4 research outputs found
Multifluorophore DNA Origami Beacon as a Biosensing Platform
Biosensors play increasingly
important roles in many fields, from
clinical diagnosis to environmental monitoring, and there is a growing
need for cheap and simple analytical devices. DNA nanotechnology provides
methods for the creation of sophisticated biosensors, however many
of the developed DNA-based sensors are limited by cumbersome and time-consuming
readouts involving advanced experimental techniques. Here we describe
design, construction, and characterization of an optical DNA origami
nanobiosensor device exploiting arrays of precisely positioned organic
fluorophores. Two arrays of donor and acceptor fluorophores make up
a multifluorophore Förster resonance energy-transfer pair that
results in a high-output signal for microscopic detection of single
devices. Arrangement of fluorophores into arrays increases the signal-to-noise
ratio, allowing detection of signal output from singular biosensors
using a conventional fluorescence microscopy setup. Single device
analysis enables detection of target DNA sequences in concentrations
down to 100 pM in <45 min. We expect that the presented nanobiosensor
can function as a general platform for incorporating sensor modules
for a variety of targets and that the strong signal amplification
properties may allow detection in portable microscope systems to be
used for biosensor applications in the field
A serum-stable RNA aptamer specific for SARS-CoV-2 neutralizes viral entry
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has created an urgent need for new technologies to treat COVID-19. Here we report a 20-fluoro protected RNA aptamer that binds with high affinity to the receptor binding domain (RBD) of SARS-CoV-2 spike protein, thereby preventing its interaction with the host receptor ACE2. A trimerized version of the RNA aptamer matching the three RBDs in each spike complex enhances binding affinity down to the low picomolar range. Binding mode and specificity for the aptamer-spike interaction is supported by biolayer interferometry, single-molecule fluorescence microscopy, and flow-induced dispersion analysis in vitro. Cell culture experiments using virus-like particles and live SARS-CoV-2 show that the aptamer and, to a larger extent, the trimeric aptamer can efficiently block viral infection at low concentration. Finally, the aptamer maintains its high binding affinity to spike from other circulating SARS-CoV-2 strains, suggesting that it could find wide-spread use for the detection and treatment of SARS-CoV-2 and emerging variants