Room-Temperature Harvesting Oxidase-Mimicking Enzymes with Exogenous ROS Generation in One Step.

Despite the advantages of low cost, high stability, and activities, a majority of nanozymes rely on strict synthesis conditions and precise size/structure control, hindering the stable, bulk, and high-yield production that is necessary for general use. To facilitate the transition of nanozymes from benchtop to real-world applications, we herein present a one-step approach, which only needs mixing of two broad commercialized reagents at room temperature, to harvest gold nanoparticles-bovine serum albumin (BSA) nanocomposite (BSA-Au) with distinct oxidase-like activity and good stability in a broad range of harsh conditions. Density functional theory (DFT) calculations demonstrate the oxidase-like activity of BSA-Au stemming from thermodynamically and kinetically favored facets for O2 activation. The reactive oxygen species (ROS) generation of BSA-Au contributes to the catalytic activities and further enables water sterilization and antibacterial applications against superbugs. This one-step strategy promises great potential in bulk production of nanozyme for broad application beyond laboratory use.

Front-end receiver electronics for a matrix transducer for 3-D transesophageal echocardiography.

There is a clear clinical need for creating 3-D images of the heart. One promising technique is the use of transesophageal echocardiography (TEE). To enable 3-D TEE, we are developing a miniature ultrasound probe containing a matrix piezoelectric transducer with more than 2000 elements. Because a gastroscopic tube cannot accommodate the cables needed to connect all transducer elements directly to an imaging system, a major challenge is to locally reduce the number of channels, while maintaining a sufficient signal-to-noise ratio. This can be achieved by using front-end receiver electronics bonded to the transducers to provide appropriate signal conditioning in the tip of the probe. This paper presents the design of such electronics, realizing time-gain compensation (TGC) and micro-beamforming using simple, low-power circuits. Prototypes of TGC amplifiers and micro-beamforming cells have been fabricated in 0.35-µm CMOS technology. These prototype chips have been combined on a printed circuit board (PCB) to form an ultrasound-receiver system capable of reading and combining the signals of three transducer elements. Experimental results show that this design is a suitable candidate for 3-D TEE.