Lysine-functionalized nanodiamonds as gene carriers: development of stable colloidal dispersion for in vitro cellular uptake studies and siRNA delivery application

Advancements in a FRET Biosensor for Live-Cell Fluorescence-Lifetime High-Throughput Screening of Alpha-Synuclein

There is a critical need for small molecules capable of rescuing pathophysiological phenotypes induced by alpha-synuclein (aSyn) misfolding and oligomerization. Building upon our previous aSyn cellular fluorescence lifetime (FLT)-Förster resonance energy transfer (FRET) biosensors, we have developed an inducible cell model incorporating the red-shifted mCyRFP1/mMaroon1 (OFP/MFP) FRET pair. This new aSyn FRET biosensor improves the signal-to-noise ratio, reduces nonspecific background FRET, and results in a 4-fold increase (transient transfection) and 2-fold increase (stable, inducible cell lines) in FRET signal relative to our previous GFP/RFP aSyn biosensors. The inducible system institutes greater temporal control and scalability, allowing for fine-tuning of biosensor expression and minimizes cellular cytotoxicity due to overexpression of aSyn. Using these inducible aSyn-OFP/MFP biosensors, we screened the Selleck library of 2684 commercially available, FDA-approved compounds and identified proanthocyanidins and casanthranol as novel hits. Secondary assays validated the ability of these compounds to modulate aSyn FLT-FRET. Functional assays probing cellular cytotoxicity and aSyn fibrillization demonstrated their capability to inhibit seeded aSyn fibrillization. Proanthocyanidins completely rescued aSyn fibril-induced cellular toxicity with EC50 of 200 nM and casanthranol supported a 85.5% rescue with a projected EC50 of 34.2 μM. Furthermore, proanthocyanidins provide a valuable tool compound to validate our aSyn biosensor performance in future high-throughput screening campaigns of industrial-scale (million-compound) chemical libraries.

Nanodiamond Integration into Niosomes as an Emerging and Efficient Gene Therapy Nanoplatform for Central Nervous System Diseases

Nanodiamonds (NDs) are promising materials for gene delivery because of their unique physicochemical and biological features, along with their possibility of combination with other nonviral systems. Our aim was to evaluate the biophysical performance of NDs as helper components of niosomes, named nanodiasomes, to address a potential nonviral gene delivery nanoplatform for therapeutic applications in central nervous system (CNS) diseases. Nanodiasomes, niosomes, and their corresponding complexes, obtained after genetic material addition at different ratios (w/w), were evaluated in terms of physicochemical properties, cellular uptake, intracellular disposition, biocompatibility, and transfection efficiency in HEK-293 cells. Nanodiasomes, niosomes, and complexes fulfilled the physicochemical features for gene therapy applications. Biologically, the incorporation of NDs into niosomes enhanced 75% transfection efficiency (p < 0.001) and biocompatibility (p < 0.05) to values over 90%, accompanied by a higher cellular uptake (p < 0.05). Intracellular trafficking analysis showed higher endocytosis via clathrins (p < 0.05) in nanodiaplexes compared with nioplexes, followed by higher lysosomal colocalization (p < 0.05), that coexisted with endosomal escape properties, whereas endocytosis mediated by caveolae was the most efficient pathway in the case of nanodiaplexes. Moreover, studies in CNS primary cells revealed that nanodiaplexes successfully transfected neuronal and retinal cells. This proof-of-concept study points out that ND integration into niosomes represents an encouraging nonviral nanoplatform strategy for the treatment of CNS diseases by gene therapy.

Oxi-Redox Selective Breast Cancer Treatment: An In Vitro Study of Theranostic In-Based Oxide Nanoparticles for Controlled Generation or Prevention of Oxidative Stress

In this article, we demonstrate that specifically engineered oxide nanoparticles (NPs) have the potential to act as theranostic materials that are able to generate or prevent oxidative stress through their oxi-redox activity in various types of malignant and nonmalignant cells. The oxi-redox activity is related to the type and presence of surface defects, which is modified with appropriate synthesis conditions. In the present work, we used MDA-MB-231 and MCF-7 human breast cancer cells and nonmalignant MCF-10A human breast cells to demonstrate how controlled oxidative stress mediated by specifically nanoengineered indium tin oxide (ITO) NPs can selectively induce cell death in the cancer cells while reducing the oxidative stress in the normal cells and supporting their proliferation. The ITO NPs are also promising nanotheranostic materials for cancer therapy and contrast agents because of their multimodal imaging capabilities. We demonstrate that the synthesized ITO NPs can selectively increase the generation of reactive oxygen species (ROS) in both breast tumor cell lines, resulting in activation of apoptosis, and can also greatly suppress the cellular proliferation in both types of tumor cells. In contrast, the ITO NPs exhibit ROS scavenging-like behavior, significantly decreasing the ROS levels in MCF-10A cells exposed to the additional ROS, hydrogen peroxide (H₂O₂), so that they protect the proliferation of nonmalignant MCF-10A cells from ROS damage. In addition, fluorescent microscopy images revealed that the ITO NPs emit strong fluorescence that could be used to reveal their location. Moreover, computed tomography imaging demonstrated that the ITO NPs exhibited a comparable capability toward anatomical contrast enhancement. These results suggest that the synthesized ITO NPs have the potential to be a novel selective therapeutic agent with a multimodal imaging property for anticancer treatment.

Niosome-Based Approach for In Situ Gene Delivery to Retina and Brain Cortex as Immune-Privileged Tissues

Non-viral vectors have emerged as a promising alternative to viral gene delivery systems due to their safer profile. Among non-viral vectors, recently, niosomes have shown favorable properties for gene delivery, including low toxicity, high stability, and easy production. The three main components of niosome formulations include a cationic lipid that is responsible for the electrostatic interactions with the negatively charged genetic material, a non-ionic surfactant that enhances the long-term stability of the niosome, and a helper component that can be added to improve its physicochemical properties and biological performance. This review is aimed at providing recent information about niosome-based non-viral vectors for gene delivery purposes. Specially, we will discuss the composition, preparation methods, physicochemical properties, and biological evaluation of niosomes and corresponding nioplexes that result from the addition of the genetic material onto their cationic surface. Next, we will focus on the in situ application of such niosomes to deliver the genetic material into immune-privileged tissues such as the brain cortex and the retina. Finally, as future perspectives, non-invasive administration routes and different targeting strategies will be discussed.

Nanodiamonds with powerful ability for drug delivery and biomedical applications: Recent updates on in vivo study and patents

Nanodiamonds are novel nanosized carbon building blocks possessing varied fascinating mechanical, chemical, optical and biological properties, making them significant active moiety carriers for biomedical application. These are known as the most 'captivating' crystals attributed to their chemical inertness and unique properties posing them useful for variety of applications in biomedical era. Alongside, it becomes increasingly important to find, ascertain and circumvent the negative aspects associated with nanodiamonds. Surface modification or functionalization with biological molecules plays a significant role in managing the toxic behavior since nanodiamonds have tailorable surface chemistry. To take advantage of nanodiamond potential in drug delivery, focus has to be laid on its purity, surface chemistry and other considerations which may directly or indirectly affect drug adsorption on nanodiamond and drug release in biological environment. This review emphasizes on the basic properties, synthesis techniques, surface modification techniques, toxicity issues and biomedical applications of nanodiamonds. For the development of nanodiamonds as an effective dosage form, researchers are still engaged in the in-depth study of nanodiamonds and their effect on life interfaces.

Stereoselective pH Responsive Peptide Dendrimers for siRNA Transfection

Transfecting nucleic acids into cells is an essential procedure in biological research usually performed using nonviral transfection reagents. Unfortunately, most transfection reagents have polymeric or undisclosed structures and require nonstandard synthetic procedures. Herein we report peptide dendrimers accessible as pure products from standard building blocks by solid-phase peptide synthesis and acting as nontoxic single component siRNA transfection reagents for a variety of cell lines with equal or better performance than the gold standard lipofectamine L2000. Structure-activity relationships and mechanistic studies illuminate their transfection mechanism in unprecedented detail. Stereoselective dendrimer aggregation via intermolecular β-sheets at neutral pH enables siRNA complexation to form nanoparticles which enter cells by endocytosis. Endosome acidification triggers protonation of amino termini and rearrangement to an α-helical conformation forming smaller dendrimer/siRNA nanoparticles, which escape the endosome and release their siRNA cargo in the cytosol. Two particularly efficient d-enantiomeric dendrimers are proposed as new reference reagents for siRNA transfection.

Graphitic and oxidised high pressure high temperature (HPHT) nanodiamonds induce differential biological responses in breast cancer cell lines

Nanodiamonds have demonstrated potential as powerful sensors in biomedicine, however, their translation into routine use requires a comprehensive understanding of their effect on the biological system being interrogated. Under normal fabrication processes, nanodiamonds are produced with a graphitic carbon shell, but are often oxidized in order to modify their surface chemistry for targeting to specific cellular compartments. Here, we assessed the biological impact of this purification process, considering cellular proliferation, uptake, and oxidative stress for graphitic and oxidized nanodiamond surfaces. We show for the first time that oxidized nanodiamonds possess improved biocompatibility compared to graphitic nanodiamonds in breast cancer cell lines, with graphitic nanodiamonds inducing higher levels of oxidative stress despite lower uptake.

Multifunctional nanodiamonds in regenerative medicine: Recent advances and future directions

With recent advances in the field of nanomedicine, many new strategies have emerged for diagnosing and treating diseases. At the forefront of this multidisciplinary research, carbon nanomaterials have demonstrated unprecedented potential for a variety of regenerative medicine applications including novel drug delivery platforms that facilitate the localized and sustained release of therapeutics. Nanodiamonds (NDs) are a unique class of carbon nanoparticles that are gaining increasing attention for their biocompatibility, highly functional surfaces, optical properties, and robust physical properties. Their remarkable features have established NDs as an invaluable regenerative medicine platform, with a broad range of clinically relevant applications ranging from targeted delivery systems for insoluble drugs, bioactive substrates for stem cells, and fluorescent probes for long-term tracking of cells and biomolecules in vitro and in vivo. This review introduces the synthesis techniques and the various routes of surface functionalization that allow for precise control over the properties of NDs. It also provides an in-depth overview of the current progress made toward the use of NDs in the fields of drug delivery, tissue engineering, and bioimaging. Their future outlook in regenerative medicine including the current clinical significance of NDs, as well as the challenges that must be overcome to successfully translate the reviewed technologies from research platforms to clinical therapies will also be discussed.

Surface Modified Multifunctional and Stimuli Responsive Nanoparticles for Drug Targeting: Current Status and Uses

Nanocarriers, due to their unique features, are of increased interest among researchers working with pharmaceutical formulations. Polymeric nanoparticles and nanocapsules, involving non-toxic biodegradable polymers, liposomes, solid lipid nanoparticles, and inorganic-organic nanomaterials, are among the most used carriers for drugs for a broad spectrum of targeted diseases. In fact, oral, injectable, transdermal-dermal and ocular formulations mainly consist of the aforementioned nanomaterials demonstrating promising characteristics such as long circulation, specific targeting, high drug loading capacity, enhanced intracellular penetration, and so on. Over the last decade, huge advances in the development of novel, safer and less toxic nanocarriers with amended properties have been made. In addition, multifunctional nanocarriers combining chemical substances, vitamins and peptides via coupling chemistry, inorganic particles coated by biocompatible materials seem to play a key role considering that functionalization can enhance characteristics such as biocompatibility, targetability, environmental friendliness, and intracellular penetration while also have limited side effects. This review aims to summarize the "state of the art" of drug delivery carriers in nanosize, paying attention to their surface functionalization with ligands and other small or polymeric compounds so as to upgrade active and passive targeting, different release patterns as well as cell targeting and stimuli responsibility. Lastly, future aspects and potential uses of nanoparticulated drug systems are outlined.