End-Functionalized Poly(vinylpyrrolidone) for Ligand Display in Lateral Flow Device Test Lines

Area of Science:

• Materials Science
• Biotechnology
• Analytical Chemistry

Background:

• Lateral flow devices (LFDs) are common point-of-care diagnostics, often using antibody-based test lines.
• Current methods for immobilizing non-protein ligands require carrier proteins, involving complex modifications and purification.
• There is a need for alternative, protein-free materials to functionalize LFD test lines.

Purpose of the Study:

• To investigate poly(vinylpyrrolidone) (PVP) as a polymeric, protein-free alternative for LFD test lines.
• To demonstrate the immobilization of small-molecule capture agents onto PVP and subsequently onto nitrocellulose.
• To validate an "all-polymer" approach for creating functional LFD test lines.

Main Methods:

• Synthesis of end-functionalized PVPs via RAFT polymerization.
• Installation of model capture ligands (biotin, galactosamine) onto PVP.
• Immobilization of PVP-ligand conjugates onto nitrocellulose stationary phase.
• Validation in flow-through and lateral flow formats using streptavidin and soybean agglutinin.

Main Results:

• PVP demonstrated a balance of water solubility for printing and adhesion to nitrocellulose.
• Successful immobilization of biotin and galactosamine onto PVP and nitrocellulose was achieved.
• The all-polymer test line was validated in both flow-through and lateral flow configurations.
• This represents the first demonstration of an all-polymer approach for capture unit installation in LFDs.

Conclusions:

• Poly(vinylpyrrolidone) is a viable candidate for protein-free LFD test lines.
• Polymeric scaffolds can serve as effective anchoring agents for small-molecule capture agents.
• Macromolecular engineering offers a pathway to develop next-generation, robust, and modular lateral flow devices.