Gadolinium labeled polyelectrolyte nanocarriers for theranostic application

Multilayered Nanocarriers as a New Strategy for Delivering Drugs with Protective and Anti-inflammatory Potential: Studies in Hippocampal Organotypic Cultures Subjected to Experimental Ischemia

Oxidative stress and neuroinflammation play a pivotal role in pathomechanisms of brain ischemia. Our research aimed to formulate a nanotheranostic system for delivering carnosic acid as a neuroprotective agent with anti-oxidative and anti-inflammatory properties to ischemic brain tissue, mimicked by organotypic hippocampal cultures (OHCs) exposed to oxygen-glucose deprivation (OGD). In the first part of this study, the nanocarriers were formulated by encapsulating two types of nanocores (nanoemulsion (AOT) and polymeric (PCL)) containing CA into multilayer shells using the sequential adsorption of charged nanoobjects method. The newly designed nanoparticles possessed favorable physicochemical characteristics as reflected by zeta potential and other parameters. Next, we demonstrated that the newly designed gadolinium-containing nanoparticles were not toxic to OHCs and did not affect the detrimental effects of OGD on the viability of the hippocampal cells. Importantly, they readily crossed the artificial blood-brain barrier based on the human cerebral microvascular endothelial (hCMEC/D3) cell line. Furthermore, the PCL-Gd carnosic acid-loaded nanoparticles displayed anti-inflammatory potential, expressed as decreased OGD-induced HIF-1α and IL-1β levels. Results of the molecular study revealed a complex mechanism of the nanoformulation on ischemia-related neuroinflammation in OHCs, including anti-inflammatory protein A20 stimulation and moderate attenuation of the NFκB signaling pathway. Summing up, this study points to acceptable biocompatibility of the newly designed CA-containing theranostic nanoformulation and emphasizes their interaction with inflammatory processes commonly associated with the ischemic brain.

Contrasting Properties of Polymeric Nanocarriers for MRI-Guided Drug Delivery

Poor pharmacokinetics and low aqueous solubility combined with rapid clearance from the circulation of drugs result in their limited effectiveness and generally high therapeutic doses. The use of nanocarriers for drug delivery can prevent the rapid degradation of the drug, leading to its increased half-life. It can also improve the solubility and stability of drugs, advance their distribution and targeting, ensure a sustained release, and reduce drug resistance by delivering multiple therapeutic agents simultaneously. Furthermore, nanotechnology enables the combination of therapeutics with biomedical imaging agents and other treatment modalities to overcome the challenges of disease diagnosis and therapy. Such an approach is referred to as "theranostics" and aims to offer a more patient-specific approach through the observation of the distribution of contrast agents that are linked to therapeutics. The purpose of this paper is to present the recent scientific reports on polymeric nanocarriers for MRI-guided drug delivery. Polymeric nanocarriers are a very broad and versatile group of materials for drug delivery, providing high loading capacities, improved pharmacokinetics, and biocompatibility. The main focus was on the contrasting properties of proposed polymeric nanocarriers, which can be categorized into three main groups: polymeric nanocarriers (1) with relaxation-type contrast agents, (2) with chemical exchange saturation transfer (CEST) properties, and (3) with direct detection contrast agents based on fluorinated compounds. The importance of this aspect tends to be downplayed, despite its being essential for the successful design of applicable theranostic nanocarriers for image-guided drug delivery. If available, cytotoxicity and therapeutic effects were also summarized.

Bionic chitosan-carbon imprinted aerogel for high selective recovery of Gd(Ⅲ) from end-of-life rare earth productions

High selective recovery of Gd(Ⅲ) from end-of-life rare earth productions is essential for cleaner production. Chitosan(CS), a biomaterial, has shown excellent results in water treatment. The amino and hydroxyl groups on the surface of CS play a vital role in adsorbing metal ions. Polydopamine has good stability, strong water dispersibility, and excellent biocompatibility. As a bio-crosslinking agent, the amino and phenolic hydroxyl groups on its surface can be combined with metal ions to help the material absorb metal ions. This paper combines the active groups of biomimetic materials and the mechanical properties of new nanomaterials multi-walled carbon nanotubes and graphene oxide, and prepared a high-performance chitosan-based aerogel MWCNT-PDA-CS-GO through heat and mass transfer at low temperature and low pressure. The adsorption mechanism of MWCNT-PDA-CS-GO for Gd(Ⅲ) was analyzed through a series of characterization and adsorption experiments. At pH 7.0, the maximum adsorption capacity of aerogel for Gd(Ⅲ) reached 150.86 mg g^-1. The relative selectivity of imprinted ions is 48.02 times higher than other ions. All the results indict MWCNT-PDA-CS-GO aerogel exhibits excellent selectivity and stability for effective recovery of Gd(Ⅲ).

Effective Detection of Nafion®-Based Theranostic Nanocapsules through 19F Ultra-Short Echo Time MRI

The application of the Three-Dimensional Ultra-Short Echo Time (3D UTE)pulse sequence at a high magnetic field for visualization of the distribution of ¹⁹F loaded theranostic core-shell nanocapsules with Nafion^® (1,1,2,2-tetrafluoroethene; 1,1,2,2-tetrafluoro-2- [1,1,1,2,3,3-hexafluoro-3-(1,2,2-trifluoroethenoxy)propan-2-yl] oxyethanesulfonic acid) incorporated into the shell is presented. The nanocarriers were formed via the layer-by-layer technique with biodegradable polyelectrolytes: PLL (Poly-L-lysine), and with Nafion^®: polymer with high ¹⁹F content. Before imaging, an MR (magnetic resonance) spectroscopy and T₁ and T₂ measurements were performed, resulting in values of T₂ between 1.3 ms and 3.0 ms, depending on the spectral line. To overcome limitations due to such short T₂, the 3D UTE pulse sequence was applied for ¹⁹F MR imaging. First Nafion^® solutions of various concentrations were measured to check the detection limit of our system for the investigated molecule. Next, the imaging of a phantom containing core-shell nanocapsules was performed to assess the possibility of visualizing their distribution in the samples. Images of Nafion^® containing samples with SNR ≥ 5 with acquisition time below 30 min for ¹⁹F concentration as low as 1.53 × 10⁻² mmol ¹⁹F/g of sample, were obtained. This is comparable with the results obtained for molecules, which exhibit more preferable MR characteristics.

Nafion-Based Nanocarriers for Fluorine Magnetic Resonance Imaging

The aim of our study was to develop a novel method for nanocarriers' preparation as a fluorine magnetic resonance imaging (19F MRI)-detectable drug delivery system. The novelty of the proposed approach is based on the application of fluorinated polyelectrolyte Nafion as a contrast agent since typical MRI contrast agents are based on paramagnetic gadolinium or ferro/superparamagnetic iron oxide compounds. An advantage of using an 19F-based tracer comes from the fact that the 19F image is detected at a different resonance frequency than the 1H image. In addition, the close to zero natural concentration of 19F nuclei in the human body makes fluorine atoms a promising MRI marker without any natural background signal. That creates the opportunity to localize and identify only exogenous fluorinated compounds with 100% specificity. The nanocarriers were formed by the deposition of polyelectrolytes on nanoemulsion droplets via the layer-by-layer technique with the saturation approach. The polyelectrolyte multilayer shell was composed of Nafion, the fluorinated ionic polymer used for labeling by 19F nuclei, and poly-l-lysine (PLL). The surface of such prepared nanocarriers was further pegylated by adsorption of pegylated polyanion, poly-l-glutamic acid (PGA). The 19F MRI-detectable hydrophobic nanocarriers with an average size of 170 nm and a sufficient signal-to-noise ratio have been developed and optimized to be used for passive tumor targeting and drug delivery.