The goal of this work is to develop an innovative approach for the coating of gold nanoparticles (AuNPs) with a synthetic functional copolymer. This stable coating with a thickness of few nanometers provides, at the same time, stabilization and functionalization of the particles. The polymeric coating consists of a backbone of polydimethylacrylamide (DMA) functionalized with an alkyne monomer that allows the binding of azido modified molecules by Cu(I)-catalyzed azide/alkyne 1,3-dipolar cycloaddition (CuAAC, click chemistry). The thin polymer layer on the surface stabilizes the colloidal suspension whereas the alkyne functions pending from the backbone are available for the reaction with azido-modified proteins. The reactivity of the coating is demonstrated by immobilizing an azido modified anti-mouse IgG antibody on the particle surface. This approach for the covalent binding of antibody to a gold-NPs is applied to the development of gold labels in biosensing techniques.

The use of gold nanoparticles (GNPs) as drug delivery system represents a promising issue for diseases without effective pharmacological treatment due to insufficient local drug accumulation and excessive systemic toxicity. Bronchiolitis obliterans syndrome (BOS) represents about 70% of cases of chronic lung allograft dysfunction, the main challenge to long-term lung transplantation. It is believed that due to repeated insults to epithelial bronchiolar cells local inflammatory response creates a milieu that favors epithelial-mesenchymal transition and activation of local mesenchymal cells (MCs) leading to airway fibro-obliteration. In a previous work, we engineered GNPs loaded with the mammalian target of rapamycin inhibitor everolimus, specifically decorated with an antibody against CD44, a surface receptor expressed by primary MCs isolated from bronchoalveolar lavage of BOS patients. We proved in vitro that these GNPs (GNP-HCe) were able to specifically inhibit primary MCs without affecting the bronchial epithelial cell. In the present work, we investigated the effect of these bioengineered nanoconstructs on inflammatory cells, given that a stimulating effect on macrophages, neutrophils or lymphocytes is strongly unwanted in graft airways since it would foster fibrogenesis. In addition, we administered GNP-HCe by the inhalatory route to normal mice for a preliminary assessment of their pulmonary and peripheral (liver, spleen and kidney) uptake. By these experiments, an evaluation of tissue toxicity was also performed. The present study proves that our bioengineered nanotools do not rise an inflammatory response and, under the tested inhalatory conditions that were used, are non-toxic.

We present a facile, one-pot procedure for the organic-to-water phase transfer and biofunctionalization of semiconductor nanocrystals (quantum dots, or QDs) which employs a synthetic functional copolymer, namely poly(DMA-NAS-MAPS), consisting of three components: a surface interacting monomer, N,N-dimethylacrylamide (DMA), a chemically reactive monomer, N-acryloyloxysuccinimide (NAS), and a silane monomer, [3-(methacryloyloxy)-propyl]-trimethoxysilane (MAPS). The nanocrystals were transferred to water by exploiting the amphiphilic character of the copolymer backbone. Hydrolyzed MAPS units contributed to improve the solubility of QDs in water, whereas NAS exhibited reactivity toward biomolecules. A solution of streptavidin in phosphate buffer exhibited good dispersion ability leading to a clear and transparent colloidal suspension, indicative of good QD dispersion during phase transfer and purification. Unlike most of the published methods, the proposed functionalization approach does not require coupling agents and multistep reactions.

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