Introduction: Contact lens has been widely investigated for biosensing and drug delivery applications to ocular diseases. Mere, we developed a smart contact lens containing biosensor and drug delivery system, and a smart eye glasses for the treatment of diabetes as a model disease. Materials and Methods: For the diagnosis of diabetes, tear glucose content was measured as a non-invasive alternative for the blood glucose content monitoring. The Ti electrode of biosensor was immobilized with glucose oxidase. When glucose binds to glucose oxidase, hydrogen peroxide is produced and oxidized on the electrode generating electrical current. For the drug delivery system, we fabricated Au membrane coated drug reservoirs on contact lens. Each reservoir was sealed at one end with a thin membrane of gold anode. When we applied electrical current, Au membrane was dissolved into AuCl_4 in NaCl solution. This flexible, biocompatible and miniaturized device was wirelessly powered by the WiTricity system of transmitter coils in smart eyeglasses and receiver coils in smart contact lens. Results: The electrical current from the glucose sensor increased from 10 microA to 200 microA with increasing tear glucose level ranging from 0.05 mM to 0.8 mM. Glucose sensor could be repeatedly used for 3 weeks in tear solution without lens corrosions and big current decrease. The thin gold anode was dissolved immediately in PBS solution by applying electrical voltage, triggering the release of drug from the reservoir. The transmitter circuit generated sine wave signals and MOSFET driver in SOIC8 package drived coils up to 60 V peaks on sine wave. For the power density calculation, the measured absolute value of the optical power was divided to the detector active area (1 cm~2). A proper power was transferred to the receiver and sufficient energy was available to power the glucose sensor, drug delivery system, and communication circuitry. Discussion: Biosensor can transmit the detected ocular signals to the smart eyeglasses for future processing and diagnostics applications. A miniaturized ocular drug-delivery system was also automatically controlled using the smart eyeglasses by user voice command. The efficient wireless power transfer system and the miniaturized microelectronic integrated circuit using CMOS and NEMS technologies will introduce a new alternative platform for future diagnostic and therapeutic applications, and human-machine interface healthcare applications. This novel smart contact lens can be further developed as a platform for the futuristic nano clinic systems. Conclusions: We successfully developed smart contact lens which is composed of glucose biosensor, on-demand drug delivery MEMS system, and remote power systems. Biosensor could measure tear glucose level in real-time for the diagnosis of diabetes, electrically controllable pulsatile ODS was applicable to deliver the drugs into the eyes, and miniaturized electrical power system made possible to drive flexible portable devices. This smart contact lens can be further developed for various theranostic applications.
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