Figure 4

Morphology and chemical composition of mineralo-organic NPs and mineral particles found in kidney tissues.

(A–E) Mineralo-organic NPs labeled as HS-NPs were prepared by adding 3 mM CaCl₂ and Na₂HPO₄ each into DMEM containing 10% HS, followed by incubation for one week in cell culture conditions. TEM observations of HS-NP thin sections showed round particles with a smooth or crystalline surface. (F–J) Mineral particles or granules observed in human renal tissues by thin-section TEM. Kidney NPs or granules showed morphologies and sizes similar to that of HS-NPs. Some kidney granules were surrounded by a lipid membrane ((H,I) black arrows) while membranes were not observed in HS-NP specimens prepared in vitro. Representative electron diffraction patterns are shown in (E) and (J) (insets). EDX analysis of (K) prepared HS-NPs, (L) kidney granules found in human renal tissues and (M) control kidney tissues. White stars indicate the areas selected for EDX analysis. Both HS-NPs and kidney granules show major peaks of carbon, calcium, oxygen and phosphorus along with other minor peaks, consistent with the presence of calcium phosphate containing additional ions. (M) EDX spectrum of control tissues surrounding the particles show no calcium or phosphate peaks. Ca:P ratios: (K) 1.18; (L) 0.65.