Biodegradable Bi2 O2 Se Quantum Dots for Photoacoustic Imaging-Guided Cancer Photothermal Therapy.

As new 2D layered nanomaterials, Bi2 O2 Se nanoplates have unique semiconducting properties that can benefit biomedical applications. Herein, a facile top-down approach for the synthesis of Bi2 O2 Se quantum dots (QDs) in a solution is described. The Bi2 O2 Se QDs with a size of 3.8 nm and thickness of 1.9 nm exhibit a high photothermal conversion coefficient of 35.7% and good photothermal stability. In vitro and in vivo assessments demonstrate that the Bi2 O2 Se QDs possess excellent photoacoustic (PA) performance and photothermal therapy (PTT) efficiency. After systemic administration, the Bi2 O2 Se QDs accumulate passively in tumors enabling efficient PA imaging of the entire tumors to facilitate imaging-guided PTT without obvious toxicity. Furthermore, the Bi2 O2 Se QDs which exhibit degradability in aqueous media not only have sufficient stability during in vivo circulation to perform the designed therapeutic functions, but also can be discharged harmlessly from the body afterward. The results reveal the great potential of Bi2 O2 Se QDs as a biodegradable multifunctional agent in medical applications.

Photonic Crystal-Integrated Optoelectronic Devices with Naked-Eye Visualization and Digital Readout for High-Resolution Detection of Ultratrace Analytes.

The detection of ultratrace analytes is highly desirable for the non-invasive monitoring of human diseases. However, a major challenge is fast, naked-eye, high-resolution ultratrace detection. Herein, a rectangular 3D composite photonic crystal (PC)-based optoelectronic device is first designed that combines the sensitivity-enhancing effects of PCs and optoelectronic devices with fast and real-time digital monitoring. A crack-free, centimeter-scale, mechanically robust ellipsoidal composite PCs with sufficient hardness and modulus, even exceeding most plastics and aluminum alloys, are developed. The high mechanical strength of ellipsoidal composite PCs allows them to be hand-machined into rectangular geometries that can be conformally covered with the centimeter-scale flat light-detection area without interference from ambient light, easily integrating 3D composite PC-based optoelectronic devices. The PC-based device's signal-to-noise ratio increases dramatically from original 30-40 to ≈60-70 dB. Droplets of ultratrace analytes on the device are identified by fast digital readout within seconds, with detection limits down to 5 µL, enabling rapid identification of ultratrace glucose in artificial sweat and diabetes risk. The developed 3D PC-based sensor offers the advantages of small size, low cost, and high reliability, paving the way for wider implementation in other portable optoelectronic devices.

Future foods: Design, fabrication and production through microfluidics.

Many delicious foods are soft matter systems with health ingredients and unique internal structures that provide rich nutrition, unique textures, and popular flavors. Obtaining these special properties in food products usually requires specialized processes. Microfluidic technologies have been developed to physically manipulate liquids to produce a broad range of microunits, providing a suitable approach for precise fabrication of functional biomaterials with desirable interior structures in a bottom-up fashion. In this review, we present how microfluidics has been applied to produce gel-based structures and highlight their use in fabricating novel foods, focusing on, among others, cultured meat as a rapidly growing field in food industry. We first discuss the behaviors of food liquids in microchannels for fluidic structure design. Then, different types of microsized building blocks with specific geometries fabricated through microfluidics are introduced, including particles (point), fibers (line), and sheets (plane). These well-defined units can encapsulate or interact with cells, forming microtissues to construct meat products with desirable architectures. After that, we review approaches to scale up microfluidic devices for mass production of the hydrogel building blocks and highlight the challenges associated with bottom-up food production.