Processing, characterisation and biocompatibility of iron-phosphate glass fibres for tissue engineering

Abstract

Iron-phosphate glass fibres based on the CaO–Na 2O–Fe 2O 3–P 2O 5 system have been processed and characterised via thermal, XRPD, dissolution rates, diameter and biocompatibility studies. The compositions investigated were fixed at 50 mol% P 2O 5, and the CaO content was varied between 30, 35 and 40 mol%. The Fe 2O 3 was added in low amounts from 1–5 mol%, substituting it for the Na 2O mol%. The number of T c (crystallisation temperature) peaks detected from the thermal analysis traces only showed correlation with XRPD analysis, for five out of the 15 compositions investigated. It has been suggested that either the crystalline phases had very similar T c temperatures or that the other phase(s) were present in very small quantities. There was a good match seen with number of T m (melting temperature) peaks picked up from the DTA traces, with the number of phases identified from XRPD analysis. The main phases identified from XRPD were NaCa(PO 3) 3, CaP 2O 6 and NaFeP 2O 7. Using network connectivity (NC), predictions on Q n species present within the compositions investigated were made. The predicted species (metaphosphates) matched with phases identified from XRPD analysis. A decrease in dissolution rates for the bulk glass and glass fibres was seen with an increase in CaO mol%, along with an increase in Fe 2O 3 mol%. An increase in fibre dissolution rates was seen with a decrease in diameter size. The biocompatibility studies were conducted using a conditionally immortal muscle precursor cell line derived from the H-2Kb-tsA58 immortomouse. It was found that iron-phosphate glass fibres containing 4–5 mol% Fe 2O 3 was sufficient for cell attachment and differentiation. It was seen that myotubes formed along the axis of the fibres (which was indicative of differentiation). The biocompatibility of these compositions was attributed to the enhanced chemical durability of the glass fibres.