Polyion complex micelle formed from tetraphenylethene containing block copolymer

Recent Progress in Polyion Complex Nanoparticles with Enhanced Stability for Drug Delivery

Polyion complex (PIC) nanoparticles, including PIC micelles and PICsomes, are typically composed of poly(ethylene glycol) block copolymers coupled with oppositely charged polyelectrolytes or therapeutic agents via electrostatic interaction. Due to a simple and rapid preparation process with high drug-loading efficiency, PIC nanoparticles are beneficial to maintaining the chemical integrity and high biological activity of the loaded drugs. However, the stability of PIC nanoparticles can be disrupted in high-ionic-strength solutions because electrostatic interaction is the DRIVING force; these disruptions can thus impair drug delivery. Herein, we summarize the advances in the use of PIC nanoparticles for delivery of charged drugs, focusing on the different chemical and physical strategies employed to enhance their stability, including enhancing the charge density, crosslinking, increasing hydrophobic interactions, forming hydrogen bonds, and the development of PIC-based gels. In particular, we describe the use of PIC nanoparticles to load peptide antibiotics targeting antibiotic-resistant and biofilm-related diseases and the use of nanoparticles that load chemotherapeutics and gaseous donors for cancer treatment. Furthermore, the application of PIC nanoparticles as magnetic resonance imaging contrast agents is summarized for the first time. Therefore, this review is of great significance for advances in the use of polymeric nanoparticles for functional drug delivery.

Polymeric Micelles as Drug Delivery System: Recent Advances, Approaches, Applications and Patents

Administering therapeutics through the oral route is a pervasive and widely approved medication administration approach. However, it has been found that many drugs show low systemic absorption when delivered through this route. Such limitations of oral drug delivery can be overcome by polymeric micelles acting as vehicles. As a result, they improve drug absorption by protecting loaded drug substances from the gastrointestinal system's hostile conditions, allowing controlled drug release at a specific site, extending the time spent in the gut through mucoadhesion, and inhibiting the efflux pump from reducing therapeutic agent accumulation. To promote good oral absorption of a weakly water-soluble medicinal drug, the loaded medicine should be protected from the hostile atmosphere of the GI tract. Polymeric micelles can be stacked with a broad assortment of ineffectively dissolvable medications, improving bioavailability. This review discusses the major mechanism, various types, advantages, and limitations for developing the polymeric micelle system and certain micellar drug delivery system applications. The primary goal of this review is to illustrate how polymeric micelles can be used to deliver poorly water-soluble medications.

Conducting Polymers, Hydrogels and Their Composites: Preparation, Properties and Bioapplications

This review is focused on current state-of-the-art research on electroactive-based materials and their synthesis, as well as their physicochemical and biological properties. Special attention is paid to pristine intrinsically conducting polymers (ICPs) and their composites with other organic and inorganic components, well-defined micro- and nanostructures, and enhanced surface areas compared with those of conventionally prepared ICPs. Hydrogels, due to their defined porous structures and being filled with aqueous solution, offer the ability to increase the amount of immobilized chemical, biological or biochemical molecules. When other components are incorporated into ICPs, the materials form composites; in this particular case, they form conductive composites. The design and synthesis of conductive composites result in the inheritance of the advantages of each component and offer new features because of the synergistic effects between the components. The resulting structures of ICPs, conducting polymer hydrogels and their composites, as well as the unusual physicochemical properties, biocompatibility and multi-functionality of these materials, facilitate their bioapplications. The synergistic effects between constituents have made these materials particularly attractive as sensing elements for biological agents, and they also enable the immobilization of bioreceptors such as enzymes, antigen-antibodies, and nucleic acids onto their surfaces for the detection of an array of biological agents. Currently, these materials have unlimited applicability in biomedicine. In this review, we have limited discussion to three areas in which it seems that the use of ICPs and materials, including their different forms, are particularly interesting, namely, biosensors, delivery of drugs and tissue engineering.

Click Chemistry-Based Injectable Hydrogels and Bioprinting Inks for Tissue Engineering Applications

BACKGROUND

The tissue engineering and regenerative medicine approach require biomaterials which are biocompatible, easily reproducible in less time, biodegradable and should be able to generate complex three-dimensional (3D) structures to mimic the native tissue structures. Click chemistry offers the much-needed multifunctional hydrogel materials which are interesting biomaterials for the tissue engineering and bioprinting inks applications owing to their excellent ability to form hydrogels with printability instantly and to retain the live cells in their 3D network without losing the mechanical integrity even under swollen state.

METHODS

In this review, we present the recent developments of in situ hydrogel in the field of click chemistry reported for the tissue engineering and 3D bioinks applications, by mainly covering the diverse types of click chemistry methods such as Diels-Alder reaction, strain-promoted azide-alkyne cycloaddition reactions, thiol-ene reactions, oxime reactions and other interrelated reactions, excluding enzyme-based reactions.

RESULTS

The click chemistry-based hydrogels are formed spontaneously on mixing of reactive compounds and can encapsulate live cells with high viability for a long time. The recent works reported by combining the advantages of click chemistry and 3D bioprinting technology have shown to produce 3D tissue constructs with high resolution using biocompatible hydrogels as bioinks and in situ injectable forms.

CONCLUSION

Interestingly, the emergence of click chemistry reactions in bioink synthesis for 3D bioprinting have shown the massive potential of these reaction methods in creating 3D tissue constructs. However, the limitations and challenges involved in the click chemistry reactions should be analyzed and bettered to be applied to tissue engineering and 3D bioinks. The future scope of these materials is promising, including their applications in in situ 3D bioprinting for tissue or organ regeneration.

Polymeric micelles as cutaneous drug delivery system in normal skin and dermatological disorders

The easy accessibility of skin made dermal application, one of the approaches for local drug therapy. Effectiveness of topical drug application is depended on different parameters such as skin barrier properties, physicochemical properties of drug and vehicle, and interaction between drug and its vehicle with the skin layers. In this review, an overview of skin structure and feature of polymeric micelles as topical nanocarriers is provided. We also summarized the research studies dealing with the application of polymeric micelles for cutaneous delivery. In the past decades, numerous types of nanocarriers have been widely investigated as a novel delivery approach to improve skin penetration and localization of drugs in normal skin and dermatological diseases. Polymeric micelles are one of them, with their specific ability to encapsulate hydrophilic drugs. These carriers can enhance the therapeutic efficacy and minimize the systemic side effects of the drugs. Polymeric micelles could enhance the deposition of drugs in targeted sites of the skin in the normal and dermatological diseases such as psoriasis and acne. Nevertheless, still there is a need to investigate the mechanism of action of these carriers and the fate of polymeric micelles in skin.