There is growing interest in the development of path coiling-based labyrinthine acoustic metamaterials for realizing extraordinary acoustical properties such as low-to-mid frequency sound absorption. We present a subwavelength labyrinthine acoustic metastructure ($\le$ 3 cm) exhibiting a superior sound absorption with a high bandwidth (more than one octave in the range of 400–1400 Hz). The metastructure is orchestrated of multiple labyrinthine unit cells of different configurations in a hexagonal array, and broadband absorption has been achieved by the dissipation of incident propagating sound waves inside the labyrinthine zigzag channels. Furthermore, the unique design of the metastructure allows for simultaneous air circulation for facilitating natural ventilation and sound absorption. The proposed unique designs may find potential applications in architectural acoustics and noise shielding where simultaneous natural ventilation and noise mitigation are required.

Owing to a steep rise in urban population, there has been a continuous growth in construction of buildings, public or private transport like cars, motorbikes, trains, and planes at a global level. Hence, urban noise has become a major issue affecting the health and quality of human life. In the current environmental scenario, architectural acoustics has been directed towards controlling and manipulating sound waves at a desired level. Structural engineers and designers are moving towards green technologies, which may help improve the overall comfort level of residents. A variety of conventional sound absorbing materials are being used to reduce noise, but attenuation of low-frequency noise still remains a challenge. Recently, acoustic metamaterials that enable low-frequency sound manipulation, mitigation, and control have been widely used for architectural acoustics and traffic noise mitigation. This review article provides an overview of the role of acoustic metamaterials for architectural acoustics and road noise mitigation applications. The current challenges and prominent future directions in the field are also highlighted.

The promising field of organic electronics has ushered in a new era of biosensing technology, thus offering a promising frontier for applications in both medical diagnostics and environmental monitoring. This review paper provides a comprehensive overview of organic electronics’ remarkable progress and potential in biosensing applications. It explores the multifaceted aspects of organic materials and devices, thereby highlighting their unique advantages, such as flexibility, biocompatibility, and low-cost fabrication. The paper delves into the diverse range of biosensors enabled by organic electronics, including electrochemical, optical, piezoelectric, and thermal sensors, thus showcasing their versatility in detecting biomolecules, pathogens, and environmental pollutants. Furthermore, integrating organic biosensors into wearable devices and the Internet of Things (IoT) ecosystem is discussed, wherein they offer real-time, remote, and personalized monitoring solutions. The review also addresses the current challenges and future prospects of organic biosensing, thus emphasizing the potential for breakthroughs in personalized medicine, environmental sustainability, and the advancement of human health and well-being.

In the past two decades, acoustic metamaterials have garnered much attention owing to their unique functional characteristics, which are difficult to find in naturally available materials. The acoustic metamaterials have demonstrated excellent acoustical characteristics that paved a new pathway for researchers to develop effective solutions for a wide variety of multifunctional applications, such as low-frequency sound attenuation, sound wave manipulation, energy harvesting, acoustic focusing, acoustic cloaking, biomedical acoustics, and topological acoustics. This review provides an update on the acoustic metamaterials’ recent progress for simultaneous sound attenuation and air ventilation performances. Several variants of acoustic metamaterials, such as locally resonant structures, space-coiling, holey and labyrinthine metamaterials, and Fano resonant materials, are discussed briefly. Finally, the current challenges and future outlook in this emerging field are discussed as well.