Bioceramics: from bone substitutes to nanoparticles for drug delivery

Abstract

Since the second half of the 20^th century, bioceramics are used for bone repair and regeneration. Inspired by bones and teeth, and aimed at mimicking their structure and composition, several artificial bioceramics were developed for biomedical applications. And nowadays, in the 21^st century, with the increasing prominence of nanoscience and nanotechnology, certain bioceramics are being used to build smart drug delivery systems, among other applications. This minireview will mainly describe both tendencies through the research work carried out by the research team of María Vallet-Regí.

Keywords: Distinguished Women in Chemistry and Chemical Engineering; biomaterials; biomedical applications; ceramics; drug delivery.

Fig. 1

Structural features of bones when observed at different magnification degrees. Plots represent XRD data of bone, enamel and dentine.

Fig. 2

Different bioceramics are used depending on the function they must play in the skeletal system. (TCP, Tricalcium Phosphate; OCP, Orthocalciumphosphate; DCPA, Dicalcium phosphate anhydrous; DCPD, dicalcium phospahtedihydrate; TetCP, tetracalcium phosphate; HA, Hydroxiapatite; HCA, carbonated hydroxyapatite).

Fig. 3

Mesoporous ordered materials can be used for tissue engineering and drug delivery applications. Yellow spheres represent the hydroxyapatite formation as a consequence of bioactive behavior of the mesoporous material. On the right hand side there are different drugs or biomolecule that can be hosted inside the pores.

Fig. 4

Pores of different sizes are necessary to play different biological actions.

Fig. 5

The hierarchical porous structure of artificial bioceramics similar to the bone.

Fig. 6

Transmission Electron Micrographs of mesoporous silica matrices with the possibility to load their pores with drugs.

Fig. 7

Evolution of research articles published on the topic of Responsive-MSNs for drug delivery. Data from Google Scholar.

Fig. 8

Schematic representation of stimuli responsive release of MSNs cargo (top), Transmission Electron Microscopy micrograph of MSN (left bottom corner), and the potential solutions to avoid premature release of the cargo (right bottom corner).

Fig. 9

Schematic representation of release of two types of agents: small molecules encapsulated into the pores and large proteins retained within the shell of nanoparticles triggered by magnetic fields [103].

Fig. 10

Schematic representation of pulsatile release from MSNs responsive to magnetic fields [104].

Fig. 11

MSNs internalized into cells (right top corner), TEM micrograph of MSNs decorated with US sensitive polymer (center), and in vial release kinetics from that platform [114].

Fig. 12

TEM micrograph of MSNs with the encapsulated enzyme on their surface (left) and schematic representation of cell penetration [129].

Fig. 13

Passive and active targeting.

Fig. 14

Schematic representation of stealth nanoparticles loaded with drugs and injected on the blood vessels (top) and tumor penetration of nanoparticles with targeting abilities (bottom).