Interactions in L-phenylalanine/L-leucine/L-glutamic Acid/L-proline + 2 M aqueous NaCl/2 M NaNO3 systems at different temperatures

Density (ρ) and speed of sound (u) in 2 M aqueous NaCl and 2 M NaNO₃ solutions of amino acids: L-phenylalanine, L-leucine, L-glutamic acid, and L-proline have been measured for several molal concentrations of amino acids at different temperatures. The ρ and u data have been used to calculate the values of isothermal compressibility and internal pressure at different temperatures. The trends of variations of κ _T and P _i with an increase in molal concentration of amino acid and temperature have been discussed in terms of solute-solvent and solute-solute interactions in the systems.     

A gold nanocage-CNT hybrid for targeted imaging and photothermal destruction of cancer cells

This communication reports the design of a novel aptamer conjugated gold nanocage decorated SWCNTs hybrid nanomaterial for targeted imaging and selective photothermal destruction of the prostate cancer cells.     

Theranostic Nanoplatforms for MRSA Detection and Destruction from Whole Blood

Bloodstream infection with methicillin‐resistant Staphylococcus aureus (MRSA) and other drug‐resistant bacteria kill several million people in the world every year. Detection of drug‐resistant bacteria in the blood stream is clinically important to save lives. Driven by this need, multifunctional theranostic nanoplatforms have been developed for simultaneous targeted imaging and multimodal photodestruction of MRSA in a whole‐blood sample. Experimental data for the whole‐blood sample spiked with MRSA show that the theranostic nanoplatform can be used for fluorescence imaging after magnetic separation even in a 10^?5:1 ratio. A targeted photodynamic and photothermal combined treatment shows that the multimodal treatment regime can dramatically enhance the possibility of destroying MRSA in vitro. Therefore, our developed theranostic nanoplatform have a great potential as a fluorescent marker and as a light absorber for combined therapy in clinical settings. The possible mechanisms and operating principles are discussed for targeted imaging and combined therapeutic actions using theranostic nanoplatform.     

Investigation of coagulation process of wet-spun sodium alginate polymannuronate fibers with varied functionality using organic coagulants and cross-linkers

Alginate fibers composed of mannuronate blocks were manufactured via a wet spinning process by varying organic coagulants and cross-linkers. As cross-linkers, both ionic (Ca²⁺, Ba²⁺, and Al³⁺) and covalent (citric acid) were used, and as coagulants, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), and tetrahydrofuran (THF) were selected. Fiber properties depended on the ionic size, valence, and chemical structure of the cross-linkers. Among the used cross-linkers, Al³⁺ being the smallest ion, could diffuse inside the polymer solution easily and form metal-carboxylate coordination with three mannuronate chains. However, Ca²⁺ and Ba²⁺ both were very large compared to it, and polymer chains were positioned at about 48° for Ca²⁺ and in a parallel manner for Ba²⁺ after forming inter and intrachain metal-carboxylate bonds. Citric acid underwent an esterification reaction with the hydroxyl groups of mannuronate chains. Coagulants stabilized the cross-linking process and formed hydrogen bonds with the polymer chains. Depending on the cross-linkers and coagulants, the fiber diameter ranged from 217 μm to 830 μm and tensile modulus ranged from 88 MPa to 2 MPa. Ca²⁺, and then Ba²⁺ ions were more effective as cross-linkers since they produced fibers with superior mechanical properties followed by citric acid and Al³⁺. For all cross-linkers except citric acid, when DMSO was used as a coagulant, the tensile modulus was the highest. This indicates that DMSO better stabilized the cross-linking process during coagulation. In phosphate buffer saline (PBS), only Ba²⁺ cross-linked fibers could retain their original structure for 24 h, and fiber formed with coagulant DMSO swelled the least because of its compact structure. It also lost the least percentage of weight during 6 weeks. Thermal properties of the samples were also different as Ba²⁺ and Ca²⁺ cross-linked samples were more resistive to high temperature than other samples. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay illustrated the non-cytotoxicity of all the manufactured fibers.     

Human T-cell line (Jurkat cell) encapsulation by nano-organized polyelectrolytes and their response assessment in vitro and in vivo

Journal of Nanoparticle Research - Silver nanoparticles (AgNPs) are of interest due to their antimicrobial attributes, which are derived from their inherent redox instability and subsequent release...     

Targeted highly sensitive detection of multi-drug resistant Salmonella DT104 using gold nanoparticles

Monoclonal antibody-conjugated popcorn-shape gold nanotechnology-driven approach to selectively detect multiple drug resistant (MDRB) Salmonella typhimurium DT104 bacteria has been developed. We demonstrate that the gold nanotechnology based assay is capable of measuring the amount of MDRB in food samples.     

Effects of concentration and temperature on molar volumes of L-serine, L-isoleucine, and L-glutamine in aqueous NaCl and NaNO3 solutions

Densities of L-serine, L-isoleucine, L-glutamine in 1.5 mol kg^?1 aqueous NaCl, and NaNO₃ solutions have been measured for several molal concentrations of amino acids at temperatures from 298.15 to 323.15 K. The partial molar volumes (? _v ⁰ ) of L-serine, L-isoleucine, and L-glutamine in 1.5 mol kg^?1 aqueous NaCl/NaNO₃ solutions have been computed using density data. The transfer partial molar volumes (Δ_tr? _v ⁰ ) of L-serine, L-isoleucine, and L-glutamine from water to 1.5 mol kg^?1 aqueous NaCl/1.5 mol kg^?1 aqueous NaNO₃ solutions have been determined at 298.15 K. The trends of variation of ? _v ⁰ and Δ_tr? _v ⁰ with change in temperature have been discussed in terms of ion-ion, ion-hydrophilic, and ion-hydrophobic interactions operative in solutions.     

Nanomaterials for targeted detection and photothermal killing of bacteria

Despite the modern treatment processes, contamination of food, water and medical equipment by pathogenic bacteria is very common in this world. Since the last two decades, one of the most important and complex problems our society has been facing is that several human pathogens became resistant to most of the clinically approved antibiotics. Recent advancement in nanoscience and nanotechnology has expanded our ability to design and construct nanomaterials with targeting, therapeutic, and diagnostic functions. These multifunctional materials have attracted our attention to be used as the promising tool for selective bacteria sensing and therapy without the current drugs. This tutorial review provides the basic concepts and critical properties of the different nanostructures that are useful for the pathogen detection and photothermal applications. In addition, bio-conjugated nanomaterial based strategies have been discussed with the aim to provide readers an overview of exciting opportunities and challenges in this field.     

Fabricated cantilever for AFM measurements and manipulations: Pre-stress analysis of stress fibers

The atomic force microscope (AFM) is a highly successful instrument for imaging of nanometer-sized samples and measurement of pico- to nano-Newton forces acting between atoms and molecules, especially in liquid. Generally, commercial AFM cantilevers, which have a sharp tip, are used for AFM experiments. In this review, we introduce micro-fabricated AFM cantilevers and show several applications for cell biology. In manipulation of samples on a cellular scale with a force of tens to hundreds of nano-Newtons, attempts have been made to secure the formation of covalent/non-covalent linkages between the AFM probe and the sample surface. However, present chemistry-based modification protocols of cantilevers do not produce strong enough bonds. To measure the tensile strength and other mechanical properties of actin-based thin filaments in both living and semi-intact fibroblast cells, we fabricated a probe with a hooking function by focused ion beam technology and used it to capture, pull and eventually break a chosen thin filament, which was made visible through fusion with fluorescent proteins. Furthermore, we fabricated a microscoop cantilever specifically designed for pulling a microbead attached to a cell. The microscoop cantilevers can realize high-throughput measurements of cell stiffness.