Modulating acrylic acid content of nanogels for drug delivery & biocompatibility studies

Pickering Emulsions Stabilized by Hybrid TiO2-pNIPAm Composites for the Photocatalytic Degradation of 4-Propylbenzoic Acid

Pickering emulsions (PEs) have demonstrated significant potential in various fields, including catalysis, biomedical applications, and food science, with notable advancements in wastewater treatment through photocatalysis. This study explores the development and application of TiO2-poly(N-isopropylacrylamide) (pNIPAm) composite gels as a novel framework for photocatalytic wastewater remediation. The research focuses on overcoming challenges associated with conventional nanoparticle-based photocatalytic systems, such as agglomeration and inefficient recovery of particles. By integrating TiO2 nanoparticles into pNIPAm gels, we aimed to achieve high emulsion stability and photocatalytic efficiency while suppressing the effects of pNIPAm's volume phase transition temperature (VPTT) to facilitate effective emulsion recovery. The study involves the synthesis of TiO2-pNIPAm composites with varying monomer-to-particle ratios, characterizing their VPTT behavior, morphology, and thermal stability. These composites were then evaluated for their emulsification properties, phase transition behavior, and photocatalytic activity in degrading 4-propylbenzoic acid, a model pollutant. The results highlight the effectiveness of the TiO2-pNIPAm Pickering emulsions in wastewater treatment, offering improved stability and reusability compared to traditional dispersion-based systems. This work provides new insights into the design of composite materials for enhanced photocatalytic applications and demonstrates the potential of Pickering emulsions in sustainable environmental remediation.

Localized Thermoresponsive Behavior in P(NIPAm‐co‐AAc) Copolymers: Structural Insights From Rheology and Small Angle X‐Ray Scattering

Stimuli‐responsive polymers stand out for their ability to respond to small environmental changes. One of the most representative thermo‐sensitive materials is poly(N‐isopropyl acrylamide) (PNIPAm), which presents reversible phase transitions close to the human body temperature. However, previous studies observed that the copolymerization of NIPAm with small quantities of different monomers like acrylic acid (AAc) results in copolymers with reduced or lost thermo‐responsivity. In this study, thermo‐sensitive PNIPAm, pH‐sensitive poly(acrylic acid) (PAAc), and various proportions of their copolymers P(NIPAm‐co‐AAc) were obtained by free radical polymerization and thoroughly characterized. Rheological and structural studies reveal the remaining thermosensitivity of the copolymers manifested at short molecular ranges. These alterations in short‐range interactions are observed in all samples containing NIPAm, and they are evidenced by changes in the fractality of their structure and flow index behavior of the Viscosity Ostwald–de Waele Model. Particularly, when the copolymer proportion of NIPAm/AAc is about 40/60, the Beaucage model reveals two structural levels, ~200 and ~10 nm. Furthermore, the model exhibits a thermal response of the lower‐size substructures, indicating possible segregation of NIPAm‐rich regions from copolymer chains. The evidence found in this work could contribute to the development of nanosystems, in which local thermoresponsive effects are sought, such as for active drug targeting.

Investigating the Impact of Network Functionalization on Protein Adsorption to Polymer Nanogels

This study explores the impact of network functionalization and chemical composition on the pH-responsive behavior of polymer nanogels and their adsorption of proteins. Using a thermodynamic theory informed by a molecular model, this work evaluates the interactions of three proteins with varying isoelectric points (insulin, myoglobin, and cytochrome c) and pH-responsive nanogels based on methacrylic acid or allylamine motifs. Three different functionalization strategies are considered, with pH-responsive segments distributed randomly, at the center, or on the surface of the polymer network. Our results show that the spatial distribution of functional units affects both the nanogels' mechanical response to pH changes and the level and localization of adsorbed proteins. The dependence of protein adsorption on the salt concentration is also investigated, with the conclusion that it is best to encapsulate proteins at low salt concentrations and aim for release at high salt concentrations. These results provide valuable information for the design of pH-responsive nanogels as vehicles for protein encapsulation, transport, and administration.

Bulk Polymerization of Acrylic Acid Using Dielectric-Barrier Discharge Plasma in a Mesoporous Material

This research investigated a non-thermal, dielectric-barrier discharge (DBD) plasma-based approach to prepare poly(acrylic acid) (PAA) from acrylic acid in its liquid state at atmospheric temperature and pressure. Neither additives nor solvents were needed, and the polymerization was accomplished both as a film and inside a sheet of mesoporous paper. All prepared samples were characterized and the DBD plasma-initiated kinetics were analyzed for the polymerization of acrylic acid. Using FTIR semi-quantitative analysis, the degree of polymerization was monitored, and the reaction followed an overall second-order kinetic model with respect to the DBD-initiated polymerization. Additionally, the application of a PAA-modified paper as a water retention cloth or 'wet wipe' was investigated. The results showed that the PAA-modified paper substrates using DBD plasma increased water retention as a function of plasma treatment time.

Preparation, thermal response mechanisms and biomedical applications of thermosensitive hydrogels for drug delivery

INTRODUCTION

Drug treatment is one of the main ways of coping with disease today. For the disadvantages of drug management, thermosensitive hydrogel is used as a countermeasure, which can realize the simple sustained release of drugs and the controlled release of drugs in complex physiological environments.

AREAS COVERED

This paper talks about thermosensitive hydrogels that can be used as drug carriers. The common preparation materials, material forms, thermal response mechanisms, characteristics of thermosensitive hydrogels for drug release and main disease treatment applications are reviewed.

EXPERT OPINION

When thermosensitive hydrogels are used as drug loading and delivery platforms, desired drug release patterns and release profiles can be tailored by selecting raw materials, thermal response mechanisms, and material forms. The properties of hydrogels prepared from synthetic polymers will be more stable than natural polymers. Integrating multiple thermosensitive mechanisms or different kinds of thermosensitive mechanisms on the same hydrogel is expected to realize the spatiotemporal differential delivery of multiple drugs under temperature stimulation. The industrial transformation of thermosensitive hydrogels as drug delivery platforms needs to meet some important conditions.

Mesoporous Silica and Oligo (Ethylene Glycol) Methacrylates-Based Dual-Responsive Hybrid Nanogels

Polymeric-inorganic hybrid nanomaterials have emerged as novel multifunctional platforms because they combine the intrinsic characteristics of both materials with unexpected properties that arise from synergistic effects. In this work, hybrid nanogels based on mesoporous silica nanoparticles, oligo (ethylene glycol) methacrylates, and acidic moieties were developed employing ultrasound-assisted free radical precipitation/dispersion polymerization. Chemical structure was characterized by infrared spectroscopy and nuclear magnetic resonance. Hydrodynamic diameters at different temperatures were determined by dynamic light scattering, and cloud point temperatures were determined by turbidimetry. Cell viability in fibroblast (NIH 3T3) and human prostate cancer (LNCaP) cell lines were studied by a standard colorimetric assay. The synthetic approach allows covalent bonding between the organic and inorganic components. The composition of the polymeric structure of hybrid nanogels was optimized to incorporate high percentages of acidic co-monomer, maintaining homogeneous nanosized distribution, achieving appropriate volume phase transition temperature values for biomedical applications, and remarkable pH response. The cytotoxicity assays show that cell viability was above 80% even at the highest nanogel concentration. Finally, we demonstrated the successful cell inhibition when they were treated with camptothecin-loaded hybrid nanogels.

Hyaluronic Acid within Self-Assembling Nanoparticles: Endless Possibilities for Targeted Cancer Therapy

Self-assembling nanoparticles (SANPs) based on hyaluronic acid (HA) represent unique tools in cancer therapy because they combine the HA targeting activity towards cancer cells with the advantageous features of the self-assembling nanosystems, i.e., chemical versatility and ease of preparation and scalability. This review describes the key outcomes arising from the combination of HA and SANPs, focusing on nanomaterials where HA and/or HA-derivatives are inserted within the self-assembling nanostructure. We elucidate the different HA derivatization strategies proposed for this scope, as well as the preparation methods used for the fabrication of the delivery device. After showing the biological results in the employed in vivo and in vitro models, we discussed the pros and cons of each nanosystem, opening a discussion on which approach represents the most promising strategy for further investigation and effective therapeutic protocol development.