English Journal

Compressive mechanical properties of demineralized and deproteinized cancellous bone.

Chen PY1, McKittrick J.Author information 1Materials Science and Engineering Program, University of California at San Diego, La Jolla, CA 92093-0411, United States.AbstractA method to completely demineralize and deproteinize bone was used to investigate the mechanical properties of either the mineral or protein phase in cancellous bone and compared to an untreated one. Compression tests on cancellous bovine femur and elk antler (Cervus elaphus canadensis) were performed on demineralized, deproteinized, and untreated samples in an air-dry condition. Results showed that the elastic modulus and compressive strength of the demineralized (protein only) and deproteinized (mineral only) samples were far lower than that of the untreated ones, indicating a strong synergetic effect between the two phases. Experimental data showed that the demineralized, deproteinized, and untreated samples can be modeled as cellular solids, with the strong dependence of mechanical properties on the relative density. Deformed samples were examined under SEM and different failure mechanisms were observed. Plastic buckling was observed in demineralized samples while brittle crushing was found in deproteinized ones.
Journal of the mechanical behavior of biomedical materials.J Mech Behav Biomed Mater.2011 Oct;4(7):961-73. doi: 10.1016/j.jmbbm.2011.02.006. Epub 2011 Feb 18.
A method to completely demineralize and deproteinize bone was used to investigate the mechanical properties of either the mineral or protein phase in cancellous bone and compared to an untreated one. Compression tests on cancellous bovine femur and elk antler (Cervus elaphus canadensis) were perform
PMID 21783106

Minerals form a continuum phase in mature cancellous bone.

Chen PY1, Toroian D, Price PA, McKittrick J.Author information 1Materials Science and Engineering Program, Department of Mechanical and Aerospace Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0411, USA. pochen@ucsd.eduAbstractBone is a hierarchically structured composite consisting of a protein phase (type I collagen) and a mineral phase (carbonated apatite). The objective of this study was to investigate the hierarchical structure of mineral in mature bone. A method to completely deproteinize bone without altering the original structure is developed, and the completion is confirmed by protein analysis techniques. Stereoscopy and field emission electron microscopy are used to examine the structural features from submillimeter- to micrometer- to nanometer-length scales of bovine femur cancellous bone. Stereoscopic images of fully deproteinized and demineralized bovine femur cancellous bone samples show that fine trabecular architecture is unaltered and the microstructural features are preserved, indicating the structural integrity of mineral and protein constituents. SEM revealed that bone minerals are fused together and form a sheet-like structure in a coherent manner with collagen fibrils. Well-organized pore systems are observed at varying hierarchical levels. Mineral sheets are peeled off and folded after compressive deformation, implying strong connection between individual crystallites. Results were compared with commercially available heat-deproteinized bone (Bio-Oss(®)), and evidence showed consistency in bone mineral structure. A two-phase interpenetrating composite model of mature bone is proposed and discussed.
Calcified tissue international.Calcif Tissue Int.2011 May;88(5):351-61. doi: 10.1007/s00223-011-9462-8. Epub 2011 Jan 28.
Bone is a hierarchically structured composite consisting of a protein phase (type I collagen) and a mineral phase (carbonated apatite). The objective of this study was to investigate the hierarchical structure of mineral in mature bone. A method to completely deproteinize bone without altering the o
PMID 21274705

Purification of RNA by SDS solubilization and phenol extraction.

Rio DC, Ares M Jr, Hannon GJ, Nilsen TW.AbstractThis protocol describes a method for RNA purification by sodium dodecyl sulfate (SDS) solubilization and phenol extraction. It is of wide utility and is used routinely to deproteinize RNAs in biological material that has been solubilized in SDS, an ionic detergent that dissolves membranes, disrupts protein-nucleic acid interactions, and inactivates ribonucleases. Once solubilized, addition of phenol or phenol:chloroform:isoamyl alcohol (PCA) completely denatures the protein, and it becomes insoluble in aqueous solution. PCA extraction is the method of choice for preparing cytoplasmic RNA from tissue culture cells or in any other situation (e.g., enzyme reactions) where solubilization in SDS is easily achievable.
Cold Spring Harbor protocols.Cold Spring Harb Protoc.2010 Jun;2010(6):pdb.prot5438. doi: 10.1101/pdb.prot5438.
This protocol describes a method for RNA purification by sodium dodecyl sulfate (SDS) solubilization and phenol extraction. It is of wide utility and is used routinely to deproteinize RNAs in biological material that has been solubilized in SDS, an ionic detergent that dissolves membranes, disrupts
PMID 20516176