Poly-L-lysine coated glass coverslips have been used for mounting samples for scanning electron microscopy. Poly-L-lysine coated wells were used for trapping of PC-12 cells on electrodes. Poly-L-lysine-coated borosilicate glass slides were used for the seeding of viral vector-transduced cells. Poly-L-lysine polymers can be used in promoting cell adhesion to solid substrates, conjugation to methotrexate for increased drug transport, microencapsulation of islets, cell microencapsulation technology, microarray glass slide coating, and chromosomal preparations. Lower molecular weight poly-L-lysine (30,000-70,000) is less viscuous in solution, but higher molecular weight versions provide more attachment sites per molecule. 50ml