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Owing to their unique optical and chemical properties, gold nanorods (AuNRs) are among the most frequently used nanomaterials for biomedical applications, including cancer therapy, imaging, and drug delivery. In particular, the longitudinal dipole plasmon wavelength of AuNRs can be verified from the visible to the near‐infrared (NIR) region, allowing AuNRs to be used as photodynamic/photothermal and imaging contrast agents. At the same time, the silica shell is important as it enhances stability and facilitates the functionalization and biocompatibility of AuNRs, offering numerous advantages in biomedical applications. In this review, silica‐coated AuNRs from a bioapplication perspective are focused. First, the importance of AuNRs for biomedical applications is explained and the purpose of silica coating on AuNRs is discussed. Then, recent studies on the development of silica‐coated AuNRs from a biomedical perspective are reviewed. Subsequently, various strategies for engineering silica coatings and their properties in the biomedical field are reviewed. This review is expected to promote further research on next‐generation silica‐coated AuNRs for biomedical applications.

Rapid industrial growth has severely impacted ecosystems and aggravated economic and health risks to society. Monitoring of ecosystems is fundamental to our understanding of how ecosystem change impacts resources and is critical for developing data-based sustainability. Thus, the design and development of optimized sensors for ecosystem monitoring have received increasing attention.This review provides a comprehensive overview of systematic sensor design strategies for ecosystem monitoring from the material level to the form factor level. We discuss the fundamental transducing mechanisms of a representative sensor system including optical, electrical, and electrochemical sensors. We then review the sensor interfacing strategy for achieving stable and real-time monitoring of environmental biochemical factors from air, water, soil, and living organisms. Finally, we provide a summary of the current performance and prospects of this state-of-the-art sensor technology and an outlook on opportunities for possible future research directions in this emerging field.

Gold nanoparticles (AuNPs) are useful nanomaterials as transducers for colorimetric sensors because of their high extinction coefficient and ability to change color depending on aggregation status. Therefore, over the past few decades, AuNP-based colorimetric sensors have been widely applied in several environmental and biological applications, including the detection of water pollutants. According to various studies, water pollutants are classified into heavy metals or cationic metal ions, toxins, and pesticides. Notably, many researchers have been interested in AuNP that detect water pollutants with high sensitivity and selectivity, while offering no adverse environmental issues in terms of AuNP use. This review provides a representative overview of AuNP-based colorimetric sensors for detecting several water pollutants. In particular, we emphasize the advantages of AuNP as colorimetric transducers for water pollutant detection in terms of their low toxicity, high stability, facile processability, and unique optical properties. Next, we discuss the status quo and future prospects of AuNP-based colorimetric sensors for the detection of water pollutants. We believe that this review will promote research and development of AuNP as next-generation colorimetric transducers for water pollutant detection.

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