Wearable skin patch can now monitor your haemoglobin in deep tissues

University of California, San Diego, engineers have developed an electronic patch to monitor biomolecules in deep tissues, like haemoglobin.

BySouth First Desk

Published Dec 20, 2022 | 4:22 PM Updated Dec 20, 2022 | 4:23 PM

Wearable skin patch

A team of engineers at the University of California San Diego has developed an electronic patch that can monitor biomolecules in deep tissues, including haemoglobin.

This is expected to give medical professionals unprecedented access to crucial information that could help spot life-threatening conditions such as malignant tumours, organ dysfunction, and even cerebral or gut haemorrhages.

“The amount and location of haemoglobin in the body provide critical information about blood perfusion or accumulation in specific locations,” said Sheng Xu, a professor of nanoengineering at UC San Diego and corresponding author of the study in a statement.

“Our device shows great potential in close monitoring of high-risk groups, enabling timely interventions at urgent moments,” added the professor.

Low blood perfusion inside the body may cause severe organ dysfunctions and is associated with a range of ailments, including heart attacks and vascular diseases of the extremities.

At the same time, abnormal blood accumulation in areas such as the brain, abdomen, or cysts could indicate cerebral or visceral haemorrhage or malignant tumours.

Continuous monitoring can aid the diagnosis of these conditions and help facilitate timely and potentially life-saving interventions.

The study

The study, published in Nature Communications, states that the new sensor overcomes some significant limitations in existing methods of monitoring biomolecules.

Magnetic resonance imaging (MRI) and X-ray-computed tomography rely on bulky equipment that can be hard to procure and usually only provide information on the immediate status of the molecule, which makes them unsuitable for long-term biomolecule monitoring.

“Continuous monitoring is critical for timely interventions to prevent life-threatening conditions from worsening quickly,” said study co-author Xiangjun Chen in a statement.

He added that wearable devices based on electrochemistry for biomolecule detection, not limited to haemoglobin, are good candidates for long-term wearable monitoring applications. However, the existing technologies only achieve the ability of skin-surface detection.

How does it work?

The new, flexible, small-form-factor wearable patch attaches to the skin, allowing for noninvasive long-term monitoring, claimed the engineers.

It can perform three-dimensional mapping of haemoglobin with a submillimeter spatial resolution in deep tissues, down to centimetres below the skin, versus other wearable electrochemical devices that only sense the biomolecules on the skin surface, they added.

It can achieve high contrast to other tissues. Due to its optical selectivity, it can expand the range of detectable molecules, integrating different laser diodes with different wavelengths, along with its potential clinical applications.

The patch is equipped with arrays of laser diodes and piezoelectric transducers in its soft silicone polymer matrix.

Laser diodes emit pulsed lasers into the tissues. Biomolecules in the tissue absorb the optical energy and radiate acoustic waves into surrounding media.

“Piezoelectric transducers receive the acoustic waves, which are processed in an electrical system to reconstruct the spatial mapping of the wave-emitting biomolecules”, said Xiaoxiang Gao, a postdoctoral researcher in Xu’s lab and co-author of the study.

They also plan to explore the wearable’s potential for core temperature monitoring.