Investigation of the Thermogelation of a Promising Biocompatible ABC Triblock Terpolymer and Its Comparison with Pluronic F127

Block copolymer micelles as ocular drug delivery systems

Block copolymer micelles, formed by the self-assembly of amphiphilic polymers, address formulation challenges, such as poor drug solubility and permeability. These micelles offer advantages including a smaller size, easier preparation, sterilization, and superior solubilization, compared with other nanocarriers. Preclinical studies have shown promising results, advancing them toward clinical trials. Their mucoadhesive properties enhance and prolong contact with the ocular surface, and their small size allows deeper penetration through tissues such as the cornea. Additionally, copolymeric micelles improve the solubility and stability of hydrophobic drugs, sustain drug release, and allow for surface modifications to enhance biocompatibility. Despite these benefits, long-term stability remains a challenge. In this review, we highlight their preclinical performance, structural frameworks, preparation techniques, physicochemical properties, current developments, and prospects as ocular drug delivery systems.

An Aggregation-Induced Emission-Based Dual Emitting Nanoprobe for Detecting Intracellular pH and Unravelling Metabolic Variations in Differentiating Lymphocytes

Monitoring T lymphocyte differentiation is essential for understanding T cell fate regulation and advancing adoptive T cell immunotherapy. However, current biomarker analysis methods necessitate cell lysis, leading to source depletion. Intracellular pH (pHi) can be affected by the presence of lactic acid (LA), a metabolic mediator of T cell activity such as glycolysis during T cell activation; therefore, it is a potentially a good biomarker of T cell state. In this work, a dual emitting enhancement-based nanoprobe, namely, AIEgen@F127-AptCD8, was developed to accurately detect the pHi of T cells to "read" the T cell differentiation process. The nanocore of this probe comprises a pair of AIE dyes, TPE-AMC (pH-sensitive moiety) and TPE-TCF, that form a donor-acceptor pair for sensitive detection of pHi by dual emitting enhancement analysis. The nanoprobe exhibits a distinctly sensitive narrow range of pHi values (from 6.0 to 7.4) that can precisely distinguish the differentiated lymphocytes from naïve ones based on their distinct pHi profiles. Activated CD8+ T cells demonstrate lower pHi (6.49 ± 0.09) than the naïve cells (7.26 ± 0.11); Jurkat cells exhibit lower pHi (6.43 ± 0.06) compared to that of nonactivated ones (7.29 ± 0.09) on 7 days post-activation. The glycolytic product profiles in T cells strongly correlate with their pHi profiles, ascertaining the reliability of probing pHi for predicting T cell states. The specificity and dynamic detection capabilities of this nanoprobe make it a promising tool for indirectly and noninvasively monitoring T cell activation and differentiation states.

Recent development of polymer nanomicelles in the treatment of eye diseases

The eye, being one of the most intricate organs in the human body, hosts numerous anatomical barriers and clearance mechanisms. This highlights the importance of devising a secure and efficacious ocular medication delivery system. Over the past several decades, advancements have been made in the development of a nano-delivery platform based on polymeric micelles. These advancements encompass diverse innovations such as poloxamer, chitosan, hydrogel-encapsulated micelles, and contact lenses embedded with micelles. Such technological evolutions allow for sustained medication retention and facilitate enhanced permeation within the eye, thereby standing as the avant-garde in ocular medication technology. This review provides a comprehensive consolidation of ocular medications predicated on polymer nanomicelles from 2014 to 2023. Additionally, it explores the challenges they pose in clinical applications, a discussion intended to aid the design of future clinical research concerning ocular medication delivery formulations.

Ionic Liquids Mediated Micellization of Pluronic Copolymers: Aggregation Behavior of Amphiphilic Triblock Copolymers

Understanding the micellization of amphiphilic triblock copolymers, especially Pluronics can play a persuasive role in engineering "smart" formulations for drug delivery applications. Their underlying self-assembly in the presence of designer solvents such as ionic liquids (ILs) provides combinatorial benefits of unique munificent properties of ILs and copolymers. The complex molecular interactions in the Pluronic copolymers/ILs mixed system influence the aggregation mechanism of copolymers depending on various aspects with no standardized factors to govern the structure-property relationship, which led to the practical applications. Here, we summarized recent progress in understanding the micellization process of IL-Pluronic mixed systems. Special emphasis was given to pure Pluronic systems (i.e., PEO-PPO-PEO) without any structural modifications, such as copolymerization with other functional groups, and ILs having cholinium and imidazolium groups. We expect that the correlation between existing/developing experimental and theoretical studies will provide the necessary basis and impetus for successful utilization in drug delivery applications.

How does the polymer architecture and position of cationic charges affect cell viability?

Polymer chemistry, composition and molar mass are factors that are known to affect cytotoxicity, however the influence of polymer architecture has not been investigated systematically. In this study the influence of the position of the cationic charges along the polymer chain on cytotoxicity was investigated while keeping constant the other polymer characteristics. Specifically, copolymers of various architectures, based on a cationic pH responsive monomer, 2-(dimethylamino)ethyl methacrylate (DMAEMA) and a non-ionic hydrophilic monomer, oligo(ethylene glycol)methyl ether methacrylate (OEGMA) were engineered and their toxicity towards a panel of cell lines investigated. Of the seven different polymer architectures examined, the block-like structures were less cytotoxic than statistical or gradient/tapered architectures. These findings will assist in developing future vectors for nucleic acid delivery.

Customising the plunge-freezing workflow for challenging conditions

Grid freezing is a critical step for successful cryo-transmission electron microscopy, and optimising freezing conditions is a considerable bottleneck in many projects. To improve reproducibility in grid preparation, temperature- and humidity-controlled chambers were built into the second generation of plunge-freezers, including the ThermoFisherScientific Vitrobot and Leica GP. Since then, for most published structures, the proteins were plunge-frozen from a cold, humid environment. This provides two benefits: many proteins are more stable at 4 °C than room temperature, and both the low temperature and the humidity help control evaporation of the tiny drop of liquid. However, for optimal stability, certain samples may have different requirements. Here, we describe various (reversible) adaptations made to a Leica GP2 system to accommodate several samples with special handling requirements: a protein that is sensitive to both light and oxygen, a sample that needs to be kept at 37 °C throughout the plunge-freezing process, and a method to freeze a polymer that gels at 37 °C in its gelled state. While some of these methods are specific to these specimens, we hope sharing the ideas behind them will help people who are dealing with tricky protein samples.

Next Generation Strategy for Tuning the Thermoresponsive Properties of Micellar and Hydrogel Drug Delivery Vehicles Using Ionic Liquids

Amongst the greatest challenges in developing injectable controlled thermoresponsive micellar and hydrogel drug delivery vehicles include tuning the cloud point (CP) and reducing the gelation temperature (Tgel), below 37 °C,...