Apparatus and methods for chirality detection
View Patent ↗Technologies are generally described for systems and methods for detecting chiral properties of materials and separating materials based on their chiral properties. A chiral vector is constructed from anisotropy properties of a polarization-dependent output signal from a sample. Different types of molecules from the sample can be differentiated based on a magnitude of the chiral vector. Chiral properties of the sample can be detected based on an angle of the chiral vector. The output signal can be a fluorescent emission from the sample and can be used to detect chiral properties of a substantially opaque sample.
1. A method comprising:
detecting a chiral property of a sample from a fluorescent emission of the sample, wherein the detecting comprises:
irradiating the sample with an excitation beam;
varying a polarization angle of the excitation beam; and
measuring an intensity of the fluorescent emission as a function of a polarization angle;
obtaining an extended anisotropic expression A(θ) defined as:
A
(
θ
)
=
I
θ
,
θ
-
I
θ
,
θ
+
90
°
I
θ
,
θ
+
2
I
θ
,
θ
+
90
°
wherein I is the intensity of the fluorescent emission measured at an excitation polarization angle θ (first subscript of I) and an emission polarization angle θ or θ+90° (second subscript of I); and
obtaining a chirality vector from the fluorescent emission based on the extended anisotropic expression;
wherein the obtaining a chirality vector comprises obtaining asymmetric factors at a plurality of different fluorescent emission polarization angles;
wherein the plurality of different fluorescent emission polarization angles include three angles; and
wherein the obtaining asymmetric factors comprises:
for chiral fluorescent molecules:
obtaining an extended anisotropy (X) at different excitation and fluorescent emission polarization angles; and
obtaining a reciprocal of the extended anisotropy (X′) at different excitation and fluorescent emission polarization angles;
for achiral fluorescent molecules:
obtaining an extended anisotropy (Y) at different excitation and fluorescent emission polarization angles; and
obtaining a reciprocal of the extended anisotropy (Y′) at different excitation and fluorescent emission polarization angles; and
calculating the asymmetric factor (X-X′)/(Y-Y′).
2. The method of claim 1 , further comprising:
differentiating different types of molecules from the sample based on a magnitude of the chirality vector.
3. The method of claim 1 , wherein the chiral property is detected based on an angle of the chiral vector.
4. The method of claim 1 , wherein the sample comprises a substantially opaque material.
5. The method of claim 4 , wherein the substantially opaque material is in at least one of a solid, a liquid suspension, a semisolid, a powder, a crystalline, or a film form.
6. The method of claim 1 , further comprising attaching an achiral fluorescent tag to the sample.
7. The method of claim 1 , further comprising: controlling a process to obtain a product with a desired chirality state.
8. The method of claim 1 , further comprising:
separating molecules with predetermined handedness from the sample based on the detecting.
9. The method of claim 1 comprising:
measuring a polarization-dependent output signal from a sample;
obtaining the plurality of asymmetric factors based on anisotropy properties of the output signal at a plurality of polarization angles; and
constructing the chiral vector using the asymmetric factors as components corresponding to the plurality of polarization angles.
10. The method of claim 9 , further comprising differentiating types of molecules from the sample based on a magnitude of the chiral vector.
11. The method of claim 9 , wherein the output signal comprises one of chemiluminescence, phosphorescence, radioisotope emission, particle bombardment caused emission, scattering, transmission, absorption, or reflection signals.
12. The method of claim 11 , wherein the sample is a substantially opaque sample.