Unveiling the molecular interactions between alkyl imidazolium ionic liquids and human serum albumin: Implications for toxicological significance.

Alkyl imidazolium-based ionic liquids (ILs) are promising for diverse industrial applications; however, their growing prevalence has raised concerns regarding human exposure and potential health implications. A critical aspect to be clarified to address the adverse health effects associated with ILs exposure is their binding mode to human serum albumin (HSA). In this study, we delved into the binding interactions between three alkyl imidazolium ILs (1-hexyl-3-methyl-imidazolium (C6[MIM]), 1-ethyl-3-methyl-imidazolium chloride (C8[MIM]) and 1-decyl-3-methyl-imidazolium (C10[MIM]) and human serum albumins (HSAs) using a comprehensive approach encompassing molecular docking and multi-spectroscopy (UV-visible, Fluorescence, Circular Dichroism, FTIR). Furthermore, for the first time, we developed an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) approach time to quantify plasma protein binding rates. Our results revealed that the ILs primarily bind to the hydrophobic cavity of HSA through hydrogen bonding and van der Waals forces, forming stable complexes via static quenching. This affected HSA's secondary structure, reducing α-helical content, particularly around specific residues. Equilibrium dialysis and ultrafiltration coupled with UPLC-MS/MS analysis showed modest plasma protein binding rates (17.84%-31.85%) for the three ILs, with no significant influence from alkyl chain effects or concentration relationship. Lower plasma protein binding rates can affect bioavailability and distribution of ILs, potentially influencing their toxicity. These findings provide critical insights into the potential toxicological implications at the molecular level, thereby contributing to continuous efforts to evaluate the risk profiles and ensure the safe utilization of these compounds.

Transdermal Delivery of Metformin Utilizing Ionic Liquid Technology: Insight Into the Relationship Between Counterion Structures and Properties.

PURPOSE: The purpose of the present study was to explore the feasibility of transdermal delivery of metformin, a commonly used oral antidiabetic drug, by ionic liquid (IL) technology. METHODS: Metformin hydrochloride (MetHCl) was first transformed into three kinds of ILs with different counterions. The physicochemical properties of the obtained ILs were characterized in depth. The simulation of stable configuration and calculation of interaction energies were conducted based on density functional theory (DFT). Skin-PAMPA was used to evaluate the intrinsic transdermal permeation properties. The cytotoxicity assay of these ILs was conducted using HaCaT cells to evaluate the toxicity to skin. These metformin ILs were then formulated into transdermal patch, and the transdermal potential was further evaluated using in vitro dissolution test and skin permeation assay. Finally, the pharmacokinetic profiles of these metformin IL-containing patches were determined. RESULTS: Among all the three Met ILs, metformin dihexyl sulfosuccinate (MetDH) with proper overall physiochemical and biological properties demonstrated the highest relative bioavailability. Metformin docusate (MetD) with the highest lipophilicity and intrinsic transdermal permeability exhibited the most significant sustained release profile in vivo. Both MetDH and MetD were the promising candidates for further clinical investigations. CONCLUSIONS: Overall, the properties of ILs were closely related to the structures of counterion. IL technology provided the opportunities to finely tune the solid-state and biological properties of Metformin and facilitated the successful delivery by transdermal route.

Gene Coexpression Connectivity Predicts Gene Targets Underlying High Ionic-Liquid Tolerance in Yarrowia lipolytica.

Microbial tolerance to organic solvents such as ionic liquids (ILs) is a robust phenotype beneficial for novel biotransformation. While most microbes become inhibited in 1% to 5% (vol/vol) IL (e.g., 1-ethyl-3-methylimidazolium acetate), we engineered a robust Yarrowia lipolytica strain (YlCW001) that tolerates a record high of 18% (vol/vol) IL via adaptive laboratory evolution. Yet, genotypes conferring high IL tolerance in YlCW001 remain to be discovered. In this study, we shed light on the underlying cellular processes that enable robust Y. lipolytica to thrive in inhibitory ILs. By using dynamic transcriptome sequencing (RNA-Seq) data, we introduced Gene Coexpression Connectivity (GeCCo) as a metric to discover genotypes conferring desirable phenotypes that might not be found by the conventional differential expression (DE) approaches. GeCCo selects genes based on their number of coexpressed genes in a subnetwork of upregulated genes by the target phenotype. We experimentally validated GeCCo by reverse engineering a high-IL-tolerance phenotype in wild-type Y. lipolytica. We found that gene targets selected by both DE and GeCCo exhibited the best statistical chance at increasing IL tolerance when individually overexpressed. Remarkably, the best combination of dual-overexpression genes was genes selected by GeCCo alone. This nonintuitive combination of genes, BRN1 and OYE2, is involved in guiding/regulating mitotic cell division, chromatin segregation/condensation, microtubule and cytoskeletal organization, and Golgi vesicle transport. IMPORTANCE Cellular robustness to cope with stressors is an important phenotype. Y. lipolytica is an industrial robust oleaginous yeast that has recently been discovered to tolerate record high concentrations of ILs, beneficial for novel biotransformation in organic solvents. However, genotypes that link to IL tolerance in Y. lipolytica are largely unknown. Due to the complex IL-tolerant phenotype, conventional gene discovery and validation based on differential gene expression approaches are time-consuming due to a large search space and might encounter a high false-discovery rate. Here, using the developed Gene Coexpression Connectivity (GeCCo) method, we identified and validated a subset of most promising gene targets conferring the IL-tolerant phenotypes and shed light on their potential mechanisms. We anticipate GeCCo being a useful method to discover the genotype-to-phenotype link.

Recent Developments in Ionic Liquid-Assisted Topical and Transdermal Drug Delivery.

Ionic liquids (ILs) have attracted growing interest as designer solvents/materials for exploring unrealized functions in many areas of research including drug formulations and delivery owing to their inherent tunable physicochemical and biological properties. The use of ILs in the pharmaceutical industry can address challenges related to the use of conventional organic solvent-based chemical permeation enhancers. Their tunability in forming ion pairs with a diverse range of ions enables the task-specific optimization of ILs at the molecular level. In particular, ILs comprising second- and third-generation cations and anions have been extensively used to design biocompatible drug delivery systems to address the challenges related to conventional topical and transdermal drug delivery, including limited permeability, high cytotoxicity, and skin irritation. This review highlights the progress in IL-related research with particular emphasis on the very recent conceptual developments in transdermal drug delivery. Technological advancement and approaches for the formation of IL-based topical and transdermal delivery systems, as well as their promising application in drug delivery, are also discussed.

Transdermal Delivery of Antigenic Protein Using Ionic Liquid-Based Nanocarriers for Tumor Immunotherapy.

Transdermal drug delivery systems (TDDSs) may be useful for preventing various diseases including cancer. However, the stratum corneum (SC) inhibits the permeation of foreign particles into the skin. To obtain an effective TDDS, we developed a protein-containing nanocarrier (PCNC) comprising an antigenic protein (ovalbumin/OVA) stabilized by a combination of surfactants, i.e., a lipid-based surface-active ionic liquid and Tween-80. The PCNC was lyophilized to remove water and cyclohexane and then dispersed in isopropyl myristate. It is biocompatible both in vitro and in vivo, and is suitable for use in a therapeutic TDDS. The skin permeability of the PCNC was significantly (p < 0.0001) enhanced, and the transdermal distribution and transdermal flux of the OVA delivery system were 25 and 28 times greater, respectively, than those of its aqueous formulation. The PCNC disrupted the order of lipid orientation in the skin's SC and increased intercellular protein delivery. It demonstrated effective antitumor activity, drastically (p < 0.001) suppressed tumor growth, increased mouse survival rates, and significantly (p < 0.001) stimulated the OVA-specific tumor immune response. The PCNC also increased the number of cytotoxic T cells expressing CD8 antibodies on their surfaces (CD8 + T-cells) in the tumor microenvironment. These findings suggest that PCNCs may be promising biocompatible carriers for transdermal antigenic protein delivery in tumor immunotherapy.

Converting Tretinoin into Ionic Liquids for Improving Aqueous Solubility and Permeability across Skin.

PURPOSE: The aim of this study is to convert tretinoin (Tr), an active pharmaceutical ingredient (API), into ionic liquid for improving aqueous solubility and permeability of Tr in transdermal drug delivery applications. METHODS: Three ionic liquids of Tr (TrILs) were synthesized through neutralization reactions, which were characterized to confirm the compositions and ionic interactions. The in vitro drug release studies and skin penetration tests were carried out to assess the performance of formulations containing TrILs. RESULTS: The TrIL formed by choline and Tr at the molar ratio of 2:1 (2[Ch][Tr]), was found to have prominent solubility, stability as well as permeability. In contrast with the insoluble Tr, 2[Ch][Tr] presented as clear and transparent aqueous solution even after diluted to 14%. The aqueous solution of 2[Ch][Tr] demonstrated better permeation effect, of which the solution with 20% of 2[Ch][Tr] showed the optimal delivery efficiency in both epidermis (2.09 ± 0.18‰) and dermis (3.31 ± 0.48‰), realizing the improvement on the permeability of API. Meanwhile, TrILs can be easily fabricated as o/w emulsions as transdermal formulation. The emulsions are also able to improve the skin permeability of Tr, though the enhanced effect is inferior to TrILs solutions. CONCLUSIONS: Ionic liquid technology can be used to improve solubility and permeability of Tr, providing a high potential strategy for the development of topical formulations and the desired transdermal application of drugs.

Pressurized Natural Deep Eutectic Solvent Extraction of Galanthamine and Related Alkaloids from Narcissus pseudonarcissus.

The isolation of a compound from a natural source involves many organic and mostly toxic solvents for extraction and purification. Natural deep eutectic solvents have been shown to be efficient options for the extraction of natural products. They have the advantage of being composed of abundantly available common primary metabolites, being nontoxic and environmentally safe solvents. The aim of this study was to develop a natural deep eutectic solvent-based extraction method for galanthamine, an important therapeutic agent for the treatment of Alzheimer's disease. This alkaloid can be produced by synthesis or by extraction from Narcissus bulbs. To develop an efficient extraction method, a number of different natural deep eutectic solvents was first tested for their solubilization capacity of galanthamine bromide salt. Promising results were obtained for ionic liquids, as well as some amphoteric and acidic natural deep eutectic solvents. In a two-cycle extraction process, the best solvents were tested for the extraction of galanthamine from bulbs. The ionic liquids produced poor yields, and the best results were obtained with some acid and sugar mixtures, among which malic acid-sucrose-water (1 : 1 : 5) proved to be the best, showing similar yields to that of the exhaustive Soxhlet extraction with methanol. Furthermore, the natural deep eutectic solvent was more selective for galanthamine.

Electromechanical response performance of a reinforced biomass gel artificial muscle based on natural polysaccharide of sodium alginate doped with an ionic liquid for micro-nano regulation.

In this paper, a reinforced Biomass Gel Artificial Muscle (BGAM) was fabricated by natural polysaccharide of Sodium Alginate (SA) doped with an Ionic Liquid (IL) of 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIm][BF4]). Micro-nano regulation effect and reinforcement mechanism of IL doping content on electromechanical response performance of BGAM were researched during a single cycle and repeated cycles. Then, a green fabrication process and a set of valid test methods for BGAM were proposed in detail. The experimental results showed that when IL doping content was 4 mL, the BGAM achieved optimal modification, with a porosity of 70.47%, where it internally adopted the porous polymer structure of ion channels. Additionally, specific capacitance of BGAM attained a maximum value of 126.98 mF/g, and the inner resistance and elastic modulus reached minimum values of 2.018 Ω and 1.871 MPa, separately. Thus, the optimal working life and output-force density values, namely, 1720 s and 13.072 mN/g, respectively, were also determined for the BGAM.

Computational analysis of the effect of [Tea][Ms] and [Tea][H2PO4] ionic liquids on the structure and stability of Aß(17-42) amyloid fibrils.

Experimental studies have reported the possibility of affecting the growth/dissolution of amyloid fibres by the addition of organic salts of the room-temperature ionic-liquid family, raising the tantalizing prospect of controlling these processes under physiological conditions. The effect of [Tea][Ms] and [Tea][H2PO4] at various concentrations on the structure and stability of a simple model of Aß42 fibrils has been investigated by computational means. Free energy computations show that both [Tea][Ms] and [Tea][H2PO4] decrease the stability of fibrils with respect to isolated peptides in solution, and the effect is significantly stronger for [Tea][Ms]. The secondary structure of fibrils is not much affected, but single peptides in solution show a marked decrease in their ß-strand character and an increase in α-propensity, again especially for [Tea][Ms]. These observations, consistent with the experimental picture, can be traced to two primary effects, i.e., the difference in the ionicity of the [Tea][Ms] and [Tea][H2PO4] water solutions and the remarkable affinity of peptides for [Ms]- anions, due to the multiplicity of H-bonds.

Thermodynamics and structure of model bio-membrane of liver lipids in presence of imidazolium-based ionic liquids.

Ionic liquids (ILs) are the attractions of researchers today due to their vast area of potential applications. For biomedical uses, it becomes essential to understand their interactions with cellular membrane. Here, the membrane is mimicked with lipid bilayer and monolayer composed of liver lipids extract. Three archetypal imidazolium based ILs, 1-decyl-3-methylimidazolium tetrafluoroborate ([DMIM][BF4] or [C10MIM][BF4]), 1-octyl-3-methylimidazolium tetrafluoroborate, ([OMIM][BF4] or [C8MIM][BF4]) and 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4] or [C2MIM][BF4]) having different alkyl chain lengths are used in the present study. The isothermal titration calorimetry (ITC) measurements showed that [DMIM][BF4] interacts strongest with the liver lipid membrane compared to other two ILs which have relatively shorter alkyl chain length. The low values of stoichiometry ratio of ILs indicates that ILs penetrate within the core of the lipid bilayer. The interaction of ILs with the liver lipid membrane is found to be mainly driven by entropy which could be due to the change in the structure of the lipid membrane at local or global scales. Dynamic light scattering (DLS) measurements indicate that there are no changes in the size of vesicles due to addition of [DMIM][BF4] indicating stability of the vesicles. On the other hand, x-ray reflectivity (XRR) measurements showed a concentration dependent change in the monolayer structure. At low concentration of the IL, the monolayer thickness decreases, exhibiting an increase in the electron density of the layer. However, at higher concentrations, the monolayer thickness increases proving a concentration dependent effects of the IL on the arrangement of the molecules.

Thermodynamic destabilization of azurin by four different tetramethylguanidinium amino acid ionic liquids.

The thermal unfolding of the copper redox protein azurin was studied in the presence of four different amino acid-based ionic liquids (ILs), all of which have tetramethylguanidium as cation. The anionic amino acid includes two with alcohol side chains, serine and threonine, and two with carboxylic acids, aspartate and glutamate. Control experiments showed that amino acids alone do not significantly change protein stability and pH changes anticipated by the amino acid nature have only minor effects on the protein. With the ILs, the protein is destabilized and the melting temperature is decreased. The two ILs with alcohol side chains strongly destabilize the protein while the two ILs with acid side chains have weaker effects. Unfolding enthalpy (ΔHunf°) and entropy (ΔSunf°) values, derived from fits of the unfolding data, show that some ILs increase ΔHunf°while others do not significantly change this value. All ILs, however, increase ΔSunf°. MD simulations of both the folded and unfolded protein conformations in the presence of the ILs provide insight into the different IL-protein interactions and how they affect the ΔHunf° values. The simulations also confirm that the ILs increase the unfolded state entropies which can explain the increased ΔSunf° values.

Newly isolated lytic bacteriophages for Staphylococcus intermedius, structurally and functionally stabilized in a hydroxyethylcellulose gel containing choline geranate: Potential for transdermal permeation in veterinary phage therapy.

In the present research work, we propose a new antimicrobial treatment for pyoderma via cutaneous permeation of bacteriophage particles conveyed in a hydroxyethylcellulose (HEC) gel integrating ionic liquid as a permeation enhancer. Ionic liquids are highly viscous fluids constituted exclusively by ions, that are usually hydrolytically stable and promote solubilization of amphipathic molecules such as proteins, hence serving as green solvents and promoting the transdermal permeation of biomolecules. In the research effort entertained herein, the synthesis and use of choline geranate for integrating a HEC gel aiming at the structural and functional stabilization of a cocktail of isolated lytic bacteriophage particles was sought, aiming at transdermal permeation in the antimicrobial treatment of animal pyoderma. The results obtained showed a high ability of the ionic liquid in enhancing transdermal permeation of the bacteriophage particles, with concomitant high potential of the HEC gel formulation in the antimicrobial treatment of animal skin infections.

Catalytic Conversion of Glucose into Levulinic Acid Using 2-Phenyl-2-Imidazoline Based Ionic Liquid Catalyst.

Levulinic acid (LA) is an industrially important product that can be catalytically valorized into important value-added chemicals. In this study, hydrothermal conversion of glucose into levulinic acid was attempted using Brønsted acidic ionic liquid catalyst synthesized using 2-phenyl-2-imidazoline, and 2-phenyl-2-imidazoline-based ionic liquid catalyst used in this study was synthesized in the laboratory using different anions (NO3, H2PO4, and Cl) and characterized using 1H NMR, TGA, and FT-IR spectroscopic techniques. The activity trend of the Brønsted acidic ionic liquid catalysts synthesized in the laboratory was found in the following order: [C4SO3HPhim][Cl] > [C4SO3HPhim][NO3] > [C4SO3HPhim][H2PO4]. A maximum 63% yield of the levulinic acid was obtained with 98% glucose conversion at 180 °C and 3 h reaction time using [C4SO3HPhim][Cl] ionic liquid catalyst. The effect of different reaction conditions such as reaction time, temperature, ionic liquid catalyst structures, catalyst amount, and solvents on the LA yield were investigated. Reusability of [C4SO3HPhim][Cl] catalyst up to four cycles was observed. This study demonstrates the potential of the 2-phenyl-2-imidazoline-based ionic liquid for the conversion of glucose into the important platform chemical levulinic acid.

Simultaneous Visualization of Wet Cells and Nanostructured Biomaterials in SEM using Ionic Liquids.

This work presents a successful methodology to image mammalian cells adhered to nanostructured titanium by using scanning electron microscopy (SEM) operating in low-vacuum mode following ionic liquid treatment. Human osteoblast-like Saos-2 cells were treated with a room-temperature ionic liquid, 1-ethyl-3-methylimidazolium tetrafluoroborate, and subsequently imaged on titanium by SEM. Titanium substrates were modified to create laser-induced periodic surface structures (LIPSS) for visualization at the submicron scale. By using a combination of fluorescence-based cell metabolism along with light microscopy and SEM image analysis, the shape and location of irradiated cells were confirmed to be unchanged after multiple irradiation sessions; the viability of minimally irradiated cells was also unaltered. The wet imaging conditions combined with a rapid facile protocol using ionic liquid allows this technique to fulfill a niche in examining cellular behavior on biomaterials with submicron surface features. The demonstrated method to track observed cell adhesion to submicron surface features by SEM has great implications for understanding cell migration on nanostructured surfaces as well as the exploration of simpler SEM preparation methods for cellular imaging.

Effect of imidazolium based ionic liquids on CO-association dynamics and thermodynamic stability of Ferrocytochrome c.

Analysis of kinetic and thermodynamic parameters measured for CO-association reaction of Ferrocytochrome c (Ferrocyt c) under variable concentrations of 1-butyl-3-methylimidazolium with varying anion ([Bmim]X) (X = Cl-, I-, Br-, HSO4-) at pH 7 revealed that the low concentration of [Bmim]X (≤0.5 M) constrains the CO-association dynamics of Ferrocyt c and typically follows the order: [Bmim]HSO4 > [Bmim]Cl > [Bmim]Br > [Bmim]I. At relatively higher concentrations (>0.5), the chaotropic action of [Bmim]+ dominates which consequently increases the thermal-fluctuations responsible to denature the protein and thus accelerates the speed of CO-association reaction. Analysis of thermal denaturation curves of Ferrocyt c measured at different concentrations of [Bmim]X revealed that the [Bmim]X decreases the thermodynamic stability of protein and typically follows the order: [Bmim]I > [Bmim]Br > [Bmim]Cl > [Bmim]CH3COO > [Bmim]HSO4, demonstrating that the effect of [Bmim]X on thermodynamic stability of protein is not in accordance to Hofmeister series effect of anions because instead of increasing the kosmotropic anion carrying [Bmim]X ([Bmim]CH3COO and [Bmim]HSO4) also decreases the thermodynamic stability of protein.

The Role of Ionic Liquids in the Pharmaceutical Field: An Overview of Relevant Applications.

Solubility, bioavailability, permeation, polymorphism, and stability concerns associated to solid-state pharmaceuticals demand for effective solutions. To overcome some of these drawbacks, ionic liquids (ILs) have been investigated as solvents, reagents, and anti-solvents in the synthesis and crystallization of active pharmaceutical ingredients (APIs), as solvents, co-solvents and emulsifiers in drug formulations, as pharmaceuticals (API-ILs) aiming liquid therapeutics, and in the development and/or improvement of drug-delivery-based systems. The present review focuses on the use of ILs in the pharmaceutical field, covering their multiple applications from pharmaceutical synthesis to drug delivery. The most relevant research conducted up to date is presented and discussed, together with a critical analysis of the most significant IL-based strategies in order to improve the performance of therapeutics and drug delivery systems.

Implication of Threonine-Based Ionic Liquids on the Structural Stability, Binding and Activity of Cytochrome†c.

Ionic liquids (ILs) are useful in pharmaceutical industries and biotechnology as alternative solvents or sources for protein extraction and purification, preservation of biomolecules and for regulating the catalytic activity of enzymes. However, the binding mechanism, the non-covalent forces responsible for protein-IL interactions and dynamics of proteins in IL need to be investigated in depth for the effective use of ILs as alternatives. Herein, we disclose the molecular level understanding of the structural intactness and reactivity of a model protein cytochrome c (Cyt c) in biocompatible threonine-based ILs with the help of experimental techniques such as isothermal titration calorimetry (ITC), fluorescence spectroscopy, transmission electron microscopy (TEM) as well as molecular docking. Hydrophobic and electrostatic forces are responsible for the structural and conformational integrity of Cyt c in IL. The ITC experiments revealed the Cyt c-IL binding free energies are in the range of 10-14 kJ/mol and the molecular docking studies demonstrated that ILs interact at the surfaces of Cyt c. The results look promising as the ILs used here are non-toxic and biocompatible, and thus may find potential applications in structural biology and biotechnology.

Delivery of ionizable hydrophilic drugs based on pharmaceutical formulation of ion pairs and ionic liquids.

New therapeutics such as antisense oligonucleotides, small interfering RNA and peptide-drug conjugates are taking great relevance in the pharmaceutical industry due to their specificity of action and their improved safety profile. However, they could present bioavailability issues due to their hydrophilic nature, such as BCS class III drugs. Therefore, the formation of ion pairs of these type of molecules allows modifying their physicochemical characteristics such as polarity and lipophilicity leading to improved permeability. By carrying out a tailored synthesis, it is possible to obtain complexes with greater stability and better performance in vitro and in vivo, where their correlation with physicochemical properties continues to be a growing field of research. Moreover, ionic liquids (IL), which are substances that melt below 100 °C, have enabled modifying various drug properties, showing promising results in vitro-in vivo, especially when they are included in suitable drug delivery systems, such as nanoparticles, microparticles, self-emulsifying drug delivery systems, and transdermal patches, among others. The drug-IL is formed from the therapeutic agent and a counterion, mainly by ionic interactions, and resulting in a wide variety of derivatives with different properties. However, the pharmaceutical field is limited to the use of some excipients or GRAS (generally recognized as safe) substances, so the search for new counterions is of great interest. In this article, we have compiled key indexes that can be obtained from databases to guide the search for suitable counterions, together with different drug delivery system strategies to choose the most appropriate formulation according to the non-parenteral route of administration selected. Intellectual property advancements in the field are also presented and analyzed.

Ionic liquid decorated AIE luminogen for selective detection of HSA in biofluids and early disease screening.

The precise evaluation of human serum albumin (HSA) contents in biofluids is critical due to its important physiological functions. A fluorescent luminogen TPE-IL is facilely fabricated in present study by decorating the aggregation induced emission (AIE) dye E-1,2-bis(4-hydroxyphenyl)-1,2-diphenylethylene (TPE-OH) with ionic liquid (IL) HOOCMIMBr. The hydrophobic and hydrogen-bond interactions between the amino acid residues of HSA and TPE-IL lead to the spontaneous and energetically favorable docking of TPE-IL molecules in the hydrophobic subdomain of HSA, inducing the significant fluorescence enhancement of this sensor. Highly sensitive and selective detection of HSA is accomplished in the linear range of 0.02-10 µg/mL, with a detection limit of 0.007 µg/mL. The practicability of this sensor is validated by the accurate detection of HSA contents in human serum and urine samples. A glass slide-based visual sensing platform is also constructed to offer simple and fast HSA content evaluation in serum for early disease screening.

Ionic liquids-modified cellulose coated magnetic nanoparticles for enzyme immobilization: Improvement of catalytic performance.

In this work, ionic liquids-modified magnetic carboxymethyl cellulose nanoparticles (IL-MCMC) were prepared and used as supports for enzyme immobilization. The specific activity of immobilized lipase PPL-IL-MCMC was 1.43 and 2.81 folds higher than that of free PPL and PPL-MCMC, respectively. Water contact angle analysis indicated that the introduction of ionic liquids increased the hydrophobicity of supports, which in tune induced the lid-opening of lipase, allowing its active sites to become more accessible. In addition, the affinity between lipase and substrate immobilized on the prepared supports was enhanced. The same method was also applied to analyze immobilize penicillin G acylase (PGA) to further investigate the general applicability of the method. The results showed that the immobilized PGA exhibited higher stability than many other reported PGAs. The developed composites may be utilized as excellent supports for enzyme immobilization in industrial application.