We herein report the preparation and investigation of antibacterial activity of biocidal ionic li... more We herein report the preparation and investigation of antibacterial activity of biocidal ionic liquids (ILs) consisting of cationic imidazolium or pyridinium and an anionic β-lactam antibiotic. The antibacterial properties were quantified by measuring the minimum inhibitory concentration and minimum bactericidal concentration against Escherichia coli O157:H7, Klebsiella pneumoniae, Staphylococcus aureus, and Enterococcus faecium. In general, the ILs had improved antibacterial activity than their parent materials, whether individually or in combination. In 83% of the experiments, the ampicillin ILs (Amp-ILs) had better antibacterial activities than their quaternary halide parent materials, whereas in 92% of the experiments, Amp-ILs outperformed the commercially available sodium ampicillin salt. Amp-ILs had up to 43 times improved antibacterial activity than sodium ampicillin. Overall, when normalized for ampicillin content, ILs had greater antimicrobial activity against E. coli O157:H7, K. pneumoniae, S. aureus, and E. faecium than sodium ampicillin alone.
Lithium ion batteries (LIBs) have been extensively studied as energy sources for devices ranging ... more Lithium ion batteries (LIBs) have been extensively studied as energy sources for devices ranging from portable electronics to electric vehicles (EVs). LIBs safety remains one of their biggest concerns due to use of flammable organic liquid as electrolytes1. In recent years, the emergence of gel polymer electrolytes (GPE) based on ionic liquid solvent opened up an avenue for safer solid-state battery technology due to the nonflammability nature of the liquid. These type of GPEs consist of a liquid electrolyte solvent with lithium salt and a polymer2. Addition of fillers in GPEs have been shown to improve both ionic conductivity and mechanical properties of the composite electrolyte3. In this work, we are reporting a gel polymer electrolyte (GPE) which was synthesized by blending of a polymerized ionic liquid (PIL) based on pyrrolidinium cation, an imidazolium cation based ionic liquid and lithium salt. Later on, the effect of addition of certain percentages of inorganic silica filler...
The use of acoustophoretic separation devices provides a feasible means in biomedical diagnostics... more The use of acoustophoretic separation devices provides a feasible means in biomedical diagnostics for label-free separation of diseased cells. Separation via acoustophoresis, however, has been restricted mainly to size contrast. Thermally-assisted acoustophoresis, as a newly-developed approach, integrates acoustic and thermal actuators on the same platform, enabling a stiffness-based separation when adjusted properly. Using this method, we have demonstrated the possibility of separating cell-mimicking liposomes based on their membrane stiffness. In a temperature-tuned microchannel with an overlaid ultrasonic standing wave, the acoustic contrast factor of a liposome is mainly determined according to its compressibility compared to that of medium. The sign of this factor was observed to flip to a negative value at a specific temperature, unique to the composition of the liposome. This sign switch was hypothesized to be due to the thermotropic phase transitions in the liposome’s membrane upon which an apparent effect on the compressibility is experienced by the liposome. By choosing the midpoint of the existing temperature window for two different compositions, within which liposomes were mechanically distinct enough to become differentiable in the acoustic radiation field, we examined the separation efficiency under different flow rate conditions.
Biomechanical properties of cells such as cellular stiffness have been increasingly considered as... more Biomechanical properties of cells such as cellular stiffness have been increasingly considered as biomarkers for diseases. For instance, stiffness of cancer cells has been correlated to the malignant potential in certain cell lines. In cells, the cholesterol content plays a crucial role in determining stiffness. Changes in the cholesterol content in cellular membranes can be an indication of pathological disorders. Acoustophoresis as a separation and diagnostic tool is well positioned to help in the separation and diagnosis of cells taking advantage of its unique separation criteria of density and compressibility. However, under the same conditions, cells and vesicles secreted by these cells often have a positive contrast factor sign and thus do not yield simple separations. Thermally-assisted acoustophoresis, also referred to as thermo-acoustophoresis, solves this problem by adding a temperature dimension to the separation. In this work, we evaluate the acoustic contrast temperatur...
ASME 2014 12th International Conference on Nanochannels, Microchannels and Minichannels, 2014
Acoustic focusing and separations is a growing field of research since it is an efficient and con... more Acoustic focusing and separations is a growing field of research since it is an efficient and continuous method for particle manipulation in microfluidic systems. Using microfabrication, microfluidic devices driven by an acoustic resonator were used to focus various microparticle suspensions. By simple tuning of frequency, amplitude, and channel geometry, controllable focusing patterns and alignments were obtained. This approach afforded the separation of particles of contrasting sizes, shapes, densities, porosities, and compressibilities. In this study we present the method for the fabrication of these lab-on-chip devices and report on their performance in the manipulation of microsized particles.
ABSTRACT Molecular electronics, where nanoscale organic species are utilized as active electronic... more ABSTRACT Molecular electronics, where nanoscale organic species are utilized as active electronic components, offers a promising approach towards ultimate miniaturization and integration of hybrid electronic materials (HEMs) with traditional silicon based complementary metal oxide semiconductors (CMOS) technology. Toward this end, fundamental research studies to understand the electronic and optical properties of these molecules are of paramount importance. In this work, conductive probe atomic force microscopy (CP-AFM) and Raman spectroscopy have been performed on ionic liquid based unique organic nanoparticles derived from a Group of Uniform Materials Based on Organic Salts (GUMBOS). Aptly named as nanoGUMBOS, the material investigated in this report is Rhodamine6G tetraphenylborate ([R6G][TPB]) as has been synthesized by a room temperature facile metathesis reaction between Rhodamine 6G chloride (R6GCl) and sodium tetraphenylborate (NaTPB) followed by an ultra-sonication-assisted, additive-free, re-precipitation reaction. To the best of our knowledge, the results reported herein are first-time evidence of electrical performance exhibited by [R6G][TPB] nanoGUMBOS. In conjunction with the supportive results of Raman spectra, the current-voltage (I-V) characteristics obtained are indicative of the potential incorporation of this unique compound in hybrid electronics with respect to potential applications in optoelectronics and chemical sensing.
We herein report the preparation and investigation of antibacterial activity of biocidal ionic li... more We herein report the preparation and investigation of antibacterial activity of biocidal ionic liquids (ILs) consisting of cationic imidazolium or pyridinium and an anionic β-lactam antibiotic. The antibacterial properties were quantified by measuring the minimum inhibitory concentration and minimum bactericidal concentration against Escherichia coli O157:H7, Klebsiella pneumoniae, Staphylococcus aureus, and Enterococcus faecium. In general, the ILs had improved antibacterial activity than their parent materials, whether individually or in combination. In 83% of the experiments, the ampicillin ILs (Amp-ILs) had better antibacterial activities than their quaternary halide parent materials, whereas in 92% of the experiments, Amp-ILs outperformed the commercially available sodium ampicillin salt. Amp-ILs had up to 43 times improved antibacterial activity than sodium ampicillin. Overall, when normalized for ampicillin content, ILs had greater antimicrobial activity against E. coli O157:H7, K. pneumoniae, S. aureus, and E. faecium than sodium ampicillin alone.
Lithium ion batteries (LIBs) have been extensively studied as energy sources for devices ranging ... more Lithium ion batteries (LIBs) have been extensively studied as energy sources for devices ranging from portable electronics to electric vehicles (EVs). LIBs safety remains one of their biggest concerns due to use of flammable organic liquid as electrolytes1. In recent years, the emergence of gel polymer electrolytes (GPE) based on ionic liquid solvent opened up an avenue for safer solid-state battery technology due to the nonflammability nature of the liquid. These type of GPEs consist of a liquid electrolyte solvent with lithium salt and a polymer2. Addition of fillers in GPEs have been shown to improve both ionic conductivity and mechanical properties of the composite electrolyte3. In this work, we are reporting a gel polymer electrolyte (GPE) which was synthesized by blending of a polymerized ionic liquid (PIL) based on pyrrolidinium cation, an imidazolium cation based ionic liquid and lithium salt. Later on, the effect of addition of certain percentages of inorganic silica filler...
The use of acoustophoretic separation devices provides a feasible means in biomedical diagnostics... more The use of acoustophoretic separation devices provides a feasible means in biomedical diagnostics for label-free separation of diseased cells. Separation via acoustophoresis, however, has been restricted mainly to size contrast. Thermally-assisted acoustophoresis, as a newly-developed approach, integrates acoustic and thermal actuators on the same platform, enabling a stiffness-based separation when adjusted properly. Using this method, we have demonstrated the possibility of separating cell-mimicking liposomes based on their membrane stiffness. In a temperature-tuned microchannel with an overlaid ultrasonic standing wave, the acoustic contrast factor of a liposome is mainly determined according to its compressibility compared to that of medium. The sign of this factor was observed to flip to a negative value at a specific temperature, unique to the composition of the liposome. This sign switch was hypothesized to be due to the thermotropic phase transitions in the liposome’s membrane upon which an apparent effect on the compressibility is experienced by the liposome. By choosing the midpoint of the existing temperature window for two different compositions, within which liposomes were mechanically distinct enough to become differentiable in the acoustic radiation field, we examined the separation efficiency under different flow rate conditions.
Biomechanical properties of cells such as cellular stiffness have been increasingly considered as... more Biomechanical properties of cells such as cellular stiffness have been increasingly considered as biomarkers for diseases. For instance, stiffness of cancer cells has been correlated to the malignant potential in certain cell lines. In cells, the cholesterol content plays a crucial role in determining stiffness. Changes in the cholesterol content in cellular membranes can be an indication of pathological disorders. Acoustophoresis as a separation and diagnostic tool is well positioned to help in the separation and diagnosis of cells taking advantage of its unique separation criteria of density and compressibility. However, under the same conditions, cells and vesicles secreted by these cells often have a positive contrast factor sign and thus do not yield simple separations. Thermally-assisted acoustophoresis, also referred to as thermo-acoustophoresis, solves this problem by adding a temperature dimension to the separation. In this work, we evaluate the acoustic contrast temperatur...
ASME 2014 12th International Conference on Nanochannels, Microchannels and Minichannels, 2014
Acoustic focusing and separations is a growing field of research since it is an efficient and con... more Acoustic focusing and separations is a growing field of research since it is an efficient and continuous method for particle manipulation in microfluidic systems. Using microfabrication, microfluidic devices driven by an acoustic resonator were used to focus various microparticle suspensions. By simple tuning of frequency, amplitude, and channel geometry, controllable focusing patterns and alignments were obtained. This approach afforded the separation of particles of contrasting sizes, shapes, densities, porosities, and compressibilities. In this study we present the method for the fabrication of these lab-on-chip devices and report on their performance in the manipulation of microsized particles.
ABSTRACT Molecular electronics, where nanoscale organic species are utilized as active electronic... more ABSTRACT Molecular electronics, where nanoscale organic species are utilized as active electronic components, offers a promising approach towards ultimate miniaturization and integration of hybrid electronic materials (HEMs) with traditional silicon based complementary metal oxide semiconductors (CMOS) technology. Toward this end, fundamental research studies to understand the electronic and optical properties of these molecules are of paramount importance. In this work, conductive probe atomic force microscopy (CP-AFM) and Raman spectroscopy have been performed on ionic liquid based unique organic nanoparticles derived from a Group of Uniform Materials Based on Organic Salts (GUMBOS). Aptly named as nanoGUMBOS, the material investigated in this report is Rhodamine6G tetraphenylborate ([R6G][TPB]) as has been synthesized by a room temperature facile metathesis reaction between Rhodamine 6G chloride (R6GCl) and sodium tetraphenylborate (NaTPB) followed by an ultra-sonication-assisted, additive-free, re-precipitation reaction. To the best of our knowledge, the results reported herein are first-time evidence of electrical performance exhibited by [R6G][TPB] nanoGUMBOS. In conjunction with the supportive results of Raman spectra, the current-voltage (I-V) characteristics obtained are indicative of the potential incorporation of this unique compound in hybrid electronics with respect to potential applications in optoelectronics and chemical sensing.
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