Amplification of RNA for identification of Zika and HCV in whole blood
- Jongwon Lim
- Hankeun Lee
- Matthew Wester
- Katherine Koprowski
- An Bao Van
- Enrique Valera
- Brian T. Cunningham
- Rashid Bashir
2026-09-04
Direct RNA amplification from whole blood is fundamentally limited by rapid enzymatic degradation and inhibitory matrix effects. Here, we present a blood drying protocol that enables sensitive and robust RNA detection without the need for extraction, purification, or cold-chain logistics. Using whole blood, the platform achieves high detection sensitivity, down to 10 copies per microliter for Zika virus and 1 international unit per microliter for hepatitis C virus (HCV). We further demonstrate that the protocol can be scaled to larger blood volumes and achieve single-copy sensitivity without any sample loss. This is accomplished through thermal treatments of the sample combined with a primer-limited reverse transcription step, which together stabilize RNA within a dried blood matrix and permit spatially resolved enzymatic amplification. The system supports multiplexed detection from a single sample, enabling simultaneous identification of multiple targets. Separately, we introduce a concept wherein the very few copies of the preserved RNA within the matrix can be accessed repeatedly for molecular analysis. Furthermore, we demonstrated the detection of Zika and HCV using a portable fluorometer for point-of-care (POC) uses. With lyophilized reagents and minimal instrumentation such as a heater and an inexpensive portable fluorometer, this platform enables robust, reusable, and field-deployable diagnostics, advancing toward truly accessible on-site RNA testing in urgent care or low-resource settings from whole blood.