A clustered regularly interspaced short palindromic repeats (CRISPR)/ Cas12a-mediated dual-mode electrochemical biosensor without polymerase chain reaction (PCR) amplification was designed for sensitive and reliable detection of genetically modified soybean SHZD32-1. A functionalized composite bionanomaterial Fe 3 O 4 @AuNPs/DNA-Fc&Ru was synthesized as the signal unit, while a characteristic gene fragment of SHZD32-1 was chosen as the target DNA (tDNA). When Cas12a, crRNA, and tDNA were present simultaneously, a ternary complex Cas12a-crRNA-tDNA was formed, and the nonspecific cleavage ability of the CRISPR/Cas12a system toward single-stranded DNA was activated. Thus, the single-stranded DNA-Fc in the signal unit was cleaved, resulting in the decrease in the fast scan voltammetric (FSV) signal from ferrocene (Fc) and the increase in the electrochemiluminescence (ECL) signal from ruthenium complex (Ru) inhibited by Fc. The linear range was 1−10 7 fmol/L for ECL and 10−10 8 fmol/L for FSV, and the limit of detection (LOD) was 0.3 fmol/L for ECL and 3 fmol/L for FSV. Accuracy, precision, stability, selectivity, and reliability were all satisfied. In addition, PCR-free detection could be completed in an hour at room temperature without requiring complicated operation and sample processing, showing great potential in the field detection of genetically modified crops.

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Abstract-MOS Current-Mode Logic (MCML) is usually used for high-speed applications. However, the large static power dissipation of MCML circuit limits its application in portable devices. In this work, we proposed a power-gating (PG) technique to reduce the standby power of the near-threshold MCML. The PG 1-bit full adder and a mod-10 counter are designed and simulated using HSPICE at 45nm CMOS technology with predictive technology model (PTM) model. The simulation results show that the standby power of the PGadder and PG-counter is only 1.0nW and 3.0 nW, respectively. And the performance of the PG MCML circuits does not deteriorate.

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