As a well-recognized expert in phage display technology, Creative Biolabs offers our worldwide clients the best phage display library screening services through our excellent biopanning strategies and state-of-the-art equipment. Our scientists are pleased to tailor the most appropriate strategies to screen the interested libraries of our customers.

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What is Phage Display Library Screening?

Phage display library screening is an in vitro technique that has become a cornerstone of modern biotechnology, particularly in therapeutic antibody discovery, vaccine development, and epitope mapping. This technology involves displaying a vast array of proteins or peptides on the surface of bacteriophages, which carry the genetic blueprint for each displayed protein. This approach enables the screening of large libraries to identify potential candidates with high specificity and affinity to various target molecules. Unlike traditional methods such as hybridoma technology, phage display does not rely on immunization or in vivo systems, making it a highly efficient, high-throughput platform for discovering antibodies against complex or non-immunogenic targets like membrane proteins and small molecules. Additionally, the flexibility of phage display allows for the rapid optimization of antibodies, improving their binding affinity and specificity - key factors in the success of therapeutic and diagnostic applications.

Acceptable Library Types

• Libraries from our customized library construction services.
• In-house premade antibody libraries, peptide libraries, scaffold libraries, etc.
• Libraries provided by our clients.
• Other commercialized libraries.

According to different demands, a series of targets can be qualified screened by our service. We accept targets provided by clients, but also provide related services to synthesize and express the interested targets.

Acceptable Target Types

• Purified targets
• Unpurified targets
• Intact cells, tissues, or any other in vivo targets

Phage display technology is one of the major approaches employed in various protein interaction studies, especially in the discovery of specific antibodies, scaffolds, or ligands. Binders with the desired specificity generally exist at low frequencies in the constructed libraries, which makes phage display library screening has become an effective technique for the enrichment and identification of binders with high affinity and specificity from interested libraries.

At Creative Biolabs, the proprietary protocol and tailored biopanning strategy allow the increase of candidates with higher affinity and desired specificity (e.g. binders recognize conformational epitope rather than linear epitope). In general, by conducting several rounds of library screening, our scientists can select antibodies with affinity of over 10^-7. By constructing serial sub-libraries of the isolated antibodies, we can increase the affinity from 10^-8 to 10^-9. Moreover, Creative Biolabs has successfully obtained scFv antibody with extremely high affinity of 10^-12.

Acceptable Screening Strategies

Based on our standard biopanning protocol, Creative Biolabs can utilize different strategies for library screening to meet our clients' project goals.

Solid-Phase Screening: the most straightforward and widely used way to select binders against interested target adsorbed onto a solid surface. Typically, the targets can be coated on the well of immunotubes or microtiter plates for isolating specific binders.

Solution-Sorting Screening: an ideal approach to isolate binders that recognize naïve targets. The target-binder interaction is carried out in solution with subsequent capture by the appropriate method.

Cell-Based Screening: a method in particular for cell surface antigen selection. It is a reliable approach to screen cell surface antigens with native conformation, especially when the antigen is hardly expressed as recombinant protein.

In Vivo Screening: a high throughput method for efficiently isolating tissue-specific binders. The selection is based on binding to target in vivo after the injection of interested phage libraries into whole animals and then rescuing phage bound to specific organs and tissues.

Ex Vivo Screening: a novel technique to employ primary cell suspensions of organs and tissues as targets. All cell types can be exposed for selection to identify the most specific binders.

More featured phage display library screening strategies.

Fig. 1 The five steps in a phage display selection experiment.^1,3

Process of Phage Display Library Screening

• Preparation of Phage Library: The phage library is introduced to a well or vial containing the presented antigen. Antigens can be presented via direct coating or capture systems.
• Binding: Phages displaying high-affinity antibodies bind to the antigen's epitopes. Non-binding phages are washed away.
• Elution: Bound phages are eluted through methods like enzymatic digestion or acidic/base solutions.
• Amplification: Eluted infective phages are amplified in E. coli with the help of helper phages.
• Repetition: The steps are repeated 1-3 times to enrich phages with high-affinity antibody fragments.

Phage output titration and polyclonal phage ELISA confirm the selection of binders. Selection can also be performed in solution, which helps maintain the native conformation of certain antigens, like blood factors and cytokines, thus enhancing the selection process.

Phage Display Library Screening in Different Species

Phage display screening can be adapted to utilize antibodies or ligands from a variety of species, each offering unique benefits for research and therapeutic applications. The adaptability of this technique across multiple species ensures that specific immunological challenges can be addressed effectively.

Phage Display Library Screening in Different Formats

Phage display library screening can generate various antibody formats, each with distinct advantages depending on the application:

Featured Screening Services at Creative Biolabs

• Premade Antibody Library Screening
• Premade Single Domain Antibody Library Screening
• Premade Peptide Library Screening
• Internalization Antibody Screening
• Protease Substrate Screening
• Thermal Stable scFv/Fab Screening
• pH-Sensitive Binder Discovery
• Repertoire Analysis

Other Applications of Our Library Screening Service

• Antibody discovery
• Affinity maturation
• Humanization
• Identify enzyme inhibitor
• Epitope mapping on antigens
• Discover/Validate new therapeutic targets
• Discover interaction between ligand and receptor

Advantages of Creative Biolabs' Phage Display Library Screening Service

Extensive Library Options: The availability of diverse peptide and antibody libraries, both commercially available and custom-built, ensures that researchers have access to the resources needed for their specific projects.

Custom Screening Strategies: Creative Biolabs tailors its screening strategies to the unique requirements of each target, ensuring high success rates in identifying high-affinity binders.

Expertise and Experience: With over 20 years of experience, Creative Biolabs has refined its methods to deliver high-quality results efficiently and reliably.

Advanced Technologies: Creative Biolabs integrates cutting-edge technologies like next-generation sequencing and advanced biophysical assays to validate and optimize candidates rapidly.

High Throughput and Quick Turnaround: The phage display platform allows for the rapid screening of large libraries, accelerating the identification and validation process for potential therapeutics.

In terms of years of experience in phage display realm, Creative Biolabs utilizes its advanced technology platforms and specialized expertise to serve our global clients with high-quality library screening services. Our scientists are confident in tailoring our customers the most reliable and cost-effective protocol to facilitate their meaningful research.

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Published Data

• Screening of Therapeutic Peptides

Fig.2 Various approaches in capturing high affinity peptide through phage display screening.^2,3

In complex solid tumors, peptides can be used to target dysfunctional tumor vascular systems, dense extracellular matrix, tumor stromal cells, or overexpressed receptors on tumors. Many peptide-based targeting ligands have shown promising results in enhancing solid tumor therapy, including increased tumor accumulation, highly specific tumor targeting, and enhanced tumor inhibition when used in combination with anticancer drugs or biological agents. Phage display technology allows the selection of target-binding peptides with high affinity and selectivity from the complex mixture pool of billions of display peptides on the phage in the combinatorial library and can be further enriched by the biopanning process. This technique can isolate various cancer-specific ligands by in situ, in vitro, in vivo, and ex vivo screening methods.

FAQ

1. What is the role of phage display library screening in drug discovery and development?

   Through phage display library screening, researchers can quickly identify high affinity antibodies or peptides that can specifically bind to disease-related proteins or other biomolecules (receptors, enzymes, antigens, etc.). This helps scientists identify new drug targets, develop targeted therapies, and design small molecules that block pathological protein interactions. In addition, phage display library screening can also be used to improve the specificity, reduce side effects, and improve the pharmacokinetic properties of existing drugs. In a word, the phage display library screening strategies accelerate the discovery and preliminary evaluation of new drug candidates and are a powerful tool for modern drug research and development.

2. How to ensure the specificity and affinity of antibodies or peptides in the process of phage display library screening?

   In order to ensure the high specificity and affinity of antibodies or peptides, several experimental procedures are usually adopted:
   Multiple rounds of affinity screening: only bacteriophages closely bound to the target were retained in each round of screening.
   Competitive elution: competitive elution using excessive free targets ensures that only bacteriophages with high affinity for the target can be selectively retained.
   Cross-affinity detection: through affinity testing with other unrelated proteins or targets, the specificity of the screened molecules is evaluated to ensure that they do not cross-react with non-target proteins.

3. What are the advantages of phage display library screening compared with other protein screening techniques?

   High-throughput screening: Billions of different sequences can be processed.
   Direct screening of complex samples: Screen target molecules directly from complex biological samples without purifying proteins, greatly simplifying the screening process.
   Wide range of applications: Not limited to protein-protein interactions, it can also be used to screen interactions with various biological macromolecules, such as small molecules and nucleic acids.
   Functional screening: In addition to affinity and specificity, proteins can also be screened based on their functional activity, providing the possibility to discover new molecules with specific biological functions.

4. How to construct a high quality phage display library?

   Diversity and high coverage: ensure that the display library has a high degree of diversity and can cover a wide range of sequence spaces. This is usually achieved through the use of a variety of coding sequence libraries, including randomized peptide libraries or diversified antibody fragment libraries.
   Correct location and expression of insertion sequence: the sequences inserted into the phage genome must be correctly located and effectively expressed to ensure that the target protein or peptide can be correctly folded and displayed on the surface of the phage.
   Quality control of the library: through sequence analysis, phage titer determination, and target display efficiency tests to ensure that the phage in the library has a high titer and can effectively display the target sequence.
   Avoid repetition: use appropriate strategies to reduce sequence repetition and increase the number of unique sequences in the library, so as to improve the efficiency and success rate of the screening process.

5. After phage display library screening, how to verify and make further use of the screened molecules?

   Affinity and specificity verification: ELISA, surface plasmon resonance (SPR), biological layer interferometer (BLI), and other techniques were used to verify the binding affinity and specificity of the selected molecules to the target.
   Functional verification: the biological activity and mechanism of molecules were further verified by functional experiments, such as cell activity determination and signal transduction analysis.
   Sequence and structure analysis: sequence analysis and structural modeling of the selected molecules were carried out to understand the molecular basis of their interaction with the target.
   Optimization and artificial modification: optimize the selected molecules as needed, such as through artificial evolution, affinity maturation, or engineering modification, to improve their drug properties or production efficiency.
   Application development: the screened molecules can be further developed as therapeutic candidates, diagnostic tools, or research reagents.

Resources

Use the resources in our library to help you understand your options and make critical decisions for your study.

All listed services and products are For Research Use Only. Do Not use in any diagnostic or therapeutic applications.