(Invited) Immobilization of Nanobodies with Vapor-Deposited Polymer Encapsulation for Robust Biosensors

Abstract

To produce next-generation, shelf-stable biosensors for point-of-care diagnostics, it is imperative to achieve rugged biomolecular recognition elements as well as innocuous deposition approaches for efficient encapsulants. Moreover, to maintain the sensitivity and specificity that is inherent to biological recognition elements in solid-state biosensing systems, site-specific immobilization chemistries must be invoked such that the function of the biomolecule remains unperturbed. In this work, we present a universally applicable strategy to establish robust solid-state biosensors using emergent nanobody (Nb) recognition elements with a vapor-deposited polymer encapsulation layer. As compared to conventional immunoglobulin G (IgG) antibodies, Nbs have multiple advantages, including higher thermal stability and pH tolerance, greater ease of recombinant production, and capable of binding antigens with high affinity and specificity. Photoinitiated chemical vapor deposition (piCVD) provides thin, protective polymer barrier layers over immobilized Nb arrays that allow for retention of biosensing activity and specificity after both storage under ambient conditions and complete desiccation. Most importantly, we also demonstrate that vapor-deposited polymer encapsulation of Nb arrays enables specific detection of target proteins, while suppressing nonspecific binding interactions in complex heterogeneous samples, such as unpurified cell lysate, which is otherwise challenging to achieve with bare Nb arrays. Figure 1