Advanced Materials Technologies最新文献

Electroporation of dye-labeled bio-molecules into bacteria has proven to be a valuable route for single-molecule tracking in living cells. However, control over cell viability, electroporation efficiency, and environment conditions before, during, and after electroporation is difficult to achieve in bulk experiments. Here, a microfluidic platform is presented capable of single-cell electroporation with in situ microscopy and demonstrate delivery of DNA into bacteria. Via real time observation of the electroporation process, it is found that the effect of electrophoresis plays an important role when performing electroporation in a miniaturized platform and show that its undesired action can be balanced by using bipolar electrical pulses. It is suggested that a low temperature of the sample during electroporation is important for cell viability due to temperature-dependant viscoelastic properties of the cell membrane. It is further found that the presence of low conductive liquid between cells and the electrodes leads to a voltage divider effect that strongly influences the success of on-chip electroporation. Finally, it is concluded that electroporation is a highly stochastic process and envision that the microfluidic system presented here, capable of single-cell read-out, can be used for further fundamental studies to increase the understanding of the electroporation process in bacterial cells.

In vitro neuronal culture is an important research platform in cellular and network neuroscience. However, neurons cultured on a homogeneous scaffold form dense, randomly connected networks and display excessively synchronized activity; this phenomenon has limited their applications in network-level studies, such as studies of neuronal ensembles, or coordinated activity by a group of neurons. Herein, polydimethylsiloxane-based microfluidic devices are developed to create small neuronal networks exhibiting a hierarchically modular structure resembling the connectivity observed in the mammalian cortex. The strength of intermodular coupling is manipulated by varying the width and height of the microchannels that connect the modules. Neuronal activity recording via calcium imaging shows that the spontaneous activity in networks with smaller microchannels (2.2–5.5 µm²) has lower synchrony and exhibits a threefold variety of neuronal ensembles. Optogenetic stimulation demonstrates that a reduction in intermodular coupling enriches evoked neuronal activity patterns and that repeated stimulation induces plasticity in neuronal ensembles in these networks. These findings suggest that cell engineering technologies based on microfluidic devices enable in vitro reconstruction of the intricate dynamics of neuronal ensembles, thus providing a robust platform for studying neuronal ensembles in a well-defined physicochemical environment.

Type-II Superlattice Infrared Sensors

In article number 2400374, Sang Jun Lee, Won Seok Chang, and co-workers fabricate a type-II superlattice mid-wavelength infrared photodetector, seamlessly integrated with a nanostructured wire grid polarizer using nanoimprint lithography. The surface of the wire grid polarizer is polished with femtosecond pulse laser, which dramatically reduces optical losses while maximizing polarization efficiency, known as the extinction ratio. This breakthrough paves the way for next-generation high-performance infrared imaging systems, revolutionizing MWIR detection with unprecedented capabilities.

A major aspiration in advanced materials is to create artificial adhesive surfaces for wearable medical devices to meet the demands of the body's challenging settings and dynamics. For instance, dentures replace missing teeth and operate within the oral cavity, where an interplay between forces, muscles, saliva, and roughness of mucosa undermine their ability to grip oral tissues. Consequently, the lack of effective retentive strategies represents a source of dissatisfaction for denture wearers globally. Nature is rich in examples that employ physical and chemical adhesive strategies to optimize interfacial forces in dry and wet environments. Here, keratin-coated octopus-like suction cups are presented at the micro- and macroscale to improve the retention of rigid poly(methyl methacrylate). Microtopographies are obtained using two-photon polymerization and maskless lithography, while denture prototypes with macrotopographies are derived via digital light processing 3D printing. Results suggest that microtopographies and keratin-coated surfaces sustain higher maximum adhesion stress than the non-topographical and non-coated surfaces in moist environments, where retention is typically lacking. Proof-of-concept dentures demonstrate higher maximum detachment forces than conventional dentures with and without denture adhesive within dry and wet environments. This interdisciplinary research highlights the potential application of a nature-inspired physico-chemical approach in the next generation of complete dentures.

Nanomechanical Transducers

In article number 2400127, Robert H. Blick and co-workers show that integrating piezoelectric ceramics with silicon nanomembranes creates a unique sensor/actuator for the tympanic membrane, enabling kHz-range sound transmission via radio frequency. Demonstrated using a nanomembrane on a piezoelectric chip, it drives an audible mechanical response. An antenna enables remote actuation, proving a feasible invisible hearing aid.

High-Throughput Screening

In article number 2400634, Sanghee Yoo, Noo Li Jeon, and co-workers introduce a high-throughput microphysiological platform for modeling the outer blood-retinal barrier (oBRB) in a 96-well format. This system enables comprehensive evaluation of retinal barrier function, including cellular interactions through transepithelial electrical resistance, permeability assays, and confocal imaging, along with gene expression (RNA analysis) and protein secretion studies. It is designed for high-content drug screening, offering valuable insights into retinal diseases such as age-related macular degeneration.

Hybrid Electrodes

In article number 2401054, Han-Ki Kim and co-workers develop highly flexible, transparent, and conductive polytetrafluoroethylene/AgPdCu/indium zinc oxide hybrid films for use in transparent and flexible thin-film heaters integrated into electric vehicles.

Aerosol Jet Printing

The image represents the use of dual-material aerosol jet printing technology to fabricate small-scale magnetically responsive soft objects with complex shapes and programmable functions whose movements can be controlled by the application of an external magnetic field. In article number 2400463, Silvia Taccola, Russell A. Harris, and co-workers show that it focuses on the in-process mixing of the materials in the form of aerosols, allowing the in-process control of the composition.

Capacitive touch screens (CTS's) are essential components in most of today's digital devices. However, for the visually impaired (VI) users due to the uneven topography of the tactile surface, CTS's are more challenging to implement and thus this field remains largely underdeveloped. Considering the limited space around the microactuators driving the typical Braille dots for a tactile screen with ten dots-per-inch (dpi) resolution, the materials used for CTS should be flexible and durable with high mechanical strength. In this work, a flexible CTS based on polyimide (PI) and silver nanowires (AgNWs) as electrodes with a total thickness of 210 µm is developed. The dimensions of the AgNWs are on average 7.9 ± 2.4 µm in length and 85 ± 24 nm in width. The AgNWs electrodes showed low resistance and good adhesion to the PI substrate. A gesture recognition application is collected from the capacitive data to classify different gestures (including single- and double-click, swipe-left and -right, scroll-up and -down as well as zoom-in and -out) with two different approaches; machine learning and deep learning are implemented. The best performance is obtained using the YOLO model with a high validation accuracy of 97.76%. Finally, a software application is developed with the proposed hand gestures in real-time to foster interaction of VI users with the tactile display allowing them to navigate a Windows file system and interact with the documents via hand gestures in a similar manner as sighted users on a conventional touch display will be able to do. This work paves the way to utilize CTS for the tactile displays in the market developed for VI users.