Isolated swine heart ventricle perfusion model for implant assisted-magnetic drug targeting

Cannabis sativa L. chemical compositions as potential plasmodium falciparum dihydrofolate reductase-thymidinesynthase enzyme inhibitors: An in silico study for drug development

This study contributes to anti-malarial research effort by conducting in silico assessment of 125 compounds originated from Cannabis sativa L. against plasmodium falciparum dihydrofolate reductase-thymidinesynthase (pfDHFR-TS) enzyme for potential inhibition activity. Drug-like and pharmacokinetic criteria were used to assess the drug-like properties of the studied compounds. AutoDock4.2.6 and AutoDock Vina software were used to calculate the possible binding pose of the studied compounds to pfDHFR-TS enzyme. The docking procedure was validated using two known inhibitors cycloguanil and WR99210. 65 out of 125 compounds violated no more than 2 of Lipinski’s rule of five and were sorted out as favorable for drug development. Amongst these 65 compounds, pharmacokinetic properties and toxicity evaluation identified 60 compounds that meet the criteria of drug-like properties and were subjected to further docking studies. Docking outcomes identified 10 compounds including compounds 4, 9, 19, 22, 23, 25, 30, 42, 43, and 59 as potential candidates for inhibiting the function of pfDHFR-TS at the active site through hydrogen bonds with Ile14, Asp54, and Ile 164 residues. Compound 9 is considered as the top “hit” with docking energy far more exceeding those of the standard compounds. High correlation coefficient between the docking energy of AutoDock4.2.6 and AutoDock Vina was recorded with the value of R 2 = 0.74.

Smart and Intelligent Stimuli Responsive Materials: An Innovative Step in Drug Delivery System

Background:

In the field of drug delivery, smart and intelligent approaches have gained significant attention among researchers in order to improve the efficacy of conventional dosage forms. Material science has played a key role in developing these intelligent systems that can deliver therapeutic cargo on-demand. Stimuli responsive material based drug delivery systems have emerged as one of the most promising innovative tools for site-specific delivery. Several endogenous and exogenous stimuli have been exploited to devise “stimuli-responsive” materials for targeted drug delivery.

Methods:

For better understanding, these novel systems have been broadly classified into two categories: Internally Regulated Systems (pH, ionic strength, glucose, enzymes, and endogenous receptors) and Externally Regulated Systems (Light, magnetic field, electric field, ultrasound, and temperature). This review has followed a systematic approach through separately describing the design, development, and applications of each stimuli-responsive system in a constructive manner.

Results:

The development includes synthesis and characterization of each system, which has been discussed in a structured manner. From advantages to drawbacks, a detailed description has been included for each smart stimuli responsive material. For a complete review in this niche area of drug delivery, a wide range of therapeutic applications including recent advancement of these smart materials have been incorporated.

Conclusion:

From the current scenario to future development, a precise overview of each type of system has been discussed in this article. In summary, it is expected that researchers working in this novel area will be highly benefited from this scientific review.

Synthesis, Functionalization, and Design of Magnetic Nanoparticles for Theranostic Applications

In order to translate nanotechnology into medical practice, magnetic nanoparticles (MNPs) have been presented as a class of non-invasive nanomaterials for numerous biomedical applications. In particular, MNPs have opened a door for simultaneous diagnosis and brisk treatment of diseases in the form of theranostic agents. This review highlights the recent advances in preparation and utilization of MNPs from the synthesis and functionalization steps to the final design consideration in evading the body immune system for therapeutic and diagnostic applications with addressing the most recent examples of the literature in each section. This study provides a conceptual framework of a wide range of synthetic routes classified mainly as wet chemistry, state-of-the-art microfluidic reactors, and biogenic routes, along with the most popular coating materials to stabilize resultant MNPs. Additionally, key aspects of prolonging the half-life of MNPs via overcoming the sequential biological barriers are covered through unraveling the biophysical interactions at the bio-nano interface and giving a set of criteria to efficiently modulate MNPs' physicochemical properties. Furthermore, concepts of passive and active targeting for successful cell internalization, by respectively exploiting the unique properties of cancers and novel targeting ligands are described in detail. Finally, this study extensively covers the recent developments in magnetic drug targeting and hyperthermia as therapeutic applications of MNPs. In addition, multi-modal imaging via fusion of magnetic resonance imaging, and also innovative magnetic particle imaging with other imaging techniques for early diagnosis of diseases are extensively provided.

Design of site-directed magnetic targeting system in acute spinal cord injury

Effective repair immediately after spinal cord injury can improve the prognosis of the patient. Injection of membrane resealing nanomaterial is one of the most promising technique to repair the membrane. In order to improve the retention rate of membrane repair material at injury site, membrane resealing nanomaterial can be combined with magnetic nanoparticle and magnetic targeting system. In this paper, a special site directed magnetic targeting system, which contain a C-shaped permanent magnet and a ferromagnetic needle, was constructed. Simulation was conducted to analyze the influence of the shape of needle on the magnetic field to provide magnetic force large enough to make the magnetic particles stay at the target site. Results showed that the appearance of ferromagnetic needle raised both the strength and the gradient of magnetic field at the target site. Moreover, with similar apex angles, longer needles with larger diameters can produced lager magnetic field, but smaller needles has better focal area at the small injury site in spinal cord injury. These results provide a basis for design and fabrication of ferromagnetic needles when the targeting system is applied in future experiments.

The use of magnetite nanoparticles for implant-assisted magnetic drug targeting in thrombolytic therapy

Implant-assisted targeting of magnetic particles under the influence of an external magnetic field has previously been verified through mathematical modeling, in vitro studies, and in vivo studies on rat carotid arteries as a feasible method for localized drug delivery. The present study focuses on the development of nanoparticles for the treatment of in-stent thrombosis. Magnetic nanoparticles in the size-range 10-30 nm were synthesized in a one-pot procedure by precipitation of ferrous hydroxide followed by oxidation to magnetite. The nanoparticles were silanized with tetraethyl orthosilicate in the presence of triethylene glycol and/or polyethylene glycol. The surface coated magnetite nanoparticles were activated with either N-hydroxysulfosuccinimide or tresyl chloride for covalent immobilization of tissue plasminogen activator (tPA). Hysteresis loops showed saturation magnetizations of 55.8, 44.1, and 43.0 emu/g for the naked nanoparticles, the surface coated nanoparticles, and the tPA-nanoparticle conjugates, respectively. The hemolytic activity of the nanoparticles in blood was negligible. An initial in vivo biocompatibility test in pig, carried out by intravascular injection of the nanoparticles in a stented brachial artery, showed no short-term adverse effects. In vitro evaluation in a flow-through model proved that the nanoparticles were captured efficiently to the surface of a ferromagnetic coiled wire at the fluid velocities typical for human arteries. A preliminary test of the tPA-nanoparticle conjugates in a pig model suggested that the conjugates may be used for treatment of in-stent thrombosis in coronary arteries.