Method for the electro-addressable functionalization of electrode arrays
A method for preparing an electrochemical biosensor uses bias-assisted assembly of unreactive -onium molecules on an electrode array followed by post-assembly electro-addressable conversion of the unreactive group to a chemical or biological recognition group. Electro-addressable functionalization of electrode arrays enables the multi-target electrochemical sensing of biological and chemical analytes.
1. A method for preparing an electrochemical biosensor, comprising:
(i) providing an electrode array comprising a plurality of conducting or semiconducting electrodes;
(ii) grafting a phenyl boronic acid diazonium salt having an unreactive group to the plurality of electrodes to form an assembly comprising a phenyl molecule comprising an unreactive group, wherein step (ii) comprises bias-assisted electrodeposition of the phenyl boronic acid diazonium salt to the plurality of conducting or semiconducting electrodes and wherein the bias-assisted electrodeposition comprises use of a first bias voltage; and
(iii) applying a second bias voltage to at least one electrode of the plurality of conducting or semiconducting electrodes to convert the unreactive group of the phenyl molecule to a reactive group;
wherein the reactive group comprises a chemical or biological recognition group that has selectivity for a target analyte.
2. The method of claim 1 , wherein grafting the phenyl boronic acid diazonium salt in step (ii) comprises use of a chronoamperometry method or a linear sweep method to provide the first bias voltage.
3. The method of claim 1 , wherein the unreactive group comprises a nitro or methoxybenzyl group.
4. The method of claim 3 , wherein applying the second bias voltage in step (iii) comprises unblocking or deprotecting the unreactive group to convert the unreactive group to the reactive group.
5. The method of claim 1 , wherein the reactive group comprises an amine, carboxyl, boronic acid, maleimide, thiol, biotin, or avidin group.
6. The method of claim 1 , further comprising:
(iv) reacting the reactive group with a chemical or biological recognition molecule to provide the chemical or biological recognition group that has selectivity for the target analyte.
7. The method of claim 6 , wherein the recognition molecule comprises a native, modified, or synthetic biological molecule or a chemical molecule.
8. The method of claim 6 , wherein the recognition molecule comprises an antibody, protein, enzyme, saccharide, DNA, RNA, peptide, or whole cell.
9. The method of claim 6 , wherein the recognition group comprises an amine, carboxyl, boronic acid, maleimide, thiol, biotin, or avidin group.
10. The method of claim 6 , wherein the unreactive group is blocked, protected, or inactive toward to the recognition molecule.
11. The method of claim 1 , wherein grafting the phenyl boronic acid diazonium salt in step (ii) comprises bias-assisted electrodepositing phenyl boronic acid pinacol ester diazonium on the plurality of electrodes, chemically deprotecting the pinacol ester blocking group of the deposited phenyl molecules with an oxidant thereby forming a phenyl boronic acid, and reprotecting the phenyl boronic acid with an unreactive methoxybenzyl group.
12. The method of claim 11 , further comprising:
(iv) reacting the reactive group of the phenyl boronic acid with one or more cells to provide reversible cell immobilization on the electrochemical biosensor.
13. The method of claim 12 , further comprising:
(v) treating the electrode array with a sugar to release one or more attached cells, thereby regenerating a surface of the electrochemical biosensor.
14. A method for preparing an electrochemical biosensor, comprising:
(i) providing an electrode array comprising a plurality of conducting or semiconducting electrodes;
(ii) grafting a phenyl boronic acid diazonium salt having an unreactive group to the plurality of electrodes to form an assembly comprising a phenyl molecule comprising an unreactive group, wherein step (ii) comprises bias-assisted electrodeposition of the phenyl boronic acid diazonium salt to the plurality of conducting or semiconducting electrodes and wherein the bias-assisted electrodeposition comprises use of a first bias voltage;
(iii) applying a second bias voltage to at least one electrode of the plurality of conducting or semiconducting electrodes to convert the unreactive group of the phenyl molecule to a reactive group; and
(iv) reacting the reactive group with a chemical or biological recognition molecule to provide a chemical or biological recognition group that has selectivity for a target analyte.
15. The method of claim 14 , wherein grafting the phenyl boronic acid diazonium salt in step (ii) comprises bias-assisted electrodepositing of the phenyl boronic acid diazonium salt on the plurality of electrodes, chemically deprotecting the deposited phenyl molecules with an oxidant thereby forming a phenyl boronic acid, and reprotecting the phenyl boronic acid with an unreactive group.