Recent studies have demonstrated that drug antimicrobial activity is enhanced when metallic nanoparticles are used as an inorganic support, obtaining synergic effects against microorganisms. The cationic antimicrobial peptide ubiquicidin 29–41 (UBI) has demonstrated high affinity and sensitivity towards fungal and bacterial infections. The aim of this research was to prepare and evaluate the antimicrobial efficacy of engineered multivalent nanoparticle systems based on silver or gold nanoparticles functionalized with UBI. Spectroscopy techniques demonstrated that NPs were functionalized with UBI mainly through interactions with the -NH2 groups. A significant increase in the antibacterial activity against Escherichia coli and Pseudomonas aeruginosa was obtained with the conjugate AgNP-UBI with regard to that of AgNP. No inhibition of bacterial growth was observed with AuNP and AuNP-UBI using a nanoparticle concentration of up to 182 μg mL−1. Nonetheless, silver nanoparticles conjugated to the UBI antimicrobial peptide may provide an alternative therapy for topical infections.

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A novel targeted drug delivery nanoparticle system based on poly(D,L-lactide-co-glycolide) acid (PLGA) for delivery of doxorubicin (DOX) was developed. DOX-PLGA NPs were obtained by the emulsification-solvent evaporation technique. Then, their surface was modified with poly(L-γ-glutamic acid) (γ-PGA) and finally conjugated to modified folic acid (FA) as a targeting ligand. The surface modification and FA conjugation were followed by UV-Vis and FT-IR spectroscopies. Morphology was observed by TEM/SEM. Particle size, PDI and zeta potential were measured using DLS studies. Encapsulation and loading efficiencies, and DOX release kinetics were determined. Specific uptake and cell viability of DOX-PLGA/γ-PGA-FA NPs were tested in HeLa cells. Quasi-spherical nanoparticles with a particle size lower than 600nm (DLS) were obtained. Spectroscopic techniques demonstrated the successful surface modification with γ-PGA and FA conjugation. Release profile of DOX-PLGA/γ-PGA-FA NPs showed a release of 55.4±0.6% after seven days, in an acidic environment. HeLa cells exhibited a decrease in viability when treated with DOX-PLGA/γ-PGA-AF NPs, and cellular uptake was attributed to FA receptor-mediated endocytosis. These results suggest that DOX-PLGA/γ-PGA-FA NPs are a potential targeted drug carrier for further applications in cancer therapy.

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A green method for synthesizing iron oxide nanorods within orange peel pith has been developed. Orange peel pith functions as both a support and a reducing agent for iron ions. The nanorods were characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. Results of the characterization indicate that iron is deposited on the surface of orange peel primarily in the form of iron, iron(II) oxide and magnetite. The nanoparticles grow to form nanorods in the range of 20-40 nm of diameter. The biocomposite was then tested for Cr(VI) reduction and removal from aqueous solutions, exhibiting removals as high as 96% for concentrations of 10 mg/L and 76% for 50 mg/L, which is almost 4 times the removal capacity of orange peel alone.