Abstract
The rapid worldwide spread of severe viral infections, often involving novel mutations of viruses, poses major challenges to our health-care systems. This means that tools that can efficiently and specifically diagnose viruses are much needed. To be relevant for broad applications in local health-care centers, such tools should be relatively cheap and easy to use. In this paper, we discuss the biophysical potential for the macroscopic detection of viruses based on the induction of a mechanical stress in a bundle of prestretched DNA molecules upon binding of viruses to the DNA. We show that the affinity of the DNA to the charged virus surface induces a local melting of the double helix into two single-stranded DNA. This process effects a mechanical stress along the DNA chains leading to an overall contraction of the DNA. Our results suggest that when such DNA bundles are incorporated in a supporting matrix such as a responsive hydrogel, the presence of viruses may indeed lead to a significant, macroscopic mechanical deformation of the matrix. We discuss the biophysical basis for this effect and characterize the physical properties of the associated DNA melting transition. In particular, we reveal several scaling relations between the relevant physical parameters of the system. We promote this DNA-based assay as a possible tool for efficient and specific virus screening.
- Received 21 October 2013
DOI:https://doi.org/10.1103/PhysRevX.4.021002
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Published by the American Physical Society
Popular Summary
Wouldn’t it be great if you could just blow your nose into a special handkerchief at your local pharmacy and within minutes learn whether you have a viral or bacterial infection? Scientists are indeed trying to engineer such smart and easy-to-use devices. In this paper, we present a theoretical proposal that may lay down the first stepping stone toward that ultimate goal: A smart wet wipe made with a special hydrated polymer gel can signal the entry of a minute amount of viruses by deforming its shape to a measurable degree after a short while.
How could this work specifically? The core physical insight of our proposed method is to use DNA molecules embedded in a polymer hydrogel film as virus-activated mechanical actuators for the hydrogel. Double-stranded DNA molecules can be grossly viewed as microscopic mechanical springs, and mechanical manipulations of them, such as stretching and twisting, are now routinely achieved in laboratories. Physical binding between certain DNA molecules and viruses can be engineered to trigger the mechanical transformation of suitably prestretched double-stranded DNA molecules into single-stranded ones. This transformation is, however, very small and hard to detect. But embedding DNA molecules in a hydrogel film solves the problem: When those DNA molecules embedded in a hydrogel undergo the transformation upon virus binding, their changes could cause the hydrogel to contract to a degree that can be detected macroscopically, leading to the ultimate detection of the viruses.
Our extensive computer simulations and statistical analysis present a rather strong case for the practical viability of this proposal and provide the essential information needed for the design and development of such a new diagnostic method.
