Capture Molecules

Phage antibody technology has generally been used to obtain large numbers of specific capture molecules; however the technology is not applicable to all targets and is protected by third party intellectual property. More recent alternatives are based on aptamers but these, for steric reasons, would not be suitable. The capture molecules that Pastel employs for its InVenio™ technology are proprietary and have been specifically chosen and engineered for purpose. Based on a novel human protein scaffold, Pastel's scientists have randomised the natural binding site to create massive libraries from which individual capture molecules can be selected.


the capture molecules are significantly smaller than antibodies having molecular weights of the order 19Kda as compared to 150Kda
they are composed of a single monomeric polypeptide chain having no cysteine bridges or post-translational modifications
this ensures that they are easily produced in prokaryotic expression systems providing significant cost savings and inexpensive product
both the amino and carboxy terminal sequences are free for engineering the addition of a reporter molecule

Pastel's scientists have expressed these as recombinant proteins and libraries in E.coli and shown excellent levels of production, signal processing and ease of purification.

importantly the target molecule is not required for either immunisation or selection techniques

Reporter molecules

Pastel's scientists have re-engineered the libraries of scaffold molecules with two types of reporter molecule fused to the carboxy terminal of the scaffold protein. This ensures that the molecules, when selected for affinity and specificity, are not subsequently compromised by the addition of a covalently attached reporter. It also simplifies the final manufacturing and quality control process as Pastel moves towards commercialisation.

The two reporter molecules have been chosen to make the capture molecules amenable to use on the two most widely used NGS platforms:
a fluorescent protein | for use on laser/camera based detection platforms
an enzyme with high turnover | for use on chip/FET based detection platforms

Alternative applications

These capture molecules (minus reporter), being based on a common human scaffold protein, have the potential to be used as therapeutics. Pastel has not yet explored this avenue although there is the possibility of creating a pharma arm to the business or out-licensing the molecules to other companies.

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