The influence of cross-linking agent onto adsorption properties, release behavior and cytotoxicity of doxorubicin-imprinted microparticles

Alginate vs chitosan composites loaded with halloysite/molecularly imprinted polymer hybrids for tetracycline removal: Comparative studies of adsorption behaviour

Tetracycline (TC) is a broad-spectrum antibiotic but poses a significant threat to ecosystems. In this study, a series of alginate-based (ALG) hydrogel beads were synthesized with the incorporation of halloysite (Hal), a molecularly imprinted polymer (MIP), and a Hal-deposited polymer (Hal@MIP). The adsorption properties of these materials were evaluated and compared with those of their chitosan-based (CS) counterparts. The findings demonstrate a significant improvement in TC removal, highlighting the potential of the alginate-based hydrogels as superior adsorbents than chitosan-based ones. The maximum TC adsorption capacity reached 281 mg g-1 for ALG_Hal@MIP, which was approximately 100 mg higher than that obtained for CS_Hal@MIP. The hydrogel beads with Hal@MIP demonstrated higher thermal stability and better accessibility to the imprinted cavities than those with MIP. The high adsorption efficiency was attributed to pore-filling, accompanied by the simultaneous contributions of electrostatic interaction, complexation, H-bonding and π-π electron donor-acceptor effect. The hydrogel beads containing imprinted polymers exhibited high selectivity and maintained their functionality in real water samples. The advantage of alginate-based adsorbents over chitosan-based ones was evident in water and soil samples. Hence, ALG_Hal@MIP emerged as the most promising material for the selective remediation of TC contamination in different environments compared to the other adsorbents.

EGDMA- and TRIM-Based Microparticles Imprinted with 5-Fluorouracil for Prolonged Drug Delivery

Imprinted materials possess designed cavities capable of forming selective interactions with molecules used in the imprinting process. In this work, we report the synthesis of 5-fluorouracil (5-FU)-imprinted microparticles and their application in prolonged drug delivery. The materials were synthesized using either ethylene glycol dimethacrylate (EGDMA) or trimethylolpropane trimethacrylate (TRIM) cross-linkers. For both types of polymers, methacrylic acid was used as a functional monomer, whereas 2-hydroxyethyl methacrylate was applied to increase the final materials’ hydrophilicity. Adsorption isotherms and adsorption kinetics were investigated to characterize the interactions that occur between the materials and 5-FU. The microparticles synthesized using the TRIM cross-linker showed higher adsorption properties towards 5-FU than those with EGDMA. The release kinetics was highly dependent upon the cross-linker and pH of the release medium. The highest cumulative release was obtained for TRIM-based microparticles at pH 7.4. The IC₅₀ values proved that 5-FU-loaded TRIM-based microparticles possess cytotoxic activity against HeLa cell lines similar to pure 5-FU, whereas their toxicity towards normal HDF cell lines was ca. three times lower than for 5-FU.

The Electrospray (ESI) and Flowing Atmosphere-Pressure Afterglow (FAPA) Mass Spectrometry Studies of Nitrophenols (Plant Growth Stimulants) Removed Using Strong Base-Functionalized Materials

The functional silica-based materials functionalized with a strong nitrogen base TBD (SiO₂-TBD) deposited via a linker or with a basic poly(amidoamine) dendrimer containing multiple terminal amine groups -NH₂ (SiO₂-EDA) and functional polymers containing a strong phosphazene base (Polymer-Phosphazene) or another basic poly(amidoamine) dendrimer (PMVEAMA-PAMAM) were tested as sorbents dedicated to a mixture of nitrophenols (p-nitrophenol and 2-methoxy-5-nitrophenol), which are analogs of nitrophenols used in plant growth biostimulants. The adsorptive potential of the studied materials reached 0.102, 0.089, 0.140, and 0.074 g of the nitrophenols g⁻¹, for SiO₂-TBD, SiO₂-EDA, polymer-phosphazene, and PMVEAMA-PAMAM, respectively. The sorptive efficiency of the analytes, i.e., their adsorption on the functional materials, the desorption from the obtained [(sorbent)H⁺ − nitrophenolates^–] complexes, and interactions with the used soil, were monitored using mass spectrometry (MS) technique with electrospray (ESI) and flowing atmosphere-pressure afterglow (FAPA) ionizations, for the analysis of the aqueous solutions and the solids, respectively. The results showed that the adsorption/desorption progress is determined by the structures of the terminal basic domains anchored to the materials, which are connected with the strength of the proton exchange between the sorbents and nitrophenols. Moreover, the conducted comprehensive MS analyses, performed for both solid and aqueous samples, gave a broad insight into the interactions of the biostimulants and the presented functional materials.

Molecularly imprinted polymers in biological applications

Molecularly imprinted polymers (MIPs) are currently widely used and further developed for biological applications. The MIP synthesis procedure is a key process, and a wide variety of protocols exist. The templates that are used for imprinting vary from the smallest glycosylated glycan structures or even amino acids to whole proteins or bacteria. The low cost, quick preparation, stability and reproducibility have been highlighted as advantages of MIPs. The biological applications utilizing MIPs discussed here include enzyme-linked assays, sensors, in vivo applications, drug delivery, cancer diagnostics and more. Indeed, there are numerous examples of how MIPs can be used as recognition elements similar to natural antibodies.