TY - JOUR
T1 - Quantitative detection of E. coli O157:H7 eaeA gene using quantum dots and magnetic particles
AU - Kim, Gha Young
AU - Son, Ahjeong
N1 - Funding Information:
This work was supported by a National Research Foundation of Korea Grant funded by the Korean Government (NRF-2009-52-D00169) and Auburn University start-up funds.
PY - 2010/12
Y1 - 2010/12
N2 - A quantitative gene detection technique targeting the pathogenic E. coli O157:H7 eaeA gene was developed using magnetic bead (MB)-quantum dots (QDs) nanoparticle complexes. MBs allowed for the separation of DNA-conjugated QD nanoparticles via magnetic field manipulation. QDs provided internal fluorescence calibration to account for the intrinsically different numbers of nanoparticles interrogated in each assay. Based on the measurement of normalized fluorescence (Cy3/QD655), the linear quantification ranges of ssDNA and dsDNA targets were determined to be 10 through 103 fM (R 2 = 0.992) and 2 × 102 through 6 × 10 7 gene copies (R2 = 0.972), with detection limits of 9.72 fM and 104 gene copies, respectively. The kinetic results indicate that adjustment of hybridization temperature in accordance to the amount of target DNA was required to maximize the efficiency of DNA hybridization. We were able to discriminate perfectly matched target DNA, 1-, 2-, and 41-base pair mismatched target DNAs in our approach and therefore demonstrated excellent selectivity. Our technique was also used on pure bacterial culture to showcase its ability to analyze environmental samples.
AB - A quantitative gene detection technique targeting the pathogenic E. coli O157:H7 eaeA gene was developed using magnetic bead (MB)-quantum dots (QDs) nanoparticle complexes. MBs allowed for the separation of DNA-conjugated QD nanoparticles via magnetic field manipulation. QDs provided internal fluorescence calibration to account for the intrinsically different numbers of nanoparticles interrogated in each assay. Based on the measurement of normalized fluorescence (Cy3/QD655), the linear quantification ranges of ssDNA and dsDNA targets were determined to be 10 through 103 fM (R 2 = 0.992) and 2 × 102 through 6 × 10 7 gene copies (R2 = 0.972), with detection limits of 9.72 fM and 104 gene copies, respectively. The kinetic results indicate that adjustment of hybridization temperature in accordance to the amount of target DNA was required to maximize the efficiency of DNA hybridization. We were able to discriminate perfectly matched target DNA, 1-, 2-, and 41-base pair mismatched target DNAs in our approach and therefore demonstrated excellent selectivity. Our technique was also used on pure bacterial culture to showcase its ability to analyze environmental samples.
KW - DNA
KW - eaeA gene
KW - Escherichia coli O157:H7
KW - hybridization-in-solution
KW - magnetic bead, quantum dot
UR - http://www.scopus.com/inward/record.url?scp=79952674382&partnerID=8YFLogxK
U2 - 10.1007/s12257-010-0032-0
DO - 10.1007/s12257-010-0032-0
M3 - Article
AN - SCOPUS:79952674382
SN - 1226-8372
VL - 15
SP - 1084
EP - 1093
JO - Biotechnology and Bioprocess Engineering
JF - Biotechnology and Bioprocess Engineering
IS - 6
ER -