Y-Shaped Deoxyribonucleic Acid Scaffold Pendulums: A One-Step Electrochemical Sensor.

The challenge of developing sensing platforms for the direct monitoring of targets within complex samples is well-recognized. To address this, a one-step electrochemical sensing detection platform was introduced, featuring an innovative Y-shaped DNA molecular pendulum design. The approach deviated from the conventional molecular pendulum mode by employing a split aptamer instead of a full one, thereby enabling the detection of small molecules and low-molecular-weight proteins. Three Y-shaped DNA molecular pendulum configurations were designed: the single-arm, the flexible double-arm, and the stable double-arm Y-shaped DNA molecular pendulum. The results revealed that the Y-shaped scaffold pendulum with a stable two-armed structure not only offered a broader detection range for target concentrations but also produced a more substantial electrical signal enhancement compared to other modes. This enhanced performance is attributed to the stable conformation of this design, which prolongs the time the probe takes to overcome fluid resistance and reach the electrode surface, leading to a more significant alteration in the electrical signal. The sensor can be utilized for one-step detection of enrofloxacin (ENR) in diluted samples (milk, artificial urine, and cosmetics), and its detection range (0.001-100 ng/mL) is fully compliant with the EU maximum residue levels (100 ng/mL) for ENR in milk. Additionally, the sensor can detect myoglobin (Myo) in artificial urine and serum by simply changing the recognized DNA strand. This work provided a simple, expandable idea for the detection of small molecules and low-molecular-weight proteins.