Reliable ferrocenyloligonucleotide-immobilized electrodes and their application to electrochemical DNase I assay.
A ferrocenyloligonucleotide (FcODN) having contiguous cytosine bases was immobilized effectively and reproducibly on a gold electrode furnished with a self-assembled monolayer (SAM) having an N-hydroxysuccinimide-activated carboxylic acid. The resulting electrode was used as a sensor chip in DNase I assay. Thus, the current response of the modified electrode decreased upon addition of DNase I, demonstrating that the phosphodiester bonds of FcODN were cleaved. The DNase I activity assessed by Deltai defined as (i0-i)/i0, where i0 and i represent the current before and after DNase I treatment, respectively, was found to be reproducible with a standard deviation not greater than 9%. The DNase I can be quantitated in the range of 10(-5) to 10(-3) units microL(-1) with a detection limit of 10(-5) units microL(-1) with this sensor chip. The current signal of the FcODN electrode was stable to storage in Biopak water up to 16 days with a 30% signal decrease over this period. DNase I activity in human sera was also determined successfully with this sensor chip.
Sato
Shinobu
S
Department of Applied Chemistry, Kyushu Institute of Technology, Kitakyushu, Fukuoka 804-8550, Japan.
Fujita
Katsuya
K
Kanazawa
Masanori
M
Mukumoto
Kosuke
K
Ohtsuka
Keiichi
K
Takenaka
Shigeori
S
D015374:Biosensing Techniques / Q000191:economics / Q000379:methods*; D002234:Carbodiimides / Q000737:chemistry*; D003850:Deoxyribonuclease I / Q000032:analysis* / Q000097:blood; D055664:Electrochemical Techniques / Q000191:economics / Q000379:methods*; D004566:Electrodes; D005296:Ferrous Compounds / Q000737:chemistry*; D006046:Gold / Q000737:chemistry; D006801:Humans; D009841:Oligonucleotides / Q000138:chemical synthesis / Q000737:chemistry*; D015203:Reproducibility of Results; D013997:Time Factors
D002234:Carbodiimides; D005296:Ferrous Compounds; D009841:Oligonucleotides; C517870:ferrocenyl carbodiimide; D006046:Gold; D003850:Deoxyribonuclease I