May 3, 2024

The Future of Vision: Scientists Develop Flexible Cornea-Thin Battery Charged by Saline Solution

Checking the existing battery with a simulated tear solution, the scientists showed that the batterys life would be extended an extra hour for every twelve-hour wearing cycle it is used.” However, previous strategies for lens batteries were not perfect as one side of the battery electrode was charged and the other was not. Co-first author Dr Yun Jeonghun, a research fellow from NTUs EEE stated: “The most common battery charging system for wise contact lenses requires metal electrodes in the lens, which are damaging if they are exposed to the naked human eye. Our tear-based battery gets rid of the 2 prospective issues that these 2 techniques posture, while likewise releasing up area for additional innovation in the advancement of smart contact lenses.”
By integrating the battery and biofuel cell into a single part, the battery can charge itself without the need for extra area for wired or wireless elements.

The NTU-developed battery is made from biocompatible materials and does not contain wires or poisonous heavy metals, such as those in lithium-ion batteries or wireless charging systems. It has a glucose-based finish that reacts with the salt and chloride ions in the saline service surrounding it, while the water the battery consists of acts as the wire or circuitry for electrical power to be generated.
The battery might also be powered by human tears as they include salt and potassium ions, at a lower concentration. Evaluating the present battery with a simulated tear option, the scientists showed that the batterys life would be extended an extra hour for every twelve-hour using cycle it is utilized. The battery can also be charged traditionally by an external power supply.
Assoc Prof Lee and research study co-first author Miss Li Zongkang, a Ph.D. trainee from NTUs EEE, presenting the battery. Credit: NTU Singapore
Partner Professor Lee Seok Woo, from NTUs School of Electrical and Electronic Engineering (EEE), who led the research study, stated: “This research study started with a simple question: Could contact lens batteries be recharged with our tears? There were comparable examples of self-charging batteries, such as those for wearable technology that are powered by human sweating.
” However, previous techniques for lens batteries were not perfect as one side of the battery electrode was charged and the other was not. Our approach can charge both electrodes of a battery through a special combination of enzymatic reaction and self-reduction response. The charging mechanism, it relies on just glucose and water to generate electrical power, both of which are safe to people and would be less hazardous to the environment when disposed of, compared to conventional batteries.”
Co-first author Dr Yun Jeonghun, a research fellow from NTUs EEE said: “The most common battery charging system for smart contact lenses requires metal electrodes in the lens, which are harmful if they are exposed to the naked human eye. On the other hand, another mode of powering lenses, induction charging, requires a coil to be in the lens to send power, similar to a cordless charging pad for a smart device. Our tear-based battery eliminates the two prospective issues that these two techniques position, while likewise maximizing space for additional innovation in the development of clever contact lenses.”
Highlighting the significance of the work done by the research group, NTU School of Mechanical & & Aerospace Engineering Associate Professor Murukeshan Vadakke Matham, who concentrates on biomedical and nanoscale optics and was not involved in the research study, stated: “As this battery is based upon glucose oxidase, which happens naturally in human beings and powered by chloride and sodium ions, such as those in our tears, they must be compatible and ideal for human use. That, the smart contact lenses market has actually been looking for a thin, biocompatible battery that does not consist of heavy metals, and this invention might help further their development to fulfill some unmet requirements of the market.”
The research study team has applied for a patent through NTUitive, NTUs innovation and business business. They are likewise working towards commercializing their creation.
The findings were just recently released in the journal Nano Energy.
Cry me an existing
The team showed their creation utilizing a simulated human eye (see video). The battery, which is about 0.5 millimetres-thin generates electrical power by responding with the basal tears– the consistent tears that create a thin film over our eyeballs– for the gadgets embedded within the lenses to function.
The flexible and flat battery discharges electrical energy through a procedure called decrease when its glucose oxidase covering reacts with the sodium and chloride ions in the tears, creating power and present within the contact lenses.
The group demonstrated that the battery might produce a current of 45 microamperes and a maximum power of 201 microwatts, which would suffice to power a smart contact lens.
Laboratory tests showed that the battery might be charged and discharged as much as 200 times. Common lithium-ion batteries have a life expectancy of 300 to 500 charging cycles.
The group recommends that the battery needs to be placed for at least eight hours in an appropriate option which contains a high quantity of potassium, glucose, and sodium ions, to be charged while the user is sleeping (see Figure 1).
Co-first author Miss Li Zongkang, a PhD student from NTUs EEE stated: “Although wireless power transmission and supercapacitors supply high power, their combination presents a considerable difficulty due to the limited quantity of space in the lens. By combining the battery and biofuel cell into a single component, the battery can charge itself without the requirement for additional space for wired or wireless parts. The electrodes put at the external side of the contact lens guarantee that the vision of the eye can not be blocked.”
The NTU team will be carrying out more research to improve the amount of electrical present their battery can discharge. They will also be dealing with numerous contact lens business to execute their technology.
Reference: “A tear-based battery charged by biofuel for clever contact lenses” by Jeonghun Yun, Zongkang Li, Xinwen Miao, Xiaoya Li, Jae Yoon Lee, Wenting Zhao and Seok Woo Lee, 13 March 2023, Nano Energy.DOI: 10.1016/ j.nanoen.2023.108344.

Associate Professor Lee Seok Woo, from NTUs School of Electrical and Electronic Engineering (EEE) holding up the versatile battery that is as thin as a human cornea. Credit: NTU Singapore
Researchers at Nanyang Technological University in Singapore (NTU Singapore) have produced a flexible battery thats as thin as a human cornea. This ingenious energy storage gadget charges itself when immersed in a saline solution and has the possible to sustain smart contact lenses in the future.
Smart contact lenses are state-of-the-art contact lenses capable of displaying visible details on our corneas and can be utilized to gain access to enhanced truth. Existing uses consist of helping to correct vision, keeping an eye on users health, and flagging and dealing with illness for individuals with chronic health conditions such as diabetes and glaucoma. In the future, clever contact lenses could be established to send and record everything a wearer hears and sees to cloud-based data storage.
However, to reach this future capacity a safe and appropriate battery needs to be established to power them. Existing rechargeable batteries depend on wires or induction coils which contain metal and are inappropriate for use in the human eye, as they are present and uneasy threats to the user.