Label-free and real-time detection technologies can dramatically reduce the time and cost of pharmaceutical testing and development. However, to reach their full promise, these technologies need to be adaptable to high-throughput automation. To demonstrate the potential of single-walled carbon nanotube field-effect transistors (SWCNT-FETs) for high-throughput peptide-based assays, we have designed circuits arranged in an 8 × 12 (96-well) format that are accessible to standard multichannel pipettors. We performed epitope mapping of two HIV-1 gp160 antibodies using an overlapping gp160 15-mer peptide library coated onto nonfunctionalized SWCNTs. The 15-mer peptides did not require a linker to adhere to the non-functionalized SWCNTs, and binding data was obtained in real time for all 96 circuits. Despite some sequence differences in the HIV strains used to generate these antibodies and the overlapping peptide library, respectively, our results using these antibodies are in good agreement with known data, indicating that peptides immobilized onto SWCNT are accessible and that linear epitope mapping can be performed in minutes using SWCNT-FET. 1. Introduction Antibody epitope mapping involves a precise localization of its binding site on target proteins and is crucial to understanding protective immune mechanisms [1]. Epitope mapping is also of vital importance to both vaccine and drug developers since exact epitope definitions are of paramount importance for patentability. Label-free and real-time epitope mapping using technologies such as surface plasmon resonance (SPR) can dramatically reduce time and effort involved in monitoring antibody binding because it does not require detection components like secondary antibodies and labeled moieties. SPR measures changes in the refractive index of binding events in real time, but the technology requires an expensive and sophisticated optical system [2, 3]. Another label-free detection technology uses single-walled carbon nanotubes field-effect transistors (SWCNT-FETs) to detect minute changes in charge of binding events. Single-walled carbon nanotubes (SWCNTs) are manufactured nanomaterials and are essentially two-dimensional graphene sheets forged into elongated tubes while retaining the polyaromatic sp2 graphite bonds [4–6]. These nanotubes have a small diameter (~1？nm), consisting solely of a surface where every single carbon atom is in direct contact with the environment. They display unique physical attributes, such as high tensile strength and have excellent semiconductor properties. Exploiting these
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