(415d) Nano-Patterning of Multiplexed Bioreceptors Using Thermal Scanning Probe Lithography

Achieving high-resolution multiplexed chemical nanopatterns on surfaces is crucial for biomedical applications, including lab-on-a-chip systems, biosensing, tissue engineering, and cell manipulation studies.

However, technology facilitating the precise nano-assembly of different biomolecules, such as antibodies or aptamers, at specified locations on a surface remains elusive. This challenge stems from various factors, including resolution limitations, the diversity of biomolecule types, spatial accuracy, and the risk of non-specific binding of analytes to unintended locations. Thermal Scanning Probe Lithography (t-SPL ), a nanofabrication technique that involves using a heated silicon probe to locally modify material on a substrate, addresses these issues by selectively patterning thin film surfaces with nanoscale precision to locally activate chemical reactions in an active polymer or resist layer, or directly remove material to expose chemically activated layers underneath a protective resist [1, 2].

To that end, we present an adaptable process, implementing thermal Scanning Probe Lithography, to conjugate different biomolecular receptors, including antibodies and aptamers, to targeted patterns with sub-20 nanometer resolution and a minimum pitch of 200 nanometers [3].

In our study, thin polymer films are deposited on silicon wafers by spin coating. Using t-SPL patterning, the polymer is heated to locally deprotect and expose amine groups for desired surface functionalization, including biotin-streptavidin interactions, thiols, or click-chemistry. Consecutive polymer patterning and surface functionalization steps by drop-casting with different bioreceptors create high resolution patterns with the ability to independently detect a variety of target molecules. Furthermore, in-situ t-SPL topographical imaging and atomic force microscopy (AFM) are used to verify the presence of each bioreceptor after each “patterning and functionalization” step by the changing in pattern depths. This approach enables the creation of chemically or biologically active surfaces for biomedical applications without the need for physical macroscopic barriers that limit the scalability of a system.

1. Albisetti, E., et al., Thermal scanning probe lithography. Nature Reviews Methods Primers, 2022. 2(1).
2. Liu, X.Y., et al., Sub-10 nm Resolution Patterning of Pockets for Enzyme Immobilization with Independent Density and Quasi-3D Topography Control. Acs Applied Materials & Interfaces, 2019. 11(44): p. 41780-41790.
3. Wright, A., et al. Transistors platform for rapid and parallel detection of multiple pathogens by nanoscale-localized multiplexed biological activation (Under Review). 2023.