A compound having the general formula: or a salt thereof, wherein: y and w are each independently an integer, such that y+w ranges from 7 to 20; A is selected from the group consisting of O, S and NR 10; T is selected from the group consisting of -S-, -O-, -CH 2 - and -NR 6 -; R 1 is selected from the group consisting of H, a substituted or unsubstituted alkyl, a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted alicyclic, a substituted or unsubstituted heterocyclic and -(CH 2) m CO 2 R 7; m is an integer ranging from 1 to 6; X is selected from the group consisting of -CH 2 -, -CR 8 R 9 -, -O-, -S- and -NR 2 - or absent; Z is selected from the group consisting of H, -CH 3, -C(=O)Q, a linking moiety, a reactive group, a polymer moiety and a polymerizable moiety, said reactive group being selected from the group consisting of amine, halo, hydroxyl, aldehyde, carbonyl, carboxyl, cyano, azide and nitro, and said linking moiety being selected from the group consisting of amide, ester or a moiety formed upon reacting any one of said reactive groups with another of said reactive groups; Q is selected from the group consisting of -OH, -OR 3, -NR 4 R 5 and -NHOH; and R 2, R 3, R 4, R 5, R 6, R 7, R 8, R 9 and R 10 are each independently selected from the group consisting of H, a substituted or unsubstituted alkyl, a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted alicyclic and a substituted or unsubstituted heterocyclic, provided that when A is O, and T is -S-,-CH 2 - or -NR 6 -, then -X is -O-; when A is O, and T is -S- or -CH 2 -, then R 1 is H or said -(CH 2) m CO 2 R 7; or when A is O and T is -NR 6 -, R 1 is selected from the group consisting of unsubstituted alkyl, a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted alicyclic, a substituted or unsubstituted heterocyclic and -(CH 2) m CO 2 R 7. y and w are each independently an integer, such that y+w ranges from 7 to 20; A is selected from the group consisting of O, S and NR 10; T is selected from the group consisting of -S-, -O-, -CH 2 - and -NR 6 -; R 1 is selected from the group consisting of H, a substituted or unsubstituted alkyl, a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted alicyclic, a substituted or unsubstituted heterocyclic and -(CH 2) m CO 2 R 7; m is an integer ranging from 1 to 6; X is selected from the group consisting of -CH 2 -, -CR 8 R 9 -, -O-, -S- and -NR 2 - or absent; Z is selected from the group consisting of H, -CH 3, -C(=O)Q, a linking moiety, a reactive group, a polymer moiety and a polymerizable moiety, said reactive group being selected from the group consisting of amine, halo, hydroxyl, aldehyde, carbonyl, carboxyl, cyano, azide and nitro, and said linking moiety being selected from the group consisting of amide, ester or a moiety formed upon reacting any one of said reactive groups with another of said reactive groups; Q is selected from the group consisting of -OH, -OR 3, -NR 4 R 5 and -NHOH; and R 2, R 3, R 4, R 5, R 6, R 7, R 8, R 9 and R 10 are each independently selected from the group consisting of H, a substituted or unsubstituted alkyl, a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted alicyclic and a substituted or unsubstituted heterocyclic, provided that when A is O, and T is -S-,-CH 2 - or -NR 6 -, then -X is -O-; when A is O, and T is -S- or -CH 2 -, then R 1 is H or said -(CH 2) m CO 2 R 7; or when A is O and T is -NR 6 -, R 1 is selected from the group consisting of unsubstituted alkyl, a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted alicyclic, a substituted or unsubstituted heterocyclic and -(CH 2) m CO 2 R 7.