Fluorescent
aptamer beacons (FABs) are a major category of biosensors
widely used in environmental analysis. However, due to their low compatibility,
it is difficult to use the common FABs for biological samples. To
overcome this challenge, construction of FABs with complex structures
to adapt the nature of biological samples is currently in progress
in this field. Unlike previous works, we moved our range of vision
from the FAB itself to the biological sample. Inspired by this idea,
in this work, flat membrane-based liquid-phase microextraction (FM-LPME)
with sufficient sample cleanup and preconcentration capacities was
integrated with FABs. With the merits of both FM-LPME and FABs, the
integrated LPME-FAB system displayed a clear synergistic enhancement
for target analysis. Specifically, LPME in the LPME-FAB system provided
purified and enriched Hg2+ for the FAB recognition, while
the FAB recognition event promoted the extraction efficiency of LPME.
Due to superior performances, the LPME-FAB system achieved highly
sensitive analysis of Hg2+ in urine samples with a detection
limit of 27 nM and accuracies in the range of 98–113%. To the
best of our knowledge, this is the first time that an integrated LPME-FAB
system was constructed for target analysis in biological samples.
We believe that this study will provide a new insight into the next
generation of biosensors, where the integration of sample preparation
with detection probes is as important as the design of complex probes
in the field of bioanalysis.