Progress in ATRP-derived materials for biomedical applications

Breaking barriers: Smart vaccine platforms for cancer immunomodulation

Despite significant advancements in cancer treatment, current therapies often fail to completely eradicate malignant cells. This shortfall underscores the urgent need to explore alternative approaches such as cancer vaccines. Leveraging the immune system's natural ability to target and kill cancer cells holds great therapeutic potential. However, the development of cancer vaccines is hindered by several challenges, including low stability, inadequate immune response activation, and the immunosuppressive tumor microenvironment, which limit their efficacy. Recent progress in various fields, such as click chemistry, nanotechnology, exosome engineering, and neoantigen design, offer innovative solutions to these challenges. These achievements have led to the emergence of smart vaccine platforms (SVPs), which integrate protective carriers for messenger ribonucleic acid (mRNA) with functionalization strategies to optimize targeted delivery. Click chemistry further enhances SVP performance by improving the encapsulation of mRNA antigens and facilitating their precise delivery to target cells. This review highlights the latest developments in SVP technologies for cancer therapy, exploring both their opportunities and challenges in advancing these transformative approaches.

A Comparative Study of Quercetin/Rutin Loaded PEG Polymeric Nanoparticles: Controlled Drug Release and Its Biological Activity

Flavonoids are natural polyphenolic compounds that primarily possess antioxidant properties and play a significant role in opposing various diseases. Current chemotherapeutic approaches are largely ineffective, thus calling for the development of alternative strategies to combat this disease. In this regard, numerous studies have reported the anticancer effect of flavonoids in different types of cancer. To enhance its therapeutic value, polymeric nanoparticles (PEG NPs) represent an ideal delivery system. Further, surface modification of NPs with PEG holds tremendous potential for improving the bioavailability and circulation time of native drugs in the blood. The present study aimed to develop Quercetin/Rutin-loaded PEG polymeric NPs (Qu-PEG/Ru-PEG NPs) with enhanced encapsulation efficiency and sustained drug release. The synthesized Qu-PEG NPs & Ru-PEG NPs were characterized by UV-Vis Spectroscopy, FTIR spectrum, NMR, and XRD and SEM analysis. In-vitro drug release study exhibited a cumulative release of Quercetin & rutin for 24 h at pH 7.4. Further, the polymeric nano-formulations of Quercetin & Rutin showed enhanced antioxidant activity, leading to defense against oxidative stress. In-vitro cellular studies demonstrated that Qu-PEG NPs and Ru-PEG NPs significantly inhibit KB cell proliferation compared to free drugs alone. The current study also showed that Qu-PEG NPs & Ru-PEG NPs enhance intracellular ROS generation compared to the drug alone. Hence, our research findings revealed that successful encapsulation of Quercetin & Rutin in PEG NPs targets the tumor microenvironment and enhances the efficacy of drugs. Based on these preliminary results, flavonoid-loaded polymeric-based NPs might be potential therapeutic molecules against cancer in the future.

Protein-Polymer Conjugates as Biocompatible and Recyclable ATRP Catalysts

Atom transfer radical polymerization (ATRP) is a leading method for creating polymers with precise control over molecular weight, yet its reliance on metal catalysts limits its application in metal-sensitive and environmental contexts. Addressing these limitations, we have developed a recyclable, biocompatible, robust, and tunable ATRP catalyst composed of a protein-polymer-copper conjugate, synthesized by polymerizing an L-proline-based monomer onto bovine serum albumin and complexing with Cu(II). The use of this conjugate catalyst maintains ATRP's precision while ensuring biocompatibility with bothEscherichia coli and HEK 293 cells, and its high molecular weight allows for easy recycling through dialysis. Therefore, our efforts extend ATRP's applicability across diverse fields, including biotechnology and green chemistry, marking a significant advance toward environmentally friendly and safe polymerization technologies.

Polymerizable Cholinium-Based Antibiotics for Polymer Carriers: Systems with Combined Load of Cloxacillin and Ampicillin

Single and dual-drug delivery systems (DDSs) based on linear choline polymers were designed through the controlled polymerization of a pharmaceutically functionalized monomer, i.e., [2-(methacryloyloxy)ethyl]trimethylammonium, with counterions of cloxacillin (TMAMA/CLX), or its copolymerization with [2-(methacryloyloxy)ethyl]trimethylammonium with ampicillin (TMAMA/AMP), providing antibiotic properties. This strategy was effective in attaining well-defined linear copolymers with 38-93 mol. % of TMAMA content, which were regulated by the initial ratio of TMAMA to methyl methacrylate comonomer. The polymer compositions were controlled by the total monomer conversion (40-75%), resulting in a variable degree of polymerization (DPn = 160-300) and pharmaceutical anion contents (CLX- 51-80% and AMP- 78-87%). In aqueous solution, the polymers formed particles with sizes ranging between 274 and 380 nm for CLX- systems and 288-348 nm for CLX-/AMP- systems. In vitro drug release, driven by the exchange of pharmaceutical anions with phosphate ions in phosphate-buffered saline (PBS), imitating a physiological fluid, demonstrated release efficiencies of 58-76% for CLX- (10.5-13.6 µg/mL) in single systems, and 91-100% for CLX- (12.9-15.1 µg/mL) and 97-100% for AMP- (21.1-23.3 µg/mL) in dual systems. Compared to conventional systems delivering antibiotics without a polymer carrier, the choline-based polymer DDS attained satisfactory levels of drug loading content and (co-)release from the polymer carriers, offering a promising alternative for antibiotic delivery.

Temperature-modulated interactions between thermoresponsive strong cationic copolymer-brush-grafted silica beads and biomolecules

Thermoresponsive polymer brushes have attracted considerable research attention owing to their unique properties. Herein, we developed silica beads grafted with poly(N-isopropylacrylamide (NIPAAm)-co-3-acrylamidopropyl trimethylammonium chloride (APTAC)-co-tert-butyl acrylamide (tBAAm) and P(NIPAAm-co-APTAC-co-n-butyl methacrylate(nBMA)) brushes. The carbon, hydrogen, and nitrogen elemental analysis of the copolymer-grated silica beads revealed the presence of a large amount of the grafted copolymer on the silica beads. The electrostatic and hydrophobic interactions between biomolecules and prepared copolymer brushes were analyzed by observing their elution behaviors via high-performance liquid chromatography using the copolymer-brush-modified beads as the stationary phase. Adenosine nucleotides were retained in the bead-packed columns, which was attributed to the electrostatic interaction between the copolymers and adenosine nucleotides. Insulin was adsorbed on the copolymer brushes at high temperatures, which was attributed to its electrostatic and hydrophobic interactions with the copolymer. Similar adsorption behavior was observed in case of albumin. Further, at a low concentration of the phosphate buffer solution, albumin was adsorbed onto the copolymer brushes even at relatively low temperatures owing to its enhanced electrostatic interaction with the copolymer. These results indicated that the developed thermoresponsive strong cationic copolymer brushes can interact with peptides and proteins through a combination of electrostatic and temperature-modulated hydrophobic interactions. Thus, the developed copolymer brushes exhibits substantial potential for application in chromatographic matrices for the analysis and purification of peptides and proteins.

Tailor-Made Polysaccharides for Biomedical Applications

Polysaccharides (PSAs) are carbohydrate-based macromolecules widely used in the biomedical field, either in their pure form or in blends/nanocomposites with other materials. The relationship between structure, properties, and functions has inspired scientists to design multifunctional PSAs for various biomedical applications by incorporating unique molecular structures and targeted bulk properties. Multiple strategies, such as conjugation, grafting, cross-linking, and functionalization, have been explored to control their mechanical properties, electrical conductivity, hydrophilicity, degradability, rheological features, and stimuli-responsiveness. For instance, custom-made PSAs are known for their worldwide biomedical applications in tissue engineering, drug/gene delivery, and regenerative medicine. Furthermore, the remarkable advancements in supramolecular engineering and chemistry have paved the way for mission-oriented biomaterial synthesis and the fabrication of customized biomaterials. These materials can synergistically combine the benefits of biology and chemistry to tackle important biomedical questions. Herein, we categorize and summarize PSAs based on their synthesis methods, and explore the main strategies used to customize their chemical structures. We then highlight various properties of PSAs using practical examples. Lastly, we thoroughly describe the biomedical applications of tailor-made PSAs, along with their current existing challenges and potential future directions.