Skin-deep microneedle sensor tracks drug clearance and reveals early kidney and liver dysfunction

The new microneedle sensor provides continuous, minimally invasive monitoring in skin. “We show that measurements taken just a millimeter beneath the skin can reveal clinically actionable information about organs deep inside the body,” said UCLA professor Sam Emaminejad.
Photo Credit: Emaminejad Lab/UCLA

Scientific Frontline: Extended "At a Glance" Summary: Microneedle Sensor for Drug Clearance and Organ Dysfunction

The Core Concept: A wearable, minimally invasive microneedle platform designed to continuously monitor the concentration of medically important molecules, such as pharmaceutical drugs, just beneath the surface of the skin.

Key Distinction/Mechanism: Unlike traditional blood tests that provide isolated snapshots of a patient's drug levels, this sensor allows for real-time, continuous tracking for up to six days. It achieves enhanced durability and sensitivity through a strongly adhered gold coating featuring nanoscale cavities; this architecture increases the sensing surface area nearly a hundredfold while protecting the delicate sensing molecules from tissue abrasion and biological buildup.

Major Frameworks/Components:

• Nanoscale Cavity Architecture: Microscopic surface depressions on the gold-coated needles that shield sensing molecules from friction and protein buildup, while exponentially expanding the active detection area.
• Continuous Pharmacokinetic Tracking: The physiological measurement framework that maps the rise and fall of drug concentrations in the body over extended periods to precisely infer the metabolic processing rates of internal organs.
• Multi-Target Compatibility: A highly sensitive and versatile design capable of supporting diverse sensing chemistries—including DNA-based mechanisms and engineered antibodies—allowing future iterations to track multiple distinct molecules simultaneously from a single patch.

Branch of Science: Bioelectronics, Nanotechnology, Pharmacology, and Medical Engineering.

Future Application: This technology is positioned to enable real-time, precision drug dosing for powerful clinical treatments, such as aggressive chemotherapies and potent antibiotics. Future mass-manufactured versions aim to expand continuous molecular monitoring across a wide range of medical conditions for personalized therapeutic intervention.

Why It Matters: By measuring exactly how quickly the body clears specific medications, this sensor can detect early-stage liver and kidney dysfunction days before standard clinical biomarkers (like blood creatinine) flag an injury. This real-time insight empowers physicians to adjust dosages or intervene proactively, preventing permanent organ damage while maximizing the effectiveness of the therapy.

With miniscule cavities on its surface, the reimagined microneedle provides nearly 100 times more surface area for sensing molecules while protecting them from abrasion and buildup.
Photo Credit: Emaminejad Lab/UCLA

Wearable technologies are starting to reshape how people manage health. Continuous glucose monitors that measure blood sugar levels in diabetes patients have already shown the power of tracking an important molecule in real time. The next leap is to track other medically important molecules. However, doing so is far more difficult because most of those molecules are present at much lower concentrations than glucose.

One area such wearable technologies could transform is drug therapy. Many powerful medications are still managed through blood tests that offer only occasional snapshots of how a patient’s body is processing treatment. For drugs that must be dosed precisely to avoid harm, clinicians can miss the point at which dosing becomes ineffective or begins to threaten the organs responsible for processing the drug.

A UCLA-led research team has now developed a microneedle sensor platform designed to address that problem through continuous, minimally invasive monitoring in skin. In a study published in Science Translational Medicine, the researchers showed in rats that the sensors could operate continuously for six days, track drug concentrations over time and provide insight into kidney and liver function by measuring how quickly the body cleared those drugs.

The advance could support a future in which doctors are better able to personalize dosing in real time and intervene earlier when organ function begins to decline. Beyond drug monitoring, the technology could also help bring continuous molecular monitoring to a wider range of conditions where changes over time carry important information about health and treatment response.

“We show that measurements taken just a millimeter beneath the skin can reveal clinically actionable information about organs deep inside the body,” said corresponding author Sam Emaminejad, an associate professor of electrical and computer engineering at the UCLA Samueli School of Engineering and a member of the California NanoSystems Institute at UCLA or CNSI. “By continuously monitoring certain drugs and how the kidneys or liver process them, we can detect organ dysfunction earlier and guide treatment with greater precision.”

Designed for signal quality and durability

Typically, a microneedle sensor works by carrying sensing molecules on its surface that are designed to recognize a specific target. When a target chemical binds to one of those sensing molecules, it changes the electrical signal generated at the needle.

The researchers’ reimagined sensor design protects those sensing molecules while also greatly increasing the microneedle’s sensitivity.

It does so through a strongly adhered gold coating with nanoscale cavities — tiny surface features visible only at the scale of billionths of a meter. When sensing molecules are attached, many of them settle inside those cavities, where they are better protected from abrasion by the skin and from buildup of proteins and other biological material that can interfere with sensing.

That protection helped extend sensor operation in freely moving rats from only hours to six days. The textured surface also dramatically expands the active area available for detection.

“By increasing the effective surface area to nearly a hundred times that of a smooth microneedle, we created much more room for sensing molecules while also helping protect them during use in tissue — increasing signal while reducing noise,” said Jialun Zhu, the study’s first author and a former member of Emaminejad’s Interconnected and Integrated Bioelectronics Lab who graduated from UCLA in 2025.

Because the researchers’ technology is highly sensitive, a single microneedle was sufficient for monitoring a single molecular target. That creates room for a broader sensing strategy: Future versions could use different needles within the same patch to track multiple molecules at once. The researchers also showed that the platform could support more than one type of sensing chemistry, working with approaches based in DNA and in engineered antibodies.

With future manufacturing in mind, the team designed the fabrication process to be scalable. The microneedles currently cost about $1.50 apiece to make in batch production.

Monitoring drug clearance and detecting organ damage earlier

In the study’s preclinical experiments, the researchers used the microneedles to track two drugs: a chemotherapy processed by the liver and an antibiotic cleared by the kidneys.

“These are drugs where, if dosing is a little too low, they may not work as intended,” Emaminejad said. “If dosing is too high, they can harm the same organs that are trying to clear them.”

By continuously tracking how drug levels rose and fell, the researchers were able to infer how well those organs were functioning. Rats with liver injury showed delayed clearance of the chemotherapy drug, while rats with kidney damage showed delayed clearance of the antibiotic.

In one experiment, the team followed animals through two weeks of worsening kidney dysfunction and then two weeks of treatment intended to stimulate recovery. The microneedle data captured a corresponding decrease in drug clearance followed by improvement during recovery.

The researchers also found that during the first week of kidney injury, the microneedle measurements already indicated impaired drug clearance. At that point, blood creatinine — the conventional biomarker commonly used to assess kidney function — remained below thresholds signaling injury. That result suggests the platform may be able to detect clinically relevant changes earlier than standard testing in some settings.

The researchers next aim to move the technology toward human studies.

“We want to determine whether this kind of monitoring can help prevent damage from antibiotics and chemotherapies,” Emaminejad said. “There is a real opportunity to better protect patients from the side effects of powerful therapies by recognizing trouble earlier and adjusting treatment sooner. More broadly, this approach could expand continuous molecular monitoring to many other targets, with the potential to guide care and reveal health problems earlier.”

Funding: National Institutes of Health, the Elisabeth K. Harris Foundation Trust, the Cystic Fibrosis Foundation, the Allan Smidt Charitable Fund, the Ralph Block Family Foundation, the Kleeman Fund, the Factor Family Foundation, the Chan Zuckerberg Biohub Chicago, CNSI’s Elman Family Foundation Innovation Fund, the UCLA Vice Chancellor for Research and Creative Activities, a UCLA Graduate Dean’s Scholar Award and a UCLA Electrical and Computer Engineering Department Fellowship.

Published in journal: Science Translational Medicine

Title: Resilient nanostructured bioanalytic microneedle longitudinally monitors preclinical renal and hepatic drug clearance and dysfunction

Authors: Jialun Zhu, Xuanbing Cheng, Mohammadreza Bahramian, Kuanming Yao, Zongqi Li, Bintao Hu, Tsung-Yu Wu, Kiarash A. Sabet, Jiarui Cui, Jiawei Tan, Junjie Fang, Yifu Li, Connie Ho, Joshua Ng, Anthony Sung, Isabel Romero, Shuyu Lin, Yichao Zhao, Kaiji Zhang, Ryan Chaiyakul, Hanie Yousefi, Connor D. Flynn, Jagotamoy Das, David Jelinek, Laurent Voisin, Aaron Ambrus, Ao Zhang, Yitian Chi, Yu Chen, Chong Liu, Hilary A. Coller, Benjamin M. Wu, Nanthia Suthana, Shana O. Kelley, Carlos Milla, Ira Kurtz, and Sam Emaminejad

Source/Credit: University of California, Los Angeles | Wayne Lewis

Reference Number: beng041826_01

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