Poly-L-Lysine (PLL) is a synthetic, positively charged amino acid chain that enhances cell adhesion by altering surface charges on the culture substrate. It is commonly used as a coating agent to promote cell adhesion in culture. In addition to promoting cell adhesion, PLL surface treatments improve the survival of many primary cells in culture and support neurite outgrowth. This concentrated solution contains polymers in the 70 – 150 kDa range.