EGF Functionalized Polymer-Coated Gold Nanoparticles Promote EGF Photostability and EGFR Internalization for Photothermal Therapy

Abstract

The application of functionalized nanocarriers on photothermal therapy for cancer ablation has wide interest. The success of this application depends on the therapeutic efficiency and biocompatibility of the system, but also on the stability and biorecognition of the conjugated protein. This study aims at investigating the hypothesis that EGF functionalized polymer-coated gold nanoparticles promote EGF photostability and EGFR internalization, making these conjugated particles suitable for photothermal therapy. The conjugated gold nanoparticles (100–200 nm) showed a plasmon absorption band located within the near-infrared range (650–900 nm), optimal for photothermal therapy applications. The effects of temperature, of polymer-coated gold nanoparticles and of UVB light (295nm) on the fluorescence properties of EGF have been investigated with steady-state and time-resolved fluorescence spectroscopy. The fluorescence properties of EGF, including the formation of Trp and Tyr photoproducts, is modulated by temperature and by the intensity of the excitation light. The presence of polymeric-coated gold nanoparticles reduced or even avoided the formation of Trp and Tyr photoproducts when EGF is exposed to UVB light, protecting this way the structure and function of EGF. Cytotoxicity studies of conjugated nanoparticles carried out in normal-like human keratinocytes showed small, concentration dependent decreases in cell viability (0–25%). Moreover, conjugated nanoparticles could activate and induce the internalization of overexpressed Epidermal Growth Factor Receptor in human lung carcinoma cells. In conclusion, the gold nanoparticles conjugated with Epidermal Growth Factor and coated with biopolymers developed in this work, show a potential application for near infrared photothermal therapy, which may efficiently destroy solid tumours, reducing the damage of the healthy tissue.

Photonic modulation of epidermal growth factor receptor halts receptor activation and cancer cell migration

“…In non‐illuminated cells, EGF induces visible EGFR activation followed by receptor internalization which is in agreement with literature . The work by Silva et al confirmed that such enhancement of green fluorescence was due to the formation of the EGFR‐EGF complex, as the presence of an antibody against EGFR has prevented EGF binding to EGFR and no enhancement of green fluorescence at the cell membrane level and complex internalization were observed .…”

Gold nanoparticles stabilized with βcyclodextrin-2-amino-4-(4-chlorophenyl)thiazole complex: A novel system for drug transport

“…In turn, surface plasmon resonance causes a strong absorption of the incident light, and a portion of this energy is dissipated as local heat, along with the release of molecules from the AuNP surface. Due to these properties, AuNPs are applied in nanomedicine for detection, using techniques such as surface-enhanced Raman spectroscopy [ 35 ] or surface-enhanced fluorescence [ 36 ]; as plasmonic sensors [ 37 ]; for drug transport and release [ 38 – 40 ]; or in photothermal treatments [ 41 – 43 ].…”

Biophysical, photochemical and biochemical characterization of a protease from Aspergillus tamarii URM4634

“…Light is another factor that induces protein conformational changes. UV excitation of the protein's aromatic pool, i.e., tryptophan (Trp), tyrosine (Tyr) and phenylalanine (Phe), also leads to protein conformational changes [16]. UV light induced photo-oxidation of,…”

“…Proteins have a specific interaction within a solvent environment that affects their dielectric relaxation mechanisms [31]. In polar environments there is a reorganization of the solvent's polar molecules along the electric field lines generated by dipoles in the protein [32] and as a consequence, the system relaxes and the protein will emit at longest wavelengths [16].…”

“…UVB excitation of aromatic residues in proteins leads to the disruption of SS bridges and to the formation of photoproducts [38], such as N-formylkynurenine (NFK), kynurenine (Kyn), dityrosine (DT), isodityrosine, trityrosine and pulcherosine [39]. Light at 320 nm excites both NFK, Kyn and DT, and at 360 nm excites NFK and Kyn but does not excite DT [16].…”