Bio-inspired microcapsule for targeted antithrombotic drug delivery

Layer-by-layer self-assembly embedding of nattokinase in chitosan/γ-polyglutamic acid: Preparation, fibrinolytic activity, stability, and in vitro digestion study

Nattokinase (NK) is a thrombolytic enzyme extracted from natto, which can be used to prevent and treat blood clots. However, it is sensitive to the environment, especially the acidic environment of human stomach acid, and its effect of oral ingestion is minimal. This study aims to increase NK's oral and storage stability by embedding NK in microcapsules prepared with chitosan (CS) and γ-polyglutamic acid (γ-PGA). The paper prepared a double-layer NK oral delivery system by layer self-assembly and characterized its stability and in vitro simulated digestion. According to the research results, the bilayer putamen structure has a protective effect on NK, which not only maintains high activity in various environments (such as acid-base, high temperature) and long-term storage (60 days), but also effectively protects the loaded NK from being destroyed in gastric fluid and achieves its slow release. This work has proved the feasibility of the design of bilayer putamen structure in oral administration and has good fibrolytic activity. Therefore, the novel CS/γ-PGA microcapsules are expected to be used in nutraceutical delivery systems.

Microcapsule fabrication by ATRP at the interface of non-aqueous emulsions

We present soft-template encapsulation of salt hydrate phase change materials (PCMs) using modified silica particles to both stabilize emulsions and serve as initiators for organocatalyzed photoredox ATRP. The resulting core-shell structures have high core loading and are robust to thermal cycling. Critically, this strategy eliminates the need for a reagent in the core phase, thus preserving purity, and offers the ability to tailor shell composition for desired applications.

Preparation, Characterization and Drug Delivery Research of γ-Polyglutamic Acid Nanoparticles: A Review

γ-Polyglutamic acid is a kind of biomaterial and environmentally friendly polymer material with the characteristics of water solubility and good biocompatibility. It has a wide range of applications in medicine, food, cosmetics and other fields. This article reviews the preparation, characterization and medical applications of γ-polyglutamic acid nanoparticles. Nanoparticles prepared by using γ- polyglutamic acid not only had the traditional advantages of enhancing drug stability and slow-release effect, but also were simple to prepare without any biological toxicity. The current methods of nanoparticle preparation mainly include the ion gel method and solvent exchange method, which use the total electrostatic force, van der Waals force, hydrophobic interaction force and hydrogen bond force between molecules to embed materials with different characteristics. At present, there are more and more studies on the use of γ-polyglutamic acid to encapsulate drugs, and the research on the mechanism of its encapsulation and sustained release has gradually matured. The development and application of polyglutamic acid nanoparticles have broad prospects.

Wettability-tuned silica particles for emulsion-templated microcapsules

Pickering emulsions play a significant role in generating advanced materials and have widespread application in personal care products, consumer goods, crude oil refining, energy management, etc. Herein, we report a class of wettability tuned silica-based Pickering emulsifiers which stabilize a diverse range of fluid-fluid interfaces: oil/water, ionic liquid/oil, and oil/oil, and their use to prepare microcapsules via interfacial polymerization. To alter particle wettability, colloidal suspensions of SiO2 particles (22 nm) were modified via silanization with reagents of varied hydrophilicity/hydrophobicity, giving particles that could be dispersed in solvents that became the continuous phase of the emulsions. To test the viability of this system as templates for the fabrication of composite materials, the different particle-stabilized emulsions were coupled with interfacial polymerization, leading to microcapsules with polyurea/silica shells. These results demonstrate that a single particle feedstock can be coupled with fundamental chemical transformation to access a versatile toolkit for the stabilization of diverse fluid interfaces and serve as a template for the preparation of hybrid architectures.

Recent Advances in Blood Cell-Inspired and Clot Targeted Thrombolytic Therapies

Myocardial infarction, stroke, and pulmonary embolism are all deadly conditions associated with excessive thrombus formation. Standard treatment for these conditions involves systemic delivery of thrombolytic agents to break up clots and restore blood flow; however, this treatment can impact the hemostatic balance in other parts of the vasculature, which can lead to excessive bleeding. To avoid this potential danger, targeted thrombolytic treatments that can successfully target thrombi and release an effective therapeutic load are necessary. Because activated platelets and fibrin make up a large proportion of clots, these two components provide ample opportunities for targeting. This review will highlight potential thrombus targeting mechanisms as well as recent advances in thrombolytic therapies which utilize blood-cells and clotting proteins to effectively target and lyse clots.

Study on physical properties of four pH responsive Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) microcapsules as controlled release carriers

This study provides a promising controlled release form of nuclear polyhedrosis virus (NPV) for targeted control of lepidopteran pests. However, the application of NPV is limited due to its sensitivity to UV inactivation. This study investigated the anti-UV properties of microcapsules of SeMNPV occlusion bodies (OBs) encapsulated by calcium alginate (CA), and also the influence of the modification of CA by chitosan (CS), whey protein (WP), and polydopamine (PDA). These capsules were used to deliver, in a controlled release manner virions under alkaline pH conditions. Characterization of the structure, morphology, particle size, encapsulation efficiency, contact angle, insecticidal activity, UV resistance and in vitro release of the microcapsules was conducted. The modified microcapsules had better sphericity, and were devoid of SeMNPV OBs on the surface. The encapsulation rate was 84.76 ± 0.59%. PDA@CA-NPV had the highest wettability and the contact angle was 74.51 ± 0.53°. The 50% lethal concentration values (LC₅₀) of CA-NPV, CS@CA-NPV, WP@CA-NPV and PDA@CA-NPV were 11.5, 10.7, 10.5 and 1.2 times that of SeMNPV OBs alone. The modified microcapsules all improved the anti-UV performance of the virus, and PDA@CA-NPV was the most UV-resistant. Using qPCR, it was observed that under alkaline conditions, a large number of virions were released from PDA@CA-NPV, CA-NPV and SeMNPV OBs. Microencapsulated virus under alkaline conditions did not change the release pattern of virions.

Systematic Reviews of the Literature Are Not Always Either Useful Or the Best Way To Add To Science

Systematic reviews are becoming more popular as a way of doing research; however, not all systematic reviews are clinically useful and sometimes another type of review (scoping, topical, or critical) would be of greater value to the clinical and scientific community. The different types of review and their use are described, illustrated by examples relevant to vascular surgery.