The protein corona (PC) that forms around nanomaterials upon exposure to human biofluids (e.g., serum, plasma, cerebral spinal fluid etc.) is personalized, i.e., it depends on alterations of the human proteome as those occurring in several cancer types [1]. This may relevant for early cancer detection when changes in concentration of typical biomarkers are often too low to be detected by blood tests.Recent advances in nanotechnology have provided promising outcomes that could pave the way to future developments of early diagnostic tools. Among nanomaterials under development for in vitro diagnostic testing, Graphene Oxide (GO) is regarded as one of the most promising ones due to its intrinsic properties and peculiar behavior in biological environments [2]. By taking advantage of these principles, herein it is proposed an innovative diagnostic technique for early cancer detection based on the characterization of the PC that forms around Graphene Oxide (GO) nanoflakes. In contrast to mass spectrometry, the power of this approach does not rely on the discovery of cancer biomarkers, but rather on the overall evaluation of the protein pattern by means of sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Moreover, the developed tool meets the ASSURED (Affordable, Sensitive, Specific, User-friendly, Rapid and robust, Equipment-free and Deliverable to end-users) criteria stated by the World Health Organization (WHO) for cancer screening and detection and needs just one drop of patient's blood. We predict that a systematic investigation of GO-PC may improve our knowledge of several tumor biology and that a PC-based technology may offer new opportunities for cancer detection and biomarkers identification.
The principle behind the project is that the graphene oxide-protein corona (GO-PC) composition changes significantly as the pathological conditions change. The diagnostic method described is highly innovative ,in fact, in the oncological medical field and especially in diagnostic research, currently, the identification of metabolic alterations in the blood is limited to high resolution proteomics techniques [1]. Among these, mass spectrometry is the most widely used internationally as it enjoys a high specificity and selectivity in the separation and identification of individual biomarkers. Nevertheless, the limit of this technique, lies in the high costs and laborious procedures that must be developed for each individual experiment. On the contrary, the technology herein described, uses highly manageable and inexpensive analytical measurements. Indeed, the exclusive use of one-dimensional electrophoretic gel (1D SDS-PAGE) for protein separation and identification does not require a high qualification degree or high timing. In addition, this technology has a greater sensibility if compared to the conventional blood tests which very often fail in the detection of small protein alterations in human proteome. We will use GO NPs, as ¿nano-concentrators¿ of blood plasma proteins. Despite an intense research activity on graphene-based nanomaterials, the corresponding perspectives of application in cancer diagnosis and screening are poorly explored. However, due to its peculiar chemical-physical properties, GO is particularly suitable for the development of NP-based blood tests. Indeed, the exposure of GO to plasma of patients with cancer significantly affects the composition of GO-PC complexes. Furthermore, with respect to other materials, GO has the lowest affinity to albumin [2]. Albumin is the most abundant protein in blood and is often found in the BC of many nanomaterials. It gives rises to a high intensity band at 60 kDa on electrophoretic gels thus lowering the resolution of the SDS-PAGE analysis. This adsorption limits the adsorption of other proteins, which are typically present at low concentration in human plasma and could be hallmark of cancerogenesis. We aim to exploit the extraordinary adsorption ability of GO NPs to improve resolution and accuracy of the protein patterns associated to different classes of tumors. This may lead to the ground-breaking ability of detecting changes in the PC even when the total quantity of single protein biomarkers is about the same for cancer and healthy patients. As a result, we predict that this approach could improve the sensitivity and specificity of NP-based blood test for early cancer diagnosis and could help identify different cancer stages by a simple, non-invasive tool.
[1] Caputo, D., et al Nanoscale 9.1 (2017) 349-354.
[2] M. Sopotnik et al., Carbon 95 (2015)