Provided herein are compositions and methods to identify a binding element (e.g., peptide, peptoid, or protein) that can be bound by an immunoreceptor (e.g., antibody). The binding element can be provided in a target binding unit comprising two binding elements separated by a spacer such that the two binding elements simultaneously bind to a single molecule comprising an antigen binding domain of an antibody. The present disclosure provides various methods to construct the spacer. The identified binding elements can be further used to manufacture an array which can be used to profile antibodies obtained from a blood sample.

Provided herein are methods and composition for trackable genetic variant libraries. Further provided herein are methods and compositions for recursive engineering. Further provided herein are methods and compositions for multiplex engineering. Further provided herein are methods and compositions for enriching for editing and trackable engineered sequences and cells using nucleic acid-guided nucleases.

Provided herein are methods for preparing biological samples for spatial proteomic analysis, methods of determining a location of a protein analyte in a biological sample, and methods of determining a location of a protein analyte and a nucleic acid analyte in a biological sample.

Provided herein are methods of determining a surgical margin and the site and size of a tissue to be resected from a subject, and methods of use thereof.

The present invention discloses a sequencing library comprising a nucleotide sequence. The sequence comprises a linker sequence and two target sequences. Two ends of the linker sequence are respectively linked to the target sequences and the two target sequences are direct repeat sequences. The present invention further discloses preparation and use of the sequencing library. The present invention overcomes the high error rate problem of current DNA sequencing technologies, especially in a way of very low coverage bias, and can be used to detect low frequency mutations in different kinds of samples.

Methods and reagents for preparing nucleic acid samples for sequencing are provided. The samples include formalin-fixed paraffin-embedded (FFPE) samples. The methods comprise contacting a nucleic acid sample with a multimeric barcoding reagent comprising barcode regions linked together and appending barcode sequences to nucleic acid sequences of a target nucleic acid molecule. Methods are also provided that additionally use in-vitro transposition, coupling sequences and/or primer-extension to append barcode sequences to nucleic acid sequences of a target nucleic acid molecule.

The present disclosure provides methods and kits for tracking nucleic acid target origin by barcode tagging of the targets when they break into smaller fragments. Nucleic acid targets are captured in vitro by clonally localized nucleic acid barcode templates on a solid support. Millions of nucleic acid targets can be processed simultaneously in a massively parallel fashion without additional partition. These captured targets are broken into small fragments, and a target specific barcode sequence is tagged on each fragment as an identification of their original target. These nucleic acid target tracking methods can be used for a variety of applications in both whole genome sequencing and targeted sequencing.

Provided herein are compositions comprising aptamers that specifically bind monocytes and/or macrophage and methods for their use. These aptamer compositions can be used in methods for isolating and/or enriching monocytes and/or macrophages or depleting cell populations of monocytes and/or macrophages. Further provided are methods of using the aptamers or cell populations generated using them in the methods disclosed herein for therapies and/or drug delivery.

Described herein are affinity-labeled polypeptide compositions, such as affinity-labeled transcription factor compositions, and methods of using such compositions to evaluate interactions of the polypeptide with other molecules such as nucleic acids.

This disclosure provides a decentralized workflow for analyzing single cell gene expression. The workflow makes use of pre-templated instant partitions to segregate cells into separate compartments to individually capture and barcode RNA from single cells in a massively parallel single tube format. The workflow includes steps for processing the RNA from the single cells for sequencing. Separate portions of the decentralized workflow are performed by a research lab and a core facility, allowing increased flexibility in time and location of protocol steps.