One method to accelerate the degradation rates of polyesters is the incorporation of cleavable moieties, as demonstrated by the incorporation of silyl ethers into acrylates or recently by Dove, who reported thiol-ene polymerizable polyorthoesters . Furthermore, Baudis recently prepared acetal-containing photopolymers that degrade rapidly at low pH values . This behaviour is particularly suitable for bone regeneration scaffolds where pH values can drop relatively low. Incorporating phosphorusnitrogen bonds into polymers can give cleavable linkages due to the susceptibility to hydrolysis . Wurm reported phosphorodiamidates bearing alkene moieties which could be polymerized by thiolene chemistry . Subsequent oxidation gave water-soluble, linear, degradable polymers. The degradation rates were fast in acidic conditions but slow under pH-neutral conditions. Amino-acids bonded to phosphates are known in biochemistry to hydrolyse readily, indeed, this hydrolysis reaction is the basis of many biochemical processes, for example, the transfer of phosphate from phosphocreatine to regenerate ATP from ADP .