Biosensors are functional devices that can translate specific recognition events between biologically relevant species into measurable signals. DNA-based biosensors, particularly hairpin DNA probe (HDP)-based biosensors, have drawn considerable interest due to the merits of HDP probes, such as the ease of signal amplification and the superb specificity in sequence recognition. Currently, HDP-based biosensors highly depend on the employment of enzymes to improve sensitivity. But enzymes are usually rather expensive, highly sequence-dependent, and vulnerable to the changes in reaction conditions, which greatly hinder the application of enzymes in biosensor development. To upgrade the detection sensitivity, another promising alternative is the construction of HDP-based solid-state...[ Read more ]

Biosensors are functional devices that can translate specific recognition events between biologically relevant species into measurable signals. DNA-based biosensors, particularly hairpin DNA probe (HDP)-based biosensors, have drawn considerable interest due to the merits of HDP probes, such as the ease of signal amplification and the superb specificity in sequence recognition. Currently, HDP-based biosensors highly depend on the employment of enzymes to improve sensitivity. But enzymes are usually rather expensive, highly sequence-dependent, and vulnerable to the changes in reaction conditions, which greatly hinder the application of enzymes in biosensor development. To upgrade the detection sensitivity, another promising alternative is the construction of HDP-based solid-state biosensing platforms. But problems still exist. There are always so many tedious procedures required to realize the detection, such as immobilization, separation and washing steps, which make the measurement time-consuming and complex.

This dissertation aims at fabricating novel HDP-based biosensors that, perform conveniently, are relatively inexpensive, while being highly sensitive and selective for the quantification of targets, including DNA and metal ions. To improve the detection sensitivity, some DNA amplification mechanisms and advanced nanomaterials are incorporated into the proposed sensing systems. To simplify the sensing systems, enzymes are not required, and only one “mix-and-measure” step is needed, which make them much easier to use than the enzyme-involved sensing systems or solid-state platforms.

All the proposed methods are relatively simple and low-cost, yet highly sensitive and specific for the determination of DNA and metal ions, which holds a promising potential for biomedical diagnosis and environmental monitoring.