China.
| | - Hongbo Wang
- Marine College, Shandong University, Weihai 264209, China
| | - Yuxin Wang
- Marine College, Shandong University, Weihai 264209, China
| | - Jingdi Chen
- Marine College, Shandong University, Weihai 264209, China; Shandong Laboratory of Advanced Materials and Green Manufacturing, Yantai 265599, China.
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Hojabri N, Kaisarly D, Kunzelmann KH. Adhesion and whitening effects of P11-4 self-assembling peptide and HAP suspension on bovine enamel. Clin Oral Investig 2021; 25:3237-3247. [PMID: 33108484 PMCID: PMC8060195 DOI: 10.1007/s00784-020-03654-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 10/20/2020] [Indexed: 02/08/2023]
Abstract
OBJECTIVES This study evaluated the adhesion and whitening effects of a combination of P11-4 self-assembling peptide and hydroxyapatite (peptide-HAP) on bovine enamel. METHODS Forty-six caries-free bovine teeth were selected, and 40 teeth were randomly allocated to one of five groups (n = 8). First, the effects of application frequency, exposure time, and storage in saliva on the whitening effects of an experimental low-concentrated peptide-HAP suspension (0.5 wt% HAP; Curodont, Credentis) were evaluated and compared with a commercial bleaching agent (VivaStyle Paint on Plus, VS, Ivoclar Vivadent). Tooth color was measured using a spectrophotometer (Gretag MacBeth), and color changes ΔE were statistically analyzed. Second, the effects of peptide-HAP concentration (low versus high: 6.25% HAP; Curodont Protect), and its interactions with saliva and postapplication restaining, were investigated. Third, enamel surfaces (n = 2) were treated with low concentration peptide-HAP and high-concentration peptide-HAP in polymeric and monomeric forms (Curodont Protect & Curodont Repair, Credentis) and analyzed by SEM. RESULTS The ΔE of the low-concentration peptide-HAP suspension did not differ from that of VS. Application frequency, exposure time, and storage in saliva did not have any significant impact on whitening efficacy of the peptide-HAP suspension. Increasing the concentration of the suspension did not promote overall ΔE. SEM observations confirmed the presence of the newly generated peptide and HAP on the enamel surface. CONCLUSIONS The peptide-HAP suspension is a mild tooth whitener, and the adhesion of peptide-HAP to enamel is concentration dependent. CLINICAL RELEVANCE This peptide-HAP suspension is effective in offsetting discoloration caused by restaining after treatment.
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Affiliation(s)
- Niloofar Hojabri
- Department of Conservative Dentistry and Periodontology, University Hospital, Ludwig-Maximilians-University Munich, Goethestr. 70, 80336, Munich, Germany
| | - Dalia Kaisarly
- Department of Conservative Dentistry and Periodontology, University Hospital, Ludwig-Maximilians-University Munich, Goethestr. 70, 80336, Munich, Germany.
- Biomaterials Department, Faculty of Oral and Dental Medicine, Cairo University, Cairo, Egypt.
| | - Karl-Heinz Kunzelmann
- Department of Conservative Dentistry and Periodontology, University Hospital, Ludwig-Maximilians-University Munich, Goethestr. 70, 80336, Munich, Germany
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Alkilzy M, Santamaria RM, Schmoeckel J, Splieth CH. Treatment of Carious Lesions Using Self-Assembling Peptides. Adv Dent Res 2018; 29:42-47. [PMID: 29355413 DOI: 10.1177/0022034517737025] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Modern approaches in caries treatment involve lesion management without tissue removal. Regenerative medicine focuses on replacing damaged tissues with biologically similar tissues. This article discusses the scientific evidence and clinical results for self-assembling peptides in modern caries management. The biomimetic remineralization promoted by self-assembling peptide P11-4 has been proven in vitro as an effective therapy for initial caries. P11-4 was rationally designed to promote formation of hydroxyapatite on its surface. The formulation was optimized to ensure the ability of monomeric P11-4 to penetrate past the subsurface lesions and assembly into a biomatrix within. Furthermore, P11-4 has shown that it assembles into fibers within carious lesions, and promotes the remineralization thereof. In a recent clinical study, the safety and efficacy of P11-4 in treatment of initial caries were evaluated. The additional effect of the application of P11-4 (Curodont Repair) was compared to the application of fluoride varnish (Duraphat) alone in active occlusal initial caries lesions on erupting permanent molars. In the 3- and 6-month recalls, the test group showed, both in the laser fluorescence readings and in the clinical assessment of the caries stage and activity, significantly superior lesion regression compared to the control group. No adverse events, medical complications, or allergic reactions related to the treatments were reported. Clinical applicability of treatment was regarded as satisfactory. Patients were happy to receive noninvasive caries treatments. In conclusion, biomimetic mineralization facilitated by P11-4 in combination with fluoride may present a simple, safe, and effective noninvasive treatment for early carious lesions.
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Affiliation(s)
- M Alkilzy
- 1 Department of Preventive and Pediatric Dentistry, Centre for Oral Health, University of Greifswald, Greifswald, Germany
| | - R M Santamaria
- 1 Department of Preventive and Pediatric Dentistry, Centre for Oral Health, University of Greifswald, Greifswald, Germany
| | - J Schmoeckel
- 1 Department of Preventive and Pediatric Dentistry, Centre for Oral Health, University of Greifswald, Greifswald, Germany
| | - C H Splieth
- 1 Department of Preventive and Pediatric Dentistry, Centre for Oral Health, University of Greifswald, Greifswald, Germany
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The Impact of Hybrid Nano-Materials in Tooth Tissue Restoration. JOURNAL OF BIOMIMETICS BIOMATERIALS AND BIOMEDICAL ENGINEERING 2018. [DOI: 10.4028/www.scientific.net/jbbbe.39.65] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Tooth loss due to dental diseases, caries, and other related pathological conditions has plagued people and is the most prevalent cause of human organ failure. Billions of people have suffered from losing teeth and dental diseases so that generating natural dental tissues are more appreciated than artificial tooth implantation. The aspiration among the dentists to restore this loss biologically is the genesis of the tooth regeneration. Current trends initiate tissue engineering with a concept of functional restoration of tissue and organ defects by the triad of biomaterial scaffolds, growth factors, and stem cells (Rosa et al. 2012). This paper, therefore, focuses on the significance of nanostructured hybrid materials in the tooth regeneration through tissue engineering. For this purpose, literature was examined and studies on nanomorphological features of stem cells, dental tissues found within the oral area, the signaling molecules utilized in the tissue engineering, and the hybrid scaffolds that guide reconstructions of periodontal tissues were selected for the review. The nanodentistry has been potential, undoubtedly, to achieve almost perfect dental health in the nearest future. However, the success will largely be determined by human requirements and resource supply (technology, economy, and time). Finally, the future and actual potentials of nanotechnologies pertaining tissue engineering will be applied in dentistry (Mitziadis, Woloszyk, & Jimenez-Rojo, 2012).Keywords: Stem cells; scaffolds; nanomaterials; hybrid materials, tissue engineering; dentistry; signaling molecules.
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Alkilzy M, Tarabaih A, Santamaria RM, Splieth CH. Self-assembling Peptide P 11-4 and Fluoride for Regenerating Enamel. J Dent Res 2017; 97:148-154. [PMID: 28892645 DOI: 10.1177/0022034517730531] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Regenerative medicine-based approaches for caries treatment focus on biomimetic remineralization of initial carious lesions as a minimal invasive therapy. In vitro, self-assembling peptide P11-4 enhances remineralization of early carious lesions. To investigate the safety and clinical efficacy of P11-4 for treatment of initial caries, a randomized controlled single-blind study was conducted on children aged >5 y with visible active early caries on erupting permanent molars. Subjects were randomized to either the test group (P11-4 + fluoride varnish) or control group (fluoride varnish alone). Caries were assessed at baseline and at 3 and 6 mo posttreatment per laser fluorescence, a visual analog scale, the International Caries Detection and Assessment System, and Nyvad caries activity criteria. Intention-to-treat analyses were performed, and safety and clinical feasibility of the treatment approaches were assessed. Compared with the control group, the test group showed clinically and statistically significant improvement in all outcomes at 3 and 6 mo. The laser fluorescence readings (odds ratio = 3.5, P = 0.015) and visual analog scale scores (odds ratio = 7.9, P < .0001) were significantly lower for the test group, and they showed regression in the International Caries Detection and Assessment System caries index (odds ratio = 5.1, P = 0.018) and conversion from active to inactive lesions according to Nyvad criteria (odds ratio = 12.2, P < 0.0001). No adverse events occurred. The biomimetic mineralization facilitated by P11-4 in combination with fluoride application is a simple, safe, and effective noninvasive treatment for early carious lesions that is superior to the presently used gold standard of fluoride alone. By regenerating enamel tissue and preventing lesion progression, this novel approach could change clinical dental practice from a restorative to a therapeutic approach. This could avoid additional loss of healthy hard tissue during invasive restorative treatments, potentially enabling longer tooth life and thereby lowering long-term health costs ( ClinicalTrials.gov NCT02724592).
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Affiliation(s)
- M Alkilzy
- 1 Department of Preventive and Paediatric Dentistry, Centre for Oral Health, University of Greifswald, Greifswald, Germany
| | - A Tarabaih
- 1 Department of Preventive and Paediatric Dentistry, Centre for Oral Health, University of Greifswald, Greifswald, Germany
| | - R M Santamaria
- 1 Department of Preventive and Paediatric Dentistry, Centre for Oral Health, University of Greifswald, Greifswald, Germany
| | - C H Splieth
- 1 Department of Preventive and Paediatric Dentistry, Centre for Oral Health, University of Greifswald, Greifswald, Germany
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Robinson C, Connell SD. Crystal Initiation Structures in Developing Enamel: Possible Implications for Caries Dissolution of Enamel Crystals. Front Physiol 2017; 8:405. [PMID: 28670283 PMCID: PMC5472850 DOI: 10.3389/fphys.2017.00405] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/29/2017] [Indexed: 12/03/2022] Open
Abstract
Investigations of developing enamel crystals using Atomic and Chemical Force Microscopy (AFM, CFM) have revealed a subunit structure. Subunits were seen in height images as collinear swellings about 30 nM in diameter on crystal surfaces. In friction mode they were visible as positive regions. These were similar in size (30–50 nM) to collinear spherical structures, presumably mineral matrix complexes, seen in developing enamel using a freeze fracturing/freeze etching procedure. More detailed AFM studies on mature enamel suggested that the 30–50 nM structures were composed of smaller units, ~10–15 nM in diameter. These were clustered in hexagonal or perhaps a spiral arrangement. It was suggested that these could be the imprints of initiation sites for mineral precipitation. The investigation aimed at examining original freeze etched images at high resolution to see if the smaller subunits observed using AFM in mature enamel were also present in developing enamel i.e., before loss of the organic matrix. The method used was freeze etching. Briefly samples of developing rat enamel were rapidly frozen, fractured under vacuum, and ice sublimed from the fractured surface. The fractured surface was shadowed with platinum or gold and the metal replica subjected to high resolution TEM. For AFM studies high-resolution tapping mode imaging of human mature enamel sections was performed in air under ambient conditions at a point midway between the cusp and the cervical margin. Both AFM and freeze etch studies showed structures 30–50 nM in diameter. AFM indicated that these may be clusters of somewhat smaller structures ~10–15 nM maybe hexagonally or spirally arranged. High resolution freeze etching images of very early enamel showed ~30–50 nM spherical structures in a disordered arrangement. No smaller units at 10–15 nM were clearly seen. However, when linear arrangements of 30–50 nM units were visible the picture was more complex but also smaller units including ~10–15 nM units could be observed. Conclusions: Structures ~10–15 nM in diameter were detected in developing enamel. While the appearance was complex, these were most evident when the 30–5 nM structures were in linear arrays. Formation of linear arrays of subunits may be associated with the development of mineral initiation sites and attendant processing of matrix proteins.
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Affiliation(s)
- Colin Robinson
- School of Dentistry, University of LeedsLeeds, United Kingdom
| | - Simon D Connell
- Molecular and Nanoscale Physics Group, School of Physics and Astronomy, University of LeedsLeeds, United Kingdom
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8
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Lin X, Xie F, Ma X, Hao Y, Qin H, Long J. Fabrication and characterization of dendrimer-functionalized nano-hydroxyapatite and its application in dentin tubule occlusion. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2017; 28:846-863. [PMID: 28325103 DOI: 10.1080/09205063.2017.1308654] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Xuandong Lin
- Department of Endodontics, Stomatological Hospital, Guangxi Medical University, Nanning, China
| | - Fangfang Xie
- Department of Endodontics, Stomatological Hospital, Guangxi Medical University, Nanning, China
| | - Xueling Ma
- Department of Endodontics, Stomatological Hospital, Guangxi Medical University, Nanning, China
| | - Yuhong Hao
- Department of Endodontics, Stomatological Hospital, Guangxi Medical University, Nanning, China
| | - Hejia Qin
- Department of Endodontics, Stomatological Hospital, Guangxi Medical University, Nanning, China
| | - Jindong Long
- Department of Endodontics, Stomatological Hospital, Guangxi Medical University, Nanning, China
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9
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Kind L, Stevanovic S, Wuttig S, Wimberger S, Hofer J, Müller B, Pieles U. Biomimetic Remineralization of Carious Lesions by Self-Assembling Peptide. J Dent Res 2017; 96:790-797. [PMID: 28346861 DOI: 10.1177/0022034517698419] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Caries is the most common disease in the world. Great efforts have been undertaken for prevention and to identify a regenerative treatment solution for dental caries. Self-assembling β-sheet forming peptides have previously shown to form 3-dimensional fiber networks supporting tissue regeneration. In particular, the self-assembling peptide P11-4 has shown potential in the treatment and prevention of dental caries. It has previously been shown that application of monomeric P11-4 solution to early carious lesions can increase net mineral gain by forming de novo hydroxyapatite crystals. The hypothesis for the mode of action was that monomeric self-assembling peptide P11-4 diffuses into the subsurface lesion body and assembles therein into higher order fibrils, facilitating mineralization of the subsurface volume by mimicking the natural biomineralization of the tooth enamel, and it remains within the lesion body as a scaffold built-in by the newly formed hydroxyapatite. The aim of the present study was to investigate the mechanism of action of the self-assembling peptide P11-4 supporting mineralization of carious enamel. By various analytical methods, it could be shown that the self-assembling peptide P11-4 diffuses into the subsurface lesion, assembles into higher formed aggregates throughout the whole volume of the lesion, and supports nucleation of de novo hydroxyapatite nanocrystals and consequently results in increased mineral density within the subsurface carious lesion. The results showed that the application of self-assembling peptide P11-4 can facilitate the subsurface regeneration of the enamel lesion by supporting de novo mineralization in a similar mode of action as has been shown for the natural formation of dental enamel.
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Affiliation(s)
- L Kind
- 1 School of Life Sciences, Department of Chemistry and Bioanalytics, University of Applied Sciences and Arts Northwestern Switzerland (FHNW), Muttenz, Switzerland
| | - S Stevanovic
- 1 School of Life Sciences, Department of Chemistry and Bioanalytics, University of Applied Sciences and Arts Northwestern Switzerland (FHNW), Muttenz, Switzerland
| | - S Wuttig
- 1 School of Life Sciences, Department of Chemistry and Bioanalytics, University of Applied Sciences and Arts Northwestern Switzerland (FHNW), Muttenz, Switzerland
| | - S Wimberger
- 1 School of Life Sciences, Department of Chemistry and Bioanalytics, University of Applied Sciences and Arts Northwestern Switzerland (FHNW), Muttenz, Switzerland
| | - J Hofer
- 1 School of Life Sciences, Department of Chemistry and Bioanalytics, University of Applied Sciences and Arts Northwestern Switzerland (FHNW), Muttenz, Switzerland
| | - B Müller
- 2 Department of Biomedical Engineering, University of Basel, Biomaterials Science Center (BMC), Allschwil, Switzerland
| | - U Pieles
- 1 School of Life Sciences, Department of Chemistry and Bioanalytics, University of Applied Sciences and Arts Northwestern Switzerland (FHNW), Muttenz, Switzerland
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Silvertown JD, Wong BPY, Sivagurunathan KS, Abrams SH, Kirkham J, Amaechi BT. Remineralization of natural early caries lesions in vitro by P11-4 monitored with photothermal radiometry and luminescence. ACTA ACUST UNITED AC 2017; 8. [DOI: 10.1111/jicd.12257] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 10/14/2016] [Indexed: 11/27/2022]
Affiliation(s)
| | | | | | | | - Jennifer Kirkham
- Department of Oral Biology; University of Leeds; St. James's University Hospital; Leeds UK
| | - Bennett T. Amaechi
- Department of Comprehensive Dentistry; University of Texas Health Science Center at San Antonio; San Antonio TX USA
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Habelitz S, Kullar A, Marshall SJ, DenBesten PK, Balooch M, Marshall GW, Li W. Amelogenin-guided Crystal Growth on Fluoroapatite Glass-ceramics. J Dent Res 2016; 83:698-702. [PMID: 15329375 DOI: 10.1177/154405910408300908] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The formation of aligned fibrous apatite crystals in enamel is predominantly attributed to the involvement of amelogenin proteins. We developed a model to study interactions of matrix proteins with apatite mineral in vitro and tested the hypothesis that amelogenin solubility affects the ability to induce protein-guided mineralization. Crystal growth experiments were performed on fluoroapatite (FAP) glass-ceramics in mineralizing solutions containing recombinant full-length amelogenin (rH174) at different concentrations. Using atomic force microscopy, we observed that mineral precipitated randomly on the substrate, but also formed thin layers (height, 10 nm) on FAP within 24 hrs. This growth pattern was unaffected when 0.4 mg/mL of rH174 was added. In contrast, crystals grew on FAP at a rate up to 20 times higher, at 1.6 mg/mL protein. Furthermore, nanospheres and mineral bound specifically to FAP and aligned in strings approximately parallel to the c-axis of FAP, leading us to the conclusion that amelogenin proteins indeed control direction and rate of growth of apatite in enamel.
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Affiliation(s)
- S Habelitz
- Department of Preventive and Restorative Dental Sciences, University of California, 707 Parnassus Avenue, D-2260, San Francisco 94143-0758, USA.
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12
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Dorozhkin SV. Calcium orthophosphates (CaPO 4): occurrence and properties. Prog Biomater 2015; 5:9-70. [PMID: 27471662 PMCID: PMC4943586 DOI: 10.1007/s40204-015-0045-z] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 11/05/2015] [Indexed: 01/02/2023] Open
Abstract
The present overview is intended to point the readers' attention to the important subject of calcium orthophosphates (CaPO4). This type of materials is of the special significance for the human beings because they represent the inorganic part of major normal (bones, teeth and antlers) and pathological (i.e., those appearing due to various diseases) calcified tissues of mammals. For example, atherosclerosis results in blood vessel blockage caused by a solid composite of cholesterol with CaPO4, while dental caries and osteoporosis mean a partial decalcification of teeth and bones, respectively, that results in replacement of a less soluble and harder biological apatite by more soluble and softer calcium hydrogenorthophosphates. Therefore, the processes of both normal and pathological calcifications are just an in vivo crystallization of CaPO4. Similarly, dental caries and osteoporosis might be considered as in vivo dissolution of CaPO4. In addition, natural CaPO4 are the major source of phosphorus, which is used to produce agricultural fertilizers, detergents and various phosphorus-containing chemicals. Thus, there is a great significance of CaPO4 for the humankind and, in this paper, an overview on the current knowledge on this subject is provided.
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Abstract
The interface between collagen and the mineral reinforcement phase, carbonated hydroxyapatite (cAp), is essential for bone's remarkable functionality as a biological composite material. The very small dimensions of the cAp phase and the disparate natures of the reinforcement and matrix are essential to the material's performance but also complicate study of this interface. This article summarizes what is known about the cAp-collagen interface in bone and begins with descriptions of the matrix and reinforcement roles in composites, of the phases bounding the interface, of growth of cAp growing within the collagen matrix, and of the effect of intra- and extrafibrilar mineral on determinations of interfacial properties. Different observed interfacial interactions with cAp (collagen, water, non-collagenous proteins) are reviewed; experimental results on interface interactions during loading are reported as are their influence on macroscopic mechanical properties; conclusions of numerical modeling of interfacial interactions are also presented. The data suggest interfacial interlocking (bending of collagen molecules around cAp nanoplatelets) and water-mediated bonding between collagen and cAp are essential to load transfer. The review concludes with descriptions of areas where new research is needed to improve understanding of how the interface functions.
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Affiliation(s)
- S R Stock
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Chicago, IL, 60611-3008, USA,
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14
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Taube F, Marczewski M, Norén J. Deviations of inorganic and organic carbon content in hypomineralised enamel. J Dent 2015; 43:269-78. [DOI: 10.1016/j.jdent.2014.09.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 08/27/2014] [Accepted: 09/05/2014] [Indexed: 11/15/2022] Open
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15
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Ono S, Tsuji T, Oaki Y, Imai H. Artificial peptides binding to the c face of hydroxyapatite obtained by molecular display technology. RSC Adv 2013. [DOI: 10.1039/c2ra22382a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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16
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Disruption of enamel crystal formation quantified by synchrotron microdiffraction. J Dent 2012; 40:1074-80. [DOI: 10.1016/j.jdent.2012.08.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 08/29/2012] [Accepted: 08/30/2012] [Indexed: 11/18/2022] Open
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17
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Shinaishin SF, Ghobashy SA, El-Bialy TH. Efficacy of light-activated sealant on enamel demineralization in orthodontic patients: an atomic force microscope evaluation. Open Dent J 2011; 5:179-86. [PMID: 22207889 PMCID: PMC3242403 DOI: 10.2174/1874210601105010179] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 08/18/2011] [Accepted: 08/19/2011] [Indexed: 01/28/2023] Open
Abstract
OBJECTIVE The purpose of this study was to investigate the efficacy of (Pro Seal) sealant in preventing enamel decalcification in-vivo and compare its effect with fluoride varnish and unfilled sealant using atomic force microscopy. MATERIALS AND METHODS Eight orthodontic patients who were candidates for extraction of all first premolars for orthodontic treatment were recruited to this study. Thirty two premolars (upper and lower) were randomly divided into four groups (n=8) for each group, 4 maxillary and 4 mandibular); Control (no -treatment); Fluoride varnish, Unfilled sealant (Light Bond) and filled sealant (Pro-Seal). After two months the brackets were debonded and the teeth were extracted and prepared for Atomic force microscopic scanning. Each sample was scanned twice at two different scan areas 50 and 10µm at the buccal cervical third of the crown. Images were recorded with slow scan rate and resolution and the mean roughness height and total surface area were calculated for each scan area. Comparison between groups was performed using one way analysis of variance test with level of significance was set to be 0.05. RESULTS Pro Seal treated samples show the lowest roughness height and total surface area. CONCLUSION Pro Seal was the most effective prophylaxis technique in preventing enamel demineralization during orthodontic treatment.
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Dorozhkin SV. Calcium orthophosphates: occurrence, properties, biomineralization, pathological calcification and biomimetic applications. BIOMATTER 2011; 1:121-64. [PMID: 23507744 PMCID: PMC3549886 DOI: 10.4161/biom.18790] [Citation(s) in RCA: 150] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The present overview is intended to point the readers' attention to the important subject of calcium orthophosphates. This type of materials is of special significance for human beings, because they represent the inorganic part of major normal (bones, teeth and antlers) and pathological (i.e., those appearing due to various diseases) calcified tissues of mammals. For example, atherosclerosis results in blood vessel blockage caused by a solid composite of cholesterol with calcium orthophosphates, while dental caries and osteoporosis mean a partial decalcification of teeth and bones, respectively, that results in replacement of a less soluble and harder biological apatite by more soluble and softer calcium hydrogenphosphates. Therefore, the processes of both normal and pathological calcifications are just an in vivo crystallization of calcium orthophosphates. Similarly, dental caries and osteoporosis might be considered an in vivo dissolution of calcium orthophosphates. Thus, calcium orthophosphates hold a great significance for humankind, and in this paper, an overview on the current knowledge on this subject is provided.
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Paine ML, Lei Y, Luo W, Snead ML. Perturbed Amelogenin Protein Self-assembly Alters Nanosphere Properties Resulting in Defective Enamel Formation. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-823-w6.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractDental enamel is a unique composite bioceramic material that is the hardest tissue in the vertebrate body, containing long-, thin-crystallites of substituted hydroxyapatite. Enamel functions under immense loads in a bacterial-laden environment, and generally without catastrophic failure over a lifetime for the organism. Unlike all other biogenerated hard tissues of mesodermal origin, such as bone and dentin, enamel is produced by ectoderm-derived cells called ameloblasts. Recent investigations on the formation of enamel using cell and molecular approaches have been coupled to biomechanical investigations at the nanoscale and mesoscale levels. For amelogenin, the principle protein of forming enamel, two domains have been identified that are required for the proper assembly of multimeric units of amelogenin to form nanospheres. One domain is at the amino-terminus and the other domain in the carboxyl-terminal region. Amelogenin nanospheres are believed to influence the hydroxyapatite crystal habit. Both the yeast two-hybrid assay and surface plasmon resonance have been used to examine the assembly properties of engineered amelogenin proteins. Amelogenin protein was engineered using recombinant DNA techniques to contain deletions to either of the two self-assembly domains. Amelogenin protein was also engineered to contain single amino-acid mutations/substitutions in the amino-terminal self-assembly domain; and these amino-acid changes are based upon point mutations observed in humans affected with a hereditary disturbance of enamel formation. All of these alterations reveal significant defects in amelogenin self-assembly into nanospheres in vitro. Transgenic animals containing these same amelogenin deletions illustrate the importance of a physiologically correct bio-fabrication of the enamel protein extracellular matrix to allow for the organization of the enamel prismatic structure.
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Cheng ZJ, Wang XM, Ge J, Chen D, Cui FZ. Disturbed enamel biomineralization in col1-caPPR mouse incisor. Calcif Tissue Int 2009; 84:494-501. [PMID: 19363665 PMCID: PMC3110700 DOI: 10.1007/s00223-009-9243-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Accepted: 03/08/2009] [Indexed: 01/30/2023]
Abstract
During the mineralization process of enamel, gene expression controls the activities of ameloblasts, the secretion and assembly of an extracellular protein matrix, affecting the final structure and functions. In this study, the enamel in the maxillary and mandibular incisors of wild-type and transgenic (col1-caPPR) mice, in which a constitutively active PTH/PTHrP receptor (PPR) was targeted to osteoblastic cells, was observed by scanning electron microscopy (SEM), Fourier transform infrared microscopy (FTIRM), and nanoindentation. The SEM studies showed that several different patterns of aberrations in crystal arrangement, disturbed prism organization without decussation, as well as abnormal enamel distribution were encountered in transgenic enamel. FTIRM analysis revealed poorer crystallinity/maturity after mutation. Nanoindentation measurement disclosed that transgenic enamel had 24.6% lower hardness and 12.3% lower elastic modulus. We attributed the inferior properties to the loosely packing crystals and abnormal prism organization. Furthermore, the col1-caPPR mouse model was substantiated to be useful to study how genes modulate the biomineralization process.
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Affiliation(s)
- Zhen-Jiang Cheng
- Laboratory of Biomaterials, State Key Laboratory of New Ceramic and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, YiFu Technology and Science Building, Room 2336, Beijing 100084, People’s Republic of China
| | - Xiu-Mei Wang
- Laboratory of Biomaterials, State Key Laboratory of New Ceramic and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, YiFu Technology and Science Building, Room 2336, Beijing 100084, People’s Republic of China
| | - Jun Ge
- Laboratory of Biomaterials, State Key Laboratory of New Ceramic and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, YiFu Technology and Science Building, Room 2336, Beijing 100084, People’s Republic of China
| | - Di Chen
- Department of Orthopedics, Center for Musculoskeletal Research, University of Rochester School of Medicine, Rochester, NY 14642, USA
| | - Fu-Zhai Cui
- Laboratory of Biomaterials, State Key Laboratory of New Ceramic and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, YiFu Technology and Science Building, Room 2336, Beijing 100084, People’s Republic of China
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Abstract
The present overview is intended to point the readers’ attention to the important subject of calcium orthophosphates. These materials are of the special significance because they represent the inorganic part of major normal (bones, teeth and dear antlers) and pathological (i.e. those appearing due to various diseases) calcified tissues of mammals. Due to a great chemical similarity with the biological calcified tissues, many calcium orthophosphates possess remarkable biocompatibility and bioactivity. Materials scientists use this property extensively to construct artificial bone grafts that are either entirely made of or only surface-coated with the biologically relevant calcium ortho-phosphates. For example, self-setting hydraulic cements made of calcium orthophosphates are helpful in bone repair, while titanium substitutes covered by a surface layer of calcium orthophosphates are used for hip joint endoprostheses and as tooth substitutes. Porous scaffolds made of calcium orthophosphates are very promising tools for tissue engineering applications. In addition, technical grade calcium orthophosphates are very popular mineral fertilizers. Thus ere calcium orthophosphates are of great significance for humankind and, in this paper, an overview on the current knowledge on this subject is provided.
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Palmer LC, Newcomb CJ, Kaltz SR, Spoerke ED, Stupp SI. Biomimetic systems for hydroxyapatite mineralization inspired by bone and enamel. Chem Rev 2008; 108:4754-83. [PMID: 19006400 PMCID: PMC2593885 DOI: 10.1021/cr8004422] [Citation(s) in RCA: 647] [Impact Index Per Article: 40.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Liam C Palmer
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
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Du C, Fan D, Sun Z, Fan Y, Lakshminarayanan R, Moradian-Oldak J. Immunogold labeling of amelogenin in developing porcine enamel revealed by field emission scanning electron microscopy. Cells Tissues Organs 2008; 189:207-11. [PMID: 18701812 DOI: 10.1159/000151385] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The present study describes a method using immunohistochemical labeling in combination with high-resolution imaging (field emission scanning electron microscopy) to investigate the spatial localization of amelogenins on apatite crystallites in developing porcine enamel. Cross-sections of developing enamel tissue from freeze-fractured pig third molar were treated with antiserum against recombinant mouse amelogenin and immunoreactivity confirmed by Western blot analysis. The samples were then treated with the goat anti-rabbit IgG conjugated with 10-nm gold particles. The control samples were treated with the secondary antibody only. The in-lens secondary electrons detector and quadrant back-scattering detector were employed to reveal the high-resolution morphology of enamel structures and gold particle distribution. The immunolabeling showed a preference of the gold particle localization along the side faces of the ribbon-like apatite crystals. The preferential localization of amelogenin in vivo on enamel crystals strongly supports its direct function in controlling crystal morphology.
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Affiliation(s)
- Chang Du
- Center for Craniofacial Molecular Biology, School of Dentistry, University of Southern California, Los Angeles, Calif. 90033, USA
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Chappell H, Duer M, Groom N, Pickard C, Bristowe P. Probing the surface structure of hydroxyapatite using NMR spectroscopy and first principles calculations. Phys Chem Chem Phys 2008; 10:600-6. [DOI: 10.1039/b714512h] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Wang L, Tang R, Bonstein T, Orme CA, Bush PJ, Nancollas GH. A new model for nanoscale enamel dissolution. J Phys Chem B 2007; 109:999-1005. [PMID: 16866472 DOI: 10.1021/jp046451d] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The dissolution kinetics of human tooth enamel surfaces was investigated using nanomolar-sensitive constant composition (CC) and in situ atomic force microscopy (AFM) under simulated caries formation conditions (relative undersaturation with respect to hydroxyapatite = 0.902, pH = 4.5). Scanning electron microscopic (SEM) examination of the resulting etched enamel surfaces showed that deminerzalization, initiated at core/wall interfaces of rods, developed anisotropically along the c-axes. After an initial rapid removal of surface polishing artifacts, the dissolution rate decreased as the reaction proceeded in accordance with our recently proposed crystal dissolution model, resulting in hollow enamel cores and nanosized remaining crystallites, resistant to further dissolution. Generally, dissolution of minerals is regarded as a spontaneous reaction in which all the solid phase can be dissolved in undersaturated solutions. However, the dissolution of some biominerals may be suppressed when the crystallites approach nanometer size. This study shows that CC demineralization of enamel in acidic medium follows this new model that can be used to mimic carious lesion formation. In dissolution studies, nanosized enamel crystallites exhibit a remarkable degree of self-preservation in the fluctuating physiological milieu.
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Affiliation(s)
- Lijun Wang
- Department of Chemistry, School of Dental Medicine, University at Buffalo, The State University of New York, Buffalo, New York 14260, USA
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Chen H, Clarkson BH, Sun K, Mansfield JF. Self-assembly of synthetic hydroxyapatite nanorods into an enamel prism-like structure. J Colloid Interface Sci 2006; 288:97-103. [PMID: 15927567 DOI: 10.1016/j.jcis.2005.02.064] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2004] [Revised: 02/17/2005] [Accepted: 02/17/2005] [Indexed: 10/25/2022]
Abstract
The application of surfactants as reverse micelles or microemulsions for the synthesis and self-assembly of nanoscale structures is one of the most widely adopted methods in nanotechnology. These synthesized nanostructure assemblies sometimes have an ordered arrangement. The aim of this research was to take advantage of these latest developments in the area of nanotechnology to mimic the natural biomineralization process to create the hardest tissue in the human body, dental enamel. This is the outermost layer of the teeth and consists of enamel prisms, highly organized micro-architectural units of nanorod-like calcium hydroxyapatite (HA) crystals arranged roughly parallel to each other. In particular, we have synthesized and modified the hydroxyapatite nanorods surface with monolayers of surfactants to create specific surface characteristics which will allow the nanorods to self-assemble into an enamel prism-like structure at a water/air interface. The size of the synthetic hydroxyapatite nanorods can be controlled and we have synthesized nanorods similar in size to both human and rat enamel. The prepared nanorod assemblies were examined using transmission electron microscopy (TEM) and atomic force microscopy (AFM). The specific Langmuir-Blodgett films were shown to be comprised of enamel prism-like nanorod assemblies with a Ca/P ratio between 1.6 and 1.7.
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Affiliation(s)
- Haifeng Chen
- School of Dentistry, University of Michigan, 1011 North University, Ann Arbor, MI 48109-1078, USA
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29
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Zhang S, Gangal G, Uludağ H. 'Magic bullets' for bone diseases: progress in rational design of bone-seeking medicinal agents. Chem Soc Rev 2006; 36:507-31. [PMID: 17325789 DOI: 10.1039/b512310k] [Citation(s) in RCA: 200] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
An ideal therapeutic agent for bone diseases should act solely on bone tissue with no pharmacological activity at other anatomical sites. Current therapeutic agents, however, do not usually display a preferential affinity to bones and non-specifically distribute throughout the body after administration. Attempts to design bone-specific agents have relied on engineering a desired therapeutic agent with bone-seeking molecules so that the latter delivers the therapeutic agents specifically to bones. In this critical review, we summarize the latest attempts to engineer bone-seeking therapeutic agents based on formulating therapeutic agents with bisphosphonates, a class of compounds with high affinity to biological apatite. We first provide a relevant summary of the structure of bone mineral and bisphosphonates, highlighting the mode of interaction between these two entities. The use of bisphosphonates in the diagnosis of bone diseases is then presented, since this application helps us to understand the bone-carrier properties of bisphosphonates under physiological conditions. A summary of recent attempts to formulate bisphosphonates with traditional therapeutic agents to restrict their activities to bone tissues is then provided, with special emphasis on the structure-function relationships of the engineered compounds. Finally, attempts to use bisphosphonates to deliver macromolecular therapeutics (i.e., proteins) are summarized, based on recent data from the authors' lab. The collective research into bone-seeking medicinal agents is progressively laying the foundation for next-generation 'magic bullets' that display desirable activities at the disease sites with no undesirable activity on other organ systems. (164 references.).
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Affiliation(s)
- Sufeng Zhang
- Department of Chemical & Materials Engineering, Faculty of Engineering, University of Alberta, Edmonton, Alberta, Canada T6G 2G6
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30
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Snead ML, Zhu D, Lei Y, White SN, Snead CM, Luo W, Paine ML. Protein self-assembly creates a nanoscale device for biomineralization. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2006. [DOI: 10.1016/j.msec.2005.08.030] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kirkham J, Andreev I, Robinson C, Brookes SJ, Shore RC, Smith DA. Evidence for direct amelogenin-target cell interactions using dynamic force spectroscopy. Eur J Oral Sci 2006; 114 Suppl 1:219-24; discussion 254-6, 381-2. [PMID: 16674689 DOI: 10.1111/j.1600-0722.2006.00290.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Increasing evidence suggests that amelogenin, long held to be a structural protein of developing enamel matrix, may also have cell signaling functions. However, a mechanism for amelogenin cell signaling has yet to be described. The aim of the present study was to use dynamic chemical force spectroscopy to measure amelogenin interactions with possible target cells. Full-length amelogenin (rM179) was covalently attached to silicon nitride AFM tips. Synthetic RGD peptides and unmodified AFM tips were used as controls. Amelogenin-RGD cell binding force measurements were carried out using human periodontal ligament fibroblasts (HPDF) from primary explants and a commercially available osteoblast-like human sarcoma cell line as the targets. Results indicated a linear logarithmic dependence between loading rate and unbinding force for amelogenin-RGD target cells across the range of loading rates used. For RGD controls, binding events measured at 5.5 nN s-1 force loading rate resulted in a mean force of 60 pN. Values for amelogenin-fibroblast and amelogenin-osteoblast-like cell unbinding forces, measured at similar loading rates, were 50 and 55 pN, respectively. These data suggest that amelogenin interacts with potential target cells with forces characteristic of specific ligand-receptor binding, suggesting a direct effect for amelogenin at target cell membranes.
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Affiliation(s)
- Jennifer Kirkham
- Department of Oral Biology, Leeds Dental Institute, University of Leeds, Leeds, UK.
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Robinson C, Yamamoto K, Connell SD, Kirkham J, Nakagaki H, Smith AD. The effects of fluoride on the nanostructure and surface pK of enamel crystals: an atomic force microscopy study of human and rat enamel. Eur J Oral Sci 2006; 114 Suppl 1:99-104; discussion 127-9, 380. [PMID: 16674669 DOI: 10.1111/j.1600-0722.2006.00275.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Atomic force microscopy (AFM) studies have revealed 30-40 nm-wide regular positively charged bands across maturation-stage rat enamel crystals. Low pH resolved these into positively charged spherical domains of approximately 30 nm diameter. Crystal surface pK values from adhesion force titrations were approximately 6.5. The effect of fluoride on this pK value and on the nanostructure of fluorosed human enamel crystals has not been reported. The nanostructure and surface chemistry (pK) of normal and fluorotic human and of fluoride-treated rat maturing enamel crystals was examined. Enamel was sectioned and polished, prior to examination, using AFM in height and friction modes. High-resolution height images revealed 30 nm-diameter spherical domains within crystals, arranged as layers of hexagons or as a shallow spiral. Fluorotic enamel showed similar, but less well ordered, nanodomains. These could represent an arrangement of original initiation sites or binding sites for modulating matrix proteins. Surface pK was derived from adhesion-force measurements between functionalized tips (OH or COOH) and crystal surfaces between pH 2 and pH 10. pK values of approximately 6.5 for normal crystals were reduced to approximately 5.5 after fluoride treatment. Reduction in surface pK by fluoride might indicate lowered protonation with possible effects on matrix protein binding.
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Affiliation(s)
- Colin Robinson
- Department of Oral Biology, Leeds Dental Institute, Leeds, UK, and Department of Preventive Dentistry, Aichi Gakuin University, Nagoya, Japan.
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Zhu D, Paine ML, Luo W, Bringas P, Snead ML. Altering biomineralization by protein design. J Biol Chem 2006; 281:21173-21182. [PMID: 16707492 DOI: 10.1074/jbc.m510757200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To create a bioceramic with unique materials properties, biomineralization exploits cells to create a tissue-specific protein matrix to control the crystal habit, timing, and position of the mineral phase. The biomineralized covering of vertebrate teeth is enamel, a distinctive tissue of ectodermal origin that is collagen-free. In forming enamel, amelogenin is the abundant protein that undergoes self-assembly to contribute to a matrix that guides its own replacement by mineral. Conserved domains in amelogenin suggest their importance to biomineralization. We used gene targeting in mice to replace native amelogenin with one of two engineered amelogenins. Replacement changed enamel organization by altering protein-to-crystallite interactions and crystallite stacking while diminishing the ability of the ameloblast to interact with the matrix. These data demonstrate that ameloblasts must continuously interact with the developing matrix to provide amelogenin-specific protein to protein, protein to mineral, and protein to membrane interactions critical to biomineralization and enamel architecture while suggesting that mutations within conserved amelogenin domains could account for enamel variations preserved in the fossil record.
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Affiliation(s)
- DanHong Zhu
- University of Southern California, Center for Craniofacial Molecular Biology, Los Angeles, California 90033
| | - Michael L Paine
- University of Southern California, Center for Craniofacial Molecular Biology, Los Angeles, California 90033
| | - Wen Luo
- University of Southern California, Center for Craniofacial Molecular Biology, Los Angeles, California 90033
| | - Pablo Bringas
- University of Southern California, Center for Craniofacial Molecular Biology, Los Angeles, California 90033
| | - Malcolm L Snead
- University of Southern California, Center for Craniofacial Molecular Biology, Los Angeles, California 90033.
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Bartlett JD, Ganss B, Goldberg M, Moradian-Oldak J, Paine ML, Snead ML, Wen X, White SN, Zhou YL. Protein–Protein Interactions of the Developing Enamel Matrix. Curr Top Dev Biol 2006; 74:57-115. [PMID: 16860665 DOI: 10.1016/s0070-2153(06)74003-0] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Extracellular matrix proteins control the formation of the inorganic component of hard tissues including bone, dentin, and enamel. The structural proteins expressed primarily in the enamel matrix are amelogenin, ameloblastin, enamelin, and amelotin. Other proteins, like biglycan, are also present in the enamel matrix as well as in other mineralizing and nonmineralizing tissues of mammals. In addition, the presence of sulfated enamel proteins, and "tuft" proteins has been examined and discussed in relation to enamel formation. The structural proteins of the enamel matrix must have specific protein-protein interactions to produce a matrix capable of directing the highly ordered structure of the enamel crystallites. Protein-protein interactions are also likely to occur between the secreted enamel proteins and the plasma membrane of the enamel producing cells, the ameloblasts. Such protein-protein interactions are hypothesized to influence the secretion of enamel proteins, establish short-term order of the forming matrix, and to mediate feedback signals to the transcriptional machinery of these cells. Membrane-bound proteins identified in ameloblasts, and which interact with the structural enamel proteins, include Cd63 (cluster of differentiation 63 antigen), annexin A2 (Anxa2), and lysosomal-associated glycoprotein 1 (Lamp1). These and related data help explain the molecular and cellular mechanisms responsible for the removal of the organic enamel matrix during the events of enamel mineralization, and how the enamel matrix influences its own fate through signaling initiated at the cell surface. The knowledge gained from enamel developmental studies may lead to better dental and nondental materials, or materials inspired by Nature. These data will be critical to scientists, engineers, and dentists in their pursuits to regenerate an entire tooth. For tooth regeneration to become a reality, the protein-protein interactions involving the key dental proteins must be identified and understood. The scope of this review is to discuss the current understanding of protein-protein interactions of the developing enamel matrix, and relate this knowledge to enamel biomineralization.
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Affiliation(s)
- John D Bartlett
- The Forsyth Institute, 140 The Fenway, Boston, MA 02115, USA
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35
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Paine ML, Snead ML. Tooth developmental biology: disruptions to enamel-matrix assembly and its impact on biomineralization. Orthod Craniofac Res 2005; 8:239-51. [PMID: 16238604 DOI: 10.1111/j.1601-6343.2005.00346.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dental enamel is a composite bioceramic material that is the hardest tissue in the vertebrate body, containing long, thin crystallites of substituted hydroxyapatite (HAP). Over a lifetime of an organism, enamel functions under repeated and immense loads, generally without catastrophic failure. Enamel is a product of ectoderm-derived cells called ameloblasts. Recent investigations on the formation of enamel using cell and molecular approaches are now being coupled to biomechanical investigations at the nanoscale and mesoscale levels. For amelogenin, the principal structural protein for forming enamel, we have identified two domains that are required for its proper self-assembly into supramolecular structures referred to as nanospheres. Nanospheres are believed to control HAP crystal habit. Other structural proteins of the enamel matrix include ameloblastin and enamelin, but little is known about their biological importance. Transgenic animals have been prepared to investigate the effect of overexpression of wild-type or mutated enamel proteins on the developing enamel matrix. Amelogenin transgenes were engineered to contain deletions to either of the two self-assembly domains and these alterations produced significant defects in the enamel. Additional transgenic animal lines have been prepared and studied and each gives additional insights into the mechanisms for enamel biofabrication. This study summarizes the observed enamel phenotypes of recently derived transgenic animals. These data are being used to help define the role of each of the enamel structural proteins in enamel and study how each of these proteins impact on enamel biomineralization.
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Affiliation(s)
- M L Paine
- School of Dentistry, University of Southern California, Los Angeles, 90033, USA.
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Robinson C, Connell S, Brookes SJ, Kirkham J, Shore RC, Smith DAM. Surface chemistry of enamel apatite during maturation in relation to pH: implications for protein removal and crystal growth. Arch Oral Biol 2005; 50:267-70. [PMID: 15721160 DOI: 10.1016/j.archoralbio.2004.11.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2004] [Accepted: 11/16/2004] [Indexed: 10/25/2022]
Abstract
Apatite crystal growth rate and morphology in mineralized tissues are considered to be controlled by surface interaction with extracellular matrix proteins. During enamel maturation where protein is finally removed from crystal surfaces to permit massive crystal growth, pH oscillates between approximately 5.8 and approximately 7.2. With this in mind, a study of enamel apatite surface chemistry in terms of local environmental pH was undertaken. Using atomic force microscopy adhesion force measurements were made between hydroxylated or carboxylated cantilever tips and maturation stage crystals between pH 2 and 10. Adhesion force increased from pH 10 to a maximum at pH 6.6 presumably due to increased hydrogen bonding due to replacement of surface cations (Na, Ca, Mg) with protons and/or protonation of phosphate per se. Below pH 6.6 adhesion force decreased and became very variable indicating that the surface had become unstable probably due to removal of fully protonated phosphate from the surface by adherence to the cantilever tip. Frictional force measurements also revealed 2-3, approximately 30 nm diameter high friction domains in bands across the crystal long axis. Their location mirrored the binding pattern of similarly sized amelogenin aggregates seen in vitro. The data suggests that specific protein binding sites may exist on crystal surfaces and may be released at lower pH by protonation which would lower cationic charge on both crystal surface and ionic charge on the protein. Instability of the crystal surface could also play a role.
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Affiliation(s)
- C Robinson
- Division of Oral Biology, Leeds Dental Institute, University of Leeds, UK.
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Chen H, Chen Y, Orr BG, Holl MMB, Majoros I, Clarkson BH. Nanoscale probing of the enamel nanorod surface using polyamidoamine dendrimers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:4168-71. [PMID: 15969412 DOI: 10.1021/la0303005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Although it is known that noncollagenous proteins of dental origin bind to the hydroxyapatite crystal surfaces, no measure of their binding strength has been calculated. This experiment used -COOH-capped generation 7 PAMAM dendrimers as nanoprobes of the biological hydroxyapatite nanorod surfaces. Dendrimer distribution was characterized using AFM. The results showed dendrimers to be spaced at intervals along the c-axis of the crystals. From these observations and assuming a fully ionized -COOH dendrimer, a mathematical model of the binding capacity of the crystal surface with the dendrimer was developed. The Monte Carlo method was used to simulate the binding process between the dendrimer and crystal surface, and the binding strength of the -COOH groups to the surface was calculated to be 90 +/- 20 kJ/mol. These results support the CFM studies which have described alternating bands of charge domains on the crystal surface and that the binding strength will be dependent on both the intensity of the charge on the protein and the crystal surface.
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Affiliation(s)
- Haifeng Chen
- School of Dentistry, Department of Physics, Program in Macromolecular Science and Engineering, Center for Biologic Nanotechnology, University of Michigan, Ann Arbor, Michigan 48109-1078, USA
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Robinson C, Connell S, Kirkham J, Shore R, Smith A. Dental enamel—a biological ceramic: regular substructures in enamel hydroxyapatite crystals revealed by atomic force microscopy. ACTA ACUST UNITED AC 2004. [DOI: 10.1039/b401154f] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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39
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Chen H, Banaszak Holl M, Orr BG, Majoros I, Clarkson BH. Interaction of dendrimers (artificial proteins) with biological hydroxyapatite crystals. J Dent Res 2003; 82:443-8. [PMID: 12766196 DOI: 10.1177/154405910308200608] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
This investigation sets out to mimic protein-crystal interaction during biomineralization with the use of artificial proteins (dendrimers). It is hypothesized that these interactions depend on the surface charge of hydroxyapatite crystals. This was investigated with the use of dendrimers with capped surfaces of different charges to probe the surface. We used AFM images of crystal-bound dendrimers to determine the distribution of the surface charge, and its magnitude was correlated to the binding capacity of the dendrimers to the surface. The binding capacity of the dendrimers in ascending order at pH 7.4 was: acetamide-capped, -NHC(O)CH3, neutral charge; carboxylic-acid-capped, -COOH, negative charge; and amine-capped, -NH2, positive charge. AFM images of the crystals showed dendrimers spaced equally along the crystal. The results suggest that the crystal surface has alternating bands of positive and negative charge or a differential charge array, i.e., alternating bands of either more or less positive or negative charge.
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Affiliation(s)
- H Chen
- School of Dentistry and Department of Chemistry, University of Michigan, 1011 N. University, Ann Arbor, MI 48109-1078, USA
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40
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Smith D, Connell S, Robinson C, Kirkham J. Chemical force microscopy: applications in surface characterisation of natural hydroxyapatite. Anal Chim Acta 2003. [DOI: 10.1016/s0003-2670(02)01374-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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41
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Abstract
The inorganic part of hard tissues (bones and teeth) of mammals consists of calcium phosphate, mainly of apatitic structure. Similarly, most undesired calcifications (i.e. those appearing as a result of various diseases) of mammals also contain calcium phosphate. For example, atherosclerosis results in blood-vessel blockage caused by a solid composite of cholesterol with calcium phosphate. Dental caries result in a replacement of less soluble and hard apatite by more soluble and softer calcium hydrogenphosphates. Osteoporosis is a demineralization of bone. Therefore, from a chemical point of view, processes of normal (bone and teeth formation and growth) and pathological (atherosclerosis and dental calculus) calcifications are just an in vivo crystallization of calcium phosphate. Similarly, dental caries and osteoporosis can be considered to be in vivo dissolution of calcium phosphates. On the other hand, because of the chemical similarity with biological calcified tissues, all calcium phosphates are remarkably biocompatible. This property is widely used in medicine for biomaterials that are either entirely made of or coated with calcium phosphate. For example, self-setting bone cements made of calcium phosphates are helpful in bone repair and titanium substitutes covered with a surface layer of calcium phosphates are used for hip-joint endoprostheses and tooth substitutes, to facilitate the growth of bone and thereby raise the mechanical stability. Calcium phosphates have a great biological and medical significance and in this review we give an overview of the current knowledge in this subject.
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Affiliation(s)
- Sergey V Dorozhkin
- Solid-State Chemistry, Faculty of Chemistry, University of Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
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42
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Dorozhkin SV, Epple M. Biological and medical significance of calcium phosphates. Angew Chem Int Ed Engl 2002. [PMID: 12207375 DOI: 10.1002/1521-3773(20020902)41:17%3c3130::aid-anie3130%3e3.0.co;2-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
The inorganic part of hard tissues (bones and teeth) of mammals consists of calcium phosphate, mainly of apatitic structure. Similarly, most undesired calcifications (i.e. those appearing as a result of various diseases) of mammals also contain calcium phosphate. For example, atherosclerosis results in blood-vessel blockage caused by a solid composite of cholesterol with calcium phosphate. Dental caries result in a replacement of less soluble and hard apatite by more soluble and softer calcium hydrogenphosphates. Osteoporosis is a demineralization of bone. Therefore, from a chemical point of view, processes of normal (bone and teeth formation and growth) and pathological (atherosclerosis and dental calculus) calcifications are just an in vivo crystallization of calcium phosphate. Similarly, dental caries and osteoporosis can be considered to be in vivo dissolution of calcium phosphates. On the other hand, because of the chemical similarity with biological calcified tissues, all calcium phosphates are remarkably biocompatible. This property is widely used in medicine for biomaterials that are either entirely made of or coated with calcium phosphate. For example, self-setting bone cements made of calcium phosphates are helpful in bone repair and titanium substitutes covered with a surface layer of calcium phosphates are used for hip-joint endoprostheses and tooth substitutes, to facilitate the growth of bone and thereby raise the mechanical stability. Calcium phosphates have a great biological and medical significance and in this review we give an overview of the current knowledge in this subject.
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Affiliation(s)
- Sergey V Dorozhkin
- Solid-State Chemistry, Faculty of Chemistry, University of Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
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43
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44
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Paine ML, Lei YP, Dickerson K, Snead ML. Altered amelogenin self-assembly based on mutations observed in human X-linked amelogenesis imperfecta (AIH1). J Biol Chem 2002; 277:17112-6. [PMID: 11877393 DOI: 10.1074/jbc.m110473200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A hallmark of biological systems is a reliance on protein assemblies to perform complex functions. We have focused attention on mammalian enamel formation because it relies on a self-assembling protein complex to direct mineral habit. The principle protein of enamel is amelogenin, a 180-amino acid hydrophobic protein that self-assembles to form nanospheres. We have used independent technical methods, consisting of the yeast two-hybrid (Y2H) assay and surface plasmon resonance (SPR), to demonstrate the importance of amelogenin self-assembly domains. In addition, we have analyzed mutations in amelogenin observed in patients with amelogenesis imperfecta who demonstrate defects in enamel formation. Assessments of self-assembly of these mutant amelogenins by either SPR or Y2H assay yield concordant data. These data support the conclusion that the amelogenin amino-terminal self-assembly domain is essential to the creation of an enamel extracellular organic matrix capable of directing mineral formation. It also suggests that a pathway through which point mutations in the amelogenin protein can adversely impact on the formation of the enamel organ is by disturbing self-assembly of the organic matrix. These data support the utilization of the Y2H assay to search for protein interactions among extracellular matrix proteins that contribute to biomineralization and provide functional information on protein-protein and protein-mineral interactions.
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Affiliation(s)
- Michael L Paine
- University of Southern California, School of Dentistry, Center for Craniofacial Molecular Biology, Los Angeles, California 90033-1004, USA.
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45
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Kirkham J, Brookes SJ, Shore RC, Wood SR, Smith D, Zhang J, Chen H, Robinson C. Physico-chemical properties of crystal surfaces in matrix–mineral interactions during mammalian biomineralisation. Curr Opin Colloid Interface Sci 2002. [DOI: 10.1016/s1359-0294(02)00017-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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46
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Paine ML, White SN, Luo W, Fong H, Sarikaya M, Snead ML. Regulated gene expression dictates enamel structure and tooth function. Matrix Biol 2001; 20:273-92. [PMID: 11566262 DOI: 10.1016/s0945-053x(01)00153-6] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Enamel is a complex bioceramic tissue. In its final form, enamel is a reflection of the unique molecular and cellular activities occurring during organogenesis. From the ectodermal origins of ameloblasts, their gene activity and protein expression profiles exist for the sole purpose of producing a mineralized shell, almost entirely devoid of protein, deposited over the 'bone-like' dentine. The interface between enamel and dentine is referred to as the dentine enamel junction and it is also unique in its biology. This review article is narrow in its scope. We restrict our review to selected advances in our understanding of the genetic, molecular and structural aspects of enamel biology. We present a model of enamel formation that relates gene expression to the assembly of an extracellular protein matrix that in turn controls the structural hierarchy and mechanical aspects of enamel and the tooth organ.
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Affiliation(s)
- M L Paine
- University of Southern California, Center for Craniofacial Molecular Biology, Los Angeles, CA 90033, USA.
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