Investigating the bioavailability of graphene quantum dots in lung tissues via Fourier transform infrared spectroscopy

Abstract

Biomolecular fractions affect the fate and behaviour of quantum dots (QDs) in living systems but how the interactions between biomolecules and QDs affect the bioavailability of QDs is a major knowledge gap in risk assessment analysis. The transport of QDs after release into a living organism is a complex process. The majority accumulate in the lungs where they can directly affect the inhalation process and lung architecture. Here, we investigate the bioavailability of graphene quantum dots (GQDs) to the lungs of rats by measuring the alterations in macromolecular fractions via Fourier transform infrared spectroscopy (FTIR). GQDs were intravenously injected into the rats in a dose-dependent manner (low (5 mg kg) and high (15 mg kg) doses of GQDs per body weight of rat) for 7 days. The lung tissues were isolated, processed and haematoxylin-eosin stained for histological analysis to identify cell death. Key biochemical differences were identified by spectral signatures: pronounced changes in cholesterol were found in two cases of low and high doses; a change in phosphorylation profile of substrate proteins in the tissues was observed in low dose at 24 h. This is the first time biomolecules have been measured in biological tissue using FTIR to investigate the biocompatibility of foreign material. We found that highly accurate toxicological changes can be investigated with FTIR measurements of tissue sections. As a result, FTIR could form the basis of a non-invasive pre-diagnostic tool for predicting the toxicity of GQDs.

Biocompatibility and Toxicity of Graphene Quantum Dots for Potential Application in Photodynamic Therapy

“…The toxicity and biosafety of GQDs has not yet been comprehensively examined [49] and uncertainties remain about how such nanomaterials interact with biological substrates, since this is also dependent on the particular physicochemical characteristics of different formulations. In vivo toxicity will further depend on pharmacokinetic and pharmacodynamic parameters as influenced by the route of administration, dose and time period of exposure.…”

“…In general, several synthesis techniques are available and have been widely used for the preparation of GQDs, such as lithography [65,66] , hydrothermal cutting [65,66] and electrochemical preparation [67] . The drawbacks of these methods are the low production yield and the problems associated with the separation and purification of the condensed amorphous carbon phase from low crystalline carbon blacks and fibres [28,49,67] . The resultant product of this partial separation and purification is an oxidized graphite framework and graphene oxide QDs rather than GQDs [65] .…”

Graphene Oxide-Based Targeting of Extracellular Cathepsin D and Cathepsin L As A Novel Anti-Metastatic Enzyme Cancer Therapy

“…Graphene is a two-dimensional sheet composed of a single layer of sp 2 -hybridized carbon atoms arranged in a honeycomb lattice [24]. Graphene and its analogues have attracted tremendous interest over the last decade for use in biomedicine owing to their unique physicochemical and mechanical properties, interesting optical and electronic properties, large surface area and good biofunctionality [25]. GO has many advantages over conventional nanosheets and other derivatives of graphene, such as a small size, chemical inertness, high specific surface area, photo-stability, good water solubility, high drug loading capacity, high purity, good fluorescence capability and biocompatibility.…”

The biomedical applications of graphene

“…Owing to their exceptional properties, in particular biocompatibility, GQDs are considered to be a novel material for biological applications. Their bioavailability in lung tissues is demonstrated by Tabish et al [6], and Justin & Chen [7] illustrate how nano-composites containing GQDs can be used in drug delivery.…”