Multiple
biomarker detection is crucial for early clinical diagnosis,
and it is significant to achieve the simultaneous detection of multiple
biomarkers with the same nanomaterial. In this work, the hairpin DNA
strands were selectively modified on the surface of gold nanorods
(AuNRs) to construct two kinds of nanoprobes by rational design. When
in the presence of dual microRNAs, AuNRs were assembled to form end-to-end
(ETE) and side-by-side (SBS) dimers. Compared with a single AuNR,
the dark-field scattering intensity and red color percentage variation
of dimers were extremely distinguished, which could be developed for
dual microRNA detection by combining the red color percentage and
scattering intensity with the data processing method of principal
component analysis to construct a two-dimensional analysis method.
Especially, the fraction of AuNR dimers presented a linear relationship
with the amount of microRNAs. Based on this, microRNA-21 and microRNA
Let-7a in breast cancer cells were detected with the detection limits
of 1.72 and 0.53 fM, respectively. This method not only achieved the
sensitive detection of dual microRNAs in human serum but also realized
the high-resolution intracellular imaging, which developed a new way
for the oriented assembly of nanomaterials and biological detection
in living cells.