Template-assisted polyelectrolyte encapsulation of nanoparticles into dispersible, hierarchically nanostructured microfibers

Aspherical, Nano-Structured Drug Delivery System with Tunable Release and Clearance for Pulmonary Applications

Addressing the challenge of efficient drug delivery to the lungs, a nano-structured, microparticulate carrier system with defined and customizable dimensions has been developed. Utilizing a template-assisted approach and capillary forces, particles were rapidly loaded and stabilized. The system employs a biocompatible alginate gel as a stabilizing matrix, facilitating the breakdown of the carrier in body fluids with the subsequent release of its nano-load, while also mitigating long-term accumulation in the lung. Different gel strengths and stabilizing steps were applied, allowing us to tune the release kinetics, as evaluated by a quantitative method based on a flow-imaging system. The micro-cylinders demonstrated superior aerodynamic properties in Next Generation Impactor (NGI) experiments, such as a smaller median aerodynamic diameter (MMAD), while yielding a higher fine particle fraction (FPF) than spherical particles similar in critical dimensions. They exhibited negligible toxicity to a differentiated macrophage cell line (dTHP-1) for up to 24 h of incubation. The kinetics of the cellular uptake by dTHP-1 cells was assessed via fluorescence microscopy, revealing an uptake-rate dependence on the aspect ratio (AR = l/d); cylinders with high AR were phagocytosed more slowly than shorter rods and comparable spherical particles. This indicates that this novel drug delivery system can modulate macrophage uptake and clearance by adjusting its geometric parameters while maintaining optimal aerodynamic properties and featuring a biodegradable stabilizing matrix.

Nanostructured Microparticles Repolarize Macrophages and Induce Cell Death in an In Vitro Model of Tumour-Associated Macrophages

Macrophages (MΦs) in their pro-inflammatory state (M1) suppress tumour growth, while tumour-associated MΦs (TAMs) can promote tumour progression. The aim of this study was to test the hypothesis that targeted delivery of the immune activator poly(I:C) in aspherical silica microrods (µRs) can repolarize TAMs into M1-like cells. µRs (10 µm × 3 µm) were manufactured from silica nanoparticles and stabilized with dextran sulphate and polyethyleneimine. The THP-1 cell line, differentiated into MΦs, and primary human monocyte-derived MΦs (HMDMs) were treated with tumour-cell-conditioned medium (A549), but only HMDMs could be polarized towards TAMs. Flow cytometry and microscopy revealed elevated uptake of µRs by TAMs compared to non-polarized HMDMs. Flow cytometry and qPCR studies on polarization markers showed desirable effects of poly(I:C)-loaded MPs towards an M1 polarization. However, unloaded µRs also showed distinct actions, which were not induced by bacterial contaminations. Reporter cell assays showed that µRs induce the secretion of the inflammatory cytokine IL-1β. Macrophages from Nlrp3 knockout mice showed that µRs in concentrations as low as 0.5 µR per cell can activate the inflammasome and induce cell death. In conclusion, our data show that µRs, even if unloaded, can induce inflammasome activation and cell death in low concentrations.

Tailoring micro/nano-fibers for biomedical applications

Nano/micro fibers have evoked much attention of scientists and have been researched as cutting edge and hotspot in the area of fiber science in recent years due to the rapid development of various advanced manufacturing technologies, and the appearance of fascinating and special functions and properties, such as the enhanced mechanical strength, high surface area to volume ratio and special functionalities shown in the surface, triggered by the nano or micro-scale dimensions. In addition, these outstanding and special characteristics of the nano/micro fibers impart fiber-based materials with wide applications, such as environmental engineering, electronic and biomedical fields. This review mainly focuses on the recent development in the various nano/micro fibers fabrication strategies and corresponding applications in the biomedical fields, including tissue engineering scaffolds, drug delivery, wound healing, and biosensors. Moreover, the challenges for the fabrications and applications and future perspectives are presented.

Cylindrical Microparticles Composed of Mesoporous Silica Nanoparticles for the Targeted Delivery of a Small Molecule and a Macromolecular Drug to the Lungs: Exemplified with Curcumin and siRNA

The transport of macromolecular drugs such as oligonucleotides into the lungs has become increasingly relevant in recent years due to their high potency. However, the chemical structure of this group of drugs poses a hurdle to their delivery, caused by the negative charge, membrane impermeability and instability. For example, siRNA to reduce tumour necrosis factor alpha (TNF-α) secretion to reduce inflammatory signals has been successfully delivered by inhalation. In order to increase the effect of the treatment, a co-transport of another anti-inflammatory ingredient was applied. Combining curcumin-loaded mesoporous silica nanoparticles in nanostructured cylindrical microparticles stabilized by the layer-by-layer technique using polyanionic siRNA against TNF-α was used for demonstration. This system showed aerodynamic properties suited for lung deposition (mass median aerodynamic diameter of 2.85 ± 0.44 µm). Furthermore, these inhalable carriers showed no acute in vitro toxicity tested in both alveolar epithelial cells and macrophages up to 48 h incubation. Ultimately, TNF-α release was significantly reduced by the particles, showing an improved activity co-delivering both drugs using such a drug-delivery system for specific inhibition of TNF-α in the lungs.

Stabilizing liquid drops in nonequilibrium shapes by the interfacial crosslinking of nanoparticles

Droplets are spherical due to the principle of interfacial energy minimization. Here, we show that nonequilibrium droplet shapes can be stabilized via the interfacial self-assembly and crosslinking of nanoparticles. This principle allows for the stability of practically infinitely long liquid tubules and monodisperse cylindrical droplets. Droplets of oil-in-water are elongated via gravitational or hydrodynamic forces at a reduced interfacial tension. Silica nanoparticles self-assemble and cross-link on the interface triggered by the synergistic surface modification with hexyltrimethylammonium- and trivalent lanthanum-cations. The droplet length dependence is described by a scaling relationship and the rate of nanoparticle deposition on the droplets is estimated. Our approach potentially enables the 3D-printing of Newtonian Fluids, broadening the array of material options for additive manufacturing techniques.

siRNA delivery to macrophages using aspherical, nanostructured microparticles as delivery system for pulmonary administration

The delivery of oligonucleotides such as siRNA to the lung is a major challenge, as this group of drugs has difficulties to overcome biological barriers due to its polyanionic character and the associated hydrophilic properties, resulting in inefficient delivery. Especially in diseases such as asthma, chronic obstructive pulmonary disease and cystic fibrosis, where increased proinflammation is present, a targeted RNA therapy is desirable due to the high potency of these oligonucleotides. To address these problems and to ensure efficient uptake of siRNA in macrophages, a microparticulate, cylindrical delivery system was developed. In the first step, this particle system was tested for its aerodynamic characteristics to evaluate the aerodynamic properties to optimize lung deposition. The mass median aerodynamic diameter of 2.52 ± 0.23 µm, indicates that the desired target should be reached. The inhibition of TNF-α release, as one of the main mediators of proinflammatory reactions, was investigated. We could show that our carrier system can be loaded with siRNA against TNF-α. Gel electrophoreses allowed to demonstrate that the load can be incorporated and released without being degraded. The delivery system was found to transport a mass fraction of 0.371% [%w/w] as determined by inductively coupled plasma mass spectroscopy. When investigating the release kinetics, the results showed that several days are necessary to release a major amount of the siRNA indicating a sustained release. The cylindrical microparticles with an aspect ratio of 3.3 (ratio of length divided by width) were then tested in vitro successfully reducing TNF-α release from human macrophages significantly by more than 30%. The developed formulation presents a possible oligonucleotide delivery system allowing due to its internal structure to load and protect siRNA.

Biodegradable Polymeric Multilayer Capsules for Therapy of Lung Cancer

Formulated forms of cancer therapeutics enhance the efficacy of treatment by more precise targeting, increased bioavailability of drugs, and an aptitude of some delivery systems to overcome multiple drug resistance of tumors. Drug carriers acquire importance for anti-cancer interventions via targeting tumor-associated macrophages with active molecules capable to either eliminate them or change their polarity. Although several packaged drug forms have reached the market, there is still a high demand for novel carrier systems to hurdle limitations of existing drugs on active molecules, toxicity, bioeffect, and stability. Here, we report a facile assembly and delivery methodology for biodegradable polymeric multilayer capsules (PMC) with the purpose of further use in injectable drug formulations for lung cancer therapy via direct erosion of tumors and suppression of the tumor-promoting function of macrophages in the tumor microenvironment. We demonstrate delivery of low-molecular-weight drug molecules to lung cancer cells and macrophages and provide details on in vivo distribution, cellular uptake, and disintegration of the developed PMC. Poly-l-arginine and dextran sulfate alternately adsorb on a ∼500 nm CaCO₃ sacrificial template followed by removal of the inorganic core to obtain hollow capsules for consequent loading with drug molecules, gemcitabine or clodronate. The capsules further compacted upon loading down to ∼250 nm in diameter via heat treatment. A comparative study of the capsule internalization rate in vitro and in vivo reveals the benefits of a diminished carrier size. We show that macrophages and epithelial cells of the lungs and liver internalize capsules with efficacy higher than 75%. Using an in vivo mouse model of lung cancer, we also confirm that tumor lungs better retain smaller capsules than the healthy lung tissue. The pronounced cytotoxic effect of the encapsulated gemcitabine on lung cancer cells and the ability of the encapsulated clodronate to block the tumor-promoting function of macrophages prove the efficacy of the developed capsule loading method in vitro. Our study taken as a whole demonstrates the great potential of the developed PMC for in vivo treatment of cancer via transporting active molecules, including those that are water-soluble with low molecular weight, to both cancer cells and macrophages through the bloodstream.

Nanomedicine Approaches for the Pulmonary Treatment of Cystic Fibrosis

Cystic fibrosis (CF) is a genetic disease affecting today nearly 70,000 patients worldwide and characterized by a hypersecretion of thick mucus difficult to clear arising from the defective CFTR protein. The over-production of the mucus secreted in the lungs, along with its altered composition and consistency, results in airway obstruction that makes the lungs susceptible to recurrent and persistent bacterial infections and endobronchial chronic inflammation, which are considered the primary cause of bronchiectasis, respiratory failure, and consequent death of patients. Despite the difficulty of treating the continuous infections caused by pathogens in CF patients, various strategies focused on the symptomatic therapy have been developed during the last few decades, showing significant positive impact on prognosis. Moreover, nowadays, the discovery of CFTR modulators as well as the development of gene therapy have provided new opportunity to treat CF. However, the lack of effective methods for delivery and especially targeted delivery of therapeutics specifically to lung tissues and cells limits the efficiency of the treatments. Nanomedicine represents an extraordinary opportunity for the improvement of current therapies and for the development of innovative treatment options for CF previously considered hard or impossible to treat. Due to the peculiar environment in which the therapies have to operate characterized by several biological barriers (pulmonary tract, mucus, epithelia, bacterial biofilm) the use of nanotechnologies to improve and enhance drug delivery or gene therapies is an extremely promising way to be pursued. The aim of this review is to revise the currently used treatments and to outline the most recent progresses about the use of nanotechnology for the management of CF.

Spinning and Applications of Bioinspired Fiber Systems

Natural fiber systems provide inspirations for artificial fiber spinning and applications. Through a long process of trial and error, great progress has been made in recent years. The natural fiber itself, especially silks, and the formation mechanism are better understood, and some of the essential factors are implemented in artificial spinning methods, benefiting from advanced manufacturing technologies. In addition, fiber-based materials produced via bioinspired spinning methods find an increasingly wide range of biomedical, optoelectronic, and environmental engineering applications. This paper reviews recent developments in the spinning and application of bioinspired fiber systems, introduces natural fiber and spinning processes and artificial spinning methods, and discusses applications of artificial fiber materials. Views on remaining challenges and the perspective on future trends are also proposed.

Silica nanoparticles of microrods enter lung epithelial cells

A novel type of microparticle has recently been engineered. It consists of amorphous silica nanoparticles and has a corncob-like shape. It has already been demonstrated in vivo that alveolar macrophages in the lung are able to engulf this particulate carrier and that it also functions successfully as a gene delivery system. This subsequently raises the question as to whether epithelial cells may also be possible targets for these microrods. For this purpose, the alveolar epithelial cell line A549 was used presently. The epithelial character of these confluent cells was documented by the presence of tight junctions using a freeze-fracture technique and transmission electron microscopy. A toxic effect of the particles incubated with these cells was largely excluded. The interaction of the microparticles with the epithelial cells was observed using confocal microscopy and live cell imaging. Interestingly, the particles entered the epithelial cells within hours. After 1 day, the intracellular particles began to disaggregate and release the silica nanoparticles. Thus, even epithelial cells may serve as targets for this novel carrier and gene delivery system. This is particularly important since safe and effective gene delivery remains an unsolved problem. In addition, delivery of anti-cancer and anti-infective drugs may be an application of this novel particulate carrier.

Sandwich-interface inspired strategy for controlled formation of nanoparticles

Nanoparticles are functional materials able to offer improved or new synergetic properties. By manipulating the interfacial properties, we demonstrate an innovative sandwich-interface method capable of forming various monodispersed nanostructures including metals, semiconductors, and inorganic and coordinated nanoparticles. By analysing of the reaction mechanism, we show that reaction time, the height of transition and presence of surfactant have the greatest influence on the formation of the products. These advances in the sandwich-interface synthesis significantly extend the scope of interface synthetic methods, facilitating a new level of structural-architectural control which may lead to future developments in the field of crystallography.

Chemistry and engineering of cyclodextrins for molecular imaging

Cyclodextrins (CDs) are naturally occurring cyclic oligosaccharides bearing a basket-shaped topology with an "inner-outer" amphiphilic character. The abundance of hydroxyl groups enables CDs to be functionalized with multiple targeting ligands and imaging elements. The imaging time, and the payload of different imaging elements, can be tuned by taking advantage of the commercial availability of CDs with different sizes of the cavity. This review aims to offer an outlook of the chemistry and engineering of CDs for the development of molecular probes. Complexation thermodynamics of CDs, and the corresponding implications for probe design, are also presented with examples demonstrating the structural and physiochemical roles played by CDs in the full ambit of molecular imaging. We hope that this review not only offers a synopsis of the current development of CD-based molecular probes, but can also facilitate translation of the incremental advancements from the laboratory to real biomedical applications by illuminating opportunities and challenges for future research.

Non-Equilibrium Self-Assembly of Monocomponent and Multicomponent Tubular Structures in Rotating Fluids

When suspended in a denser rotating fluid, lighter particles experience a cylindrically symmetric confining potential that drives their crystallization into either monocomponent or unprecedented binary tubular packing. These assemblies form around the fluid's axis of rotation, can be dynamically interconverted (upon accelerating or decelerating the fluid), can exhibit preferred chirality, and can be made permanent by solidifying the fluid. The assembly can be extended to fluids forming multiple concentric interfaces or to systems of bubbles forming both ordered and "gradient" structures within curable polymers.

Aspherical, Nanostructured Microparticles for Targeted Gene Delivery to Alveolar Macrophages

Introducing novel shapes to particulate carrier systems adds unique features to modern drug and gene delivery. Depending on the route of administration, particle geometry can influence deposition and fate within biological environments. In this work, a template-assisted engineering technique is applied, providing full control of size and shape in the preparation of aspherical, nanostructured microparticles. Based on the interconnection of nanoparticles, stabilized by a functional layer-by-layer (LbL) coating, the resulting cylindrical micrometer architecture is especially qualified for pulmonary delivery. Designed as gene delivery system, plasmid-DNA (pCMV-luciferase) and branched polyethylenimine are used to reach both structural integrity of the carrier system and delivery of genes into the cells of interest. Due to their size, particles are exclusively taken up by phagocytes, which also adds a targeting effect to the introduced system. The luciferase expression is demonstrated in macrophages showing increasing levels over a time period of at least 7 d. Furthermore, it is shown for the first time that the expression is depending on the LbL design. From in vivo experiments, corresponding luciferase expression is observed in mice alveolar macrophages. Combining site specific transport with the possibility of genetically engineering immunocompetent phagocytes, the presented system offers promising potential to improve applications for cell-based immunotherapy.

Universal Method to Transfer Membrane-Templated Nano-Objects to Aqueous Solutions

A wide range of nano-objects are synthesized by combining template synthesis, using polycarbonate membrane as template, with different material deposition methods. The resulting nanostructures varied from robust inorganic gold nanowires grown by electrodeposition to rigid polypyrrole nanotubes synthesized by chemical polymerization and softer nanotubes made of different combinations of synthetic and natural polyelectrolytes fabricated by layer-by-layer (LbL) assembly. The morphology of these various nano-objects is characterized prior to and after their immersion in water, revealing that the rigidity degree of LbL nanotubes strongly decreases after being in contact with water, leading to highly swollen and flexible nanotubes in aqueous solution that tend to stick to any surface and are very difficult to collect and disperse quantitatively in aqueous solution. Different processes to collect these nano-objects and disperse them in aqueous medium for further analysis and application were then studied. Among them, a method based on simple filtration of nanotubes in the presence of a powdered dextran adjuvant leads to the quantitative collection and dispersion in water of all types of tested cylindrical nano-objects. This universal method to efficiently collect membrane templated nano-objects paves the way to further characterization of a large variety of nanotubes in aqueous solution and to their potential use as cargo nanocarriers or as nanoreactors.

Macrophage uptake of cylindrical microparticles investigated with correlative microscopy

Cylindrical particles offer the opportunity to develop controlled and sustained release systems for the respiratory tract. One reason is that macrophages can phagocyte such particles only from either of the two ends. We investigated the uptake behaviour of murine alveolar macrophages incubated with elongated submicron-structured particles. For that purpose, fluorescent model silica nanoparticles were interconnected with the biocompatible polysaccharide agarose, building up cylindrical particles within the pores of track-etched membranes. In contrast to common approaches we determined the uptake at different time points with scanning electron microscopy, fluorescence microscopy, and the combination of both techniques - correlative microscopy (CLEM). As a consequence, we could securely identify uptake events and observe in detail the engulfment of particles and confirm, that phagocytosis could only be observed from the tips of the cylinders. CLEM allowed a comparison of the uptake measured with different techniques at identical macrophages. Qualitative and quantitative evaluation of this cylindrical particle uptake showed substantial differences between fluorescence microscopy, electron microscopy and the combination of both (CLEM) within 24h.

Alignment of nanostructured tripeptide gels by directional ultrasonication

We demonstrate an in situ ultrasonic approach to generate anisotropic organo- and hydrogels consisting of oriented tripeptides self-assembled structures.

Monocyte-mediated delivery of polymeric backpacks to inflamed tissues: a generalized strategy to deliver drugs to treat inflammation

Targeted delivery of drugs and imaging agents to inflamed tissues, as in the cases of cancer, Alzheimer's disease, Parkinson's disease, and arthritis, represents one of the major challenges in drug delivery. Monocytes possess a unique ability to target and penetrate into sites of inflammation. Here, we describe a broad approach to take advantage of the natural ability of monocytes to target and deliver flat polymeric particles ("Cellular Backpacks") to inflamed tissues. Cellular backpacks attach strongly to the surface of monocytes but do not undergo phagocytosis due to backpack's size, disk-like shape and flexibility. Following attachment of backpacks, monocytes retain important cellular functions including transmigration through an endothelial monolayer and differentiation into macrophages. In two separate in vivo inflammation models, backpack-laden monocytes exhibit increased targeting to inflamed tissues. Cellular backpacks, and their abilities to attach to monocytes without impairing monocyte functions and 'hitchhike' to a variety of inflamed tissues, offer a new platform for both cell-mediated therapies and broad targeting of inflamed tissues.

Non-spherical micro- and nanoparticles: fabrication, characterization and drug delivery applications

INTRODUCTION

Micro- and nanoparticles in drug and vaccine delivery have opened up new possibilities in pharmaceutics. In the past, researchers focused mainly on particle size, surface chemistry and the use of various materials to control particle characteristics and functions. Lately, shape has been acknowledged as an important design parameter having an impact on the interaction with biological systems.

AREAS COVERED

In this review, we report on the latest developments in fabrication methods to tailor particle geometry, summarize analytical techniques for non-spherical particles and highlight the most important findings regarding their interaction with biological systems and their potential applications in drug delivery.

EXPERT OPINION

The impact of shape on particle internalization into different cell types and particle biodistribution has been extensively studied in the past. Current research focuses on shape-dependent uptake mechanisms and applications for tumour therapy and vaccination. Different fabrication methods can be used to produce a variety of different particle types and shapes. Key challenges will be the transfer of new non-spherical particle fabrication methods from lab-scale to industrial large-scale production. Not all techniques may be scalable for the production of high quantities of particles. It will also be challenging to transfer the promising in vitro findings to suitable in vivo models.

Hybrid inverse opals for regulating cell adhesion and orientation

Cell adhesion and alignment are two important considerations in tissue engineering applications as they can regulate the subsequent cell proliferation activity and differentiation program. Although many effects have been applied to regulate the adhesion or alignment of cells by using physical and chemical methods, it is still a challenge to regulate these cell behaviors simultaneously. Here, we present novel substrates with tunable nanoscale patterned structures for regulating the adhesion and alignment of cells. The substrates with different degrees of pattern orientation were achieved by customizing the amount of stretching applied to polymer inverse opal films. Cells cultured on these substrates showed an adjustable morphology and alignment. Moreover, soft hydrogels, which have poor plasticity and are difficult to cast into patterned structures, were applied to infiltrate the inverse opal structure. We demonstrated that the adhesion ratio of cells could be regulated by these hybrid substrates, as well as adjusting the cell morphology and alignment. These features of functional inverse opal substrates make them suitable for important applications in tissue engineering.

Carrier interactions with the biological barriers of the lung: advanced in vitro models and challenges for pulmonary drug delivery

In recent years significant progress has been made to improve particle deposition in the lung. However, the development of strategies to overcome the air-blood lung barrier is still needed. The combination of complex in vitro models and sophisticated particulate carriers is promising as a strategy by which that goal could be achieved. In this review we discuss currently available in vitro lung models, including some recent tissue-engineering approaches, as well as the challenges associated to implement such complex in vitro systems. Furthermore, we discuss available carrier technologies, often based on nanotechnology, to target specific regions of the lungs and to overcome the respective biological barriers, ideally resulting in safe and effective delivery to the desired pulmonary destination.

Pulmonary drug delivery: from generating aerosols to overcoming biological barriers-therapeutic possibilities and technological challenges

Research in pulmonary drug delivery has focused mainly on new particle or device technologies to improve the aerosol generation and pulmonary deposition of inhaled drugs. Although substantial progress has been made in this respect, no significant advances have been made that would lead pulmonary drug delivery beyond the treatment of some respiratory diseases. One main reason for this stagnation is the still very scarce knowledge about the fate of inhaled drug or carrier particles after deposition in the lungs. Improvement of the aerosol component alone is no longer sufficient for therapeutic success of inhalation drugs; a paradigm shift is needed, with an increased focus on the pulmonary barriers to drug delivery. In this Review, we discuss some pathophysiological disorders that could benefit from better control of the processes after aerosol deposition, and pharmaceutical approaches to achieve improved absorption across the alveolar epithelium, prolonged pulmonary clearance, and targeted delivery to specific cells or tissues.

Porous Pr(OH)3 nanostructures as high-efficiency adsorbents for dye removal

Herein we report the electrochemical synthesis of porous Pr(OH)(3) nanobelt arrays (NBAs), nanowire arrays (NWAs), nanowire bundles (NWBs), and nanowires (NWs) and their applications as dye absorbents in water treatment. These Pr(OH)(3) nanostructures exhibit high efficient and selective adsorption of the dyes with amine (-NH(2)) functional groups such as Congo red, reactive yellow, and reactive blue. The high efficiency and selectivity is attributed to the large effective surface area of the porous structure, plentiful hydroxyl groups, and basic sites on the Pr(OH)(3) surface. Furthermore, the toxicity studies of these porous Pr(OH)(3) nanostructure show a negligible effect on seed germination, indicating that they hold great potential as environmentally friendly absorbents in water treatment.

Control of the length of microfibers

Uniform polymeric microfibers of prescribed lengths were synthesized in microfluidic devices using two different approaches--valve actuation and pulses of ultraviolet (UV) light. The more versatile valve approach was employed to demonstrate control of the length of the microfiber as a function of the frequency of valve actuation.

Templating assembly of multifunctional hybrid colloidal spheres

3D hybrid colloidal spheres with integrated functions and collective properties are fabricated using a variety of common inorganic nano-objects as building blocks in association with polyelectrolyte encapsulation through a facile template strategy. The fabrication strategy is generally suited for design of functional colloidal spheres in a simple and controllable manner, and thus opens a new avenue for developing hybrid materials with multiple functions and collective properties.

Patchiness of embedded particles and film stiffness control through concentration of gold nanoparticles

Patchy particles are fabricated using a method of embedding-into and extracting-from thick, biocompatible, gel-like HA/PLL films. Control over the patchiness is achieved by adjusting the stiffness of films, which affects embedding and masking of particles. The stiffness is adjusted by the concentration of gold nanoparticles adsorbed onto the surface of the films.

Novel approaches for drug delivery systems in nanomedicine: effects of particle design and shape

The identification of novel drug candidates for the treatment of diseases like cancer, infectious diseases, or allergies (especially asthma) assigns new tasks for pharmaceutical technology. With respect to drug delivery several problems occur such as low solubility and hence low bioavailability or restriction to inconvenient routes of administration. Nanotechnological approaches promise to circumvent some of these problems, therefore being well suited for future applications as nanomedicines. Furthermore, efficient and sufficient loading is a critical issue that is approached through mesoporous particles and/or through nonspherical particles both offering larger volumes and surfaces. Special interest is laid on the effect of shape of particulate materials on the body and related physiological mechanisms. The modified response of biological systems on different shapes opens a new dimension to adjust particle system interaction. Finally, the biological response to these systems will determine the fate with respect to their therapeutic value. Therefore, the interaction pattern between nonspherical particulate materials and biological systems as well as the production processes are highlighted.