Construction of Antimicrobial Material-Loaded Porous Tricalcium Phosphate Beads for Treatment of Bone Infections

β-tricalcium phosphate synthesized in organic medium for controlled release drug delivery application in bio-scaffolds

β-tricalcium phosphate (β-TCP) was synthesized in an organic medium (acetone) to obtain a single-phase product while calcium carbonate (CaCO3) and ortho-phosphoric acid (H3PO4) were the sources of Ca, and P, respectively. The synthesized β-TCP was characterized by employing a number of sophisticated techniques vis. XRD, FTIR, FESEM, VSM and UV-Vis-NIR spectrometry. On the other hand, cytotoxicity, hemolysis, and antimicrobial activity for Gram-negative as well as Gram-positive (E. coli and S. aureus) bacteria were explored using this synthesized sample in powder format. However, to assess the drug loading and releasing profile, these powdered samples were first compressed into disks followed by sintering at 900 °C. Prior to loading the drug, porosity, density, and water absorbance characteristics of the scaffolds were examined in deionized water. Both loading and releasing profiles of the antibiotic (ciprofloxacin) were looked over at various selected time intervals which were continued up to 28 days. The observed results revealed that 2.87% of ciprofloxacin was loaded while 37% of this loaded drug was released within the selected time frame as set in this study. The scaffold was also immersed in SBF solution maintaining identical interim periods for the bioactivity evaluation. Furthermore, all three types of samples (e.g. drug-loaded, drug-released, and SBF-soaked) were characterized by FESEM and EDX while antimicrobial activity (against E. coli, S. typhi, and S. aureus) and efficacy to prevent hemolysis were also investigated. The drug-loaded scaffold presented a larger inhibition zone than the standard for all three types of microbes. Although powdered β-TCP was inactive in killing the Gram-negative bacteria, surprisingly the drug-released scaffold showed an inhibition zone.

Construction of a drug-containing microenvironment for in situ bone regeneration

Bioactive glass-coated hierarchical porous tricalcium phosphate ceramics were constructed as both bone scaffolds and drug delivery devices to treat S. aureus-infected bone defects.