Abstract
Optical spectroscopy can be used to quickly characterise the structural properties of individual molecules. However, it cannot be applied to biological assemblies because light is generally blind to the spatial distribution of the component molecules. This insensitivity arises from the mismatch in length scales between the assemblies (a few tens of nm) and the wavelength of light required to excite chromophores (≥150 nm). Consequently, with conventional spectroscopy, ordered assemblies, such as the icosahedral capsids of viruses, appear to be indistinguishable isotropic spherical objects. This limits potential routes to rapid high-throughput portable detection appropriate for point-of-care diagnostics. Here, we demonstrate that chiral electromagnetic (EM) near fields, which have both enhanced chiral asymmetry (referred to as superchirality) and subwavelength spatial localisation (∼10 nm), can detect the icosahedral structure of virus capsids. Thus, they can detect both the presence and relative orientation of a bound virus capsid. To illustrate the potential uses of the exquisite structural sensitivity of subwavelength superchiral fields, we have used them to successfully detect virus particles in the complex milieu of blood serum.
Highlights
One of the markers of the transition from chemistry to biology is when individual molecular building blocks selfassemble into complex biological architectures
The asymmetry parameters for nonspecifically bound Turnip yellow mosaic virus (TYMV) and TYMVThiol are calculated relative to the positions of the optical rotatory dispersion (ORD) resonances for unfunctionalised template plasmonic substrates” (TPSs) in buffer, while the bound TYMV shifts are relative to the functionalised layer
The primary and most significant result of this work is the sensitivity of chiral near fields to the higher order
Summary
One of the markers of the transition from chemistry to biology is when individual molecular building blocks selfassemble into complex biological architectures. Optical spectroscopy cannot generally do the same for molecular assemblies[1,2]. Characterisation of the static and dynamic structural properties of biological assemblies is achieved through alternative techniques, diffraction and NMR, which lack the advantages of ease of use and rapidity of optical spectroscopy. There are exceptions to this, such as J-aggregates, which have a different spectroscopic response than the individual component monomer[4] This requires wavefunction mixing, which occurs for relatively simple aromatic molecules, that creates new electronic states correlated with the structure of the aggregate that provide a spectroscopic fingerprint.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
