Polysaccharide-based hemostats: recent developments,challenges, and future perspectives

Cellulose - Excessive hemorrhage is a leading cause of death to trauma patients, especially in combat and civilian accidents. The main priority in the medical treatment of trauma patients is to...     

Surface Modification of Ultra-high Molecular Weight Polyethylene Membranes Using Underwater Plasma Polymerization

Ultra-high molecular weight polyethylene membranes were modified and subsequently polymer coated using the underwater plasma produced by glow discharge electrolysis. This plasma pretreatment generated various O-functional groups among them OH groups have dominated. This modified inner (pore) surface of membranes showed complete wetting and strong adhesion to a hydrogel copolymerized by glow discharge electrolysis also. The deposited hydrogel consists of plasma polymerized acrylic acid crosslinked by copolymerization with the bifunctional N,N′-methylenebis(acrylamide). Tuning the hydrogel hydrophilicity and bio-compatibility poly(ethylene glycol) was chemically inserted into the copolymer. Such saturated polymer could only be inserted on a non-classic way by (partial) fragmentation and recombination thus demonstrating the exotic properties of the underwater plasma. The modification of membrane was achieved by squeezing the reactive plasma solution into the pores by plasma-induced shock waves and supported by intense stirring. The deposited copolymer hydrogel has filled all pores also in the inner of membrane as shown by scanning electron microscopy of cross-sections. The copolymer shows the characteristic units of acrylic acid and ethylene glycol as demonstrated by infrared spectroscopy. A minimum loss in carboxylic groups of acrylic acid during the plasma polymerization process was confirmed by X-ray photoelectron spectroscopy. Additional cell adhesion tests on copolymer coated polyethylene using IEC-6 cells demonstrated the bio-compatibility of the plasma-deposited hydrogel.     

Metabolic profile of glyburide in human liver microsomes using LC‐DAD‐Q‐TRAP‐MS/MS

The sulfonylurea urea drug glyburide (glibenclamide) is widely used for the treatment of diabetes milletus and gestational diabetes. In previous studies monohydroxylated metabolites were identified and characterized for glyburide in different species, but the metabolite owing to the loss of cyclohexyl ring was identified only in mouse. Glyburide upon incubation with hepatic microsomes resulted in 10 metabolites for human. The current study identifies new metabolites of glyburide along with the hydroxylated metabolites that were reported earlier. The newly identified drug metabolites are dihydroxylated metabolites, a metabolite owing to the loss of cyclohexyl ring and one owing to hydroxylation with dehydrogenation. Among the 10 identified metabolites, there were six monohydroxylated metabolites, one dihydroxylated metabolite, two metabolites owing to hydroxylation and dehydrogenation, and one metabolite owing to the loss of cyclohexyl ring. New metabolites of glyburide were identified and characterized using liquid chromatography–diode array detector–quadruple‐ion trap–mass spectrometry/mass spectrometry (LC‐DAD‐Q‐TRAP‐MS/MS). An enhanced mass scan–enhanced product ion scan with information‐dependent acquisition mode in a Q‐TRAP‐MS/MS system was used to characterize the metabolites. Liquid chromatography with diode array detection was used as a complimentary technique to confirm and identify the metabolites. Metabolites formed in higher amounts were detected in both diode array detection and mass spectrometry detection. Copyright © 2012 John Wiley & Sons, Ltd.     

Nano-bio interface study between Fe content TiO2 nanoparticles and adenosine triphosphate biomolecules

The advent of nano-biotechnology has inspired the interface interaction study between engineered nanoparticles (NPs) and biomolecules. The interaction between Fe content titanium dioxide (TiO₂) NPs and adenosine triphosphate (ATP) biomolecules has been envisioned. The effect of Fe content in TiO₂ matrix was studied using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The increase in Fe content caused a decrease in particle size with change in morphology from spherical to one-dimensional rod structure. The Fe incorporation in the TiO₂ matrix reduced the transition temperature from anatase to rutile (A-R) phase along with formation of haematite phase of iron oxide at 400°C. The interaction of Fe content TiO₂ NPs with ATP molecule has been studied using spectroscopic method of Raman scattering and infrared vibration spectrum along with TEM. Fe content in TiO₂ has enhanced the interaction efficiency of the NPs with ATP biomolecules. Raman spectroscopy confirms that the NPs interact strongly with nitrogen (N₇) site in the adenine ring of ATP biomolecule. Engineering of Fe content TiO₂ NP could successfully tune the coordination between metal oxide NPs with biomolecules, which could help in designing devices for biomedical applications.     

A rapid,highly efficient,and general protocol for the synthesis of functionalized triarylmethanes: a straightforward access for the synthesis of (−)-tatarinoid C

A rapid, efficient, and convenient synthesis of functionalized triarylmethane is described by the Friedel–Crafts alkylation of methoxybenzenes with a variety of aldehydes in the presence of BF₃·OEt₂. The generality of the method is demonstrated by screening a variety of di- or tri-substituted arenes as well as substituted aromatic, heteroaromatic, and aliphatic aldehydes. (−)-Tatarinoid C is synthesized in a single step following the same protocol.     

Self‐emulsion polymerization of amphiphilic monomers—a green route to synthesis of polymeric nanoscaffolds

Self‐emulsion polymerization (SEP), a green route developed by us for the polymerization of amphiphilic monomers, does not require any emulsifier or an organic solvent except that the water‐soluble initiators such as 2,2′‐azobis[2‐(2‐imidazolin‐2‐yl)propane]dihydrochloride (VA‐044) and potassium persulfate (KPS) are only used. We report here the polymer nanoscaffolds from a number of amphiphilic monomers, which can be used for in situ encapsulation of a variety of nanoparticles. As a demonstration of the efficacy of these nanoscaffolds, the synthesis of a biocompatible hybrid nanoparticle (nanohybrid), prepared by encapsulating Fe₃O₄ magnetic nanoparticle (Fe₃O₄ MNPs) in poly(2‐hydroxyethyl methacrylate) in water, for MRI application is presented. The nanohybrid prepared following the SEP in the form of an emulsion does not involve the use of any stabilizing agent, crosslinker, polymeric emulsifier, or surfactant. This water‐soluble, spherical, and stable nanohybrid containing Fe₃O₄ MNPs of average size 10 ± 2 nm has a zeta potential value of ?41.89 mV under physiological conditions. Magnetic measurement confirmed that the nanohybrid shows typical magnetic behavior having a saturation magnetization (Ms) value of 32.3 emu/g and a transverse relaxivity (r2) value of 29.97 mM^?1 s^?1, which signifies that it can be used as a T2 contrast agent in MRI. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019     

Total and Semi‐Syntheses of Antimicrobial Thuggacin Derivatives

The total and semi‐synthesis of 13 new macrolactones derived from thuggacin, which is a secondary metabolite from the myxobacterium Sorangium cellulosum, are reported. The thuggacins have attracted much attention due to their strong antibacterial activity, particularly towards Mycobacterium tuberculosis. This study focuses on 1) thuggacin derivatives that cannot equilibrate by transacylation between the three natural thuggacins A–C, 2) the roles of the thiazole ring, and 3) the hexyl side chain at C2. Semi‐synthetic O‐methylation at C17 suppressed the transacylations without a substantial loss of antibacterial activity. Exchanging the C17–C25 side chain for simplified hydrophobic chains led to complete loss of antibacterial activity. Exchange of the thiazole by an oxazole ring or removal of the hexyl side chain at C2 had no substantial effect on the biological properties.     

An experimental investigation on heat transfer enhancement in circular jet impingement on hot surfaces by using Al2O3/water nano-fluids and aqueous high-alcohol surfactant solution

The present article reports the heat transfer characteristics of a vertical stainless steel foil of 0.15 mm thickness (SS304) by circular impinging jets of various fluids such as pure water, nano-fluids (Al₂O₃-water, ф = 0.15%, 0.6%), and aqueous high-alcohol surfactant (HAS, i.e., 2-ethyl-hexanol, 100–400 ppm) studied using an infrared thermal imaging camera (A655sc, FLIR System). The enhancement in the heat transfer rates for Al₂O₃-water nano-fluids with ф = 0.15%, ф = 0.60%, and aqueous surfactant solution (150ppm) is found to be 140%, 207%, and 117% higher compared to pure water results, respectively. The surface characteristics of the foil after jet impingement by various fluids are also studied using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and surface wettability.     

Ultrafast Excited State Relaxation Dynamics of New Fuchsine- a Triphenylmethane Derivative Dye

An all-inclusive investigation of the ultrafast excited state relaxation dynamics of a triphenylmethane derivative molecule, New Fuchsine (NF), using a combined approach of density functional theory (DFT), femtosecond transient absorption spectroscopy (fs-TAS), and photoluminescence spectroscopy is presented in this work. The DFT calculations confirmed the formation of twisted molecular structure in the excited state of NF in ethanol solution with bond rotation of ≈86°. TAS measurements of NF solution exhibited ultrafast ground state-recovery pathway via a conical intersection confirming an ultrafast structural reorientation. On the contrary, TAS measurements of NF thin-film exhibited a longer excited-state lifetime suggesting a hindered molecular twisted state formed as an intermediate step. Photophysical kinetic models are proposed to globally fit the fs-TAS data establishing the twisted intramolecular charge transfer (TICT) state mediated ground state recovery for NF in solution and thin film, respectively. Temperature-dependent photoluminescence study of NF film provided a clear insight into the effect of rotational motion of phenyl rings in NF molecules over the TICT mediated emission.