Anorganische Nanopartikel zum Transport von Nucleinsäuren in Zellen

Biological and Medical Applications of Calcium Phosphate Nanoparticles

Calcium phosphate nanoparticles have a high biocompatibility and biodegradability due to their chemical similarity to human hard tissue, for example, bone and teeth. They can be used as efficient carriers for different kinds of biomolecules such as nucleic acids, proteins, peptides, antibodies, or drugs, which alone are not able to enter cells where their biological effect is required. They can be loaded with cargo molecules by incorporating them, unlike solid nanoparticles, and also by surface functionalization. This offers protection, for example, against nucleases, and the possibility for cell targeting. If such nanoparticles are functionalized with fluorescing dyes, they can be applied for imaging in vitro and in vivo. Synthesis, functionalization and cell uptake mechanisms of calcium phosphate nanoparticles are discussed together with applications in transfection, gene silencing, imaging, immunization, and bone substitution. Biodistribution data of calcium phosphate nanoparticles in vivo are reviewed.

Branched Antisense and siRNA Co-Assembled Nanoplatform for Combined Gene Silencing and Tumor Therapy

Chemically modified DNA has been widely developed to fabricate various nucleic acid nanostructures for biomedical applications. Herein, we report a facile strategy for construction of branched antisense DNA and small interfering RNA (siRNA) co-assembled nanoplatform for combined gene silencing in vitro and in vivo. In our design, the branched antisense can efficiently capture siRNA with 3' overhangs through DNA-RNA hybridization. After being equipped with an active targeting group and an endosomal escape peptide by host-guest interaction, the tailored nucleic acid nanostructure functions efficiently as both delivery carrier and therapeutic cargo, which is released by endogenous RNase H digestion. The multifunctional nucleic acid nanosystem elicits an efficient inhibition of tumor growth based on the combined gene silencing of the tumor-associated gene polo-like kinase 1 (PLK1). This biocompatible nucleic acid nanoplatform presents a new strategy for the development of gene therapy.

Gene Therapy Based on Nucleic Acid Nanostructure

During the past decades, nucleic acids have been employed for the construction of versatile nanostructures with well-defined shapes and sizes. Owing to the remarkable programmability, addressability, and biocompatibility, nucleic acid nanostructures are extensively applied in biomedical researches, such as bioimaging, biosensing, and drug delivery. In particular, nucleic acid nanostructures can act as promising candidates for the delivery of gene-related nucleic acid drugs based on the inherent homology. In this review, the recent progress in the design of multifunctional nucleic acid nanocarriers for gene therapy through antisense, RNA interference, gene editing, and gene expression is summarized. Furthermore, the challenges and future opportunities of nucleic acid nanotechnology in biomedical applications will be discussed.

The siRNAsome: A Cation-Free and Versatile Nanostructure for siRNA and Drug Co-delivery

Nanoparticles show great potential for drug delivery. However, suitable nanostructures capable of loading a range of drugs together with the co-delivery of siRNAs, which avoid the problem of cation-associated cytotoxicity, are lacking. Herein, we report an small interfering RNA (siRNA)-based vesicle (siRNAsome), which consists of a hydrophilic siRNA shell, a thermal- and intracellular-reduction-sensitive hydrophobic median layer, and an empty aqueous interior that meets this need. The siRNAsome can serve as a versatile nanostructure to load drug agents with divergent chemical properties, therapeutic proteins as well as co-delivering immobilized siRNAs without transfection agents. Importantly, the inherent thermal/reduction-responsiveness enables controlled drug loading and release. When siRNAsomes are loaded with the hydrophilic drug doxorubicin hydrochloride and anti-P-glycoprotein siRNA, synergistic therapeutic activity is achieved in multidrug resistant cancer cells and a tumor model.

Biomineralization State of Viruses and Their Biological Potential

In nature, viruses can realize self-mineralization under metal-ion-abundant conditions. Interestingly, the mineralized state is a transition state of the virus when the host is not available. Mammalian viruses that share the similar chemical properties also stand a chance of transformation into a mineralized state. In this review, we focus on the possibility of mammalian viruses to undergo mineralization under a physiological environment and the development of biomineralized-based virus engineering. We will introduce the effect of biomineralization on the physiochemical or biological properties of viruses and we will discuss the relationship between mineral composition and biological potentials. The new biological prospects of mineralized-state viruses, including bypassing biological barriers, protection, and virus-host recognition, will provide new insight for the biosecurity and prevention of viral infection. With respect to vaccines, the mineralized state can modulate the immune recognition, change the immunization route, and elevate the vaccine efficacy. Together, these findings of the mineralized state of the virus may lead to a new understanding of virus biology, application, and prevention.

Mesoporous Silica Nanoparticles Decorated with Carbosilane Dendrons as New Non-viral Oligonucleotide Delivery Carriers

A novel nanosystem based on mesoporous silica nanoparticles covered with carbosilane dendrons grafted on the external surface of the nanoparticles is reported. This system is able to transport single-stranded oligonucleotide into cells, avoiding an electrostatic repulsion between the cell membrane and the negatively charged nucleic acids thanks to the cationic charge provided by the dendron coating under physiological conditions. Moreover, the presence of the highly ordered pore network inside the silica matrix would make possible to allocate other therapeutic agents within the mesopores with the aim of achieving a double delivery. First, carbosilane dendrons of second and third generation possessing ammonium or tertiary amine groups as peripheral functional groups were prepared. Hence, different strategies were tested in order to obtain their suitable grafting on the outer surface of the nanoparticles. As nucleic acid model, a single-stranded DNA oligonucleotide tagged with a fluorescent Cy3 moiety was used to evaluate the DNA adsorption capacity. The hybrid material functionalised with the third generation of a neutral dendron showed excellent DNA binding properties. Finally, the cytotoxicity as well as the capability to deliver DNA into cells, was tested in vitro by using a human osteoblast-like cell line, achieving good levels of internalisation of the vector DNA/carbosilane dendron-functionalised material without affecting the cellular viability.

Calcium Carbonate Mineralized Nanoparticles as an Intracellular Transporter of Cytochrome c for Cancer Therapy

A new intracellular delivery system based on an apoptotic protein-loaded calcium carbonate (CaCO3 ) mineralized nanoparticle (MNP) is described. Apoptosis-inducing cytochrome c (Cyt c) loaded CaCO3 MNPs (Cyt c MNPs) were prepared by block copolymer mediated in situ CaCO3 mineralization in the presence of Cyt c. The resulting Cyt c MNPs had a vaterite polymorph of CaCO3 with a mean hydrodynamic diameter of 360.5 nm and exhibited 60% efficiency for Cyt c loading. The Cyt c MNPs were stable at physiological pH (pH 7.4) and effectively prohibited the release of Cyt c, whereas, at intracellular endosomal pH (pH 5.0), Cyt c release was facilitated. The MNPs enable the endosomal escape of Cyt c for effective localization of Cyt c in the cytosols of MCF-7 cells. Flow cytometry showed that the Cyt c MNPs effectively induced apoptosis of MCF-7 cells. These findings indicate that the CaCO3 MNPs can meet the prerequisites for delivery of cell-impermeable therapeutic proteins for cancer therapy.

Engineering cytochrome-modified silica nanoparticles to induce programmed cell death

A low native membrane permeability and ineffective access to the cellular cytosol, together with aggressive proteolytic degradation, often severely hampers the practical application of any therapeutic protein or antibody. Through engineering the charging profile of mesoporous silica nanoparticles, cellular uptake and subsequent subcellular distribution can be controlled. We show herein that programmed cell death can subsequently be induced across a population of cancer cells with remarkable efficacy on conjugating a specific caspase-cascade-activating cytochrome to such cytosol-accessing particles.

Graphene oxide protected nucleic acid probes for bioanalysis and biomedicine

Recently, the binding ability of DNA on GO and resulting nuclease resistance have attracted increasing attention, leading to new applications both in vivo and in vitro. In vivo, nucleic acids absorbed on GO can be effectively protected from enzymatic degradation and biological interference in complicated samples, making it useful for targeted delivery, gene regulation, intracellular detection and imaging with high uptake efficiencies, high intracellular stability, and very low toxicity. In vitro, the adsorption of ssDNA on GO surface and desorption of dsDNA or well-folded ssDNA from GO surface result in the protection and deprotection of DNA from nucleic digestion, respectively, which has led to target-triggered cyclic enzymatic amplification methods (CEAM) for amplified detection of analytes with sensitivity 2-3 orders of magnitude higher than that of 1:1 binding strategies. This Concept article explores some of the latest developments in this field.

Silver as antibacterial agent: ion, nanoparticle, and metal

The antibacterial action of silver is utilized in numerous consumer products and medical devices. Metallic silver, silver salts, and also silver nanoparticles are used for this purpose. The state of research on the effect of silver on bacteria, cells, and higher organisms is summarized. It can be concluded that the therapeutic window for silver is narrower than often assumed. However, the risks for humans and the environment are probably limited.