a-rapid-chemical-free-hemoglobin-assay-with-photothermal-angular

A Rapid and Chemical-free Hemoglobin Assay with Photothermal Angular Light Scattering

Photo-thermal angular light scattering (PT-AS) is a novel optical method for measuring the hemoglobin concentration ([Hb]) of blood samples. On the basis ...

Yonsei University

We present an implementation of spectrally encoded slit confocal microscopy. The method employs a rapid wavelength-swept laser as the light source and illuminates a specimen with a line focus that scans through the specimen as the wavelength sweeps. The reflected light from the specimen is imaged with a stationary line scan camera, in which the finite pixel height serves as a slit aperture. This scanner-free operation enables a simple and cost-effective implementation in a small form factor, while allowing for the three-dimensional imaging of biological samples.

Spectrally encoded slit confocal microscopy using a wavelength-swept laser.

We describe a three-dimensional microscopy technique based on spectral and frequency encoding. The method employs a wavelength-swept laser to illuminate a specimen with a spectrally-dispersed line focus that sweeps over the specimen in time. The spatial information along each spectral line is further mapped into different modulation frequencies. Spectrally-resolved detection and subsequent Fourier analysis of the back-scattered light from the specimen therefore enable high-speed, scanner-free imaging of the specimen with a single-element photodetector. High-contrast, three-dimensional imaging capability of this method is demonstrated by presenting images of various materials and biological specimens.

Frequency- and spectrally-encoded confocal microscopy.

We present a direct, rapid and chemical-free detection method for hemoglobin concentration ([Hb]), based on photothermal angular light scattering. The iron oxides contained in hemoglobin molecules exhibit high absorption of 532-nm light and generate heat under the illumination of 532-nm light, which subsequently alters the refractive index of blood. We measured this photothermal change in refractive index by employing angular light scattering spectroscopy with the goal of quantifying [Hb] in blood samples. Highly sensitive [Hb] measurement of blood samples was performed by monitoring the shifts in angularly dispersed scattering patterns from the blood-loaded microcapillary tubes. Our system measured [Hb] over the range of 0.35-17.9 g/dL with a detection limit of ~0.12 g/dL. Our sensor was characterized by excellent correlation with a reference hematology analyzer (r>0.96), and yielded a precision of 0.63 g/dL for a blood sample of 9.0 g/dL.

Soocheol Kim

School of Mechanical Engineering

Yonsei University

A Rapid and Chemical-free Hemoglobin Assay with Photothermal Angular Light Scattering