Metal-organic frameworks (MOFs) are well-ordered, lattice-like crystals. The nodes of the lattices are metals, which are connected by organic molecules. Their size-controllable nanopores, special structure and large surface area make MOFs very attractive materials for next-generation, highly sensitive gas sensors. In new work, researchers demonstrate a process that can be used for developing low-cost and highly sensitive gas sensors. By increasing the sensitivity, the amount of gas sensitive material and device size can be reduced which in turn would reduce the overall cost of the device and energy consumption.
Nanotechnology materials are going to open new realms of possibility for flexible and stretchable monitoring gadgets that are wearable directly on the skin. Here we look at the latest developments in a class of electronic devices, commonly referred to as electronic skin, epidermal electronics, or electronic tattoos, from the materials, devices, and medical applications perspectives. While such devices can also be used for prosthetics and rehabilitation, optogenetics, and human-machine interfaces, this review focuses on the properties of the materials that enable skin-mounted sensors for use as diagnostic tools in the medical field.
The incidence of food allergies, food sensitivities, and autoimmune reaction is increasing worldwide, particularly among children. Designing a novel device for food testing, researchers have developed a portable, point-of-use technology for rapid, integrated exogenous antigen testing (iEAT). The system consists of a disposable allergen extraction device and an electronic keychain reader for sensing and communication. The extraction kit captures and concentrates food antigens from dispersed food. Captured allergens are then quantified using the miniaturized key-chain reader.
Perovskite materials have attracted great attention in the fields of optoelectronics due to their significant optoelectronic properties. So far, the applications of perovskite thin-films have been limited to solar cells because the required high-definition patterning for optoelectronic devices hadn't been achieved yet. Now, though, researchers in Korea have realized a high-resolution spin-on-patterning (SoP) process for the fabrication of optoelectronic devices arrays such as image sensors.
Current insulin detection methods are time-consuming with a low sensitivity, and are hence not adequate for rapid and direct detection of insulin at clinically appropriate concentrations. A novel graphene nanotechnology sensor is highly sensitive to changes in the charge distribution on and in the immediate vicinity of the graphene surface and can respond to physiological insulin concentration variations in a sensitive and rapid manner, thereby enabling real-time insulin monitoring.
Synthetic nanomotors and DNA walkers, which mimic a cell's transportation system, are intricately designed systems that draw chemical energy from the environment and convert it into mechanical motion. Using such DNA walkers as signal amplifier for nucleic acids detection has only recently been reported. Researchers now report that they converted a DNA walker into a linear fluorescence signal amplifier on a rectangle DNA origami that can improve the detection of target molecules such as nucleic acids.
Researchers have developed a stretchable and transparent graphene-based electronic tattoo (GET) sensor that is only hundreds of nanometers thick but demonstrates high electrical and mechanical performance. They show that a GET can be fabricated through a simple wet-transfer/dry-patterning process directly on tattoo paper, allowing it to be transferred on human skin exactly like a temporary tattoo, except this sensor is transparent. Due to its ultra-thinness, a GET can fully conform to the microscopic morphology of human skin via just van der Waals interactions and can follow arbitrary skin deformation without mechanical failure or delamination for an extended period of time.
Flexible sensors hold great promise for various innovative applications in fields such as medicine, healthcare, environment, and biology. Over the past decade, the development of flexible and stretchable sensors for various functions has been accelerated by rapid advances in materials, processing methods, and platforms. For practical applications, new expectations are arising in the pursuit of highly economical, multifunctional, biocompatible flexible sensors.