Smartphone-enabled detection of hepatitis B DNA


New nanotechnology research using MXenes for the detection of hepatitis B virus (HBV) has been published in the Journal of Colloid and Interface Science. This innovative research aimed to develop a colorimetric biosensor using a DNA probe to advance the management of HBV.

Study: CRISPR-Cas12a-regulated DNA adsorption and metallization on MXenes as enhanced enzyme mimics for sensitive colorimetric detection of hepatitis B virus DNA. Image Credit: Kateryna Kon/


MXenes are a type of inorganic compound, which can be described as two-dimensional transition metal carbides, nitrides and carbonitrides. These were first introduced in 2011 and include the combination of metallic conductivity of transition metal carbides as well as hydrophilicity.

These nanomaterials have a graphene-like structure, built by exfoliating MAX phases, new structural and functional ceramics with a layered structure; they also have a highly accessible hydrophilic surface compared to graphene and possess a large specific surface area, adjustable lateral size, high electrical conductivity and mechanical robustness.

The desirable properties of MXenes make this innovative nanomaterial versatile for various applications such as photocatalysts, supercapacitors, antibacterial agents as well as biosensors using DNA probes.

The development of a biosensor with the use of MXene would enable the detection of various viruses such as hepatitis B virus, which may be important in advancing disease diagnosis and the field of medicine.

MXene challenges: developing a biosensor

While titanium carbide (Ti3VS2) MXenes have already been shown to have peroxidase-like activity, its catalytic performance is even less effective than nanozymes comprising metals and metal oxides.

To address this challenging aspect of increasing the catalytic performance of MXenes, researchers have previously involved combining MXenes with other nanomaterials, such as double nanoparticles of copper hydroxide or sulfide layered with nickel and iron. , which would generate nanohybrids of MXene.

This improvement in the catalytic performance of MXene can still be difficult to develop with a simple approach; however, the use of noble metal nanomaterials has gained popularity for this application, along with DNA metallization and the use of DNA to guide metal nanofabrication.

Single-stranded template DNA can be efficiently adsorbed on Ti3VS2JX MXenes through the use of chelation of phosphate groups in DNA, with titanium ions on the MXenes used for subsequent metallization reactions.

Metallization of DNA on MXenes can efficiently generate MXene-metal nanohybrids as effective enzyme mimetics for sensitive colorimetric detection.

To this end, researchers in this study investigated the use of the DNA probe to increase the catalytic behavior of modified silver-palladium (Ag/Pt) nanoparticles-Ti3VS2JX MXene nanostructures to produce CRISPR-Cas12a-based colorimetric biosensors to detect HBV DNA.

The probe DNA can be used as a template for the synthesis of bimetallic Ag/Pt nanoparticles, as well as an activator to increase the catalytic activity of MXene. This research resulted in the production of high performance MXene-probe DNA-Ag/Pt nanohybrids with high peroxidase mimetic activity.

How it works?

This system works thanks to the Cas12a enzyme which can be activated by DNA probes in the presence of HBV targets; this causes inhibition of DNA metallization and enzyme enhancer DNA adsorbed on MXene, resulting in minimal catalytic activity.

The CRISPR-Cas12a enzyme and a colorimetric amplification nanoplatform based on Mxene-probe DNA-Ag/Pt nanohybrids can produce the first and second signal amplification, respectively. This ultimately provides a new method for the accurate and sensitive naked-eye analysis of HBV DNA without requiring a target DNA amplification process.

Additionally, this nanotechnology-based colorimetric biosensor enables sensitive visible detection of HBV DNA, compatible with smartphones, offering great potential for out-of-lab bioassays in remote areas.

Translational significance

The use of this innovative dual-amplification colorimetric nanoprobe has advanced both nanotechnology and biomedical research with the naked-eye inspection of hepatitis B virus targets that have high sensitivity. Moreover, the possibility of using this detection method in a smartphone could revolutionize the concept of biosensors, since it could allow diagnosis in remote areas.

This application could be particularly useful in rural areas and countries where access to extensive laboratory equipment may be difficult.

Accurate and sensitive diagnosis of HBV in countries where this disease is widespread can help increase diagnostic rates, which can guide treatments at an earlier stage to prevent it from developing further into hepatitis such as as chronic hepatitis or cirrhosis of the liver.

The future of this research and technology can also be translated to the diagnosis of other diseases, which would also help reduce the health crisis in countries around the world.


Tao, Y., Yi, K., Wang, H., Kim, H., Li, K., Zhu, X. & Li, M., (2022) CRISPR-Cas12a regulated DNA adsorption and metallization on MXenes as improved enzyme mimics for sensitive colorimetric detection of hepatitis B virus DNA. Journal of Colloid and Interface Science, 613, pp.406-414. Available at:

Further reading

Rongjun Yu, Jian Xue, Yang Wang et al. Roman Ti3VS2JX MXene Nanozyme with Manageable Catalytic Activity and Application to Electrochemical Biosensor, February 15, 2022, PREPRINT Available at:

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