The invention provides a method for optimizing isHCR for multiplexed labeling, which combines binder-biomolecule interactions with hybridization Chain Reaction (HCR).

This specification discloses a novel methodology for labelling RNA via enzymatic incorporation of a minimally perturbing fluorescent tricyclic cytosine analogue. This analogue is shown to be 100% incorporated in example transcripts and is fully compatible with both in vitro and in cell transcription. Spectroscopic characterization shows that the incorporation rate of the cytosine analogue is on par with its natural counterpart. Using live cell imaging and flow cytometry, labelled mRNAs are efficiently and correctly translated upon transfection into living cells and cell-free systems. The spectral properties of the modified transcripts and their correct translation product allow for their straightforward and simultaneous visualization. This technology therefore offers a general route to understanding the biological behaviour of RNA of interest, including RNA based drugs. The fluorescent tricyclic cytosine analogue has formula (I):

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The invention relates to methods, compositions, kits, and assay systems for assay signal amplification. Also provided herein is a signal amplification reagent, wherein the signal amplification reagent is an antibody or antigen-binding fragment thereof.

The present application discloses an electrochemiluminescence immunosensor. The immunosensor includes an electrode functionalized by a nanocomposite film. The film further includes carbon nanohorns dispersed in Nafion® perfluorinated resin solution. The polymeric solution is further stabilized by magnetic nanoparticles. The immunosensor is a Point of care (POC)-based. The immunosensor is configured to work in the range from 100 ng/mL to 1 fg/mL, and has tendency to detect even traces of the tropomyosin. The immunosensor is capable to detect traces even less than 1 fg/mL, hence having high specificity for Tro-Ag detection in food products with distinguished repeatability.

The present disclosure relates to methods and kits for performing an identification of a terminal amino acid residue of the polypeptide, or performing a polypeptide sequencing. The methods include a step of contacting the terminal amino acid residue of the polypeptide with a coupler, followed by attaching the coupler-polypeptide complex to the solid support and cleaving the coupler-polypeptide complex from the polypeptide, thereby isolating the terminal amino acid residue of the polypeptide from the remaining amino acid residues of the polypeptide in complex with the coupler, thereby enabling efficient identification of the terminal amino acid residue via recognition by binding agents capable of binding to the coupler-amino acid complex. In some embodiments, the coupler and the polypeptide are both associated with stabilizing components, and after binding of the coupler to the terminal amino acid of the polypeptide, tethering complex is formed between the stabilizing components releasably attached to the solid support.

Disclosed herein are embodiments of nanohoop compounds and conjugates thereof that can be used myriad biological applications. The nanohoop compounds described herein can exhibit beneficial properties that are useful in biotechnology, such as a fluorescent tag, probe, or label.

There are provided a compound of Formula (1) and a labeled biological substance having the compound.

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Z.sup.1 and Z.sup.2 represent a specific 6-membered ring. However, at least one of Z.sup.1 or Z.sup.2 is a benzene ring having a specific substituent at an ortho position with respect to a nitrogen atom to which L.sup.1 or L.sup.2 is bonded, or a specific nitrogen-containing 6-membered ring in which a ring-constituting atom located at the ortho position is a nitrogen atom.

R.sup.1 to R.sup.4, R.sup.11 to R.sup.13, L.sup.1, L.sup.2, and R.sup.21 represents specific groups, and n, α1, α2, and m represent specific numbers.

The compound has at least one structure represented by —(CH.sub.2—CH.sub.2—O).sub.m-R.sup.21 on a heterocyclic ring and has at least one substituent capable of being bonded to a carboxy group or a biological substance at a specific position, and in a case where at least one of Z.sup.1 or Z.sup.2 is the specific nitrogen-containing 6-membered ring, the specific substituents may be bonded to each other to form a ring.

The near-infrared window of fluorescent heptamethine cyanine dyes greatly facilitates biological imaging because there is deep penetration of the light and negligible background fluorescence. But dye instability, aggregation, and poor pharmacokinetics are current drawbacks that limit performance and the scope of possible applications. All these limitations are simultaneously overcome with a new molecular design strategy that produces a charge balanced and sterically shielded fluorochrome. The key design feature is a meso-Aryl group that simultaneously projects two shielding arms directly over each face of a linear heptamethine polyene. Cell and mouse imaging experiments compared a shielded heptamethine cyanine dye (and several peptide and antibody bioconjugates) to benchmark heptamethine dyes and found that the shielded systems possess an unsurpassed combination of photophysical, physiochemical and biodistribution properties that greatly enhance bioimaging performance.

Techniques for multi-dimensional signal analysis are described herein. The techniques may be used in one or more sequencing applications. For example, according to some aspects, there is provided a method comprising: determining information about a sample that emits emission light in response to excitation light based on at least one of pulse duration and interpulse duration and at least two of wavelength, intensity, and lifetime of the emission light, wherein the sample comprises a reagent configured to be coupled to a luminescent label, and wherein a shielding element is disposed between the reagent and the luminescent label.

Polymers, monomers, chromophoric polymer dots and related methods are provided. Highly fluorescent chromophoric polymer dots with narrow-band emissions are provided. Methods for synthesizing the chromophoric polymers, preparation methods for forming the chromophoric polymer dots, and biological applications using the unique properties of narrow-band emissions are also provided.