About Us

Nebulabio is a specialized discovery biology CRO with over 15 years of expertise in combinatorial library technologies and high-throughput screening. Our Premade Peptide Library Screening Platform is built upon one of the industry's largest and most diverse collections of pre-constructed, quality-validated peptide phage display libraries. We serve pharmaceutical companies, academic institutions, and biotech startups worldwide, accelerating the discovery of peptide leads for therapeutic development, diagnostic reagent creation, and fundamental biological research. Our platform is designed to deliver functional peptide ligands against even the most challenging targets—including protein-protein interfaces, allosteric sites on enzymes, and cell-surface receptors—within weeks, not months. By eliminating the need for custom library construction, we provide our partners with a fast, cost-effective, and de-risked path from target to validated hit.

☞Introduction to Peptide Library Screening Platform

Our Peptide Library Screening Platform is a powerful application of phage display technology tailored for the discovery of short, functional peptide sequences. The platform utilizes premade libraries where billions of unique, random peptide sequences (typically 7-12 amino acids in length) are genetically fused to a coat protein of the M13 bacteriophage. Each phage particle displays a single peptide variant on its surface while encapsulating the DNA encoding it, creating a direct physical link between the peptide's function and its genetic sequence.

The core discovery engine is biopanning, an iterative in vitro selection process. The diverse peptide-phage library is incubated with an immobilized target of interest. Phages displaying peptides with binding affinity are captured, while non-binders are washed away. The bound phages are then eluted, amplified in E. coli, and subjected to additional rounds of selection under increasingly stringent conditions. This process rapidly enriches the population for phages displaying the highest-affinity, most specific peptide ligands.

Our premade libraries are the key differentiator. They are constructed, amplified, and subjected to rigorous next-generation sequencing (NGS) quality control before being banked. This allows any screening project to begin immediately with a library of known, exceptional diversity and quality, shaving months off the traditional discovery timeline.

☞Why Use a Peptide Library?

Peptide library screening offers unique strategic advantages for early-stage discovery and development:

• Rapid Exploration of Chemical Space: A single library contains up to 10^9 unique sequences, enabling the simultaneous interrogation of a vast landscape of potential binders in a single experiment. This is far more efficient than synthesizing and testing individual peptide candidates.

• Access to Cryptic and Allosteric Sites: Due to their small size and flexibility, peptides can often bind to shallow grooves, protein-protein interaction interfaces, or allosteric regulatory sites that are inaccessible to larger antibody fragments.

• Ideal Starting Point for Drug Discovery: Identified peptide hits serve as excellent pharmacophores—they define the minimal structural elements required for target interaction. These hits can be developed into therapeutic leads themselves or used as blueprints for designing small-molecule mimetics.

• Cost-Effective & Versatile: Peptide libraries are less complex to generate and screen than large antibody libraries, offering a highly cost-effective method for initial target validation, epitope mapping, and lead identification across a wide range of applications.

• Excellent for "Undruggable" Targets: This platform is particularly powerful for historically difficult targets like transcription factors or other intracellular proteins where traditional small-molecule screening has failed.

☞Peptide Library Screening Process

The screening process follows a well-established, iterative methodology that leverages the physical linkage of phenotype to genotype in phage display.

 Standard Screening Workflow: 

1. Target Immobilization: The protein, peptide, or small-molecule target is immobilized onto a solid support (e.g., streptavidin-coated beads for biotinylated targets, or directly onto plastic wells).

2. Negative Selection (Optional): To remove non-specific binders, the library may first be incubated with a blank support or a related counter-target.

3. Positive Selection (Binding): The pre-cleared library is incubated with the immobilized target to allow peptide-phage binding.

4. Stringent Washing: Unbound and weakly bound phages are removed through a series of washes. The stringency (buffer, time, detergent) can be increased over successive rounds.

5. Elution: Specifically bound phages are recovered, typically by acidic elution (low-pH glycine buffer) or competitive elution with soluble target.

6. Amplification: Eluted phages are used to infect E. coli, which are then grown with helper phage to produce an amplified, enriched phage pool for the next selection round.

7. Iteration: Steps 3-6 are repeated for a total of 3-4 rounds, each time using the output of the previous round as input, leading to exponential enrichment of specific binders.

8. Analysis: After the final round, individual clones are isolated, sequenced, and the displayed peptides are synthesized for validation in binding assays (ELISA, SPR).

Figure1.SLAY Workflow

☞Our Premade Peptide Library Screening Service

We offer a complete, end-to-end service that manages the entire screening campaign, from library selection to deliverable validated hits. Our process is transparent, collaborative, and optimized for success.

Our Integrated Service Workflow:

Phase 1: Project Consultation & Design

We begin by understanding your target, desired peptide properties (length, linear/cyclic, specific modifications), and project goals. We then select the most appropriate premade library from our portfolio, which includes:

• Linear Peptide Libraries (e.g., 7-mer, 12-mer)

• Constrained (Cyclic) Peptide Libraries (via disulfide bridges, offering improved stability and selectivity)

• Specialized Libraries (e.g., with phosphorylatable residues, unnatural amino acids, or focused around a known motif).

Phase 2: Target Preparation & Panning Strategy

You provide the purified target. Our scientists design a customized panning strategy, deciding on the optimal immobilization method and whether negative selection or competitive elution steps are required to enhance specificity.

Phase 3: High-Efficiency Screening Execution

Using the selected, pre-amplified premade library, we execute the 3-4 round biopanning campaign in our dedicated labs. We monitor enrichment progress after each round via titering and polyclonal phage ELISA, providing you with interim reports.

Phase 4: Hit Deconvolution & Sequence Analysis

Individual bacterial clones (typically 96-192) from the final enriched output are picked and sequenced. Our bioinformatics team analyzes the results to:

• Identify consensus binding motifs.

• Cluster related peptide families.

• Provide a ranked list of unique peptide hits.

Phase 5: Hit Validation & Characterization

The top 10-20 unique peptide sequences are chemically synthesized (standard or with tags like biotin). We then perform initial validation:

• Binding Confirmation: ELISA or surface plasmon resonance (SPR) to verify target interaction.

• Specificity Assessment: Testing against related proteins to determine cross-reactivity.

• Affinity Measurement: Determination of approximate binding constants (KD) for the most promising hits.

Phase 6: Delivery & Reporting

You receive a comprehensive final report containing all sequencing data, alignment files, validation data, and strategic analysis. Physical deliverables include the synthesized, characterized peptide hits and the original sequencing files.

 Our Service Process Flowchart: 

Partner with us to leverage the power of pre-validated Peptide Library antibody diversity. Contact our team to begin your accelerated discovery campaign and unlock the potential of nanobody technology for your most ambitious targets.