Interactions of tumour-targeting nanoparticles with proteins: potential of using capillary electrophoresis as a direct probe

Abstract

Metal-based nanoscale particles possess unique optoelectronic or magnetic properties that make them highly promising as imaging agents in cancer therapy research. The fate of nanoparticles in vivo and particularly, the delivery to tumours are closely related to their interactions with plasma proteins. Furthermore, proteins can be used to modify the nanoparticle surface in order to facilitate active targeting to tumours. Therefore, there is an ongoing need for new and more capable analytical methodologies to characterize the protein-nanoparticle binding. Due to the small-sample volume requirement, high degree of resolution and, most importantly, mild, species-friendly separation conditions, capillary electrophoresis (CE) is gaining increasing popularity in the analysis of protein-nanoparticle interaction. This perspective article highlights the potential of CE in studying reactions associated with protein-mediated transformations of nanoparticles, with the focus on quantum dots, gold and iron oxide nanoparticles. Different ways by which CE can be applied to such monitoring are summarized and critically assessed using a representative coverage of recent publications.

Speciation of metal-based nanomaterials in human serum characterized by capillary electrophoresis coupled to ICP-MS: a case study of gold nanoparticles

“…Although previous studies have suggested that increasing the pH of the background electrolyte improves the migration behavior of nanoparticles (by virtue of a greater electrostatic repulsion from negatively charged capillary walls), 10 the preference was given to the buffers with marked buffering capacity around the physiological pH, i.e. pH 7.4.…”

“…7,8 Of these methods, our choice here fell on capillary electrophoresis (CE) due to its proven record in biospeciation analysis. 9 Furthermore, as follows from a recent review in this journal, 10 the benefits of mild, species-friendly separation conditions, a high degree of resolution, and acceptable tolerance to proteinaceous samples paved the way for CE as a direct probe to study the protein binding of MBNs, mostly nanoparticles. One of the few disadvantages of CE in this application area, insufficient sensitivity, can be overcome by employing inductively coupled plasma mass spectrometry (ICP-MS) as a detection method.…”

Detection, characterization and quantification of inorganic engineered nanomaterials: A review of techniques and methodological approaches for the analysis of complex samples

“…As in the case of GE, functionalization of the nanoparticles also plays a critical role in their separation. In this sense, bioconjugated quantum dots [175,176] and protein-nanoparticle interactions [177] are commonly studied by CE. Although metal and metal oxide nanoparticles have been separated by using different inorganic buffers as electrolytes, the addition of ionic surfactants appears to be the most convenient mode for separation of metallic nanoparticles [168][169][170].…”

Functionalized nanomaterials: their use as contrast agents in bioimaging: mono- and multimodal approaches

“…Regardless of composition, surface functionalization of the nanomaterial is required to enable targeting and stealth for long circulation times with minimal nonspecific binding [239]. There is a plethora of entities that can be incorporated onto a NP's surface, with covalent bonding preferred over electrostatic interactions: DNA, RNA, [472] oligonucleotides (aptamers), [29,434,[473][474][475][476] peptides, [36,175,201,[477][478][479][480][481][482] proteins, [483][484][485][486][487] enzymes, [488][489][490][491] antibodies [492]. No matter what the surface moiety, its activity must not be altered once anchored to the NP surface ( Figure 13).…”