This review provides a comprehensive description of nonlinear optical (NLO) properties of gold nanoparticles, which can be used in biological applications The main focus is placed on two-photon absorption (2PA) and two-photon excited photoluminescence (2PEL) - the processes crucial for multiphoton microscopy, which allows deeper imaging of the material and causes less damage to the biological samples in comparison to conventional (one-photon) microscopy We present the basics of 2PA measurement techniques and a summary of recent achievements in the understanding of multiphoton excitation and the resulting photoluminescence in gold nanoparticles, both plasmonic ones and small nanoclusters with molecule-like properties The examples of 2PA applications in bioimaging are also presented, with a comment on future challenges and applications

Two-photon absorption and photoluminescence of colloidal gold nanoparticles and nanoclusters

Multifunctionality of gold nanoparticles: Plausible and convincing properties.

Anisotropic gold nanoparticles: A survey of recent synthetic methodologies

Wearable human machine interfaces (HMI) such as smart gloves have attracted considerable interest in recent years. The quality of the interactive experience with the real and virtual world using wearable HMI technologies depends on the intuitive two‐way haptic interfaces they offer and the real‐time touch‐based information they send and receive. Herein, various smart glove solutions and their application in interaction, rehabilitation, virtual (VR) and augmented reality (AR), and augmentative and alternative communication (AAC) tasks are reviewed. While the early variants of such systems were based on commercial touch sensors and displays integrated (e.g., stitched) on wearables, electronic skin (e‐skin)‐type technologies with multifunctional capabilities are being explored nowadays for rich user experience and comfort. In this regard, instead of using separate touch sensors and actuators, miniaturized integrated devices providing both touch sensing and vibrotactile actuation have also been reported recently. Such advances, the associated challenges, and the advantages they offer for users to enjoy the full characteristic benefits of VR/ARs for interaction, immersion, and imagination are discussed. Finally, the huge potential the smart‐glove‐type solutions hold for advances in various application areas such as robotics, health care, sensorial augmentation for nondisabled and tactile Internet is also discussed.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/aisy.202100091

Smart Tactile Gloves for Haptic Interaction, Communication, and Rehabilitation

Gold Nanostars (GNS) have attracted tremendous attention toward themselves owing to their multi-branched structure and unique properties. These state of the art metallic nanoparticles possess intrinsic features like remarkable optical properties and exceptional physiochemical activities. These star-shaped gold nanoparticles can predominantly be utilized in biosensing, photothermal therapy, imaging, surface-enhanced Raman spectroscopy and target drug delivery applications due to their low toxicity and extraordinary optical features. In the current review, recent approaches in the matter of GNS in case of diagnosis, bioimaging and biomedical applications were summarized and reported. In this regard, first an overview about the structure and general properties of GNS were reported and thence detailed information regarding the diagnostic, bioimaging, photothermal therapy, and drug delivery applications of such novel nanomaterials were presented in detail. Summarized information clearly highlighting the superior capability of GNS as potential multi-functional materials for biomedical applications.

Gold nanostars-diagnosis, bioimaging and biomedical applications

Facile room temperature synthesis of multifunctional CTAB coated gold nanoparticles

Highly Durable Piezoelectric Nanogenerator by Heteroepitaxy of GaN Nanowires on Cu Foil for Enhanced Output Using Ambient Actuation Sources

Flexible self-powered piezoelectric pressure sensor based on GaN/p-GaN coaxial nanowires

Surface enhanced Raman scattering (SERS) is an excellent technique for detecting the trace concentration of targets However, SERS based detection of fluorescent targets is tricky as the fluorescence signal can severely interfere with the SERS signal upon resonance excitation This can limit the trace detection capability of SERS Herein, the authors demonstrate that Au nanostars (NSs) are excellent for fluorescence quenching and trace detection by SERS The NS based SERS substrate was used to measure the R6G concentrations as low as 10 pM upon laser excitation that are in resonance with the fluorescence absorption The authors used a simple seed-mediated and surfactant assisted method to synthesize AuNSs in a wide size range The size of the NSs can be tuned from 55 nm to about 1 μm simply by varying the seed to HAuCl4 ratio in the growth solution

Ameer Abdullah

Papers

Facile room temperature synthesis of multifunctional CTAB coated gold nanoparticles

Highly Durable Piezoelectric Nanogenerator by Heteroepitaxy of GaN Nanowires on Cu Foil for Enhanced Output Using Ambient Actuation Sources

Flexible self-powered piezoelectric pressure sensor based on GaN/p-GaN coaxial nanowires

Facile synthesis of gold nanostars over a wide size range and their excellent surface enhanced Raman scattering and fluorescence quenching properties

Toward stable photoelectrochemical water splitting using NiOOH coated hierarchical nitrogen-doped ZnO-Si nanowires photoanodes