Identification of erlotinib adsorption pattern onto silver nanoparticles: SERS studies

Abstract

In this study, we present surface‐enhanced Raman spectroscopy (SERS) investigations for the erlotinib adsorbed onto silver nanoparticles (AgNPs). The observed spectral patterns, namely, changes in width and wavenumber of the SERS bands in comparison with these occurring in the corresponding Raman spectrum suggest how the investigated drug interacts with the applied metal nanoparticles. Moreover, the physicochemical investigations including transmission electron microscope, UV–Vis spectroscopy, and electrophoretic mobility measurements were used for characterization of the nanoparticles and erlotinib/nanoparticles stability. Briefly, the performed measurements suggest that the erlotinib strong interacts with the applied AgNPs. Additionally, the studied interaction seems to be the strongest for the acetylene moiety, which undergoes deprotonation. Also the –CNH and –OCH3 groups play an important role in the erlotinib–metal nanoparticles interaction. This is opposite for the CH2, which is only in certain distance from this nanosurface. In the case of the aromatic rings the two different ways of interaction were recognized. The phenyl ring interacts rather weak with the AgNPs and is oriented perpendicular onto the surface. Whereas, the quanizoline moiety only participates in this interaction with more or less tilted orientation with regards to the AgNPs. On the other hand, the SERS analysis for the different erlotinib concentration indicates that the discussed interaction is sensitive for the drug dilution.

Nanoscale image of the drug/metal mono-layer interaction: Tapping AFM-IR investigations

“…The abovementioned spectral patterns indicate that the methoxy moiety is situated perpendicular to the metal surface and contributes significantly to drug adsorption on the AgNPs, while the amino and ethoxy groups are located at a certain distance from the metal mono-layer. The erlotinib orientation on the AgNPs distinguished at nanoscale spatial resolution by the AFM-IR technique corresponds very well with the previously published results obtained using SERS for this drug immobilized on aggregated AgNPs [44]. Different adsorption behaviours of erlotinib immobilized on the AuNP mono-layer (erlotinib-AuNPs) are observed.…”

“…The association of erlotinib with nanoparticle carriers should improve its delivery and decrease its unfavourable cytotoxic effects (e.g., skin rash, diarrhoea, scalp hair loss, increased facial hair) [42,43]. Previously published SERS data have shown that erlotinib adsorbed on silver nanoparticles dispersed in suspensions manifests a strong interaction with the metal surface [44]. However, those SERS data do not answer the question of how the drugs interact locally with the applied metal nanoparticles.…”

Vibrational Fingerprint of Erlotinib: FTIR, RS, and DFT Studies

“…Previously, we have shown surface-enhanced Raman spectroscopy (SERS) investigation of erlotinib immobilized onto potential silver colloidal nanocarriers [9]. ese studies present vibrational spectroscopy characterization by means of Raman spectroscopy (RS) and Fourier-transform infrared absorption spectroscopy (FTIR) of the molecular structure of erlotinib in the solid state and solution in different pH conditions.…”

Recent advances in linear and nonlinear Raman spectroscopy. Part XIII

“…Piergies et al were able to identify adsorption of the pattern of erlotinib onto silver NPs using SERS. They found that the phenyl ring interacts rather weakly with the AgNPs and is oriented perpendicularly onto the surface, whereas the quanizoline moiety only participates in this interaction with a tilted orientation . Pilot described the SERS detection of food contaminants by means of portable Raman instruments.…”

“…They found that the phenyl ring interacts rather weakly with the AgNPs and is oriented perpendicularly onto the surface, whereas the quanizoline moiety only participates in this interaction with a tilted orientation. [46] Pilot described the SERS detection of food contaminants by means of portable Raman instruments. Their investigation included several analytes, including toxins, virus, bacteria, pesticides, forbidden food dyes, and preservatives and reported on the limits of detection and on eventually correlating the SERS results with concentration or separation techniques.…”