A molecular logic gate is a basic element and plays a key role in molecular computing. Herein, we have developed a label-free and enzyme-free three-input visual majority logic gate which is realized for the first time according to DNA hybridization only, without DNA replacement and enzyme catalysis. Furthermore, a one-vote veto function was integrated into the DNA-based majority logic gate, in which one input has priority over other inputs. The developed system can also implement multiple basic and cascade logic gates.

A logically reversible Feynman gate was successfully realized under enzyme-free conditions by integrating graphene oxide and DNA for the first time. The gate has a one-to-one mapping function to identify inputs from the corresponding outputs. This type of reversible logic gate may have great potential applications in information processing and biosensing systems.

A DNA-based 2:1 multiplexer and 1:2 demultiplexer have been conceptually realized in enzyme-free conditions. For the first time, the designed DNA-based multiplexer could be implemented by keeping input/output signal homogeneity, which has great potential application in information processing.

•A simple and enzyme-free colorimetric assay was developed for cancer cell detection.•The assay was based on nanotechnology and dual-aptamer target recognition.•The developed assay presents high sensitivity, specificity and reproducibility.•Target cancer cells can be distinguised from normal ones and othert cancer cell types.Simple, rapid, sensitive and specific detection of cancer cells is of great importance for early and accurate cancer diagnostics and therapy. By coupling nanotechnology and dual-aptamer target binding strategies, we developed a colorimetric assay for visually detecting cancer cells with high sensitivity and specificity. The nanotechnology including high catalytic activity of PtAuNP and magnetic separation & concentration plays a vital role on the signal amplification and improvement of detection sensitivity. The color change caused by small amount of target cancer cells (10 cells/mL) can be clearly distinguished by naked eyes. The dual-aptamer target binding strategy guarantees the detection specificity that large amount of non-cancer cells and different cancer cells (104 cells/mL) cannot cause obvious color change. A detection limit as low as 10 cells/mL with detection linear range from 10 to 105 cells/mL was reached according to the experimental detections in phosphate buffer solution as well as serum sample. The developed enzyme-free and cost effective colorimetric assay is simple and no need of instrument while still provides excellent sensitivity, specificity and repeatability, having potential application on point-of-care cancer diagnosis.The color change caused by small amount of target cancer cells (10 cells/mL) can be clearly distinguished by naked eyes, which can be used to distinguish target cancer cells (MCF-7) not only from non-cancer cells but also from different cancer cell types.

By a combination of graphene oxide and DNA, a universal platform was developed for integration of multiple logic gates to implement both half adder and half subtractor functions. A constant undefined threshold range between high and low fluorescence output signals was set for all the developed logic gates.

A DNA machine finds its application to construct an enzyme-free, label-free, cost-effective and novel approach for amplified DNA detection. The present approach is endowed with high sensitivity and selectivity. A detection limit as low as 0.2 nM was obtained by practical measurement.

In recent years, aptamer-based biosensors have been quickly developed due to its characteristic such as high sensitivity & selectivity, excellent stability and extensive application in various fields. According to different principles various aptamer biosensors have been designed. In this review, we mainly focused on the development of electrochemical, fluorescent and colorimetric aptamer sensors. The potential development of aptamer-based biosensors has also been discussed.In recent years, aptamer-based biosensors have been quickly developed due to its characteristic such as high sensitivity & selectivity, excellent stability and extensive application in various fields. According to different principles various aptamer biosensors have been designed. In this review, we mainly focused on the development of electrochemical, fluorescent and colorimetric aptamer sensors. The potential development of aptamer-based biosensors has also been discussed.

As a powerful material, DNA presents great advantages in the fabrication of molecular devices and higher-order logic circuits. Herein, by making use of the hybridization and displacement of DNA strands, as well as the formation and dissociation of a G-quadruplex, a simple and universal DNA-based platform is developed to implement half-adder and half-subtractor arithmetic processes. The novel feature of the designed system is that the two required logic gates for the half adder (an AND and an XOR logic gate integrated in parallel) or the half subtractor (an XOR and an INHIBIT logic gate integrated in parallel) are achieved simultaneously with the same platform and are triggered by the same set of inputs. Another novel feature is that the developed half adder and half subtractor are operated by the same DNA platform in an enzyme-free system and share a constant threshold setpoint. These investigations provide a new route towards prototypical DNA-based arithmetic operations and promote the development of advanced logic circuits.

A logically reversible Feynman gate was successfully realized under enzyme-free conditions by integrating graphene oxide and DNA for the first time. The gate has a one-to-one mapping function to identify inputs from the corresponding outputs. This type of reversible logic gate may have great potential applications in information processing and biosensing systems.

A DNA-based 2:1 multiplexer and 1:2 demultiplexer have been conceptually realized in enzyme-free conditions. For the first time, the designed DNA-based multiplexer could be implemented by keeping input/output signal homogeneity, which has great potential application in information processing.

A DNA machine finds its application to construct an enzyme-free, label-free, cost-effective and novel approach for amplified DNA detection. The present approach is endowed with high sensitivity and selectivity. A detection limit as low as 0.2 nM was obtained by practical measurement.

By a combination of graphene oxide and DNA, a universal platform was developed for integration of multiple logic gates to implement both half adder and half subtractor functions. A constant undefined threshold range between high and low fluorescence output signals was set for all the developed logic gates.

A molecular logic gate is a basic element and plays a key role in molecular computing. Herein, we have developed a label-free and enzyme-free three-input visual majority logic gate which is realized for the first time according to DNA hybridization only, without DNA replacement and enzyme catalysis. Furthermore, a one-vote veto function was integrated into the DNA-based majority logic gate, in which one input has priority over other inputs. The developed system can also implement multiple basic and cascade logic gates.