Publications

This study investigates the synthesis and optimization of nanobots (NBs) loaded with pDNA using the layer-by-layer (LBL) method and explores the impact of their collective motion on the transfection efficiency. NBs consist of biocompatible and biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles and are powered by the urease enzyme, enabling autonomous movement and collective swarming behavior. In vitro experiments were conducted to validate the delivery efficiency of fluorescently labeled NBs, using two-dimensional (2D) and three-dimensional (3D) cell models: murine urothelial carcinoma cell line (MB49) and spheroids from human urothelial bladder cancer cells (RT4). Swarms of pDNA-loaded NBs showed enhancements of 2.2- to 2.6-fold in delivery efficiency and 6.8- to 8.1-fold in material delivered compared to inhibited particles (inhibited enzyme) and the absence of fuel in a 2D cell culture. Additionally, efficient intracellular delivery of pDNA was demonstrated in both cell models by quantifying and visualizing the expression of eGFP. Swarms of NBs exhibited a >5-fold enhancement in transfection efficiency compared to the absence of fuel in a 2D culture, even surpassing the Lipofectamine 3000 commercial transfection agent (cationic lipid-mediated transfection). Swarms also demonstrated up to a 3.2-fold enhancement in the amount of material delivered in 3D spheroids compared to the absence of fuel. The successful transfection of 2D and 3D cell cultures using swarms of LBL PLGA NBs holds great potential for nucleic acid delivery in the context of bladder treatments.

JTD Keywords: Animals, Barrier, Cell line, tumor, Dna, Drug delivery, Drug-delivery, Enzyme catalysis, Gene delivery, Gene transfer techniques, Humans, Lactic acid, Mice, Nanobots, Nanoparticles, Pdna, Plasmids, Polyglycolic acid, Polylactic acid-polyglycolic acid copolymer, Swarming, Transfectio, Transfection, Urease, Urinary bladder neoplasms

A bottom-up approach to fabricating monodisperse, two-component polymersomes that possess phase-separated ("patchy") chemical topology is presented. This approach is compared with already-existing top-down preparation methods for patchy polymer vesicles, such as film rehydration. These findings demonstrate a bottom-up, solvent-switch self-assembly approach that produces a high yield of nanoparticles of the target size, morphology, and surface topology for drug delivery applications, in this case patchy polymersomes of a diameter of ≈50 nm. In addition, an image processing algorithm to automatically calculate polymersome size distributions from transmission electron microscope images based on a series of pre-processing steps, image segmentation, and round object identification is presented.© 2023 Wiley-VCH GmbH.

JTD Keywords: assemblies, copolymers, evolution, membranes, micelles, ph, phase separation, polymersomes, rafts, self-assembly, size, vesicles, Cell biology, Drug delivery, Phase separation, Polymersomes, Self-assembly, Vesicles

© 2021 Elsevier B.V. The current decline in antimalarial drug efficacy due to the evolution of resistant Plasmodium strains calls for new strategies capable of improving the bioavailability of antimalarials, especially of those whose lipophilic character imparts them a low solubility in biological fluids. Here we have designed, synthesized and characterized amphiphilic zwitterionic block copolymers forming nanoparticles capable of penetrating the intestinal epithelium that can be used for oral administration. Poly(butyl methacrylate-co-morpholinoethyl sulfobetaine methacrylate) (PBMA-MESBMA)-based nanoparticles exhibited a specific targeting to Plasmodium falciparum-infected vs. parasite-free red blood cells (74.8%/0.8% respectively), which was maintained upon encapsulation of the lipophilic antimalarial drug curcumin (82.6%/0.3%). The in vitro efficacy of curcumin upon encapsulation was maintained relative to the free compound, with an IC50 around 5 μM. In vivo assays indicated a significantly increased curcumin concentration in the blood of mice one hour after being orally fed PBMA-MESBMA-curcumin in comparison to the administration of free drug (18.7 vs. 2.1 ng/ml, respectively). At longer times, however, plasma curcumin concentration equaled between free and encapsulated drug, which was reflected in similar in vivo antimalarial activities in Plasmodium yoelii yoelii-infected mice. Microscopic analysis in blood samples of fluorescently labeled PBMA-MESBMA revealed the presence of the polymer inside P. yoelii yoelii-parasitized erythrocytes one hour after oral administration to infected animals.

JTD Keywords: curcumin, drug delivery, malaria, pbma-mesbma, plasmodium, zwitterionic block copolymers, Curcumin, Drug delivery, Malaria, Pbma-mesbma, Plasmodium, Zwitterionic block copolymers

Vitronectin (VN) adsorption on a family of model substrates consisting of copolymers of ethyl acrylate and hydroxyl ethylacrylate in different ratios (to obtain a controlled surface density of -OH groups) was investigated by Atomic Force Microscopy (AFM). It is shown that the fraction of the substrate covered by the protein depends strongly on the amount of hydroxyl groups in the sample and it monotonically decreases as the -OH density increases. Isolated globular-like VN molecules are observed on the surfaces with the higher OH density. As the fraction of hydroxyl groups decreases, aggregates of 3-5 VN molecules are observed on the sample. Overall cell morphology, focal adhesion formation and actin cytoskeleton development are investigated to assess the biological activity of the adsorbed VN on the different surfaces. Dermal fibroblast cells show excellent material interaction on the more hydrophobic samples (OH contents lower than 0.5), which reveals enhanced VN activity on this family of substrates as compared with other extracellular matrix proteins (e.g., fibronectin and fibrinogen).

JTD Keywords: Copolymers, Vitronectin, AFM, Self-assembled monolayers, Cell-adhesion, Thermal transitions, Protein adsorption, Surfaces, Fibronectin, Biomaterials, Attachment, Fibrinogen

Iniferter-mediated surface-initiated photopolymerization was used to graft poly(methacrylic acid) (PMAA) brush layers obtained from surface-attached iniferters in self-assembled monolayers to a gold surface. The tethered chains were subsequently functionalized with the cell-adhesive arginine-glycine-aspartic acid (RGD) motif. The modified brushes were extended by reinitiating the polymerization to obtain an additional layer of PMAA, thereby burying the peptide-functionalized segments inside the brush structure. Contact angle measurements and Fourier transform infrared (FTIR) spectroscopy were employed to characterize the wettability and the chemical properties of these platforms. Time of flight secondary ion mass spectroscopy (TOF-SIMS) measurements were performed to monitor the chemical composition of the polymer layer as a function of the distance to the gold surface and obtain information concerning the depth of the RGD motifs inside the brush structure. The brush thickness was evaluated as a function of the polymerization (i.e.. UV-irradiation) time with atomic force microscopy (AFM) and ellipsometry. Cell adhesion tests employing human osteoblasts were performed on substrates with the RGD peptides exposed at the surface as well as covered by a PMAA top brush layer. Immunofluorescence studies demonstrated a variation of the cell morphology as a function of the position of the peptide units along the grafted chains.

JTD Keywords: Ion mass-spectrometry, Transfer radical polymerization, Asymmetric diblock copolymers, Arg-gly-asp, Swelling behaviour, Endothelial-cells, Thin-films, fibronectin, Surfaces, SIMS