High throughput method and apparatus for measuring multiple optical properties of a liquid sample
An apparatus for the high throughput measurement of optical properties of liquid samples placed into the wells of a multiwell plate is disclosed. An optical fiber within a fiber bundle containing no corrective optics between the fiber ends and the well plate bottom illuminates the sample in order to induce fluorescence, and multiple fibers collect emission radiation and transmit it to a fluorescence detector such as a spectrometer. Other embodiments involve a light scattering illumination source with detection fibers located in either the same bundle containing the fluorescence monitoring fibers or an independent light scattering detection bundle for the measurement of static and/or dynamic light scattering. Some embodiments of the invention permit the measurement of phase analysis light scattering. Thus the measurement of multiple optical properties of a liquid sample may be made simultaneously or in succession. A method for these measurements is also disclosed.
1. An apparatus comprising:
a multiwell plate comprising at least one vessel to contain a suspended liquid sample, wherein the at least one vessel comprises a transparent bottom surface;
a primary optical fiber bundle comprising a probe end and a system end, wherein the primary optical fiber bundle comprises:
at least one illumination fiber optically coupled to an excitation radiation source on the system end of the primary optical fiber bundle and positioned to illuminate the suspended liquid sample on the probe end of the primary optical fiber bundle, and
a plurality of collection fibers positioned, on the probe end of the primary optical fiber bundle, to collect radiation from the liquid sample illuminated by the at least one illumination fiber and optically coupled, on the system end of the primary optical fiber bundle, to at least one detector,
wherein a chosen quantity of the at least one illumination fiber maximizes a light gathering efficiency of the plurality of collection fibers and a detection signal to noise ratio of the plurality of collection fibers;
a translation device coupled to the probe end of the primary optical fiber bundle,
wherein the translation device is to provide relative motion between the probe end of the primary optical fiber bundle and the transparent bottom surface;
wherein the plurality of collection fibers are arranged concentrically about the at least one illumination fiber on the probe end of the primary optical fiber bundle;
wherein the probe end of the primary optical fiber bundle is positioned at an angle to the bottom surface of the at least one vessel of the multiwell plate and in the absence of additional light gathering optics between the primary optical fiber bundle and the bottom surface;
wherein the translation device is to move the probe end of the primary optical fiber bundle along x-, y-, and z-axes with respect to the transparent bottom surface;
wherein the multiwell plate is stationary and the translation device is to move the probe end of the primary optical fiber bundle relative to the multiwell plate; and
wherein non-beam passing surfaces of the vessel absorb light at wavelengths of the excitation radiation source.
2. The apparatus of claim 1
wherein the plurality of collection fibers, on the system end of the primary optical fiber bundle, are arranged in a linear array, and
further comprising a linear slit located between the linear array and the at least one detector.
3. The apparatus of claim 1 further comprising a light scattering detection optical fiber bundle mechanically coupled to the translation device,
wherein the light scattering detection optical fiber bundle comprises at least one optical fiber comprising a probe end and a system end,
wherein the at least one optical fiber of the light scattering detection optical fiber bundle is oriented so as to be able to collect light scattered from the sample by at least one of a light scattering illumination source and the excitation radiation source on the probe end of the at least one optical fiber and is optically coupled to at least one light scattering detector on the system end of the at least one optical fiber.
4. The apparatus of claim 3 wherein the light scattering illumination source is a laser.
5. The apparatus of claim 1 wherein at least one optical fiber of the primary optical fiber bundle is optically coupled on the system end of the primary optical fiber bundle to a static light scattering detector.
6. The apparatus of claim 1 wherein at least one optical fiber of the primary optical fiber bundle is optically coupled on the system end of the primary optical fiber bundle to a dynamic light scattering detector.
7. The apparatus of claim 1 wherein the at least one detector is a fluorescence spectrometer.
8. The apparatus of claim 1 wherein the excitation radiation source is a variable wavelength source.
9. The apparatus of claim 1 wherein the excitation radiation source is a light emitting diode.