SPATIALLY OFFSET RAMAN SPECTROSCOPY
more helpful data
X-ray-based diagnostics, by far the most widely
used techniques for diagnosing bone disorders
and diseases, are largely blind to the protein component of bone. But proteins determine important mechanical properties of bone, and changes
in proteins have been associated with a number
of bone diseases. Now, British researchers have
demonstrated the use of spatially offset Raman
spectroscopy (SORS) to detect a known compositional abnormality in the bones of a patient suffering from the genetic bone disorder osteogenesis imperfecta (“brittle bone disease”). 1 The work
confirms the principle that bone diseases in living
patients can be detected noninvasively, and points
the way to larger studies that focus on osteoporosis and other chronic debilitating bone diseases.
The SORS method involves shining a laser
through the skin to analyze the underlying chemistry of the bone, and can reveal differences
between healthy and diseased bone. The research
team includes scientists from University College
London (UCL; London, England), the Science and
Technology Facilities Council (STFC; Swindon, Wiltshire, England), and the Royal National Orthopaedic Hospital (RNOH; also in London). The custom-built SORS instrument was developed by Cobalt
Light Systems (Abingdon, Oxfordshire, England).
According to Allen Goodship of UCL’s Institute
of Orthopaedics and Musculoskeletal Science,
who led the research, the SORS method could
become a routine tool that doctors can use during an annual check-up. This would allow physicians to advise patients on lifestyle changes that
could slow the progress of the disease. With regular screening, SORS could monitor effects directly,
1. K. Buckley et al., IBMS BoneKEy, 11, 602 (2014);
SINGLE-MOLECULE MICROSCOPY/PORTABLE PATHOLOGY
Compact devices compete with high-
One compact device converts an ordinary smartphone into a fluorescence
microscope capable of single-molecule detection and
measurement, while another
uses holography to do the
work of large pathology lab
microscopes. Both are new
innovations from the lab of
Aydogan Ozcan at the University of California, Los
Single molecule-capable smartphone
UCLA researchers reported the first demonstration of imaging and measuring the size of individual DNA molecules using a smartphone. 1 The inexpensive, 3D-printed optical add-on uses a camera phone to visualize and
measure the length of single-molecule DNA strands. An attachment to the
device creates a high-contrast, dark-field imaging setup using an inexpensive
external lens, thin-film interference filters, a miniature dovetail stage, and a
laser diode that obliquely excites the fluorescently labeled DNA.
Labeled molecules are stretched on disposable chips that fit in the smartphone attachment. An app connects the smartphone to a server at UCLA;
it transmits raw images to the server, which quickly measures the length of
each DNA strand. The detection and measurement results can be seen on
the mobile phone and on remote computers linked to the server.
Sizing accuracy is better than 1 kilobase-pair (kbp) for 10 kbp and longer DNA samples imaged over a 2 mm2 field of view. The innovation holds
promise for myriad applications for point-of-care medicine and global health.
Compact, lens-free pathology
The lens-free microscope works by using a laser or LED to illuminate tissue
or blood on a slide that is inserted into the device. 2 A cellphone-camera-style sensor array on a microchip captures and records the pattern of shadows created by the sample. The device processes these patterns as a series of
holograms, forming 3D images of the specimen that provide a virtual depth-of-field view. An algorithm color-codes the reconstructed images, making
the contrasts in the samples more apparent than they would be in the holograms, and highlighting abnormalities for easier detection.
A 3D-printed smartphone add-on images and
measures single-molecule DNA strands.
Laser diode Focusing knob