Luminescent gold nanoclusters for bioimaging applications

Abstract

Luminescent nanomaterials have emerged as attractive candidates for sensing, catalysis and bioimaging applications in recent years. For practical use in bioimaging, nanomaterials with high photoluminescence, quantum yield, photostability and large Stokes shifts are needed. While offering high photoluminescence and quantum yield, semiconductor quantum dots suffer from toxicity and are susceptible to oxidation. In this context, atomically precise gold nanoclusters protected by thiol monolayers have emerged as a new class of luminescent nanomaterials. Low toxicity, bioavailability, photostability as well as tunable size, composition, and optoelectronic properties make them suitable for bioimaging and biosensing applications. In this review, an overview of the sensing of pathogens, and of in vitro and in vivo bioimaging using luminescent gold nanoclusters along with the limitations with selected examples are discussed.

Methylcellulose–Cellulose Nanocrystal Composites for Optomechanically Tunable Hydrogels and Fibers

“…Therefore, as is acknowledged from the start, the aim of the MC-based optical fibers is not to pursue superior long-distance performance and usurp the GOFs; the additional loss caused by the dopants may often be acceptable and not compromise the envisioned applications. Moreover, the dopants may allow multifunctional optical fibers by coupling the material with sensory or luminescent properties, or higher tunable mechanical strength, as has been demonstrated via the addition of gold nanoclusters (AuNCs) ( Figure 8 d,e) [ 36 , 140 , 141 , 142 ]. While such properties and analogous dopants can be typically added to GOFs mainly via their modified cladding layers, in MC fibers, and other biopolymeric fibers, it is possible to make the actual fiber core active and responsive to its environment while still allowing for the further finetuning of the properties via suitable coatings [ 36 , 118 , 120 , 126 , 130 ].…”

Luminescent Gold Nanocluster‐Methylcellulose Composite Optical Fibers with Low Attenuation Coefficient and High Photostability

“…[ 15 ] However, most of the existing luminescent dye molecules and nanomaterials are prone to photobleaching, oxidation, and can be cytotoxic. [ 16–20 ] The POFs have inherently higher attenuation coefficients (0.16–0.30 dB m −1 ) than those of GOFs. [ 7,21 ] Nevertheless, the attenuation coefficient of POFs is sufficient for short length scale applications.…”

Molecular reactivity of thiolate-protected noble metal nanoclusters: synthesis, self-assembly, and applications

“…Due to their small size, strong luminescence, good biocompatibility and efficient renal clearance, metal NCs have potential applications in diverse sectors of biomedicine, like bioimaging, 224,225 cancer therapy 226 and antimicrobial activity. 126,227 The most commonly used molecular reaction of metal NCs in these biomedical applications is covalent conjugation reaction that confers additional functional moieties to NCs, including active targeting moieties 122,124,228,229 and therapeutic moieties.…”