Acetal-capped poly-L-lysine (Acetal-poly-L-Lysine, Acetal-PLL) is a positively charged synthetic polyamino acid. It is a crystalline solid soluble in water. Applications for poly-L-lysine include the promotion of cell adhesion to solid substrates for culture dishes or slides, the conjugation to active molecules for improved activities, the layer-by-layer deposition techniques, and the complexation with nucleic acids for gene expression.
Acetal-functionalized polymers can be easily reduced to aldehyde group using acidic aqueous conditions (pH=2-4). Aldehyde group can selectively react with amine or thiol group in aqueous solution.