Vector and Cell Line Engineering Technologies Toward Recombinant Protein Expression in Mammalian Cell Lines

The rapid growth of global biopharmaceutical market in the recent years has been a good indication of its significance in biotechnology industry. During a long period of time in recombinant protein production from 1980s, optimizations in both upstream and downstream processes were launched. In this regard, one of the most promising strategies is expression vector engineering technology based on incorporation of DNA opening elements found in the chromatin border regions of vectors as well as targeting gene integration. Along with these approaches, cell line engineering has revealed convenient outcomes in isolating high-producing clones. According to the fact that more than 50% of the approved therapeutic proteins is being manufactured in mammalian cell lines, in this review, we focus on several approaches and developments in vector and cell line engineering technologies in mammalian cell culture.     

Podophyllotoxin extraction from Linum usitatissimum plant and its anticancer activity against HT‐29, A‐549 and MDA‐MB‐231 cell lines with and without the presence of gold nanoparticles

In recent years, gold nanoparticles (Au‐NPs) have been taken into consideration in nanomedicine due to their excellent biocompatibility, chemical stability and promising optical properties. In this research, podophyllotoxin conjugated with gold nanoparticles (Au‐NPs‐POT) was synthesized and the conjugation of POT with Au‐NPs was confirmed using scanning electron microscopy, mass spectrometry and Fourier transform infrared spectroscopy. The anticancer effects of the product on preclinical models of lung, colon and breast cancers were investigated using MTT test. The analyses showed a direct dose–response relationship. It was found that higher concentrations of POT have more positive effects on the inhibition of cancer cell growth. At POT concentrations of 1, 2.5, 5, 7.5, 10, 15 and 20 ng ml^?1, approximately 50% of the growth of colorectal, lung and breast cancer cell lines was inhibited, while similar results were obtained in the presence of 1, 2, 3, 4 and 5 μg ml^?1 Au‐NPs‐POT. Au‐NPs‐POT exhibited the lowest cytotoxicity due to the presence of POT. The anticancer feature of Au‐NPs‐POT proved the potential to develop better anticancer therapeutics and to open new avenues for treatment of cancers.     

Cell biomechanics and its applications in human disease diagnosis

Certain diseases are known to cause changes in the physical and biomechanical properties of cells.These include cancer,malaria,and sickle cell anemia among others.Typically,such physical property changes can result in several fold increases or decreases in cell stiffness,which are significant and can result in severe pathology and eventual catastrophic breakdown of the bodily functions.While there are developed biochemical and biological assays to detect the onset or presence of diseases,there is always a need to develop more rapid,precise,and sensitive methods to detect and diagnose diseases.Biomechanical property changes can play a significant role in this regard.As such,research into disease biomechanics can not only give us an in-depth knowledge of the mechanisms underlying disease progression,but can also serve as a powerful tool for detection and diagnosis.This article provides some insights into opportunities for how significant changes in cellular mechanical properties during onset or progression of a disease can be utilized as useful means for detection and diagnosis.We will also showcase several technologies that have already been developed to perform such detection and diagnosis.     

Antibacterial and antibiofilm activity of nanochelating based silver nanoparticles against several nosocomial pathogens

The emergence of multi‐drug resistant (MDR) bacteria and dynamic pattern of infectious diseases demand to develop alternative and more effective therapeutic strategies. Silver nanoparticles (AgNPs) are among the most widely commercialized engineered nanomaterials, because of their unique properties and increasing use for various applications in nanomedicine. This study for the first time aimed to evaluate the antibacterial and antibiofilm activities of newly synthesized nanochelating based AgNPs against several Gram‐positive and ‐negative nosocomial pathogens. Nanochelating technology was used to design and synthesize the AgNPs. The cytotoxicity was tested in human cell line using the MTT assay. AgNPs minimal inhibitory concentration (MIC) was determined by standard broth microdilution. Antibiofilm activity was assayed by a microtiter‐plate screening method. The two synthesized AgNPs including AgNPs (A) with the size of about 20‐25 nm, and AgNPs (B) with 30‐35 nm were tested against Staphylococcus aureus, Staphylococcus epidermidis, Acinetobacter baumannii, and Pseudomonas aeruginosa. AgNPs exhibited higher antibacterial activity against Gram‐positive strains. AgNPs were found to significantly inhibit the biofilm formation of tested strains in concentration 0.01 to 10 mg/mL. AgNPs (A) showed significant effective antibiofilm activity compared to AgNPs (B). In summary, our results showed the promising antibacterial and antibiofilm activity of our new nanochelating based synthesized AgNPs against several nosocomial pathogens.     

Spectral Investigations of Preferential Solvation and Solute–Solvent Interactions of Free Base and Protonated 5,10,15,20-Tetrakis(4-trimethyl-ammonio-phenyl)-porphine Tetratosylate in Aqueous Organic Mixed Solvents

The solvatochromic properties of the free base and the protonated 5,10,15,20-tetrakis(4-trimethyl-ammonio-phenyl)-porphine tetratosylate (TTMAPP) were studied in pure water, methanol, ethanol, 2-propanol, and their corresponding aqueous mixtures. The correlation of the empirical solvent polarity scale (E _T) values of TTMAPP with composition of the solvents were analyzed by the solvent exchange model of Bosch and Roses to clarify the preferential solvation of the probe dyes in the binary mixed solvents. The solvation shell composition effects in preferential solvation of the solute dyes were investigated in terms of both solvent–solvent and solute–solvent interactions and also the local mole fraction of each solvent composition was calculated in the cybotactic region of the probe. The effective mole fraction variation may provide significant physicochemical insights in the microscopic and molecular level of interactions between TTMAPP species and the solvent components and, therefore, can be used to interpret the solvent effect on kinetics and thermodynamics of TTMAPP.     

Surface modification of cellulose nanocrystal with chitosan oligosaccharide for drug delivery applications

A novel drug delivery system based on two of the most abundant natural biopolymers was developed by modifying the surface of oxidized cellulose nanocrystal (CNC) with chitosan oligosaccharide (CS_OS). First, the primary alcohol moieties of CNC were selectively oxidized to carboxyl groups using the 2,2,6,6-tetramethylpiperidine-1-oxyl radical catalyst. The amino groups of CS_OS were then reacted with carboxylic acid groups on oxidized CNC (CNC-OX) via the carbodiimide reaction using N-hydroxysuccinimide and 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide as coupling agents. Successful grafting of CS_OS to CNC-OX was confirmed by infrared spectroscopy, thermogravimetry, potentiometric titration, and zeta potential measurements. The grafting resulted in a conversion of ~90 % carboxyl groups on CNC-OX and the degree of substitution was 0.26. CNC–CS_OS nanoparticles showed a binding efficiency of 21.5 % and a drug loading of 14 % w/w. A drug selective electrode was used to directly measure the concentration of procaine hydrochloride released from CNC–CS_OS particles. The in vitro drug release was studied at pH 8 and the nanoparticles revealed a fast release of up to 1 h, which can be used as biocompatible and biodegradable drug carriers for transdermal delivery applications.     

Nitrogen lasers: Optical devices of variable gain coefficient

A N₂-laser system, consists of an oscillator and an amplifier of different electrode lengths, ranged from 5 to 31 cm, operating under the optimized gas pressures conditions and 14 kV input voltage, was used to measure small signal gain, g₀, and saturation energy density, E_s. It was found that g₀-parameter follows a profile of the type m + n/l_AMP, where l_AMP is the effective electrode length of the laser amplifier, and (m, n) are some constants. So, by reducing the active length a gain value as high as ∼1.2 cm⁻¹ for l_AMP = 5 cm was obtained. The proposed function, with a rather good approximation, can be used to explain almost all the reported g₀-values of laser systems with moderate current densities. For explaining more details of the reported gain coefficients, the g₀l_AMP-parameter was introduced, where it was realized that with a good approximation a Gaussian profile is a suitable function for explaining the reported g₀l_AMP-products. Furthermore, we found that at a constant input voltage the saturation energy density and output energy density, E_out, regardless of the type of N₂-lasers and their operational conditions, are linearly correlated. Based on this observation, and by operating the system at different input voltages, the functional dependence of the measured E_s/E_out-values with respect to the operational voltages is introduced. Details of our present observations, along with the previously reported g₀, and E_s-measurements are presented graphically, or tabulated. The results are giving some interesting features of TE/TEA N₂-lasers for lasers g₀, E_s predictions which are valuable for laser designs and also for further theoretical investigations.     

Comparison of Air-Assisted,Vortex-Assisted and Ultrasound-Assisted Dispersive Liquid–Liquid Microextraction for the Determination of BTEX Compounds in Water Samples Prior to GC-FID Analysis

Three new dispersive liquid–liquid microextraction (DLLME) methods, air-assisted (AA-DLLME), vortex-assisted (VA-DLLME) and ultrasound-assisted (UA-DLLME), were compared from the point of view of their analytical application for preconcentration of trace amounts of benzene, toluene, ethylbenzene and xylene isomers (BTEX) in water samples. In all of these methods, no dispersive solvent is required and dispersion of extractant is carried out by air bubbles, vortex and ultrasound for AA-DLLEM, VA-DLLME, and UA-DLLME, respectively. Advantages and disadvantages of these three liquid phase microextraction methods and their capability in dispersion of a similar extractant phase in sample solutions were comprehensively compared. All other extraction parameters, which have an influence on the microextraction, were also investigated and optimized. Under optimized conditions, analytical figures of merit for the three techniques were determined and compared. It was found that the limit of detection of the three methods is almost the same, while AA-DLLME has a wider linear dynamic range and the shortest analysis time. Enrichment factors of 182, 45 and 245 were achieved for AA-DLLEM, VA-DLLME, and UA-DLLME, respectively.     

Efficient and solvent-free synthesis of 1-amidoalkyl-2-naphthols using <Emphasis Type="Italic">N,N,N’,N’</Emphasis>-tetrabromobenzene-1,3-disulfonamide

N,N,N,’N’-Tetrabromobenzene-1,3-disulfonamide [TBBDA] is found to be a reusable catalyst for efficient synthesis of various amidoalkyl naphthols from β-naphthol, aromatic aldehydes and urea in good to high yields under solvent-free conditions.