Figure 5. Micro-Raman spectroscopy of NLP and NB reveals the presence of both carbonate and phosphate.

(A–D) NLP were prepared as in Fig. 3 and submitted to micron-Raman spectroscopy (A) immediately after formation, or after the following periods of incubation at 37°C in DMEM: (B) overnight and (C) one week. (D) NLP were prepared by addition of 10 mM each of Na₂CO₃ and (NH₄)₂CO₃ in DMEM. Carbonate peaks were seen at 290 cm⁻¹ and 1,070 cm⁻¹, while phosphate peaks were seen at 440 cm⁻¹, 581 cm⁻¹, 962 cm⁻¹, 1,048 cm⁻¹, and 1,076 cm⁻¹. The four NLP specimens show marked variability of peaks. (E) NB obtained from a culture of DMEM containing 10% HS reveal small peaks of phosphate at 440 cm⁻¹ and 962 cm⁻¹ as well as a carbonate peak at 1070 cm⁻¹. (F) “Nanons” showing low peaks of phosphate at 440 cm⁻¹, 581 cm⁻¹, and 962 cm⁻¹. Commercial powders of (G) CaCO₃, (H) Ca₃(PO₄)₂, and (I) HAP were included as controls.