Evaluation of bioceramic bone substitutes – hydroxyapatite (HAP), tricalcium phosphate (TCP) and biphasic ceramic (HAP/TCP) in vitro and in vivo

Efficient non-contact heat generation on flexible, ternary hydroxyapatite/curdlan/nanomagnetite hybrids for temperature controlled processes

The ternary HAp/curdlan/nanomagnetite hybrids with ceramic and polymer phase incorporation of magnetite nanoparticles (MNPs) were fabricated to study their heating ability under action of the alternating magnetic field (AMF), 808 nm near infrared laser radiation (NIR) and their synergic stimulation. The energy conversion was evaluated in terms of the specific absorption rate (SAR) as a function of the MNPs concentration in composites and to estimate their potential in temperature-controlled regenerative processes and hyperthermia. Measurements were carried out on dry and Ringer's solution soaked composite materials in order to mimic in situ conditions. It was found that the MNPs release during prolonged experiment is limited and has no significant effect on energy conversion emphasizing stability of the hybrids. Incorporation of the MNPs in polymer phase of the hybrid can additionally limit particle leaking as well as plays a role as insulating layer for the heat dissipation lowering the risk of sample overheating. In general, it was shown that maximum temperature of hybrid can be achieved in a relatively short time of exposure to stimulating factors whereas its control can be done through optimization of experiment conditions. MNPs incorporation into the curdlan (polymer phase) lead to strengthening of the mechanical properties of the whole network.

Multifunctional nanocrystalline calcium phosphates loaded with Tetracycline antibiotic combined with human adipose derived mesenchymal stromal stem cells (hASCs)

Osteoconductive drug delivery system composed of nanocrystalline calcium phosphates (Ca10(PO4)6(OH)2/β-Ca3(PO4)2) co-doped with Yb(3+)/Er(3+) ions loaded with Tetracycline antibiotic (TC) was developed. Their effect on human adipose derived mesenchymal stromal stem cells (hASCs) as a potential reconstructive biomaterial for bone tissue regeneration was studied. The XRD and TEM measurements were used in order to determine the crystal structure and morphology of the final products. The characteristics of nanocomposites with the TC and hASCs as potential regenerative materials as well as the antimicrobial activity of the nanoparticles against: Staphylococcus aureus ATCC 25923 as a model of the Gram-positive bacteria, Escherichia coli ATCC 8739 of the Gram-negative bacteria, were shown. These combinations can be a promising material for theranostic due to its regenerative, antimicrobial and fluorescent properties.

An up-converting HAP@β-TCP nanocomposite activated with Er3+/Yb3+ ion pairs for bio-related applications

A HAP@β-TCP nanocomposite doped with Er³⁺/Yb³⁺ ions was prepared and its cytotoxicity was tested on canine osteosarcoma and murine macrophage cells. Metronidazole release from the nanocomposite was studied and its up-conversion properties measured.