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Efficient intracellular drug delivery in nanomedicine strongly depends on ways to induce cellular uptake. Conjugation of nanoparticles (NPs) with cell-penetrating peptides (CPPs) is a known means to induce uptake via endocytosis. Here, we functionalized NPs consisting of either poly(D,L-lactide-co-glycolide) (PLGA) or polyethene glycol (PEG)-PLGA block-copolymer with a lactoferrin-derived cell-penetrating peptide (hLF). To enhance the association between the peptide and the polymer NPs, we tested a range of acyl moieties for N-terminal acylation of the peptide as a means to promote noncovalent interactions. Acyl moieties differed in chain length and number of acyl chains. Peptide-functionalized NPs were characterized for nanoparticle size, overall net charge, storage stability, and intracellular uptake. Coating particles with a palmitoylated hLF resulted in minimal precipitation after storage at −20C and homogeneous particle size (

The clinical and commercial development of polymeric sub-micron size formulations based on poly(lactic-co-glycolic acid) (PLGA) particles is hampered by the challenges related to their good manufacturing practice (GMP)-compliant, scale-up production without affecting the formulation specifications. Continuous process technologies enable large-scale production without changing the process or formulation parameters by increasing the operation time. Here, we explore three well-established process technologies regarding continuity for the large-scale production of sub-micron size PLGA particles developed at the lab scale using a batch method. We demonstrate optimization of critical process and formulation parameters for high-shear mixing, high-pressure homogenization and microfluidics technologies to obtain PLGA particles with a mean diameter of 150–250 nm and a small polydispersity index (PDI, ≤0.2). The most influential parameters on the particle size distribution are discussed for each technique with a critical evaluation of their suitability for GMP production. Although each technique can provide particles in the desired size range, high-shear mixing is found to be particularly promising due to the availability of GMP-ready equipment and large throughput of production. Overall, our results will be of great guidance for establishing continuous process technologies for the GMP-compliant, large-scale production of sub-micron size PLGA particles, facilitating their commercial and clinical development.

Contains fulltext : 244666.pdf (Publisher’s version ) (Open Access) Nanomedicines based on poly(lactic-co-glycolic acid) (PLGA) carriers offer tremendous opportunities for biomedical research. Although several PLGA-based systems have already been approved by both the Food and Drug Administration (FDA) and the European Medicine Agency (EMA), and are widely used in the clinics for the treatment or diagnosis of diseases, no PLGA nanomedicine formulation is currently available on the global market. One of the most impeding barriers is the development of a manufacturing technique that allows for the transfer of nanomedicine production from the laboratory to an industrial scale with proper characterization and quality control methods. This review provides a comprehensive overview of the technologies currently available for the manufacturing and analysis of polymeric nanomedicines based on PLGA nanoparticles, the scale-up challenges that hinder their industrial applicability, and the issues associated with their successful translation into clinical practice.

Small-angle X-ray scattering (SAXS) and atomic force microscopy (AFM) were used to study orientation patterns of two polyphilic liquid crystals (LC) confined to cylindrical pores of anodic aluminum oxide (AAO). The hierarchical hybrid systems had the LC honeycomb (lattice parameter 3.5-4 nm) inside the pores of the AAO honeycomb (diameters 60 and 400 nm). By conducting complete reciprocal space mapping using SAXS, we conclude that the columns of both compounds align in planes normal to the AAO pore axis, with a specific crystallographic direction of the LC lattice aligning strictly parallel to the pore axis. AFM of LC-containing AAO fracture surfaces further revealed that the columns of the planar anchoring LC (compound 1) formed concentric circles in the plane normal to the pore axis near the AAO wall. Toward the pore center, the circles become anisometric "racetrack" loops consisting of two straight segments and two semicircles. This mode compensates for slight ellipticity of the pore cross section. Indications are, however, that for perfectly circular pores, circular shape is maintained right to the center of the pore, the radius coming down to the size of a molecule. For the homeotropically anchoring compound 2, the columns are to the most part straight and parallel to each other, arranged in layers normal to the AAO pore axis, like logs in an ordered pile. Only near the pore wall the columns splay somewhat. In both cases, columns are confined to layers strictly perpendicular to the AAO pore axis, and there is no sign of escape to the third dimension or of axial orientation, the latter having been reported previously for some discotic LCs. The main cause of the two new LC configurations, the "racetrack" and the "logpile", and of their difference from those of confined nematic LC, is the very high splay energy and low bend energy of columnar phases.

An effective and low-cost method to fabricate hexagonally patterned, vertically aligned Si/Ge superlattice nanowires with diameters below 20 nm is presented. By combining the growth of Si/Ge superlattices by molecular beam epitaxy, prepatterning the substrate by anodic aluminum oxide masks, and finally metal-assisted chemical wet etching, this method generates highly ordered hexagonally patterned nanowires. This technique allows the fabrication of nanowires with a high area density of 10(10) wires/cm(2), including the control of their diameter and length.

Ordered nanofiber arrays are a promising material platform for artificial adhesive structures, tissue engineering, wound dressing, sensor arrays, and self-cleaning surfaces. Their production via self-ordered porous alumina hard templates serving as shape-defining molds is well-established. However, their release requires the destruction of the hard templates, the fabrication of which is costly and time-consuming, by wet-chemical etching steps with acids or bases. We report the nondestructive mechanical extraction of arrays of cross-linked polyacrylate nanofibers from thus recyclable self-ordered nanoporous alumina hard templates. Silica replicas of the latter were synthesized using the extricated nanofiber arrays as secondary molds that could be mechanically detached from the molded material. The approach reported here, which can be combined with microstructuring, may pave the way for the high-throughput production of both functional nanofiber arrays and ordered nanoporous membranes consisting of a broad range of material systems.

The fabrication of one-dimensional (1D) nanostructures and microstructures inside the pores of porous templates is intensively investigated. The release of these structures is commonly accomplished by etching and destroying the templates. The 1D nanostructures and microstructures tend to condense because of the occurrence of capillary forces during drying of the specimens. It is shown that highly ordered arrays of polymer microfibers can be easily detached from silanized porous templates by mechanical lift-off. This procedure leaves the templates intact, thus allowing their recycling, and does not involve the use of solutions or solvents, thus circumventing condensation. Therefore, mechanical lift-off may enable the up-scaling of template-based approaches to the fabrication of highly ordered assemblies of 1D nanostructures and microstructures.

Mesoporous silica monoliths containing arrays of aligned macropores oriented perpendicular to their surfaces were prepared by non-destructive imprinting of sol/gels with polymer nanorod arrays. Crack-free monoliths with areas of up to 2.5 cm2 were obtained by a combination of slow drying under ambient conditions and optimized freeze-drying.

Biodegradable extracellular matrices (ECMs) consisting of mechanically stable arrays of aligned poly(lactide) nanorods (nanorod diameter ≈ 200 nm; lattice constant ≈ 500 nm) with areas up to 9 cm2 were prepared by nondestructive extraction from recyclable self-ordered nanoporous alumina hard templates. Fibroblasts formed dense tissue layers on the heparin/gelatin activated nanorod arrays, showed excellent adhesion and exhibited a highly elongated morphology such as in natural tissue. The synthetic approach reported here combining advantages of top-down lithography (well-defined topography) and self-assembly (low costs, high throughput, feature size in the 100 nm range) may yield ECMs for biomedical applications. Remarkably, on microrod arrays with four times larger feature sizes the fibroblasts were significantly less elongated and their proliferation was strongly reduced.

The uniformity of the properties of array elements was evaluated by statistical analysis of microscopic images of array structures, assuming that the brightness of the array elements correlates quantitatively or qualitatively with a microscopically probed quantity. Derivatives and autocorrelation functions of cumulative frequency distributions of the object brightnesses were used to quantify variations in object properties throughout arrays. Thus, different specimens, the same specimen at different stages of its fabrication or use, and different imaging conditions can be compared systematically. As an example, we analyzed scanning electron micrographs of microrod arrays and calculated the percentage of broken microrods.