Enrichment of lysophosphatidic acids with templated polymeric materials
Embodiments of templated polymeric materials capable of binding lysophosphatidic acids (LPAs) are disclosed. Methods of making and using the templated polymeric materials also are disclosed. The disclosed templated polymeric materials are molecularly imprinted polymers that bind LPAs and facilitate the production of lysophosphatidic acid-enriched samples, for instance through extraction of lysophosphatidic acids from biological samples, such as plasma or serum samples.
1. A molecularly imprinted polymer, comprising:
a plurality of first structural units derived from monomers comprising (a) at least one functional moiety selected from an amino, —N(H)C(O)N(H), —N(H)—C(S)—N(H)—, pyridyl, imidazolyl, pyrimidinyl, pyrazinyl, or cyclenyl moiety, or any combination thereof, and (b) at least one polymerizable moiety, the molecularly imprinted polymer having a molecular imprint having a size and shape complementary to a lysophosphatidic acid, wherein the molecularly imprinted polymer is obtained by:
polymerizing the monomers in a solution comprising (i) a solvent, (ii) a guest molecule comprising an anionic head group comprising a phosphate or phosphonic acid group and a hydrophobic tail portion comprising a single hydrocarbon chain with a length of from 12-24 carbons, wherein the guest molecule is not a lysophosphatidic acid, (iii) a crosslinker, and (iv) a radical polymerization initiator to produce a polymer containing the guest molecule, and
removing the guest molecule from the polymer containing the guest molecule to produce the molecularly imprinted polymer.
2. The molecularly imprinted polymer of claim 1 , wherein:
(a) at least some of the monomers comprise a plurality of functional moieties capable of binding to a phosphate group; or
(b) the polymerizable moiety comprises a terminal ethenyl group; or
(c) both (a) and (b).
3. The molecularly imprinted polymer of claim 1 , wherein the first structural units are derived from monomers according to one of the following five chemical structures or a combination of two or more thereof:
4. The molecularly imprinted polymer of claim 1 , further comprising a plurality of second structural units derived from 2 vinylpyridine, 4-vinylpyridine, 1-vinylimidazole, 4-vinylimidazole, 1-allylthiourea, methacrylic acid, or a combination of two or more thereof.
5. The molecularly imprinted polymer of claim 4 , wherein the first structural unit and the second structural unit are present in a mole ratio from 10:1 to 1:10.
6. The molecularly imprinted polymer of claim 1 , wherein:
(a) the crosslinker comprises ethylene glycol dimethacrylate (EGDMA), divinylbenzene (DVB), tetraethylene glycol dimethacrylate (TEGDMA), N,O-bismethacrylolyl ethanolamine (NOBE), N,N′-methylenebismethacrylamide (MMAA), triallyl isocyanurate (TAIL), trimethylolpropane trimethacrylate (TRIM), or a combination of two or more thereof; or
(b) the radical polymerization initiator comprises 2,2′-azobisisobutyronitrile; or
(c) both (a) and (b).
7. The molecularly imprinted polymer of claim 3 , wherein:
(a) the polymer comprises first structural units derived from monomer 1 and the crosslinker in a mole ratio of 1:5 to 1:50; or
(b) the molecularly imprinted polymer comprises first structural units derived from monomer 1, second structural units derived from methacrylic acid, and EGDMA in a 1:1:20 mole ratio.
8. The molecularly imprinted polymer of claim 1 , wherein the first structural units are derived from monomer 1, monomer 2, or a combination thereof:
9. A molecularly imprinted polymer, comprising:
a plurality of first structural units derived from monomers comprising (a) at least one functional moiety selected from an amino, —N(H)C(O)N(H), —N(H)—C(S)—N(H)—, pyridyl, imidazolyl, pyrimidinyl, pyrazinyl, or cyclenyl moiety, or any combination thereof, and (b) at least one polymerizable moiety, the molecularly imprinted polymer having a molecular imprint having a size and shape complementary to a lysophosphatidic acid, wherein the molecularly imprinted polymer is obtained by:
polymerizing the monomers in a solution comprising (i) a solvent, (ii) a guest molecule, wherein the guest molecule is octadecylphosphonic acid, (iii) a crosslinker, and (iv) a radical polymerization initiator to produce a polymer containing the guest molecule, and
removing the guest molecule from the polymer containing the guest molecule to produce the molecularly imprinted polymer.
10. A method for producing a molecularly imprinted polymer for binding a lysophosphatidic acid, the method comprising:
polymerizing monomers comprising (a) at least one functional moiety selected from an amino, —N(H)—C(O)—N(H)—, —N(H)—C(S)—N(H)—, pyridyl, imidazolyl, pyrimidinyl, pyrazinyl, or cyclenyl moiety, or any combination thereof, and (b) at least one polymerizable moiety in a solution comprising (i) a solvent, (ii) a guest molecule comprising an anionic head group comprising a phosphate or phosphonic acid group and a hydrophobic tail portion comprising a single hydrocarbon chain with a length of from 12-24 carbons, wherein the guest molecule is not a lysophosphatidic acid, (iii) a crosslinker, and (iv) a radical polymerization initiator to produce a polymer containing the anionic guest molecule; and
removing the guest molecule from the polymer containing the guest molecule to produce a molecularly imprinted polymer having a molecular imprint having a size and shape complementary to lysophosphatidic acid.
11. The method of claim 10 , wherein the monomers are monomers according to one of the following five chemical structures or a combination of two or more thereof:
12. The method of claim 10 , wherein the monomers further comprise 2-vinylpyridine, 4-vinylpyridine, 1-vinylimidazole, 4-vinylimidazole, 1-allylthiourea, methacrylic acid, or a combination of two or more thereof.
13. A method of preparing a lysophosphatidic acid-enriched sample, comprising:
loading a solution comprising one or more lysophosphatidic acid species onto a solid-phase extraction cartridge including a stationary phase comprising a molecularly-imprinted polymer according to claim 1 (MIP SPE cartridge);
flowing chloroform and subsequently a lower alkyl alcohol through the MIP SPE cartridge; and
flowing an alkaline solution comprising a lower alkyl alcohol through the MIP SPE cartridge, thereby eluting at least a portion of the lysophosphatidic acid species from the MIP SPE cartridge to provide a lysophosphatidic acid-enriched sample.
14. The method of claim 13 , further comprising preparing the solution comprising one or more lysophosphatidic acid species by:
combining a sample comprising plasma or serum with a solvent comprising a lower alkyl alcohol and chloroform to form a mixture;
separating the mixture to provide a supernatant and a precipitate;
acidifying the supernatant to provide the solution comprising one or more lysophosphatidic acid species.
15. The method of claim 14 , wherein acidifying the supernatant further comprises:
after separating the mixture, loading the supernatant onto a SPE cartridge including a stationary phase comprising a non-imprinted polymer comprising (i) a plurality of first structural units derived from monomers comprising (a) at least one functional moiety capable of binding to a phosphate group and (b) at least one polymerizable moiety (NIP SPE cartridge), and (ii) a crosslinker;
flowing an alkaline solution comprising a lower alkyl alcohol through the NIP SPE cartridge to provide an eluent; and
acidifying the eluent to provide the solution comprising one or more lysophosphatidic acid species.
16. The method of claim 15 , wherein the first structural units of the non-imprinted polymer are derived from monomers according to one of the following five chemical structures or a combination of two or more thereof:
17. The method of claim 15 , wherein the first structural units of the non-imprinted polymer are derived from monomers having the same chemical composition as the monomers from which the first structural units of the molecularly imprinted polymer are derived.
18. The method of claim 15 , wherein:
(a) flowing an alkaline solution comprising a lower alkyl alcohol through the NIP SPE cartridge comprises flowing 0.05 wt % NH 4 OH in methanol through the NIP SPE cartridge;
(b) acidifying the eluent comprises adding concentrated formic acid to provide a pH within a range of 1-5;
(c) flowing chloroform and subsequently a lower alkyl alcohol through the MIP SPE cartridge comprises flowing chloroform and subsequently methanol through the MIP SPE cartridge;
(d) flowing an alkaline solution comprising a lower alkyl alcohol through the subsequent SPE cartridge comprises flowing 0.05 wt % NH 4 OH in methanol through the subsequent SPE cartridge; or
(e) any combination of (a)-(d).
19. The method of claim 14 , further comprising determining a total concentration of lysophosphatidic acid species in the sample comprising plasma or serum by:
separating lysophosphatidic acid species in the lysophosphatidic acid-enriched sample using a reversed-phase high-performance liquid chromatography (HPLC) column; and
detecting individual lysophosphatidic acid species as or after the separated lysophosphatidic acid species exit the reversed-phase HPLC column.
20. The method of claim 19 , further comprising determining a concentration of individual lysophosphatidic acid species in the sample comprising plasma or serum.
21. The method of claim 13 , wherein:
(a) the molecularly imprinted polymer comprises first structural units derived from monomer 1 and the crosslinker in a mole ratio of 1:5 to 1:50; or
(b) the molecularly imprinted polymer comprises first structural units derived from monomer 1, second structural units derived from methacrylic acid, and EGDMA in a 1:1:20 mole ratio.
22. A kit comprising at least one molecularly imprinted polymer according to claim 1 .