Gold nanoparticles/glycine derivatives/graphene quantum dots composite with tunable fluorescence and surface enhanced Raman scattering signals for cellular imaging

Nisika

Advanced Optical Materials

2020

years, great advances have been made to grow various shaped semiconductor nanocrystals (SNCs) like quantum dots, [7] nanowires, [8] nanorods (NR), [9] and other advanced shaped nanostructures, [10-12] with great precision. However, these semiconductor nanostructures have small extinction cross-sections (even smaller than geometric cross-section), leading to limited absorbance and emission quantum yields. This hinders the progress of semiconductor nanostructures in several areas ranging from clean energy production to various sensing applications. Among many promising solutions, integrating plasmonic nanoparticles (PNPs) with semiconductor nanostructures emerges as the most prominent way to alleviate aforementioned issue. The PNPs have greater extinction cross-section than SNCs (even greater than geometric cross-section), owing to light absorption and scattering by collective and coherent electron oscillations. [13,14] Moreover, these coherent oscillations can couple with electromagnetic wavelengths far greater than particle size, enabling them to guide light to subwavelength scales, thus overcoming diffraction limit. [15] Besides this, proper control over size and shape of plasmonic nanostructures enables engineering of their intrinsic properties to meet the criteria of required application. [16] For instance, by changing the aspect ratio (length to diameter ratio) of nanorods, one can cover wide spectral regions ranging from visible to near-infrared (NIR) regimes. [17] Thus, the integration of plasmonic and semiconductor nanostructures to obtain greater extinction cross-sections and modified properties in these hybrid nanostructures has received great attention from the research community over the past years. The properties of these hybrid nanostructures can be very different from the two nanoconstituents (metal and semiconductor nanostructures), owing to plasmon-exciton interactions. [18-20] Various configurations of metal/semiconductor nanostructures have been synthesized like metallic core/semiconductor shell, [21] semiconductor NR/metal nanoparticles (MNPs), [22] Janus metal/ semiconductor nanostructures, [23] and many others have been reported, [24-26] with varying absorption and emissive properties, targeting high performance applications. The energy transfer between metal-semiconductor nanostructures resulting from integration of PNPs and SNCs Hybrid nanostructures composed of metal and semiconducting nanocrystals have drawn tremendous attention owing to their extraordinary absorption and emission properties. The energy transfer in metal-semiconductor hybrids as a result of synergetic plasmon-exciton interactions leads to numerous applications in the field of solar energy harvesting, photocatalytic reactions, imaging, photonics, sensing, and many more. Various breakthroughs in advanced characterization techniques over the past decade have disclosed several factors affecting the energy transfer processes leading to modified absorption and emission properties in metal-semiconductor hybrids. Herein, various ...

Section: Plasmonic Nanostructures Enhanced Applicationsmentioning

confidence: 99%

Modified Absorption and Emission Properties Leading to Intriguing Applications in Plasmonic–Excitonic Nanostructures

Nisika

Advanced Optical Materials

2020

“…For example, the enhancement factor of Au nanoparticles at NIR excitation wavelength has been found decreasing in the order: nanostars > nanorods > nanosphere . Hollow shell Au nanoparticles are morphologies with high enhancement factors utilized for cancer cell imaging. Studies showed discrimination among normal cells and subtypes of cancer cells based on the density and expression of folate receptor in cell membranes due to their expression in several cancer types.…”

Section: In Vitro Detection Of Cells/tissuesmentioning

confidence: 99%

Advances in surface‐enhanced Raman spectroscopy for cancer diagnosis and staging

Chakraborty

Ghosh

Barui

2019

J Raman Spectroscopy

Surface‐enhanced Raman spectroscopy (SERS) is rapidly emerging as a bioanalytical tool for cancer diagnosis and therapy. The SERS‐based molecular diagnostics have progressed from proof‐of‐concept studies towards analysis in animal models as well as for in vitro clinical diagnostics in the last decade. Recently, SERS has also been implemented in screening, diagnosis, and staging of clinical cancer samples. Moreover, in vivo SERS imaging has been implemented for mapping the extent of tumor growth and metastasis; SERS nanoparticles have also enabled image‐guided therapies strongly indicating SERS technology can significantly complement the practice of oncology. Despite the progress, widespread clinical translation of SERS nanoparticles is still challenging. Current SERS strategies in diagnostic oncology require further development and standardization to progress from bench‐top to point‐of‐care applications. The present review critically analyzes the current state of the art about various strategies for SERS‐based cancer detection and staging from cellular metabolites, exosomes, circulating tumor cells, extracellular fluids, and cancer cells.

ACS Appl. Mater. Interfaces

“…These nanomaterials include quantum dots (QDs), metal nanoparticles, rare-earth-metal-doped nanoparticles, inorganic dye-doped silica nanoparticles, polymer-encapsulated organic nanoparticles, and carbon nanomaterials. − Previously, semiconducting QDs were ideal fluorescent probes, but due to the fact that most of these QDs are composed of heavy metals such as cadmium, which can cause both biological and environmental hazards in large enough quantities, alternative materials such as graphene and carbon have been considered. , The derivative material of graphene has several important properties from mechanical to thermal with recent developments that have shown an increase in research interest for graphene quantum dots (GQDs). The most favorable characteristics include low toxicity, chemical inertness, stability, and biocompatibility compared to traditional QDs. − GQDs also present fluorescence properties, which allows GQDs to be used in the detection of both inorganic and organic materials such as metal ions, organic polymer molecules, and anions . In particular, fluorescence itself has been a vital tool for the development of imaging techniques to visualize key details in living cells and animals without involving potentially harmful radioactivity or electron burning .…”

Section: Introductionmentioning

confidence: 98%

Synthesis of Highly Near-Infrared Fluorescent Graphene Quantum Dots Using Biomass-Derived Materials for In Vitro Cell Imaging and Metal Ion Detection

Reagen

Liu

et al. 2021

Graphene quantum dots (GQDs) are a subset of fluorescent nanomaterials that have gained recent interest due to their photoluminescence properties and low toxicity and biocompatibility features for bioanalysis and bioimaging. However, it is still a challenge to prepare highly near-infrared (NIR) fluorescent GQDs using a facile pathway. In this study, NIR GQDs were synthesized from the biomass-derived organic molecule ciscyclobutane-1,2-dicarboxylic acid via one-step pyrolysis. The resulting GQDs were then characterized by various analytical methods such as UV−Vis absorption spectroscopy, fluorescence spectroscopy, dynamic light scattering, high-resolution transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Moreover, the photostability and stability over a wide pH range were also investigated, which indicated the excellent stability of the prepared GQDs. Most importantly, two peaks were found in the fluorescence emission spectra of the GQDs, one of which was located in the NIR region of about 860 nm. Finally, the GQDs were applied for cell imaging with human breast cancer cell line, MCF-7, and cytotoxicity analysis with mouse macrophage cell line, RAW 246.7. The results showed that the GQDs entered the cells through endocytosis on the fluorescence images and were not toxic to the cells up to a concentration of 200 μg/mL. Thus, the developed GQDs could be a potential effective fluorescent bioimaging agent. Finally, the GQDs depicted fluorescence quenching when treated with mercury metal ions, indicating that the GQDs could be used for mercury detection in biological samples as well.