Comparative evaluation of the biocompatible and physical–chemical properties of poly(lactide-co-glycolide) and polydopamine as coating materials for bacterial cellulose

The aim of this study was to investigate the influence of poly(lactide-co-glycolide) (PLGA) and polydopamine (PDA) as coating materials on the tensile strength, surface performance, in vitro cell behavior and the in vivo material-tissue reaction of bacterial cellulose (BC) membranes.

Natural ageing responses of duplex structured Mg-Li based alloys

Natural ageing responses of duplex structured Mg-6%Li and Mg-6%Li-6%Zn-1.2%Y alloys have been investigated. Microstructural analyses revealed that the precipitation and coarsening process of α-Mg particles could occur in β-Li phases of both two alloys during ageing process. Since a certain amount of Mg atoms in β-Li phases were consumed for the precipitation of abundant tiny MgLiZn particles, the size of α-Mg precipitates in Mg-6%Li-6%Zn-1.2%Y alloy was relatively smaller than that in Mg-6%Li alloy. Micro hardness measurements demonstrated that with the ageing time increasing, the α-Mg phases in Mg-6%Li alloy could have a constant hardness value of 41 HV, but the contained β-Li phases exhibited a slight age-softening response. Compared with the Mg-6%Li alloy, the age-softening response of β-Li phases in Mg-6%Li-6%Zn-1.2%Y alloy was much more profound. Meanwhile, a normal age-hardening response of α-Mg phases was maintained. Tensile results indicated that obvious ageing-softening phenomenon in terms of macro tensile strength occurred in both two alloys. Failure analysis demonstrated that for the Mg-6%Li alloy, cracks were preferentially initiated at α-Mg/β-Li interfaces. For the Mg-6%Li-6%Zn-1.2%Y alloy, cracks occurred at both α-Mg/β-Li interfaces and slip bands in α-Mg and β-Li phases.

The relationship between microstructure and in vivo degradation of modified bacterial cellulose sponges

The interaction between the nanofibers of bacterial cellulose and hydroxyapatite has an extensive influence on the microstructure and the macroscopic properties of this type of composite, but the structural anisotropy and the speed of granulation ingrowth are strongly interdependent.