Unpacking the “First Molecular Electronics Chip” from Roswell Biotechnologies

Roswell Biotechnologies Inc, a molecular electronics company, recently announced that it has used its patented molecular electronics (ME) platform to create a so-called industry first: an ME semiconductor designed to address biosensing applications. 

 

Molecular electronics sensor on a chip. Image used courtesy of Roswell Biotechnologies

 

From its inception, Roswell Biotechnologies has aimed to digitize biological processes by fabricating molecular electronics that can predict, prevent, and even cure various diseases.

For the ME platform, Roswell has integrated sets of single molecules into electronic circuits that act as sensors. The sensors are said to interpret the dynamic process of molecular interactions into electrical measurements in real-time. The programmable sensor is wired into a fabricated chip to build a universal, scalable, and smart biosensor for a broad range of applications.

Currently, Roswell’s ME platform is being used in drug recovery, molecular diagnostics, and DNA sequencing. 

 

Molecular Sensors on Chip?

Biosensors face various challenges, including detection limits and the requirement for high precision. In the past, engineers have added signal amplification to increase a biosensor system's sensitivity to detect input data. Adding an amplifier, however, yields an overall larger footprint and may generate noise that could create false negatives in rapid testing. 

 

Biosensor embedded in CMOS chip. 

 

Through the ME platform, Roswell says it has demonstrated a programmable biosensor with single-molecule sensitivity. These findings, featured in the Proceedings of the National Academy of Sciences (PNAS), indicate that the biosensor could observe critical molecular interactions that may forge new drug discovery, diagnostics, and DNA sequencing.

Rapidly detecting sensitive measurements is a difficult goal of molecular biotechnology. Complications arise when observing single-molecule analytes that give high signal-to-noise ratios due to fundamental limitations in signal and resolution.

 

Reaping the Benefits of CMOS

Roswell researchers moved away from limiting photon detection methodologies to an electronic approach that doesn't have the same constraints. Each sensor is equipped with a CMOS transimpedance amplifier that scales the currents to millivolt, which helps the circuit measure changes in current flowing through the target. 

 

The architecture of the CMOS sensor array chip. 

 

The team discovered that leveraging CMOS technology—with its proven effectiveness, small size, and scalability—would not only avoid signal feedback limits but also measure smaller molecular movement through a circuit.

The resulting CMOS integrated circuit can support an array of nanoelectrode-based molecular electronics, such as biosensors. The sensors have a molecular wire called a “bridge” that spans an approximately 20nm gap between the ends of nanoelectrodes. The bridge allows for current to flow through and provides current monitoring capabilities.

 

A depiction of sensor nanoelectrodes, illustrating the 20nm gap for the molecular bridge. Image used courtesy of PNAS

 

As the current pulses across the bridge, it represents changes in electrical resistance induced by any dynamic interaction. This results in a direct measurement of molecular interactions with kinetic applications, similar to a photon-detection method but without any signal and resolution issues. 

 

A Goal of Low-cost Testing and Rapid Detection

In the experiments on the sensor’s sensitivity, the researchers found that even at the lowest concentrations, electrical signal pulsed strong enough for the sensor to record an accurate reading and reduce the limits of detection for any test substance. Because the biosensor is CMOS-based, researchers can also produce low-cost testing and rapid label-free detection in real-time.

In the future, Roswell Biotechnologies anticipates that this technology may transform full-genome sequencing, drug-target interactions, and DNA data storage.