Bone is a hierarchical architecture that consists of both inorganic and organic components. The organic components, including collagen and numerous non-collagenous biomolecules, are crucial for maintaining the mechanical strength and physiological functions of bone. The native structures of organic components and especially the mutual interactions between different components are important questions to be addressed. Among different analytical techniques, solid-state nuclear magnetic resonance (SSNMR) spectroscopy is a powerful tool to reveal the chemical and interactional information at an atomic level. Recent advancements of SSNMR technology and experimental protocols have brought great advances in understanding the molecular details in native bones. In this review, we summarize the progresses on the SSNMR studies of various organic components in the bone matrix. In the first part, we review the studies on collagen from four different aspects: (1) water-associated molecular dynamics; (2) the intrahelical/interhelical interactions in collagen residues; (3) the interactions between collagen and citrate; and (4) the cross-linking between collagen and inorganic surface. In the second part, we review the studies on the non-protein biomolecules including sugar species, citrate, lipids, and nucleic acids. In the end, we propose an outlook of future directions for SSNMR investigations on bones.

Metal–organic frameworks (MOFs) are being investigated as the potential materials for future drug delivery and gene therapy systems thanks to their tunable functionality and biocompatibility. However, the structure of MOFs could be altered in a biological environment or in a buffer solution. It is of great importance to evaluate the stability of MOFs and understand the degradation processes for the sake of the biomedical applications. In this work, we investigate the stability of UiO-66, a generally-perceived stable MOF, in different amino acid solutions. We find that UiO-66 loses crystallinity in relatively mild basic conditions (when pH ≥ 9) in the presence of amino acids. The instability is more pronounced in the lysine and arginine solutions which have stronger basicity. It can be attributed to the accelerated ligand exchange of UiO-66 under basic conditions. With a combination of techniques, we show that the amino acids can replace the organic linkers and form zirconium-amino acid complexes. Our research reveals one possible mechanism of MOF degradation in biological environment, yet such degradability could be also an important designable property for MOFs in biomedical applications.