Anodic aluminum oxide (AAO) has been investigated and utilized in numerous products for almost a century. But the rapidly increasing interest in nanoscale materials and their outstanding properties has propelled nanoporous AAO to be used as a substrate for sensors and biosensors. Fluorescence-based biosensors are one type of optical biosensors which are very popular for detecting a variety of targets (DNA, RNA, glucose, enzyme, bacteria, etc.). The recent discovery of AAO fluorescence enhancement effect makes AAO more attractive since it has the great potential to be used in biosensing field to improve the sensor sensitivity. However, the mechanism of the AAO fluorescence enhancement effect has not be understood thoroughly. Based on the experimental and modeling results, it has been found that the main contributing factor to the fluorescence enhancement is probably the plasmonic Al nanoparticles (NPs) embedded in the film, while the nanopore dimensions have a limited contribution. Based on its fluorescence enhancement effect, a new class of molecular beacon biosensors is developed to detect specific hairpin DNA sequence. The sensor demonstrates excellent specificity and selectivity, indicating the great promise of this type of sensor for diagnostic applications. Furthermore, another optical biosensor has been developed based on AAO. TGF-β1 which is one type of growth factor secreted by pancreatic stellate cell (ITAF) has successfully detected by this sensor. It has been found that 10 ng/ml of purified transforming growth factor β1 (TGF-β1) can be readily detected in buffer with high specificity. TGF-β1 in a conditioned cell medium has also been detected successfully. By comparing with the reference data of purified TGF-β1, concentration of TGF-β1 secreted in the conditioned cell medium has been reasonable estimated. Finally, Transcranial magnetic stimulation (MS) effects on single neuron cell (N27) have been studied on both glass and AAO substrate. It has been found that MS not only has a negligible cytotoxic effect on N27 cells but also can speed up the N27 cell proliferation and regeneration.