Fiber-Optic DNA Sensor for Fluorometric Nucleic Acid Determination

Abstract

Single-stranded deoxyribonucleic acid (ssDNA) thymidylic acid icosanucleotides (dT20) were synthesized on the surfaces of derivatized quartz optical fibers to create an optical DNA biosensor. The synthesis made use of an automated solid-phase synthesizer and phosphoramidite synthons. The covalently immobilized oligomers were found to hybridize with complementary ssDNA (cDNA) or ssRNA (cRNA) from solution, and the device was regenerable for multiple cycles of application. Hybridization on optical fibers was detected by the use of the fluorescent DNA stain ethidium bromide (EB). The procedure used hybridization assay techniques and provided a detection limit of 86 ng x mL(-1) cDNA and a sensitivity of 200% fluorescence intensity increase per 100 ng x mL(-1) of cDNA, with one cycle of hybridization analysis requiring 45 min. The sensor has been observed to be regenerable (minimum of five cycles) and to sustain full activity after prolonged storage times (1 year), harsh washing conditions (sonication), and sterilization (autoclaving). The extent of hybridization between the immobilized and complementary nucleic acid strands was determined by UV absorbance thermal denaturation studies wherein all 20 bases on each strand of the nucleic acid were found to be involved in duplex formation.

Structural basis for the RNA binding selectivity of oligonucleotide analogues containing alkylsulfide internucleoside linkages and 2′-substituted 3′-deoxyribonucleosides

“…The development of oligonucleotides with selective hybridization properties may prove useful in the design of more selective antisense systems and novel hybridization probes for nucleic acids biosensors (42,43).…”

Recent advances in fiber-optic DNA biosensors

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Biosensor Based Cell-Phone Integrated Point of Care Diagnostic Devices: Challenges

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