Lactate-induced decomposition of layer-by-layer films composed of phenylboronic acid-modified poly(allylamine) and poly(vinyl alcohol) under extracellular tumor conditions

Multilayer films that decompose in the presence of lactate were prepared by depositing phenylboronic acid-modified poly(allylamine) (PBA-PAH) and poly(vinyl alcohol) (PVA) on a lactate oxidase (LOx) layer. The layers adhered through boronate ester bonds. The resulting LOx(PBA-AH/PVA) ₁₀ film was stable in pH 7.4 solution but decomposed following the addition of lactate. The carbon-boron bonds in PBA residues were cleaved by oxidative reaction with H ₂ O ₂ produced by the enzymatic reaction of LOx. Approximately 90% of the film decomposed following exposure for 120 and 30 min to 0.05 and 20 mM lactate at pH 7.4, respectively. The multilayer film therefore decomposed under conditions comparable to the extracellular environment of tumors (20 mM lactate at pH 6.5). Our results show that LOx/(PBA-PAH/PVA) ₁₀ multilayer film could be used for cancer drug delivery systems.