# Selection and Characterization of SARS‐CoV‐2 Spike Binding Clickmers

## TL;DR

Scientists developed modified DNA aptamers that bind to the SARS-CoV-2 spike protein and work against multiple variants, including Omicron.

## Contribution

A new method using click-SELEX produced DNA aptamers with benzofuran or indole groups that bind SARS-CoV-2 spike with nanomolar affinity and work across variants.

## Key findings

- Clickmers BF1 and N2 bind wild-type SARS-CoV-2 spike with nanomolar affinity and work against Alpha, Delta, and Mu variants.
- A 31-nucleotide indole-functionalized clickmer retains binding to the Omicron variant.
- Structure–function analysis identifies key positions for clickmer binding to the spike protein.

## Abstract

Expanding the chemical repertoire of canonical nucleotides is key to unlocking the full functional potential of aptamers for diagnostic use. Herein, click‐systematic evolution of ligands by exponential enrichment (SELEX) is employed to generate chemically modified DNA aptamers, termed clickmers, that target the SARS‐CoV‐2 spike (CoV2‐S) glycoprotein. Two independent split‐combine selection strategies yield distinct clickmer families functionalized with benzofuran or indole moieties. Lead candidates (BF1 and N2) demonstrate nanomolar affinity for wild‐type CoV2‐S and maintain binding to multiple variants, including Alpha, Delta, and Mu, as validated by flow cytometry, surface plasmon resonance, and microscale thermophoresis. Structure–function analysis reveals essential click‐in positions for both full‐length clickmers and a truncated N2 variant, as short as 31 nucleotides, which displays increased binding to the Omicron variant. These results highlight the versatility of the click‐SELEX platform and exemplify its successful application to a clinically relevant target, advancing previous developments in the field.

Split‐combine click‐systematic evolution of ligands by exponential enrichment against wild‐type SARS‐CoV‐2 spike glycoprotein yields benzofuran‐ and indole‐functionalized DNA aptamers (clickmers). These clickmers retain specific binding to multiple variants with nanomolar affinity, and the 31 nt indole‐functionalized truncate T2 retains binding to Omicron, highlighting the versatility of the platform for diagnostic aptamers.© 2026 WILEY‐VCH GmbH