Freeform Bioprinting of Liver Encapsulated in Alginate Hydrogels Tissue Constructs for Pharmacokinetic Study

An in vitro model that can be realistically and inexpensively used to predict human response to various drug administration and toxic chemical exposure is needed. By fabricating a microscale 3D physiological tissue construct consisting of an array of channels and tissue-embedded chambers, one can selectively develop various biomimicking mammalian tissues for a number of pharmaceutical applications, for example, experimental pharmaceutical screening for drug efficacy and toxicity along with apprehending the disposition and metabolic profile of a candidate drug. This paper addresses issues relating to the development and implementation of a bioprinting process for freeform fabrication of a 3D cell-encapsulated hydrogel-based tissue construct, the direct integration onto a microfluidic device for pharmacokinetic study, and the underlying engineering science for the fabrication of a 3D microscale tissue chamber as well as its application in pharmacokinetic study. To this end, a prototype 3D microfluidic tissue chamber embedded with liver cells encapsulated within a hydrogel matrix construct is bioprinted as a physiological in vitro model for pharmacokinetic study. The developed fabrication processes are further validated and parameters optimized by assessing cell viability and liver cell phenotype, in which metabolic and synthetic liver functions are quantitated.Mechanical Engineerin

Hydrolysis of Phenyl Furyl Ketimine - The Relative Negativity Effect

Phenyl furyl ketimine hydrochloride has been prepared and the velocity of its hydrolysis to the corresponding ketone measured. The velocity constant has been found to be of the order of l0xl0-3 measured at 25°C. The constant for diphenyl ketimine hydrochloride is 5.5x103measured at 0° or about 50x10-3 when calculated to 25 °. In view of the generally considered more highly negative character of the furyl radical over the phenyl, this result is in line with an observed rule that the ketimine salts are more resistant to hydrolysis the more negative the radicals attached to the carbimino group. The hydrolytic velocities of these and other ketimines already studied are compared on the basis of Kharasch\u27s table of relative negativities of aromatic radicals

A Study of the Hoesch-Houben Synthesis in the Preparation of Aromatic Ketimines and Hydroxy-Phenyl Iminoesters

This synthesis involves the condensation of a phenol with a nitrile (aliphatic or aromatic). It is effected by the passage of dry hydrogen chloride through their solution in anhydrous ether, with or without the addition of dry zinc chloride. Anhydrous aluminum chloride was substituted for zinc chloride in some cases

The Preparation and Properties of Furyl Phenyl Ketimine

This ketimine has been prepared through the condensation of furonitrile with magnesium phenyl bromide, followed by treatment with ice and ammonium chloride at about -15 degrees C. The hydrochloride, a white solid, is rather quickly hydrolyzed to the corresponding ketone, benzoyl furane. The velocity of this hydrolysis and the basic strength of the free ketimine base are determined

Effects of Hydrogen Ion Concentration upon the Hydrolysis Rates of Ketimines (Abstract)

Measurements have been made upon the hydrolysis rates of ketimine hydrochlorides to obtain information concerning the relation between their varied structures and stability toward hydrolysis1. The hydrogen ion concentration might appear as a catalytic factor in this hydrolysis2. It would thus seem necessary to determine these hydrolysis rates at the same hydrogen ion concentration if this factor has a marked effect. Different ketimine hydrochlorides alone in water produce, in the dilute solutions usually employed, pH values ranging initially from about a.6 to 5.3 and increasing in each case toward the pH of the equivalent ammonium chloride formed as the result of hydrolysis. Certain measurements on the hydrolysis rates of ketimine hydrochlorides of widely different initial pH values in water, to which an equivalent of hydrochloric acid was added, showed that their speed was actually lowered by this hydrogen ion increase although not enough to affect the general order of the rate

The Velocites of Hydrolysis of the Three Monomethoxy-Diphenyl Ketimines

The 2- and the 3-methoxy-diphenyl ketimines have been prepared employing the general method of Moureu and Mignonac. The 4-methoxy-diphenyl ketimine had been prepared previously

The Velocites of Hydrolysis of Mono- and Polyhydroxy-Diphenyl Ketimines

The velocities of hydrolytic decomposition of the three monohydroxy-diphenyl, the resorcyl phenyl and the phloroglucinyl phenyl ketimine hydrochlorides have been measured. As a result of these measurements it has been found that the phenolic group in the 2- and 4-positions in the monohydroxy diphenyl ketimines gives rise to a marked retardation of the hydrolysis velocity compared with that of diphenyl ketimine, while the velocity of the 3-hydroxydiphenyl ketimine was even faster than that of the diphenyl ketimine

Preparation and Stability of Diphenyl Amine Hydronitrate

In connection with certain proposed studies the question of the preparation of diphenyl amine hydronitrate, or diphenyl ammonium nitrate, arose. A search of the literature revealed no record of this substance. The nearest equivalent reported was the perchlorate salt of diphenyl amine (Ber. 43, 1085-86. 1910). This compound was obtained upon treatment of a carbon tetrachloride solution of the amine with 70% perchloric acid added dropwise

The Strengths of Phenolic Ketimines and Their Methyl Ethers as Bases

The ionization constants of the monohydroxy-diphenyl ketimines and their methyl ethers are calculated from measurements of the hydrogen ion concentration of aqueous solutions of their hydrochlorides through the use of the quinhydrone electrode. This data has been collected as a part of the information expected to throw light on the varied stability toward hydrolysis shown by different ketimines