molecules-logo

Journal Browser

Journal Browser

Special Issue "Biological Molecules in Ionic Liquids, Deep Eutectic Solvents, and Biosolvents"

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Molecular Liquids".

Deadline for manuscript submissions: closed (31 December 2021) | Viewed by 2596

Special Issue Editors

Dr. Tamar Greaves
E-Mail Website
Guest Editor
School of Science, RMIT University, Melbourne, VIC 3000, Australia
Interests: Ionic liquids; protic ionic liquids; self-assembly; SAXS; liquid crystals; high throughput
Special Issues, Collections and Topics in MDPI journals
Dr. Jorge Pereira
E-Mail Website
Guest Editor
Department of Chemical Engineering, CIEPQPF, University of Coimbra, Coimbra, Portugal
Interests: Ionic liquids; bioprocessing; proteins; enzymes; stability; downstream
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Interaction between solvents and biological molecules is crucial for controlling their stability, function, activity, and solubility. However, the lack of suitable solvents is currently a limitation for many biological applications, such as bioprocessing, biocatalysis, protein crystallization, and cryopreservation. Ionic liquids and deep eutectic solvents are showing great potential as solvents which can address this. In particular, the vast array of possible cations and anions allows great variability and control over specific ion effects, and.many hydrophilic ionic liquids are miscible with water, thus removing salt insolubility concentration limits.

The aim of this Special Edition is to focus on experimental and computational approaches which are being used to explore biological molecules in ionic liquids, deep eutectic solvents, and other biosolvents. We anticipate this to include fundamental and applied studies that explore the field in between biological molecules and eco-friendly solvents.

We hope that this proposed Special Edition will offer a broad range of insights into this emerging and exciting area of ionic liquid and other biomolecules-friendly solvent research.

Dr. Tamar Greaves
Prof. Dr. Jorge Pereira
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2300 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • ionic liquids
  • deep eutectic solvents
  • biosolvents
  • proteins
  • cells
  • enzymes
  • bioprocessing
  • toxicity

Published Papers (2 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Article
Protic Ionic Liquid Cation Alkyl Chain Length Effect on Lysozyme Structure
Molecules 2022, 27(3), 984; https://doi.org/10.3390/molecules27030984 - 01 Feb 2022
Viewed by 630
Abstract
Solvents that stabilize protein structures can improve and expand their biochemical applications, particularly with the growing interest in biocatalytic-based processes. Aiming to select novel solvents for protein stabilization, we explored the effect of alkylammonium nitrate protic ionic liquids (PILs)-water mixtures with increasing cation [...] Read more.
Solvents that stabilize protein structures can improve and expand their biochemical applications, particularly with the growing interest in biocatalytic-based processes. Aiming to select novel solvents for protein stabilization, we explored the effect of alkylammonium nitrate protic ionic liquids (PILs)-water mixtures with increasing cation alkyl chain length on lysozyme conformational stability. Four PILs were studied, that is, ethylammonium nitrate (EAN), butylammonium nitrate (BAN), hexylammonium nitrate (HAN), and octylammonium nitrate (OAN). The surface tension, viscosity, and density of PIL-water mixtures at low to high concentrations were firstly determined, which showed that an increasing cation alkyl chain length caused a decrease in the surface tension and density as well as an increase in viscosity for all PIL solutions. Small-angle X-ray scattering (SAXS) was used to investigate the liquid nanostructure of the PIL solutions, as well as the overall size, conformational flexibility and changes to lysozyme structure. The concentrated PILs with longer alkyl chain lengths, i.e., over 10 mol% butyl-, 5 mol% hexyl- and 1 mol% octylammonium cations, possessed liquid nanostructures. This detrimentally interfered with solvent subtraction, and the more structured PIL solutions prevented quantitative SAXS analysis of lysozyme structure. The radius of gyration (Rg) of lysozyme in the less structured aqueous PIL solutions showed little change with up to 10 mol% of PIL. Kratky plots, SREFLEX models, and FTIR data showed that the protein conformation was maintained at a low PIL concentration of 1 mol% and lower when compared with the buffer solution. However, 50 mol% EAN and 5 mol% HAN significantly increased the Rg of lysozyme, indicating unfolding and aggregation of lysozyme. The hydrophobic interaction and liquid nanostructure resulting from the increased cation alkyl chain length in HAN likely becomes critical. The impact of HAN and OAN, particularly at high concentrations, on lysozyme structure was further revealed by FTIR. This work highlights the negative effect of a long alkyl chain length and high concentration of PILs on lysozyme structural stability. Full article
Show Figures

Figure 1

Article
Solubility and Stability of Some Pharmaceuticals in Natural Deep Eutectic Solvents-Based Formulations
Molecules 2021, 26(9), 2645; https://doi.org/10.3390/molecules26092645 - 30 Apr 2021
Cited by 15 | Viewed by 1539
Abstract
Some medicines are poorly soluble in water. For tube feeding and parenteral administration, liquid formulations are required. The discovery of natural deep eutectic solvents (NADES) opened the way to potential applications for liquid drug formulations. NADES consists of a mixture of two or [...] Read more.
Some medicines are poorly soluble in water. For tube feeding and parenteral administration, liquid formulations are required. The discovery of natural deep eutectic solvents (NADES) opened the way to potential applications for liquid drug formulations. NADES consists of a mixture of two or more simple natural products such as sugars, amino acids, organic acids, choline/betaine, and poly-alcohols in certain molar ratios. A series of NADES with a water content of 0–30% (w/w) was screened for the ability to solubilize (in a stable way) some poorly water-soluble pharmaceuticals at a concentration of 5 mg/mL. The results showed that NADES selectively dissolved the tested drugs. Some mixtures of choline-based NADES, acid-neutral or sugars-based NADES could dissolve chloral hydrate (dissociated in water), ranitidine·HCl (polymorphism), and methylphenidate (water insoluble), at a concentration of up to 250 mg/mL, the highest concentration tested. Whereas a mixture of lactic-acid–propyleneglycol could dissolve spironolacton and trimethoprim at a concentration up to 50 and 100 mg/mL, respectively. The results showed that NADES are promising solvents for formulation of poorly water-soluble medicines for the development of parenteral and tube feeding administration of non-water-soluble medicines. The chemical stability and bioavailability of these drug in NADES needs further studies. Full article
Show Figures

Graphical abstract

Back to TopTop