Chemically reactive enzyme immobilization

1. An analyte sensor comprising:

a sensing layer in contact with a surface of an electrode, wherein the sensing layer comprises:

backbone chains comprising

first methacrylate-derived monomeric units, each of which is covalently bound to an analyte sensing component through a hydrophilic linker, and

second methacrylate-derived monomeric units;

hydrophilic crosslinks between the second methacrylate-derived units in different backbone chains; and

third methacrylate-derived monomeric units, each having a hydrophilic side chain,

wherein the third methacrylate-derived units are present in at least one of the sensing layer or an additional layer provided on the sensing layer; and

wherein the sensing layer has a thickness of about 10 μm to about 30 μm.

2. The sensor of claim 1 , wherein the third methacrylate-derived monomeric units are present in the sensing layer.

3. The sensor of claim 1 , wherein

the third methacrylate-derived monomeric units are present in an additional layer, and

the additional layer is a protective membrane comprising:

backbone chains comprising;

third methacrylate-derived monomeric units, each unit having a hydrophilic side chain, and

fourth methacrylate-derived monomeric units; and

hydrophilic crosslinks between the fourth methacrylate-derived units in different backbone chains.

4. The sensor of claim 1 , wherein the first methacrylate-derived monomeric units have the structure of formula (I):

wherein L is a hydrophilic linker and A is an analyte sensing component.

5. The sensor of claim 1 , wherein the first methacrylate-derived monomeric units have the structure of formula (Ia):

wherein

X is —O—, —NR′— or —S—,

wherein R′ is hydrogen or —C 1 -C 12 alkyl;

y is 0-10;

L 1 is a linker; and

A is an analyte sensing component.

6. The sensor of claim 1 , wherein the third methacrylate-derived units have the structure of formula (IIa):

wherein

Y is —O—, —NR′— or —S—;

x is 0-10; and

R 1 is hydrogen, —C 1 -C 12 alkyl, —C 1 -C 12 alkyl-OH, —SiR′ 3 , —C(O)—C 1 -C 12 alkyl, —C 1 -C 12 alkyl-C(O)OR′;

wherein each R′ is independently hydrogen or —C 1 -C 12 alkyl.

7. The sensor of claim 1 , wherein the third methacrylate-derived units have the structure:

8. The sensor of claim 1 , wherein the third methacrylate-derived units have the structure of formula (IIb):

wherein

Y is —O—, —NR′— or —S—;

x is an average value of from about 2 to about 250; and

R 2 is hydrogen, —C 1 -C 12 alkyl, —C 1 -C 12 alkyl-OH, —SiR′ 3 , —C(O)—C 1 -C 12 alkyl, —C 1 -C 12 alkyl-C(O)OR′;

wherein each R′ is independently hydrogen or —C 1 -C 12 alkyl.

9. The sensor of claim 1 , wherein the hydrophilic crosslinks between the second or fourth methacrylate-derived units in different backbone chains comprise one or more alkylene oxide units.

10. The sensor of claim 1 , wherein the hydrophilic crosslinks between the second or fourth methacrylate-derived units in different backbone chains have the structure of formula (IIIa):

wherein w is 1-10.

11. The sensor of claim 1 , wherein the hydrophilic crosslinks between the second or fourth methacrylate-derived units in different backbone chains have the structure of formula (IIIa):

wherein w is an average value of from about 2 to about 250.

12. The sensor of claim 1 , wherein the hydrophilic crosslinks between the second or fourth methacrylate-derived units in different backbone chains are derived from the di(ethylene glycol) portion of di(ethylene glycol) dimethacrylate.

13. The sensor of claim 1 , wherein the analyte sensing component comprises glucose oxidase.

14. The sensor of claim 2 , wherein the sensing layer comprises:

first methacrylate-derived monomeric units having the structure of formula (I):

wherein L is a hydrophilic linker and A is an analyte sensing component;

third methacrylate-derived monomeric units having the structure of formula (IIb):

wherein

Y is —O—, —NR′— or —S—;

x is an average value of from about 2 to about 250; and

R 2 is hydrogen, —C 1 -C 12 alkyl, —C 1 -C 12 alkyl-OH, —SiR′ 3 , —C(O)—C 1 -C 12 alkyl, —C 1 -C 12 alkyl-C(O)OR′;

wherein each R′ is independently hydrogen or —C 1 -C 12 alkyl; and

crosslinks between the second methacrylate-derived units in different backbone chains having the structure of formula (IIIa):

wherein w is an average value of from about 2 to about 250.

15. The analyte sensor of claim 3 , wherein

the sensing layer comprises:

first methacrylate-derived monomeric units having the structure of formula (I):

wherein L is a hydrophilic linker and A is an analyte sensing component; and

crosslinks between the second methacrylate-derived units in different backbone chains having the structure of formula (IIIa):

wherein w is an average value of from about 2 to about 250; and

the protective membrane comprises:

third methacrylate-derived monomeric units having the structure of formula (IIb):

wherein

Y is —O—, —NR′— or —S—;

x is an average value of from about 2 to about 250; and

R 2 is hydrogen, —C 1 -C 12 alkyl, —C 1 -C 12 alkyl-OH, —SiR′ 3 , —C(O)—C 1 -C 12 alkyl, —C 1 -C 12 alkyl-C(O)OR′;

wherein each R′ is independently hydrogen or —C 1 -C 12 alkyl; and

crosslinks between the fourth methacrylate-derived units in different backbone chains having the structure of formula (IIIa):

wherein w is an average value of from about 2 to about 250.

16. A method of making an analyte sensor, comprising:

forming a first mixture comprising a first methacrylate monomer, a first dimethacrylate monomer, and a first initiator, wherein the first methacrylate monomer has a covalent bond to an analyte sensing component;

depositing the first mixture on a surface of an electrode;

curing the deposited first mixture to provide a sensing layer; and

including a second methacrylate monomer in at least one of the first mixture or a second mixture deposited on the sensing layer,

wherein the sensing layer has a thickness of about 10 μm to about 30 μm.

17. The method of claim 16 , wherein the first mixture further comprises the second methacrylate monomer.

18. The method of claim 16 , further comprising:

forming a second mixture comprising the second methacrylate monomer, a second dimethacrylate monomer, and a second initiator;

depositing the second mixture onto the sensing layer; and

curing the deposited second mixture to provide a protective membrane on the sensing layer.

19. The method of claim 16 , wherein the first methacrylate monomer has the structure of formula (IV):

wherein L is a hydrophilic linker and A is an analyte sensing component.

20. The method of claim 16 , wherein the first methacrylate monomer have the structure of formula (IVa):

wherein

X is —O—, —NR′— or —S—,

wherein R′ is hydrogen or —C 1 -C 12 alkyl;

y is 0-10;

L 1 is a linker; and

A is an analyte sensing component.

21. The method of claim 16 or 18 , wherein the second methacrylate monomer has the structure of formula (Va):

wherein

Y is —O—, —NR′— or —S—;

x is 0-10; and

R 1 is hydrogen, —C 1 -C 12 alkyl, —C 1 -C 12 alkyl-OH, —SiR′ 3 , —C(O)—C 1 -C 12 alkyl, —C 1 -C 12 alkyl-C(O)OR′;

wherein each R′ is independently hydrogen or —C 1 -C 12 alkyl.

22. The method of claim 16 or 18 , wherein the second methacrylate monomer has the structure:

23. The method of claim 16 or 18 , wherein the second methacrylate monomer has the structure of formula (Va):

wherein

Y is —O—, —NR′— or —S—;

x is an average value of from about 2 to about 250; and

R 1 is hydrogen, —C 1 -C 12 alkyl, —C 1 -C 12 alkyl-OH, —SiR′ 3 , —C(O)—C 1 -C 12 alkyl, —C 1 -C 12 alkyl-C(O)OR′;

wherein each R′ is independently hydrogen or —C 1 -C 12 alkyl.

24. The method of claim 16 or 18 , wherein the first or second dimethacrylate monomer comprises alkylene oxide units.

25. The method of claim 16 or 18 , wherein the first or second dimethacrylate monomer has a structure of formula (VI):

wherein w is 1-10.

26. The method of claim 16 or 18 , wherein the first or second dimethacrylate monomer has a structure of formula (VI):

wherein w is an average value of from about 2 to about 250.

27. The method of claim 16 or 18 , wherein the first or second dimethacrylate monomer is di(ethylene glycol) dimethacrylate.

28. The method of claim 16 , wherein the analyte sensing component comprises glucose oxidase.

29. The method of claim 16 or 18 , wherein curing the deposited first or second mixture comprises exposing the deposited first or second mixture to ultraviolet light.

30. The method of claim 16 or 18 , wherein first or second initiator is 2,2-dimethoxy-2-phenylacetophenone.