About Us

Nebulabio is a globally recognized leader in antibody discovery and engineering, providing end-to-end solutions through our state-of-the-art Antibody Phage Display Platform. With more than 15 years of dedicated experience, our team of scientists has successfully executed thousands of discovery campaigns, delivering high-affinity leads against an extensive array of targets, from soluble proteins and peptides to complex multi-pass membrane receptors. We partner with pharmaceutical giants, innovative biotech startups, and academic institutions to transform novel target concepts into validated, developable antibody candidates. Our platform is built on a foundation of scientific excellence, cutting-edge automation, and a deep commitment to project success, offering a seamless, integrated path from library construction and screening to lead optimization and characterization.

☞Why Choose Our Platform?

Selecting our Antibody Phage Display Platform provides a decisive strategic advantage, combining proven technology with unmatched service expertise.

• Proven Track Record & Therapeutic Relevance: We have a documented history of success, with numerous discovered antibodies advancing into preclinical and clinical development. Our platform is not just an R&D tool; it's a pipeline engine designed to deliver therapeutic-grade leads.

• Full Spectrum of Antibody Formats: We are experts in all major formats—Fab, scFv, and VHH (Nanobody). This allows us to recommend and execute the optimal strategy for your specific target biology and desired drug profile, whether you need the native IgG-like structure of a Fab, the compact versatility of an scFv, or the unique stability and epitope access of a VHH.

• End-to-End, Integrated Service: We offer a complete solution. From custom library construction (immune, naïve, or synthetic) and access to our vast premade library collection, through high-stringency screening and multi-parameter lead validation, to downstream affinity maturation and humanization—we manage the entire process. This integration ensures consistency, quality, and speed.

• High-Throughput & Automation-Driven: Our platform utilizes automated liquid handlers, high-content screening systems, and advanced bioinformatics pipelines. This enables us to screen billions of clones with high efficiency, perform deep sequence analysis, and deliver comprehensive data packages rapidly and reproducibly.

• Focus on Developability: We prioritize leads not only for affinity but also for biophysical properties critical for drug development. Early-stage assessment of stability, solubility, and aggregation propensity is integrated into our screening and validation cascade, de-risking your downstream development path.

Dedicated Project Partnership: You are assigned a dedicated project manager and a team of PhD-level scientists. We provide transparent, regular communication, expert data interpretation, and act as a true extension of your R&D team.

☞Common Antibody Phage Display Platforms (Formats)

Our comprehensive platform supports the three predominant and most effective antibody fragment formats for phage display, each with distinct advantages.

 1.Fab (Fragment antigen-binding) Platform: 

• Structure: A heterodimer of the Fd fragment (VH+CH1) and the light chain (VL+CL), linked by a disulfide bond. It mimics the full antigen-binding arm of a natural IgG.

• Advantages: Provides the most native antibody architecture, often leading to superior stability, expression yields, and straightforward reformatting into full-length IgGs. Ideal for targets where correct domain folding is critical.

• Best For: Therapeutic lead discovery where seamless conversion to IgG is required, and for projects needing excellent developability profiles from the start.

 2.scFv (Single-chain variable fragment) Platform: 

• Structure: The VH and VL domains are connected by a flexible peptide linker (e.g., (G4S)3) into a single polypeptide chain.

• Advantages: Compact size (~27 kDa) enables good tissue penetration and access to some cryptic sites. The single-gene system simplifies genetic manipulation, making it ideal for engineering into bispecifics, CAR-T domains, and antibody-drug conjugates (ADCs).

• Best For: High-throughput discovery, intracellular applications (intrabodies), and as building blocks for advanced therapeutic modalities.

 3.VHH (Nanobody) Platform: 

• Structure: A single-domain antibody (~15 kDa) derived from camelid heavy-chain-only antibodies.

• Advantages: Exceptional thermal and chemical stability, high solubility, and the ability to bind unique, recessed epitopes (e.g., enzyme active sites) due to long CDR3 loops. Excellent for in vivo imaging and targeting difficult epitopes.

• Best For: Targeting "undruggable" epitopes, developing stable diagnostic and imaging reagents, and creating robust biologics for harsh formulation or delivery routes.

Figure1.Monoclonal Antibodies and Antibody Like Fragments Derived from Immunised Phage Display Libraries

☞Antibody Phage Display Platform Construction Process

The power of our platform originates from our ability to construct high-diversity, high-quality libraries for any of these formats. The core construction process follows a refined molecular biology pipeline.

 Phase 1: Repertoire Sourcing & Gene Amplification 

• Source: B-cells from immunized or naïve donors (human/animal), or synthetic gene fragments.

• Processing: RNA extraction, cDNA synthesis, and PCR amplification of antibody gene fragments (VH/VL for scFv/Fab; VHH only for Nanobodies).

 Phase 2: Library Assembly & Cloning 

• Format Assembly: For scFv, VH and VL genes are spliced together with a linker. For Fab, Fd and light chain genes are prepared for co-expression. VHH genes are used directly.

• Vector Ligation: The antibody gene pool is cloned into a specialized phagemid vector. This vector fuses the antibody gene to gene III (g3p) of the M13 bacteriophage and contains origins for both bacterial and phage replication.

Phase 3: Library Transformation & Primary Stock Creation 

• The ligated phagemid DNA is introduced into E. coli via high-efficiency electroporation.

• Transformed cells are grown to create the primary bacterial glycerol stock, which represents the physical library of clones (typically with >10^9 - 10^10 individual members).

Phase 4: Phage Rescue & Quality Control

• Bacteria from the library stock are infected with helper phage (e.g., M13K07). The helper phage provides all viral proteins needed for packaging, but the phagemid DNA (containing the antibody gene) is packaged, resulting in phage particles displaying the antibody fragment.

• Stringent QC includes titering, insert rate analysis, and Next-Generation Sequencing (NGS) to validate library size and diversity.

Figure2.The five steps in a phage display selection experiment

☞Our Service Workflow

Our client-facing process is designed for clarity, collaboration, and maximum efficiency, guiding your project from concept to deliverable leads.

 Step 1: Project Initiation & Strategic Planning 

We begin with an in-depth consultation to understand your target, therapeutic goals, and success criteria. Together, we select the optimal antibody format (Fab/scFv/VHH), library strategy (custom build or premade), and design the screening and validation cascade.

 Step 2: Library Preparation 

• Path A (Custom): We execute the library construction process as outlined in Section 4.

• Path B (Premade): We select and prepare the optimal pre-validated library from our extensive collection.

All libraries undergo final QC before screening commences.

 Step 3: High-Stringency Biopanning 

Our screening specialists execute a tailored 3-4 round panning campaign. We optimize binding conditions, washing stringency, and elution methods for your specific target. Progress is monitored via polyclonal phage ELISA.

 Step 4: Hit Deconvolution & Bioinformatics Analysis 

Hundreds of individual clones are screened via monoclonal phage ELISA. All positive clones are sequenced. Our proprietary bioinformatics pipeline analyzes the data to:

• Identify unique antibody sequences.

• Cluster them into families based on CDR homology.

• Provide a ranked, diverse list of lead candidates for validation.

 Step 5: Lead Expression & Multi-Parameter Validation 

Lead antibody genes are expressed as soluble fragments (or full IgGs) and purified. They undergo a comprehensive validation tier:

• Tier 1 - Binding & Specificity: Confirmation via ELISA, SPR/BLI, and cross-reactivity screening.

• Tier 2 - Affinity & Kinetics: Accurate determination of KD, kon, and koff.

• Tier 3 - Functional & Developability: Functional assays (neutralization, blocking) and early developability assessment (thermal stability, aggregation propensity).

 Step 6: Delivery, Reporting & Next Steps 

You receive a complete project dossier: all raw and analyzed data, expression plasmids, antibody sequences, and purified protein samples. We hold a detailed review to discuss results and plan potential next steps, such as affinity maturation or cell line development.

 Our Integrated Service Flowchart: 

Partner with Nebulabio for a reliable, expert-led journey from antigen to functional  antibody library. Our integrated service provides the unique advantages of Nanobodies with the assurance of professional production standards.