Surface Modification of Luminescent Ln^III Fluoride Core–Shell Nanoparticles with Acetylsalicylic acid (Aspirin): Synthesis, Spectroscopic and in Vitro Hemocompatibility Studies

Abstract

Luminescent lanthanide fluoride core–shell (LaF3:Tb3+,Ce3+@SiO2‐NH2) nanoparticles, with acetylsalicylic acid (aspirin) coated on the surface have been obtained. The synthesized products, which combine the potential located in the silica shell with the luminescent activity of the core, were characterized in detail with the use of luminescence spectroscopy, Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), and transmission electron microscopy (TEM) methods. The in vitro effects of the modified luminescent nanoparticles on human red blood cell (RBC) membrane permeability, RBC shape, and sedimentation rate were investigated to assess the hemocompatibility of the obtained compounds. This study demonstrates that LaF3: Tb3+ 5 %, Ce3+ 10 %@SiO2‐NH2 nanoparticles with acetylsalicylic acid (aspirin) coated on the surface are very good precursors for multifunctional drug‐delivery systems or bio‐imaging probes that can be used safely in potential biomedical applications.

Ligand‐Sensitised LaF3:Eu3+ and SrF2:Eu3+ Nanoparticles and in Vitro Haemocompatiblity Studies

“…The broad emission peak at 414 nm belong to the n!π* transitions of the aspirin molecule. [38,42] The weak emission of Eu 3 + is because of the very weak energy transfer from the ligand to the Eu 3 + ion due to the lesser overlap between Eu 3 + absorption and aspirin emission (Figure 2d). In the case of 1,2,4,5-BTCA-capped LaF 3 :Eu 3 + NPs, the emission spectrum is similar to IA-capped LaF 3 :Eu 3 + NPs, only in the excitation spectra the peak maxima's are observed at 259 nm (high intensity) and 293 nm (low intensity; Figure 2e).…”

“…Based on the results of the standard haemocompatibility assays, it can be concluded that all tested nanoparticles: 1) are nonhaemolytic, namely, no increase in the RBC membrane permeability was observed after both short and long-time incubation, 2) do not alter the discoid shape of RBC (in vitro results mean that they will not adversely affect the rheological properties of RBC and the viscosity of blood in vivo), 3) do not significantly affect the RBC sedimentation rate, 4) compound 6 interacts with the RBC membrane without inducing alteration in the molecular membrane structure, 5) ligand-sensitised LaF 3 :Eu 3 + and SrF 2 :Eu 3 + nanoparticles seem to have similar properties to the previously studied LaF 3 :Tb 3 + , Ce 3 + , @SiO 2 -NH 2 nanoparticles. [38] These findings may be useful in the process of creating new nanoparticles that are nontoxic in vitro for living cells and subsequent research on the delivery of biomolecules, for example, to their target tissues or organs. Our observations proved that the tested nanomaterials are highly biocompatible compounds in vitro and can be further investigated for biomedical application in vivo.…”

“…[39] Moreover, for the compound 5 (aspirin capped LaF 3 :Eu 3 + NPs), the degree of haemolysis is below 5 % after 24 h incubation at the concentrations 1 mg/mL and 0.1 mg/mL which is similar to our previously reported aspirin coted on LaF 3 :Tb 3 + , Ce 3 + @SiO 2 -NH 2 NPs (6.43 % � 1.98). [38] It should also be emphasised here that the most important result of the assessment of the suitability of NPs for in vivo applications is the estimation of their haemolytic activity, after in vitro standard (short-term, namely 1 h) incubation. Therefore, our in vitro results, indicating no significant haemolysis (> 5 % but < 8 %) for compounds 1, 3, 6, and 7 (in the concentration range from 0.1 to 10 mg/mL) after long-term incubation, do not disqualify them from further in vivo research and potential biomedical applications.…”

“…The haemolytic assay is the standard method to determine the cytotoxicity and haemocompatibility of any novel compounds with potential biomedical applications. [35][36][37][38] The in vitro detrimental effects of any new synthetized blood-contacting compounds on the molecular structure of the RBC membrane do not allow their further use in in vivo studies.…”

“…There are many factors responsible for the haemolytic effect of NPs, including their surface properties, chemical structure, the dose used for incubation with cells, type of cells and time of incubation, respectively. The haemolytic assay is the standard method to determine the cytotoxicity and haemocompatibility of any novel compounds with potential biomedical applications [35–38] . The in vitro detrimental effects of any new synthetized blood‐contacting compounds on the molecular structure of the RBC membrane do not allow their further use in in vivo studies.…”