Figure 4. Selected time-lapse photos of the reaction tubes with RT-RPA reactions performed on the 3D printer’s heated bed.
The top photo was taken with ambient light. It shows the placement of the LEDs and reaction tubes. The photos show that one can identify most of the ZIKV positive samples within 10 min (the tubes were vortexed briefly after 4.5 min). One can determine that the samples (10−1, 10−2, 10−3, 10−4, and 10−5 dilution) can be detected by using phone camera as early as 5.5, 5.5, 6, 7.5, and 12 min, respectively. The fluorescent signal growth at the 10−6 tube could not be confidently confirmed. Signals of both negatives remained low throughout the 15 min incubation. Extending the imaging time from 10 to 15 min did not further increase the sensitivity although the final fluorescent signals are higher in the ZIKV positive tubes.