Library Preparation

Highly Sensitive Protein Analysis with Nanogram Inputs

Unlock biological samples with Library Prep Kit V3 for robust library construction from 200 ng protein.

Talk to an Expert
Two boxes labeled Quantum SI Library Prep Kit with bold blue text. The library prep kit packaging features blue and magenta gradient borders on a clean white background.

Library Preparation Kits

High-confidence protein sequencing from nanogram inputs with Library Preparation Kit V3.

Library Prep Kits

Protein Sequencing Kits

Achieve deeper protein insights with ready-to-sequence chips, recognizers, and aminopeptidases.

Library Preparation KIts

Assess scarce samples with Library Prep Kit V3

A blue and white laboratory micropipette, essential for precise handling during library prep kit workflows, is shown dispensing a single drop of liquid.

Nanogram input

Construct NGPS libraries with 200 ng total protein, delivering high-confidence sequencing from limited protein sources

A green circular icon with a white sine wave symbol in the center, representing sound or frequency, reminiscent of the precision found in a Library prep kit.

Low-abundance detection

Reliably detect low-abundance proteins with high coverage down to 1 ng or 0.5% in a mixture

A test tube with pink liquid and bubbles, labeled as a library prep kit, sits next to a magnified stylized virus or germ depicted in vibrant pink and orange colors.

Resolve immunoprecipitates

Enhanced bioinformatics assess proteins immunoprecipitated from biological samples, like cell lysates, uniquely differentiating proteins in a mixture with precision

A round clock showing the time as 3:00, with blue edges and black hands, on a light gray background, reminiscent of precision timing needed when using a library prep kit.

Fast and familiar workflow

Updated protocol yields sequenceable libraries within 48 hours, with less than two hours of hands-on time

Reduced Input for Targeted Proteomics

  • Library Preparation Kit V3 was designed to significantly reduce the input needed to produce high-quality NGPS libraries.
  • More data from less protein: 5-protein mix libraries were produced from 200 ng compared to 8-40 μg with the V2 kit, delivering elevated peptide coverage with over 95% confidence.
  • Resolve protein mixtures with confidence: 10-protein mixture sequenced at 200 ng (~20 ng per protein) with the V3 kit compared to 7.6–33 μg (0.76–3.3 μg per protein) from the V2 kit showed improved precision.
Two scatter plots compare V3 (blue) and V2 (pink) across markers (CDNF, HGF, etc.), utilizing data generated with a Library prep kit. The plots display the number of patients (top) and likelihood of response (bottom), with a dashed line marking the 95% threshold in both plots.

Resolve Immunoprecipitated Protein Mixtures

  • Upgrades to the inference software enhance confidence in identifying proteins in complex mixtures, with only nanogram amounts of input protein.
  • Libraries were generated using the V3 kit from HEK293 cell extracts derived from 106 cells expressing FLAG-tagged integrin alpha-1 (ITGA1) following immunoprecipitation.
  • NGPS accurately identified the ITGA1 protein with top-ranked inference using Sequencing Kit V4 on the Platinum Pro platform.

A gel image with a protein band at 130 kDa on the left; on the right, protein ITGA1_HUMAN is listed with inference rank 1, 3 peptides inferred, and peptide alignments at 1%, 5%, and 10% FDR—generated using a premium library prep kit for optimal proteomic analysis.
ITGA1 protein, enriched from HEK293 cell extracts, sequenced with Sequencing Kit V4 on Platinum Pro. ITGA1 showed three aligned peptides and was identified with top rank inference.

Sensitive Identification of Protein Mixtures

Proteins have diverse intrinsic properties that impact their performance across proteomics assays. To characterize the limit of detection of low-abundance proteins in a mixture, a panel of five proteins was titrated in mixtures with a constant total protein of 200 ng per library. Here, ADML was maintained at high abundance (40–196 ng), while four others (LMNB1, PD-l1, HSA, and ILI8R) stepped down from 0.5–40% (1–40 ng) per protein to model performance at low abundance.

Libraries were prepared with Library Preparation Kit V3, sequenced on a full chip using Sequencing Kit V4 on Platinum Pro.

Highest-coverage proteins (LMNB1, PD-L1, HSA):

  • Accurately detected with ≥95% confidence
  • LMNB1: reliably inferred at 1 ng in the mixture (0.5% abundance)
  • PD-L1 and HSA: reliably inferred at 2 ng (1% abundance)

Lower-coverage proteins (IL18R, ADML):

  • Required higher mass for high-confidence detection
  • IL18R: required 80 ng (40% abundance) to reach high-confidence inference
  • ADML: required 160 ng (80% abundance)
Bar graph showing likelihood inferred vs. total mass (ng) for LMNB1, PD-L1, HSA, ADML, and L18R using the library prep kit. Most bars are above 95%, except for HSA and ADML, which drop at 10, 20, and 40 ng.
Proteins with the highest coverage (LMNB1, PD-L1, and HSA) can be inferred at 1–2 ng in a 200 ng mixture, <1% relative abundance. Proteins with lower coverage (ADML, IL18R) require higher mass — 80–160 ng — for comparably confident identification.


Explore our resources to discover how Next-Gen Protein Sequencing with Platinum Pro can enhance your protein research

The Platinum instrument, kits, and software contain everything you need to prepare, sequence, and analyze proteins. Library preparation is the initial step in Quantum-Si’s Next-Generation Protein Sequencing workflow.

Download the Data Sheet

The Platinum instrument, kits, and software contain everything you need to prepare, sequence, and analyze proteins. Sequencing Kit is the second step in Quantum-Si’s Next-Generation Protein Sequencing workflow.

Download the Data Sheet

In this study, published in the Journal of Proteome Research, Gloria Sheynkman and her team evaluated the ability of the recently released Platinum single-molecule protein sequencer to detect proteoform-informative peptides. Platinum employs fluorophore-labeled recognizers that reversibly bind to cognate N-terminal amino acids (NAAs), enabling polypeptide sequencing within nanoscale apertures of a semiconductor chip that can accommodate single peptide molecules.

Download the Paper

This article, published in Science, illustrates how the study of the proteome would benefit greatly from methods to directly sequence and digitally quantify proteins and detect posttranslational modifications with single-molecule sensitivity.

View the Article

Since our groundbreaking debut in Science in 2022, Quantum-Si has been at the forefront of protein sequencing innovation. Our commitment to progressive innovation has led to significant advancements in our next-gen protein sequencing technology.

Download the Brochure

Have Questions?