Remote region sensor for essential vitamin deficiency

An electrochemical sensor designed to address a global health issue that particularly impacts people in the Middle East and North Africa (MENA) has been created by a multidisciplinary team at KAUST. The sensor detects low vitamin D levels in blood samples, providing early warning of an essential vitamin deficiency that can have severe health consequences if left untreated^[1].

“Vitamin D deficiency can result in broad health complications including cardiovascular disease, autoimmune disorders, neurodegenerative diseases and skeletal deformities,” says Sharat Chandra Barman, a postdoc in the labs of Husam Alshareef and Dana Alsulaiman, the project’s co-leaders. “Early diagnosis of vitamin D deficiency is crucial.”

The body makes vitamin D in the skin when exposed to sunlight, but in hot regions of the world people often minimize their sun exposure.

“Despite ample sunshine in Saudi Arabia and the MENA region, the prevalence of vitamin D deficiency is alarmingly high, making it a critical and often overlooked public health challenge,” Alsulaiman says. Around 80 percent of the region’s population is deficient in vitamin D, and 16 percent of people in Saudi Arabia are severely deficient.

It is difficult to measure the essential vitamin at clinically relevant concentrations in a blood sample.

“The molecule’s small size, low circulating concentrations in the blood, and its structural similarity to other biomolecules all present challenges,” Alsulaiman says. As a result, vitamin D testing is typically carried out on specialized equipment only available in large urban centers.

To create a simple yet accurate vitamin D testing device for use even in remote healthcare centers, the team created a novel electrochemical sensor that combined MXene 2D nanomaterials and vitamin D selective antibodies.

“MXenes have several features that suit biosensor applications,” Barman explains. “They are biocompatible, possess excellent electrical conductivity, and their surface is covered with tunable chemical groups that can enable further device functionality to be incorporated.”

The team used these chemical groups to attach vitamin D-binding antibodies to the MXene surface.

“Combining MXenes with antibodies resulted in a very sensitive and highly selective material for point-of-care vitamin D detection,” Barman says. The team was able to show that when the antibodies on the device bound to vitamin D, the current flow through the biosensor fell measurably, with the size of the electrical response proportional to the concentration of vitamin D in the sample.

The sensor had a vitamin D detection limit of just 1 picogram per milliliter of sample, with a dynamic range of 0.1–500 nanograms per milliliter. “This range effectively covers clinically relevant vitamin D levels, from deficiency to insufficiency, sufficiency, and toxicity ranges,” Barman says.

“The sensor also demonstrated high selectivity, showing minimal interference from non-target biomolecules like glucose, vitamin C, and vitamin B12,” he adds.

“Our synergistic combination of MXenes and antibodies enabled us to develop a biosensing platform for vitamin D deficiency that is low-cost, rapid, and decentralized – this advances accessible healthcare solutions in line with the goals of Saudi’s visionary Health Sector Transformation Program,” Alsulaiman says.