Over the past decade, the treatment of type 1 diabetes has been reshaped by closed-loop insulin delivery systems, often called artificial pancreas devices. These systems combine a continuous glucose monitor (CGM) and an insulin pump with an algorithm that automatically adjusts insulin delivery based on real-time glucose readings. While current artificial pancreas devices significantly improve glycemic control and reduce the burden of constant self-management, they still rely on sensor components that must be replaced every seven to fourteen days and that eventually contribute to medical waste. A new wave of research is exploring the use of biodegradable sensors that could dissolve or safely break down inside the body after their functional lifespan. These sensors promise to reduce surgical risks, improve patient comfort, and lower the environmental footprint of diabetes care. This article examines the science behind biodegradable sensors, their potential integration into next-generation artificial pancreas systems, the hurdles that remain, and the outlook for clinical adoption.

How Today’s Artificial Pancreas Devices Work

An artificial pancreas device, more precisely termed a hybrid closed-loop system, consists of three main components: a CGM that measures interstitial glucose levels every few minutes, an insulin pump that delivers rapid-acting insulin, and a control algorithm that uses the CGM data to command the pump to increase, decrease, or suspend insulin delivery. The goal is to keep blood glucose within a target range as much as possible, reducing both hyperglycemia and hypoglycemia. Current commercial systems such as the Medtronic MiniMed 670G, Tandem t:slim X2 with Control-IQ, and the Omnipod 5 have demonstrated improved time-in-range and lower HbA1c levels in clinical trials. However, the CGM sensors used in these systems are typically disposable, electrochemical devices that must be replaced every 7–14 days, and the sensor insertion requires a new subcutaneous placement each time. Moreover, these sensors and their transmitters generate electronic waste over the lifetime of a patient—a significant concern given that a person with type 1 diabetes may use hundreds of sensors each year.

What Are Biodegradable Sensors?

Biodegradable sensors are implantable or wearable devices constructed from materials that can break down into harmless byproducts after they have served their purpose. In the context of artificial pancreas systems, a biodegradable sensor would ideally function as a CGM for a defined period—potentially weeks or months—and then degrade into substances that the body can safely metabolize or excrete. This eliminates the need for a separate removal procedure and reduces the accumulation of non-degradable waste from used sensors. Research into biodegradable electronics has accelerated in the past five years, driven by advances in materials science and microfabrication. Common biodegradable materials include silk fibroin, cellulose, poly(lactic-co-glycolic acid) (PLGA), magnesium, zinc, and certain organic semiconductors. These materials can be engineered to degrade at controlled rates, from days to several months, depending on the application.

Key Material Candidates for Biodegradable Glucose Sensors

Silk fibroin is a protein derived from silkworm cocoons. It is biocompatible, mechanically robust, and can be processed into thin films or hydrogels that host glucose-sensitive enzymes or nanoparticles. Silk-based sensors can be tailored to degrade over weeks to months by adjusting the processing conditions. Magnesium and zinc are metals that corrode rapidly in physiological environments. They can serve as conductive traces or electrodes that dissolve after use. PLGA and other synthetic polymers are commonly used in resorbable sutures and drug delivery systems; they degrade into lactic and glycolic acids, which are naturally eliminated. A biodegradable glucose sensor might use a combination of these materials: a silk-based substrate, magnesium electrodes, and a glucose-oxidase enzyme layer encapsulated in a PLGA membrane that releases the enzyme as the sensor corrodes.

Integrating Biodegradable Sensors into the Artificial Pancreas

Moving from current disposable CGMs to fully biodegradable sensors requires rethinking the entire sensor design, power supply, and wireless communication. While the sensor material itself can be made biodegradable, the associated electronics—transmitter, antenna, battery—must also be biodegradable or be designed to remain outside the body. One approach under investigation is a two-part system: a biodegradable subcutaneous sensor that uses a simple electrochemical cell powered by a biofuel cell (also biodegradable) and a wearable patch that reads data via short-range wireless and relays it to the insulin pump and controller. The biofuel cell could harvest energy from glucose and oxygen in the tissue, eliminating the need for an external battery. Researchers at institutions such as MIT’s Media Lab and the ETH Zürich have demonstrated prototype biofuel cells that operate for extended periods in animal models. However, integrating a biodegradable sensor with the reliability and accuracy needed for closed-loop insulin delivery is a major engineering challenge.

Potential System Architecture

  • Subcutaneous biodegradable sensor array: A small, flexible patch placed under the skin containing multiple glucose-sensing elements, each with a slightly different degradation time to provide continuous coverage.
  • Biodegradable biofuel cell: Converts glucose and oxygen into electricity to power the sensor and a tiny transmitter. The fuel cell also degrades after its energy output drops.
  • Transient wireless tag: A circuit made from magnesium and silk that transmits glucose data to an external receiver. The tag can be designed to dissolve when wetted or after a set period.
  • External relay and controller: A wearable device (e.g., a smartwatch or pump) that receives the sensor data, runs the closed-loop algorithm, and commands the insulin pump.

Clinical and Environmental Benefits

Biodegradable sensors offer several advantages over permanent or repeatedly replaced sensors:

  • Elimination of sensor-retrieval procedures. Because the sensor dissolves, there is no need for a second surgery to remove it, reducing infection risk and scarring. This is particularly beneficial for pediatric patients who may require many sensor replacements over a lifetime.
  • Reduced medical waste. Each non-degradable CGM sensor contributes to sharps waste and electronic waste. A biodegradable sensor that turns into CO₂, water, and minerals drastically cuts this environmental load. The World Health Organization has highlighted the growing problem of medical waste, and biodegradable electronics align with sustainability goals.
  • Improved patient comfort and compliance. A longer-lived sensor that does not require weekly insertion can reduce the pain, inconvenience, and skin irritation associated with frequent sensor changes. Some patients develop allergic reactions to adhesive patches; a biodegradable sensor might use a bioadhesive derived from chitosan or alginate that is less irritating.
  • Potential for deeper tissue monitoring. Because the sensor does not need to be removed, it could be implanted in tissues that are not easily accessed for frequent replacement, enabling measurement of glucose at alternative sites (e.g., intramuscular or in the peritoneal cavity).
  • Lower long-term cost of care. Although the initial research and manufacturing may be expensive, a single implantable biodegradable sensor that lasts several months could be cheaper than dozens of disposable sensors over the same period, especially when factoring in reduced clinic visits for sensor insertion training.

Current Challenges and Technical Hurdles

Despite the promise, several significant obstacles must be overcome before biodegradable sensors can be used in artificial pancreas devices:

Sensor Stability and Accuracy Over Lifetime

The primary challenge is maintaining accurate glucose readings during the entire functional period, especially as the sensor begins to degrade. As the material corrodes or breaks down, the electrochemical properties change, leading to drift in the calibration. Current CGMs require calibration every few hours or days using finger-stick blood glucose readings; a biodegradable sensor would need either a self-calibrating mechanism or a long stable period to be clinically acceptable. Researchers are exploring the use of rationetric sensing—measuring the ratio of two signals, one of which is a reference that also degrades—to correct for drift. A study in Nature Biomedical Engineering demonstrated a silk-based glucose sensor that maintained accuracy for over two weeks in rats, but scaling to human use and extending durability to months remains an active area of investigation.

Biocompatibility and Foreign Body Response

Even biodegradable materials can trigger an immune response. The body may encapsulate the sensor in a fibrous capsule, isolating it from the interstitial fluid and causing signal loss. Researchers are coating sensors with immunomodulatory coatings (e.g., with dexamethasone-releasing PLGA) to suppress the foreign body reaction. The degradation byproducts themselves must also be non-toxic and should not cause local inflammation. Magnesium degradation releases hydrogen gas, which can create subcutaneous pockets; designs must allow gas to diffuse safely.

Power and Wireless Communication

Powering a biodegradable sensor is non-trivial. Biofuel cells that harvest glucose have limited power output (on the order of microwatts per square centimeter), which may not be enough for continuous wireless transmission. Researchers are investigating energy storage using biodegradable supercapacitors made from carbon nanotubes and cellulose, which could store energy to allow intermittent bursts of transmission. Alternatively, the sensor could be powered wirelessly from an external source via inductive coupling using a dissolving coil. A team at the University of Zurich has reported a fully biodegradable wireless power receiver that could enable implanted sensors to communicate without internal batteries.

Manufacturing and Cost Scalability

Producing biodegradable sensors with consistent properties at a commercial scale is challenging. Many of the materials (e.g., silk fibroin) are sourced from natural products with batch-to-batch variability. Clean-room fabrication processes must be adapted to handle biodegradable components without degrading them during assembly. The economic feasibility of biodegradable sensors versus established disposable sensors depends on the cost of biocompatible materials and the yield of reliable devices. Industry collaboration, such as the partnership between Medtronic and academic labs, will be essential to bridge the gap from prototype to product.

Regulatory Hurdles

Regulatory agencies, including the FDA and EMA, have not yet established a clear pathway for biodegradable medical electronics. Combination products that involve both a drug (e.g., anti-inflammatory coating) and a device require more complex submissions. The degradation products must be proven safe over the long term, and the sensor's performance must be equivalent to or better than existing CGMs. Early-stage clinical trials are underway in Europe for biodegradable sensors for other applications (e.g., intracranial pressure monitoring), which may pave the way for diabetes devices.

Future Directions and Ongoing Research

Several exciting lines of research could accelerate the transition to biodegradable sensors for artificial pancreas systems:

  • Multiplexed sensors that measure glucose along with other biomarkers (e.g., ketones, lactate) could provide a more complete metabolic picture. Using the same biodegradable platform, researchers at TU Darmstadt have fabricated arrays that detect glucose and pH simultaneously.
  • Smart hydrogels that swell or change color in response to glucose can act as optical sensors that do not require electricity. These could be read by an external near-infrared light source, eliminating the need for implanted electronics altogether.
  • Closed-loop biodegradation timing – designing sensors that degrade at a controlled rate so that multiple sensors can be implanted in a staggered manner, ensuring continuous coverage as one degrades and the next becomes active.
  • Machine learning algorithms that can interpret data from a degrading sensor and compensate for signal drift could extend the usable life of the sensor even as it begins to break down.
  • Integration with microneedle patches that dissolve completely—these would allow painless insertion and then disappear, leaving no trace.

The Path to Clinical Adoption

While the vision of a fully biodegradable artificial pancreas sensor is still years away, incremental progress is being made. The most likely near-term application is a biodegradable CGM that lasts for 2–4 weeks and replaces the current disposable sensors, while still being wirelessly connected to an external transmitter. That alone would reduce waste and insertion frequency. The next step would be a fully implantable biodegradable system with a biofuel cell, operating for 3–6 months. Clinical trials for such devices could begin within 5–7 years, assuming successful resolution of the power and accuracy challenges. Key milestones include:

  1. Demonstration of stable glucose sensing for at least 30 days in a large animal model.
  2. Development of a wireless, biodegradable data link that meets medical-grade communication standards (e.g., Medical Implant Communication Service).
  3. Phase I human trials to confirm biocompatibility and no adverse degradation effects.
  4. Pivotal trials comparing the biodegradable artificial pancreas system to a standard closed-loop system in terms of time-in-range and safety.

Conclusion

Biodegradable sensors represent a frontier in diabetes technology that aligns with the broader push toward sustainable, patient-friendly medical devices. By eliminating surgical removals, reducing waste, and potentially enabling longer-term implantation, they could improve the quality of life for millions of people with type 1 diabetes. The challenges are substantial, but the convergence of materials science, bioelectronics, and algorithmic control is bringing this possibility closer to reality. As research continues and manufacturing scales, the next-generation artificial pancreas may not only regulate glucose automatically but also leave no trace behind.