Fluorescence Screening of DNA-AgNCs with Pulsed White Light Excitation.

ABSTRACT

DNA-stabilized silver nanoclusters (DNA-AgNCs) are a class of fluorophores with interesting photophysical properties dominated by the choice of DNA sequence. Screening methods with ultraviolet excitation and steady state well plate readers have previously been used for deepening the understanding between DNA sequence and emission color of the resulting DNA-AgNCs. Here, we present a new method for screening DNA-AgNCs by using pulsed white light excitation (λex ≈ 490-900 nm). By subtraction and time gating we are able to circumvent the dominating scatter of the white excitation light and extract both temporally and spectrally resolved emission of DNA-AgNCs over the visible to near-infrared range. Additionally, we are able to identify weak long-lived emission, which is often buried underneath the intense nanosecond fluorescence. This new approach will be useful for future screening of DNA-AgNCs (or other novel emissive materials) and aid machine-learning models by providing a richer training data set.