Microparticle-based methods and systems and applications thereof

Abstract

Microparticle-based analytical methods, systems and applications are provided. Specifically, the use of resonant resonant light scattering as an analytical method for determining either or both a particle's identity and the presence and optionally, the concentration of one or more particular target analytes is described. Applications of these microparticle-based methods in biological and chemical assays are also disclosed.

Description

FIELD OF INVENTION [0001] This invention generally relates to methods, systems, and applications for microparticle-based measurements using resonant light scattering, comprising one or more of the following elements: particle identification, determining the identity and degree of analyte binding, and application of these methods in multiplexed biological and chemical assays. BACKGROUND [0002] Advances in bioanalysis are increasingly driven by miniaturization and multiplexing, i.e. the ability to measure many samples simultaneously. [0003] The ability to measure more analytes from smaller sample volumes, dictated in many cases by limited sample size, has led to development of miniaturized microfluidics-based sample manipulation systems and novel methods for analysis in micro-scale systems. Examples include a wide variety of existing biological and chemical measurements, for example DNA sequencing, protein analysis, single-nucleotide polymorphism (SNP) analysis, high-speed and high-re...

AI Technical Summary

Benefits of technology

"The present invention provides methods for identifying analytes using unique light scattering patterns of particles. These methods involve scanning particles with a light source to produce light scattering signatures that identify each particle. The particles are then contacted with a capture probe that binds to the surface of the particle, and the particles are optionally scanned again to produce a second binding resonant light scattering signature. The second signature is compared to the first signature to detect any analyte that may be present in a sample. The methods can be used to identify analytes in a sample using the unique light scattering patterns of the particles."

Problems solved by technology

These “biochip” systems can carry out large numbers of analyses simultaneously, but they suffer from known disadvantages.

For example, microarrays have inherently inefficient binding kinetics.

Because of poor mixing at the surface and the dimensions of a typical biochip, an analyte must cover relatively large diffusion distances to bind to its complementary probe.

This results in slow diffusion of analytes to and on the surface, incomplete binding reactions, and substantial lengthening of the protocol.

Additionally, the application and measurement of samples on microarrays is inherently a batch process, not particularly-well suited for automation.

Some types of microarrays can be expensive and difficult to customize quickly as the needs of an experiment or assay might require.

Variability across a microarray can lead to degraded reproducibility and precision, requiring in some cases substantial redundancy in the measurements.

Sensitivity and dynamic range are frequently reported to be problematic in the analysis of microarray data.

Also, with fixed microarrays it is not typically possible to recover, sort, post-process, or perform subsequent measurements on the analyte.

The resulting measurement in most microarray systems is thus an end-point measurement; i.e. the microarray is not capable of real-time, continuous measurement of binding between analyte and probe.

As mentioned previously, although non-labeled binding detection has been reported for fixed array systems, the continuing use of external reporter groups in particle-based assays remains a key disadvantage since the associated drawbacks are the same as for fixed arrays.

Because the microparticles can be in free suspension in some applications, it is not possible in those cases to link the identity of the probe to a fixed position, as done in fixed arrays.

Thus, the number of particle-based assays that can be performed in parallel is limited by the number of distinguishable combinations provided by the specific labels employed, e.g. the number of fluorophores, and possibly their relative abundance.

However, use of resonant light scattering spectra for identification of microparticles or for detection in biological and chemical assays is not taught in that disclosure.

However, how such measurements could be made is not taught in that disclosure.

The principal drawbacks to existing labeling techniques include limited multiplicity, i.e., limited combinations of unique identifying features, difficulties in preparing the encoded particles, speed and accuracy of decoding, and, in some cases, cost.

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