Efficient Isolation of Bacterial RNAs Using Silica-Based Materials Modified with Ionic Liquids

High quality nucleic acids (with high integrity, purity, and biological activity) have become indispensable products of modern society, both in molecular diagnosis and to be used as biopharmaceuticals. As the current methods available for the extraction and purification of nucleic acids are laborious, time-consuming, and usually rely on the use of hazardous chemicals, there is an unmet need towards the development of more sustainable and cost-effective technologies for nucleic acids purification. Accordingly, this study addresses the preparation and evaluation of silica-based materials chemically modified with chloride-based ionic liquids (supported ionic liquids, SILs) as potential materials to effectively isolate RNAs. The investigated chloride-based SILs comprise the following cations: 1-methyl-3-propylimidazolium, triethylpropylammonium, dimethylbutylpropylammonium, and trioctylpropylammonium. All SILs were synthesized by us and characterized by solid-state 13C Nuclear Magnetic Resonance (NMR), Scanning Electron Microscopy (SEM), elemental analysis, and zeta potential measurements, confirming the successful covalent attachment of each IL cation with no relevant changes in the morphology of materials. Their innovative application as chromatographic supports for the isolation of recombinant RNA was then evaluated. Adsorption kinetics of transfer RNA (tRNA) on the modified silica-based materials were investigated at 25 °C. Irrespective to the immobilized IL, the adsorption experimental data are better described by a pseudo first-order model, and maximum tRNA binding capacities of circa 16 µmol of tRNA/g of material were achieved with silica modified with 1-methyl-3-propylimidazolium chloride and dimethylbutylpropylammonium chloride. Furthermore, the multimodal character displayed by SILs was explored towards the purification of tRNA from Escherichia coli lysates, which in addition to tRNA contain ribosomal RNA and genomic DNA. The best performance on the tRNA isolation was achieved with SILs comprising 1-methyl-3-propylimidazolium chloride and dimethylbutylpropylammonium chloride. Overall, the IL modified silica-based materials represent a more efficient, sustainable, and cost-effective technology for the purification of bacterial RNAs, paving the way for their use in the purification of distinct biomolecules or nucleic acids from other sources.

Advances Achieved by Ionic-Liquid-Based Materials as Alternative Supports and Purification Platforms for Proteins and Enzymes

Ionic liquids (ILs) have been applied in several fields in which enzymes and proteins play a noteworthy role, for instance in biorefinery, biotechnology, and pharmaceutical sciences, among others. Despite their use as solvents and co-solvents, their combination with materials for protein- and enzyme-based applications has raised significant attention in the past few years. Among them, significant advances were brought by supported ionic liquids (SILs), in which ILs are introduced to modify the surface and properties of materials, e.g., as ligands when covalently bond or when physiosorbed. SILs have been mainly investigated as alternative supports for enzymes in biocatalysis and as new supports in preparative liquid chromatography for the purification of high-value proteins and enzymes. In this manuscript, we provide an overview on the most relevant advances by using SILs as supports for enzymes and as purification platforms for a variety of proteins and enzymes. The interaction mechanisms occurring between proteins and SILs/ILs are highlighted, allowing the design of efficient processes involving SILs. The work developed is discussed in light of the respective development phase and innovation level of the applied technologies. Advantages and disadvantages are identified, as well as the missing links to pave their use in relevant applications.

Halloysite Nanoclay with High Content of Sulfonic Acid-Based Ionic Liquid: A Novel Catalyst for the Synthesis of Tetrahydrobenzo[b]pyrans

One of the main drawbacks of supported ionic liquids is their low loading and consequently, low activity of the resultant catalysts. To furnish a solution to this issue, a novel heterocyclic ligand with multi imine sites was introduced on the surface of amino-functionalized halloysite support via successive reactions with 2,4,6-trichloro-1,3,5-triazine and 2-aminopyrimidine. Subsequently, the imine sites were transformed to sulfonic acid-based ionic liquids via reaction with 1,4-butanesultone. Using this strategy, high loading of ionic liquid was loaded on halloysite nanoclay. The supported ionic liquid was then characterized with XRD, SEM, TEM, EDS, FTIR, BET, TGA and elemental mapping analysis and utilized as a metal-free Brønsted acid catalyst for promoting one-pot reaction of aldehydes, dimedone and malononitrile to furnish tetrahydrobenzo[b]pyrans. The catalytic tests confirmed high performance of the catalyst. Moreover, the catalyst was stable upon recycling.

Novel and Reusable Mesoporous Silica Supported 4-Methylbenzenesul- fonate-functionalized Ionic Liquids for Room Temperature Highly Efficient Preparation of 2,4,5-Triaryl-1H-imidazoles

A series of mesoporous materials supported ionic liquids were prepared and tested as effective and practical catalysts for the synthesis of 2,4,5-triaryl-1H-imidazoles. The effects of type of catalysts, catalyst amount, and catalyst stability have also been investigated in detail, the catalyst Ti-SBA-15@ILTsO exhibited excellent activity in excellent yields of 92 % ~ 99 % with low catalyst amount at room temperature within 1 h. In addition, the supported ionic liquid can be easily recovered and reused for six times with satisfactory catalytic activity. Furthermore, a general synergetic catalytic mechanism for the reaction was proposed. Maybe this work employing Ti-SBA-15@ILTsO as highly efficient and stable catalyst for the synthesis of 2,4,5-triaryl-1H-imidazoles has potential commercial applications. Resumen. Se prepararon y probaron una serie de materiales mesoporosos soportados con líquidos iónicos como catalizadores eficaces y prácticos para la síntesis de 2,4,5-triaryl-1H-imidazoles. También se investigaron en detalle los efectos del tipo de catalizadores, la cantidad de catalizador y la estabilidad del catalizador. El catalizador Ti-SBA-15@ILTsO mostró una excelente actividad con rendimientos excelentes del 92 % ~ 99% con una baja cantidad de catalizador a temperatura ambiente en 1 h. Además, el líquido iónico soportado puede recuperarse fácilmente y reutilizarse durante seis veces con una actividad catalítica satisfactoria. Por otro lado, se propuso un mecanismo catalítico sinérgico general para la reacción. Este trabajo que emplea Ti-SBA-15@ILTsO como catalizador altamente eficiente y estable para la síntesis de 2,4,5-triaril-1H-imidazoles puede tener aplicaciones potencialmente comerciales.