Balancing Miniaturization, Power, and Compliance in Sensor Design

MDB: How have recent advances in sensor miniaturization and packaging changed the design trade-offs for implantable and wearable medical devices?

Klitzke: One of the most important drivers in medical devices has been the transition to minimally invasive procedures. These reduce recovery times and complications such as infection or bleeding, but they also demand much smaller implantables and delivery systems. Early versions of these devices often contained fewer sensors because of limited space. Now, with continued miniaturization, we can integrate more intelligence into much smaller footprints.

The sensors themselves have shrunk dramatically — some are just 200 µm, about two widths of a human hair. Connecting them requires electrical contacts as small as 40 µm, far thinner than a human hair, which creates real packaging challenges. TE has focused on assemblies that allow these tiny sensors to be incorporated reliably into devices.

MDB: Which packaging materials or techniques at TE are proving most effective for long-term reliability?

For implantables, titanium remains the gold standard in packaging because it resists corrosion and maintains its properties over decades. Ceramics and glass are also highly effective for long-term reliability. We continue to see promising developments with advanced polymers, but metals and ceramics still offer the most robust protection today.

On the wearable side, miniaturization has also transformed design priorities. Older devices could be the size of a pager. Now, there’s a shift toward lifestyle-compatible formats such as patches. That shift has increased therapy compliance, since patients are more likely to use devices that don’t disrupt daily life. At first, this came with trade-offs — many sensors were eliminated to make devices thinner and more discreet. But as packaging and miniaturization have improved, sensors are being reincorporated to provide richer patient data without compromising comfort. This trend is bringing wearables closer to clinical-grade performance.

MDB: TE works across many sensing modalities. How do you decide which type — MEMS, pressure, bioimpedance, optical flow, etc. — is best for a given application?

Klitzke: The choice depends entirely on the clinical objective. Take implantables that run on batteries: here, power consumption is critical. Pressure can be measured by piezoresistive, capacitive, or MEMS sensors — each has different trade-offs in power and accuracy. If you need to measure force, you might use foil strain gauges, silicon-based gauges, or MEMS devices. Foil gauges consume more power and are less accurate, while MEMS provide higher accuracy with better efficiency.

We often develop selection matrices that weigh factors such as accuracy, power consumption, sensor size, and array potential. This helps medical device manufacturers evaluate trade-offs and decide what will have the most impact on patient outcomes.

Consider force sensing in cardiac procedures: in ablation, physicians need to know the exact magnitude of force applied, requiring high-precision sensors such as strain gauges or optical systems. In cardiac mapping, however, the goal is simply to detect contact between the catheter and heart tissue — a simpler requirement that opens up very different sensor options.

Ultrasound is another good example. Traditional prenatal ultrasound systems use piezoelectric ceramics (PZT) because they offer deep penetration and can accommodate large arrays. But when you move to small catheters for intracardiac echocardiography (ICE), space is severely limited. Here, piezoelectric micromachined ultrasound transducers (PMUTs) or capacitive micromachined ultrasound transducers (CMUTs) provide higher resolution in a small footprint, even if they trade off some penetration depth.

Each sensing modality has its strengths, and our role is to guide customers through those trade-offs to ensure the selected sensor aligns with the therapy’s clinical goals.

MDB: What are the biggest challenges and practical solutions for ensuring sensor biocompatibility and sterilization compatibility without degrading performance?

Klitzke: Sterilization is often the defining constraint. Techniques such as ethylene oxide (EtO), electron beam, gamma radiation, and autoclave sterilization all place unique demands on materials. Gamma and electron beam sterilization, for example, can cause polymers to cross-link, creating long molecular chains that harden and eventually become brittle. If a polymer encapsulates a sensor, this change in mechanical properties can stress the sensor, altering calibration and degrading performance. Sometimes you see this effect immediately after sterilization; other times, it emerges years later due to ambient radiation exposure.

That’s why implantable devices still rely heavily on titanium, ceramics, and glass. These materials withstand sterilization while maintaining their mechanical and electrical properties. They also have long histories of biocompatibility, which simplifies regulatory approval. Still, manufacturers must maintain strict contamination controls during assembly to prevent issues that even the most robust materials cannot mitigate.

We are seeing encouraging progress with polymers engineered to tolerate sterilization, but achieving both biocompatibility and stability over years of implantation remains a major hurdle.

MDB: As devices become more connected and data-rich, how is TE addressing power, connectivity, and data integrity constraints for continuous physiological monitoring?

Klitzke: It starts with the sensing element. Different sensor types inherently consume different amounts of power. A resistive strain gauge will drain more energy than a capacitive MEMS device. By selecting the right technology, we can reduce power demands from the ground up.

But equally important is how data is collected. “Continuous” monitoring doesn’t always mean sampling thousands of times per second. For some applications, such as cardiac diagnostics, you might only need 60 Hz to capture the waveform accurately. For slower physiological changes, even lower sampling rates may suffice. Event-triggered sensing is another approach: the device measures at a low duty cycle, then increases sampling when it detects an anomaly. This preserves battery life while still capturing critical data.

In wearables, these techniques extend battery life. In implantables, they are essential — patients may need a device to function reliably for five or ten years. Reducing the need for surgical replacement is critical to patient safety and healthcare costs. That’s why we also explore low-power amplifiers, analog-to-digital converters, and optimized data pathways to maximize efficiency across the entire signal chain.

MDB: How are improvements in signal conditioning, on-sensor preprocessing, and AI changing downstream system architecture and regulatory requirements for medical OEMs?

Klitzke: Moving intelligence closer to the sensor has several benefits. It reduces latency, which is important for time-critical signals such as cardiac events. It also improves signal-to-noise ratio, especially in noisy environments like operating rooms where electromagnetic interference is common.

But embedding firmware or software at the sensor level means the sensor itself may now be considered a regulated medical device. That introduces new requirements for documentation, validation, and regulatory approval. Historically, intelligence was concentrated downstream in external monitors or computing systems. Now, with preprocessing and AI occurring at the point of measurement, the regulatory focus shifts closer to the patient.

Pacemakers have always had this level of regulation, but we’re now seeing similar requirements extend to catheters and other devices where real-time sensing and analysis occur in situ. This shift highlights the growing need to balance innovation with compliance, ensuring both safety and data integrity as intelligence moves to the edge.

Summary

Sensor technology is enabling medical devices to become smaller, smarter, and more aligned with patient needs. Advances in miniaturization and packaging have made minimally invasive procedures and lifestyle-compatible wearables possible without sacrificing performance. Robust materials such as titanium, ceramics, and glass ensure long-term reliability, while power optimization strategies and event-triggered sensing extend device lifetimes.

Looking ahead, on-sensor intelligence and AI will further enhance performance but also raise the regulatory bar, requiring device makers to validate safety at the sensing point itself.

This article was written by Sherrie Trigg, Editor and Director of Content for Medical Design Briefs. She can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it. .