Creative Biolabs offers a novel in vivo phage display method for clients all over the world. This method can be used for specifically and efficiently isolating the tissue-specific peptides bound to cell markers or cell-penetrating peptides (CPPs) for transporting chemotherapeutic agents. Our technical scientists are aimed to provide a reliable and robust selection system to meet our customer’s individual requirements.

Background

In vivo phage display is a unique high-throughput method for biopanning by which the peptide phage libraries are directly injected into animals for isolating and identifying the phages bound to specific tissues. Compared with other panning methods, the targets used for isolating phage-displayed peptides are more "intact" with the natural molecular structure and are in the functional states in vivo. Those selected peptides can be used as selective protein transduction domains (PTD) or cell-penetrating peptides (CPPs) for transporting chemotherapeutic agents to the specific tissue, thus improving drug specificity and efficacy in reducing toxicity. Furthermore, some selected peptides can block the function of their ligand proteins by themselves. Using this method, we can offer the functional analysis of new receptors and potential identification and development of novel drug target candidates for the customers.

Our services of identifying targeting peptides for different tissues/organs by in vivo phage display including but not limited to:

• Tumors Targeting via In Vivo Phage Display Screening
• Atherosclerosis Targeting via In Vivo Phage Display Screening
• Vascular Endothelium Targeting via In Vivo Phage Display Screening
• Muscle Targeting via In Vivo Phage Display Screening
• Human Synovium Targeting via In Vivo Phage Display Screening

In Vivo Phage Library Screening Platform

Creative Biolabs has adopted this novel in vivo phage display technology to develop a specific platform for selecting tissue-specific peptides. Through this platform, our scientists can generate high diversity phage display libraries with more than 10⁹ different clones. The libraries will then be used to broadly interrogate the surface of various cells and specific isolate protein ligands from target tissues. The selection results may display homology to known proteins which can be developed as diagnosis, or uncharacterized proteins which represent potential novel biomarkers.

Creative Biolabs has years of experience in the field of in vivo phage display. Our scientists are professional in isolating highly specific binders for various targets and confident in providing clients with the best service at the most competitive cost.

Fig 1. The process of phage selection in vivo.

Other optional phage display library screening services:

• Ex vivo Phage Display Services
• Magic™ Therapeutic Antibody Discovery Service
• Protease Substrate Screening
• Solid-phase Library Screening
• Solution-sorting Library Screening
• Cell-based Library Screening
• Premade Phage Display Antibody Library Screening Service
• Premade Phage Display Peptide Library Screening Service
• Rapid Recovery of scFv

Published Data

• Methodological Advances of In Vivo Phage Display by Integrating Deep Sequencing to Identify Organ-specific Peptides

Fig.2 Percentage of reliable peptides during in vivo selection rounds 1 and 2.¹

The study advances the methodology of in vivo phage display by integrating deep sequencing with a bioinformatics approach to identify peptides that target specific organs. This innovative technique enhances the efficiency of screening and identifying organ-specific homing peptides, crucial for targeted therapeutic applications. By adopting high-throughput sequencing (HTS) for analyzing peptide binding across different tissues, the research offers a streamlined, more accurate process for pinpointing peptides with specific affinity to target organs, thereby increasing the success rate and reproducibility of phage display screens. This method's significance lies in its potential to revolutionize the development of targeted drug delivery systems, minimizing off-target effects and maximizing therapeutic efficacy. The application of in vivo phage library screening in this context is pivotal for advancing precision medicine.

FAQ

1. What is in vivo phage display library screening?

   In vivo phage display library screening is a technique used to identify peptides, proteins, or antibodies that specifically bind to targeted tissues or organs within a living organism. This method uses bacteriophages to display vast libraries of peptides or proteins and identifies those with high affinity for specific biological targets through biopanning in live models.

2. How does in vivo phage display differ from in vitro phage display?

   While both methods use phage libraries to identify binding peptides or proteins, in vivo phage display involves biopanning directly within living organisms, allowing for the identification of ligands that can target tissues in their natural physiological context. In contrast, in vitro phage display is conducted in a controlled lab environment, often using purified proteins or fixed cells.

3. What are the applications of in vivo phage display?

   In vivo phage display is widely applied in drug development, particularly for creating targeted therapies that home to specific tissues or tumors, improving the efficacy and reducing side effects of treatments. It is also used in diagnostic imaging and the development of targeted imaging agents, as well as in basic research to understand ligand-receptor interactions.

4. What types of molecules can be screened using in vivo phage display?

   In vivo phage display can screen a variety of biological molecules including peptides, proteins, antibody fragments, and other ligands. The versatility of phage libraries allows for the construction of libraries containing billions of unique sequences, significantly enhancing the diversity and potential for finding high-affinity binders.

5. What are the advantages of using in vivo phage display in research?

   The primary advantage of in vivo phage display is its ability to identify target-specific ligands in the context of an organism's biological environment, accounting for complex factors like tissue penetration and non-specific binding. This method can also rapidly accelerate the discovery phase of drug development by identifying functional ligands that are already optimized for in vivo use.

6. What organisms are typically used in in vivo phage display screening?

   Mice are the most commonly used organisms for in vivo phage display due to their physiological similarities to humans, the availability of numerous genetically defined strains, and their relatively low cost. Other models, such as rats or larger animals, may be used depending on the specific requirements of the research project.

7. What challenges are associated with in vivo phage display?

   In vivo phage display faces challenges including the immune clearance of phage particles, the complexity of in vivo environments affecting phage behavior, and the need for extensive validation of target specificity.

8. How is the specificity of binding agents confirmed in in vivo phage display?

   Specificity is typically confirmed through competitive binding assays, where identified peptides are tested against a range of similar and non-related targets to verify selective binding. Further validation involves the use of blocking experiments and, where possible, knockout models to demonstrate that binding and biological activity are mediated through the intended target.

9. What are the typical outputs of an in vivo phage display experiment?

   The outputs include a set of peptides or proteins that have been enriched in the target tissue over multiple rounds of biopanning. These candidates are then sequenced and synthesized for further characterization in vitro and in vivo to confirm their binding affinity, specificity, and potential therapeutic or diagnostic utility.

10. How is data from in vivo phage display processed and analyzed?

    Data analysis in in vivo phage display involves sequencing the DNA of phages that were recovered from the target tissue to identify the displayed peptides or proteins. Bioinformatics tools are used to analyze sequencing data, compare peptide frequencies, and identify statistically significant enrichments that suggest strong binding to the target.

Resources

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