Zinc ion release from novel hard tissue biomaterials

Area of Science:

• Biomaterials Science
• Orthopedic Engineering
• Dental Materials

Background:

• Zinc polyalkenoate cements (ZPCs) and glass polyalkenoate cements (GPCs) show promise for orthopedic applications due to their setting properties.
• Current ZPCs and GPCs have drawbacks, including fibrous encapsulation and defective bone mineralization caused by ion release.
• Modifications involving hydroxyapatite (HA) in ZPCs and zinc in GPCs aim to improve bioactivity and biocompatibility.

Purpose of the Study:

• To formulate and evaluate novel ZPCs and GPCs for potential orthopedic applications.
• To investigate the ion release profiles of modified ZPCs and GPCs.
• To correlate material composition and processing parameters with ion release and potential bioactivity.

Main Methods:

• Formulation of ZPCs using zinc oxide (ZnO), hydroxyapatite (HA), and poly(acrylic acid) (PAA).
• Formulation of GPCs using calcium zinc silicate glass and PAA.
• Analysis of cement moduli, ion release (Zn2+), and factors influencing release (polymer concentration, HA content, temperature, agitation).

Main Results:

• Both modified ZPCs and GPCs can be formulated via acid-base reactions with moduli comparable to bone and acrylic cements.
• For ZPCs, increased polymer concentration and HA content, along with decreased ZnO content, reduce zinc ion release.
• For GPCs, increased PAA concentration and P:L ratio minimize active ion release, which is exacerbated by temperature and agitation.

Conclusions:

• Modified ZPCs and GPCs demonstrate potential for biomedical applications due to favorable mechanical properties and tunable ion release.
• Controlling ion release is crucial for improving the in vitro bioactivity and biocompatibility of these cements.
• Further in vivo studies are necessary to fully assess the clinical benefits of these modified polyalkenoate cements.