A comparison of lithium-substituted phosphate and borate bioactive glasses for mineralised tissue repair

Abstract

Objectives Wnt/β-catenin signalling plays important roles in regeneration, particularly in hard tissues such as bone and teeth, and can be regulated by small molecule antagonists of glycogen synthase kinase 3 (GSK3); however, small molecules can be difficult to deliver clinically. Lithium (Li) is also a GSK3 antagonist and can be incorporated into bioactive glasses (BG), which can be used clinically in dental and bone repair applications and tuned to quickly release their constituent ions. Methods Here, we created phosphate (P)- and borate (B)-based BG that also contained Li (LiPBG and LiBBG) and examined their ion release kinetics and the toxicity of their dissolution ions on mouse 17IA4 dental pulp cells. Results We found that although LiPBG and LiBBG can both quickly release Li at concentrations known to regulate Wnt/β-catenin signalling, the P and B ions they concomitantly release are highly toxic to cells. Only when relatively low concentrations of LiPBG and LiBBG were placed in cell culture medium were their dissolution products non-toxic. However, at these concentrations, LiPBG and LiBBG’s ability to regulate Wnt/β-catenin signalling was limited. Significance These data suggest that identifying a BG composition that can both quickly deliver high concentrations of Li and is non-toxic remains a challenge.

In Vivo Assessment of Bone Enhancement in the Case of 3D-Printed Implants Functionalized with Lithium-Doped Biological-Derived Hydroxyapatite Coatings: A Preliminary Study on Rabbits

“…Usually, lithium is incorporated into CaPs in form of Li 2 O [59,60]. In the current study, we selected to mix it with HA in form of Li 2 CO 3 and Li 3 PO 4 .…”

The anomaly in bioactive sol–gel borate glasses

“…25 SGBGs have also been incorporated into polymer matrices to enhance composite bioactivity, 26 while compositions doped with silver, have demonstrated antibacterial properties. 27 Interest in bioactive borate glasses has led to many 'unique' compositions [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] such as ''1605''. [44][45][46] However, despite fundamental differences between borate and silicate glass structure, many borate compositions, including our previous work, [23][24][25][26]47 have been based on ''traditional'' silicate glass compositions like Bioglass s ''45S5'', 15,[23][24][25][26][47][48][49][50] ''13-93'', 14,16,17,[51][52][53][54][55][56][57]…”

Improvement of the mechanical and biological properties of bioactive glasses by the addition of zirconium oxide (ZrO2) as a synthetic bone graft substitute

“…The most important application of bioactive synthetic bone graft substitutes (SBG) is to regenerate bone in defects that can be induced by trauma or disease 1 . In this regard, SBG have been used to reconstruct bone in jaw and maxillofacial defects through dentistry during the past few decades 1‐4 . The ideal SBG have several important properties, namely, biocompatibility, bioresorbability, plasticity, osteoconductivity and/or osteoinductivity 5,6 …”

“…It has been well established that the characteristics of BAG depend on its composition, and according to glass network theory, it is possible to control BAG properties by adjusting the chemical composition for enhancing hard or soft tissue regeneration 3,13,16 …”