HIV‐1 Tat Peptide‐Gemcitabine Gold (III)‐PEGylated Complex—Nanoflowers: A Sleek Thermosensitive Hybrid Nanocarrier as Prospective Anticancer

Abstract

This paper focuses on the synthesis of novel metal‐drugs nanoparticles based onto gold‐gemcitabine complexes relevant for biomedical applications. Gold (HAuCl4) is mixed with antitumor compounds (gemcitabine (GEM)) and dicarboxylic acid–terminated polyethylene‐glycol (PEG), which plays a double role as surfactants and reducing agent. The proposed methodology is fast and reproducible and leads the formation of hybrid‐metal nanoflowers called GEM ION‐PEG‐AuNPs, in which drug solubility and efficiency are improved. The emerging role of GEM ION PEG‐AuNPs in the hyperthermic treatment was applied in pancreatic cancer cells under specific experimental conditions. For this purpose GEM ION‐PEG‐AuNPs are decorated with HIV‐1 Tat peptide, a potent trans‐activator of transcription from the viral promoter and is essential for viral replication containing an activation domain and a nucleic acid‐binding domain. All products are evaluated by various spectroscopic techniques (Raman and UV–vis) and transmission electron microscopy (TEM). This study, revealing an original chemical approach, will employ an important position in the field of nanomedicine, with novel perspectives that will be proposed for the development of new drugs and active targeting in cancer therapy.

Novel Synthesis and Characterization of Doxycycline‐Loaded Gold Nanoparticles: The Golden Doxycycline for Antibacterial Applications

“…This spectroscopical finger print was associated to π-π* electronic transitions due to interactions between the DOXY ring and AuCl 4 − ions [30] making a clear demonstration of the complex formation. In agreement with previously studies, [16,26,27] we arrogate that this band is due to electronic delocalization of aromatic ring and HOMO-LUMO transition and clear up that DOXY was really involved into the nucleation process and builds a complex with Au.…”

“…Gold ions are consequently reduced on the surface of gold nuclei, therefore involving the achievement of spherical gold nanoparticles of smaller sizes, which are embedded and stabilized by DOXY ( Schemes A and ). In order to improve the stability and biological activity of the gold nanoparticles in object, we decided to apply some modification to original synthesis, through the methodology ON and IN extensively described by Spadavecchia and co‐workers …”

“…The AuNPs thus formed were characterized by TEM and have spherical shape (Figure B–b) with a diameter close to 23 ± 4.2 nm, confirmed by the hydrodynamic diameter measured by zetasizer (Table S1, Supporting Information). Previously Spadavecchia and co‐workers have reported the synthesis of similar nanostructures using dicarboxylic PEG obtaining PEG AuNPs as building block of nanovectors …”

“…In order to improve the stability and biological activity of the gold nanoparticles in object, we decided to apply some modification to original synthesis, through the methodology ON and IN extensively described by Spadavecchia and co-workers. [16,19,26,27] Scheme 1B showed a chemical procedure, named methodology IN, in which DOXY and PEG both participate actively to the stabilization of AuNPs via chelation between their chetone and amino groups with chloride auric ions. Chelation sites www.advancedsciencenews.com www.particle-journal.com include the β-diketone system (positions 11 and 12), the enol (positions 1 and 3) and carboxamide (position 2) groups of the A ring (see Figure S1, Supporting Information).…”

“…Previously Spadavecchia and co-workers have reported the synthesis of similar nanostructures using dicarboxylic PEG [16,19,26,31,33] obtaining PEG AuNPs as building block of nanovectors. [16,19,26,27] On the basis of previous studies, when DOXY was conjugate to PEG-AuNPs by carbodiimide chemistry to form DOXY ON-AuNPs, we obtain a nanoconjugate in which DOXY was grafted on the surface of polymer nanoparticle, taking on a different chemical and conformation (see Scheme 4) . We observe a red shift plasmon peak from 515 nm relative at PEG-AuNPs ( Figure 1A, black line) to 525 nm ( Figure 1A, green line) with a different chemical and steric arrangement between PEG and DOXY onto the surface of AuNPs that influences the final size of the nanoparticles.…”