A polymeric compound having the general formula I: wherein: m is zero or a positive integer; n is an integer which is at least 5; Y is a backbone unit which forms a polymeric backbone; L is absent or is a linking moiety; Z has the general formula II: wherein: A is a substituted or unsubstituted hydrocarbon; B is an oxygen atom or is absent; and R 1 -R 3 are each independently selected from the group consisting of hydrogen, alkyl, cycloalkyl, heteroalicyclic, aryl and heteroaryl; and X is a lipid moiety having the general formula III: wherein: W 1 and W 2 are each independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl and acyl, wherein at least one of W 1 and W 2 is not hydrogen; J is -P(=O) -O- or absent; K is a substituted or unsubstituted hydrocarbon from 1 to 10 carbon atoms in length; M is a linking group selected from the group consisting of -O-, -S-, amino, sulfinyl, sulfonyl, phosphate, phosphonyl, phosphinyl, carbonyl, thiocarbonyl, urea, thiourea, carbamyl, thiocarbamyl, amido, carboxy, and sulfonamide, or absent; and Q is a substituted or unsubstituted hydrocarbon from 1 to 10 carbon atoms in length, or absent, wherein when M is absent, Q is also absent. m is zero or a positive integer; n is an integer which is at least 5; Y is a backbone unit which forms a polymeric backbone; L is absent or is a linking moiety; Z has the general formula II: wherein: A is a substituted or unsubstituted hydrocarbon; B is an oxygen atom or is absent; and R 1 -R 3 are each independently selected from the group consisting of hydrogen, alkyl, cycloalkyl, heteroalicyclic, aryl and heteroaryl; and X is a lipid moiety having the general formula III: wherein: W 1 and W 2 are each independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl and acyl, wherein at least one of W 1 and W 2 is not hydrogen; J is -P(=O) -O- or absent; K is a substituted or unsubstituted hydrocarbon from 1 to 10 carbon atoms in length; M is a linking group selected from the group consisting of -O-, -S-, amino, sulfinyl, sulfonyl, phosphate, phosphonyl, phosphinyl, carbonyl, thiocarbonyl, urea, thiourea, carbamyl, thiocarbamyl, amido, carboxy, and sulfonamide, or absent; and Q is a substituted or unsubstituted hydrocarbon from 1 to 10 carbon atoms in length, or absent, wherein when M is absent, Q is also absent. A is a substituted or unsubstituted hydrocarbon; B is an oxygen atom or is absent; and R 1 -R 3 are each independently selected from the group consisting of hydrogen, alkyl, cycloalkyl, heteroalicyclic, aryl and heteroaryl; and X is a lipid moiety having the general formula III: wherein: W 1 and W 2 are each independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl and acyl, wherein at least one of W 1 and W 2 is not hydrogen; J is -P(=O) -O- or absent; K is a substituted or unsubstituted hydrocarbon from 1 to 10 carbon atoms in length; M is a linking group selected from the group consisting of -O-, -S-, amino, sulfinyl, sulfonyl, phosphate, phosphonyl, phosphinyl, carbonyl, thiocarbonyl, urea, thiourea, carbamyl, thiocarbamyl, amido, carboxy, and sulfonamide, or absent; and Q is a substituted or unsubstituted hydrocarbon from 1 to 10 carbon atoms in length, or absent, wherein when M is absent, Q is also absent. W 1 and W 2 are each independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl and acyl, wherein at least one of W 1 and W 2 is not hydrogen; J is -P(=O) -O- or absent; K is a substituted or unsubstituted hydrocarbon from 1 to 10 carbon atoms in length; M is a linking group selected from the group consisting of -O-, -S-, amino, sulfinyl, sulfonyl, phosphate, phosphonyl, phosphinyl, carbonyl, thiocarbonyl, urea, thiourea, carbamyl, thiocarbamyl, amido, carboxy, and sulfonamide, or absent; and Q is a substituted or unsubstituted hydrocarbon from 1 to 10 carbon atoms in length, or absent, wherein when M is absent, Q is also absent.