Three-dimensional perfused cell culture

Compelling evidence suggests the limitation and shortcomings of the current and well established cell culture method using multi-well plates, flasks and Petri dishes. These are particularly important when cell functions are sensitive to the local microenvironment, cell–cell and cell–extracellular matrix interactions. There is a clear need for advanced cell culture systems which mimic in vivo and more physiological conditions. This review summarises and analyses recent progress in three dimensional (3D) cell culture with perfusion as the next generation cell culture tools, while excluding engineered tissue culture where three dimensional scaffold has to be used for structural support and perfusion for overcoming mass transfer control. Apart from research activities in academic community, product development in industry is also included in this review.     

Probing binding mechanism of interleukin-6 and olokizumab: in silico design of potential lead antibodies for autoimmune and inflammatory diseases

Computer-aided antibody engineering has been successful in the design of new biologics for disease diagnosis and therapeutic interventions. Interleukin-6 (IL-6), a well-recognized drug target for various autoimmune and inflammatory diseases such as rheumatoid arthritis, multiple sclerosis, and psoriasis, was investigated in silico to design potential lead antibodies. Here, crystal structure of IL-6 along with monoclonal antibody olokizumab was explored to predict antigen–antibody (Ag???Ab)-interacting residues using DiscoTope, Paratome, and PyMOL. Tyr56, Tyr103 in heavy chain and Gly30, Ile31 in light chain of olokizumab were mutated with residues Ser, Thr, Tyr, Trp, and Phe. A set of 899 mutant macromolecules were designed, and binding affinity of these macromolecules to IL-6 was evaluated through Ag???Ab docking (ZDOCK, ClusPro, and Rosetta server), binding free-energy calculations using Molecular Mechanics/Poisson Boltzman Surface Area (MM/PBSA) method, and interaction energy estimation. In comparison to olokizumab, eight newly designed theoretical antibodies demonstrated better result in all assessments. Therefore, these newly designed macromolecules were proposed as potential lead antibodies to serve as a therapeutics option for IL-6-mediated diseases.     

Mode of action of a surfactant–polymer formulation to support performance of the entomopathogenic nematode Steinernema carpocapsae for control of diamondback moth larvae (Plutella xylostella)

The use of entomopathogenic nematodes on cabbage leaves against larvae of the diamondback moth (DBM) Plutella xylostella requires the addition of formulation adjuvants to achieve satisfying control. Without adjuvants nematodes settle in the tank mix of backpack sprayers causing uneven distribution. The polymers arabic and guar gum, alginate and xanthan were used in concentrations between 0.05 and 0.3% to retard sedimentation of Steinernema carpocapsae. Arabic gum had no effect, guar gum prevented sedimentation at 0.3% but the effect dropped significantly at lower concentration. At 0.05%, xanthan prevented nematode sedimentation better than alginate. Deposition of nematodes on the leaves was significantly increased by the addition of any of the polymers. Spraying nematodes on leaves with an inclination of 45° without the addition of any formulation resulted in 70% run-off. Adding 0.2% alginate or xanthan reduced the losses to <20%. The use of a surfactant–polymer formulation significantly reduced defoliation by DBM larvae. Visual examinations provided evidence that nematodes are not ingested by DBM larvae. Invasion of S. carpocapsae is an active process via the anus. The function of the formulation is not to prolong nematode survival, but to provide environmental conditions which enable rapid invasion of the nematodes. Nematode performance was improved by selection of the best surfactant in combination with xanthan and by optimisation of the concentrations of the surfactant Rimulgan® and the polymer xanthan. The best control results were achieved with Rimulgan® at 0.3% together with 0.3% xanthan, causing DBM mortality of >90% at 80% relative humidity and >70% at 60%. The formulation lowered the LC₅₀ from 12 to 1 nematode/larva. The viscosity of the surfactant–polymer formulations correlated well with nematode efficacy, prevention of sedimentation and adherence to the leave. This physical parameter can therefore be recommended for improvement of nematode formulations to be used for foliar application against DBM.     

Nature of Novel 2D van der Waals Heterostructures for Superior Potassium Ion Batteries

Novel 2D van der Waals heterostructures with innovative bimetallic oxychloride (Bi‐ and Sb‐based oxychloride) nanosheets that are well dispersed on reduced graphene oxide nanosheets, are established through element engineering for superior potassium ion battery (PIBs) anodes. This material displays an exceptional electrochemical performance, obtaining a discharge capacity as high as 360 mAh g^?1 at 100 mA g^?1 after running 1000 cycles for over 9 months with a capacity preservation percentage of 88.5% and achieving a discharge capacity as high as 319 mAh g^?1 at 1000 mA g^?1, in addition to the low charge/discharge plateaus for anodes and promising full cell performance. More significantly, the nature of such 2D van der Waals heterostructures, including the element engineering for morphology control, the function of each component of heterostructures, the mechanism of potassium ion storage, and the process of K⁺ intercalation accompanied with the lattice distortion and chemical bond breakages, is explored in depth. This study is critical for not only paving the way for the practical application of PIBs but also shedding light on fundamentals of potassium ion storage in 2D van der Waals heterostructures.     

Shewanella biofilm development and engineering for environmental and bioenergy applications

The genus Shewanella comprises about 70 species of Gram-negative, facultative anaerobic bacteria inhabiting various environments, which have shown great potential in various biotechnological applications ranging from environmental bioremediation, metal(loid) recovery and material synthesis to bioenergy generation. Most environmental and energy applications of Shewanella involve the biofilm mode of growth on surfaces of solid minerals or electrodes. In this article, we first provide an overview of Shewanella biofilm biology with the focus on biofilm dynamics, biofilm matrix, and key signalling systems involved in Shewanella biofilm development. Then we review strategies recently exploited to engineer Shewanella biofilms to improve biofilm-mediated bioprocesses.     

Study of accumulation behaviour of tungsten based composite using electron probe micro analyser for the application in bone tissue engineering

In this research, a proto-type study we have conducted, where we have synthesized tungsten based composite materials which are tungsten along with combined oxides of other elements like calcium, scandium, barium, and aluminium in the form of powder with bones powder of mice devised by high energy ball mill and later on fabricating high dense pellets by sintering by spark plasma. The particle sizes of the composite materials are found to be 1–2 µm, as evidenced by the electron microscope, suggesting synthesized materials are of micron size. The quantitative and qualitative analysis of sintered pellets are well confirmed by electron probe micro analyzer (EPMA) and energy dispersive X-ray spectrometer (EDS) which illustrate the greater percentage of tungsten presents in the profound scan areas with other elements of the composite. The absence of pores across the 3D geometry suggesting dense sample, which is quite revealed by the X-ray tomography inspection. The prepared sintered pellets from the tungsten based composites are found to be ≈ 99.5% density with the observation of tungsten to be accumulated uniformly across the scan regions along with focussed hot spots as implied by EPMA. This study paves the way, to examine how the tungsten accumulation and the distribution with the other elements for future understanding in bone tissue engineering application and the in vivo specification of tungsten.     

Extension of cell membrane boosting squalene production in the engineered Escherichia coli

Squalene is a lipophilic and non-volatile triterpene with many industrial applications for food, pharmaceuticals, and cosmetics. Metabolic engineering focused on optimization of the production pathway suffer from little success in improving titers because of a limited space of the cell membrane accommodating the lipophilic product. Extension of cell membrane would be a promising approach to overcome the storage limitation for successful production of squalene. In this study, Escherichia coli was engineered for squalene production by overexpression of some membrane proteins. The highest production of 612 mg/L was observed in the engineered E. coli with overexpression of Tsr, a serine chemoreceptor protein, which induced invagination of inner membrane to form multilayered structure. It was also observed an increase in unsaturated fatty acid in membrane lipids composition, suggesting cellular response to maintain membrane fluidity against squalene accumulation in the engineered strain. This study potentiates the capability of E. coli for squalene production and provides an effective strategy for the enhanced production of such compounds.     

Low-volume application by mist-blower compared with conventional compression sprayer treatment of houses with residual pyrethroid to control the malaria vector Anopheles albimanus in Mexico

Abstract. Village-scale trials were carried out in southern Mexico to compare the efficacy of indoor-spraying of the pyrethroid insecticide lambda-cyhalothrin applied either as low-volume (LV) aqueous emulsion or as wettable-powder (WP) aqueous suspension for residual control of the principal coastal malaria vector Anopheles albimanus. Three indoor spray rounds were conducted at 3-month intervals using back-pack mist-blowers to apply lambda-cyhalothrin 12.5 mg a.i./m² by LV, whereas the WP was applied by conventional compression sprayer at a mean rate of 26.5 mg a.i./m².
Both treatments caused mosquito mortality indoors and outdoors (collected inside house curtains) as a result of contact with treated surfaces before and after feeding, but had no significant impact on overall population density of An. albimanus resting indoors or assessed by human bait collections. Contact bioassays showed that WP and LV treatments with lambda-cyhalothrin were effective for 12–20 weeks (>75% mortality) without causing excito-repellency.
Compared to the WP treatment (8 houses/man/day), LV treatment (25 houses/man/day) was more than 3 times quicker per house, potentially saving 68% of labour costs. This is offset, however, by the much lower unit price of a compression sprayer (e.g. Hudson 'X-pert' at US120) than a mist-blower (e.g. 'Super Jolly' at US350), and higher running costs for LV applications. It was calculated, therefore, that LV becomes more economical than WP after 18.8 treatments/100 houses/10 men at equivalent rates of application, or after 7.6 spray rounds with half-rate LV applications.     

Use of two formulations and two application techniques to deliver Bacillus thuringiensis var. israelensis for the control of Musca domestica (Diptera: Muscidae) larvae and adults in poultry houses

A field study was carried out for 6 wks to assess, from both an efficiency and economic perspective, the effect of individual and integrated success of feeding and topical applications of two formulations of Bacillus thuringiensis var. israelensis (Bti) in controlling house fly (Musca domestica L.) larvae and adults in poultry houses. There was no significant difference between the 1 g and 2 g L^?1 spray applications of Bti. In the absence of spray applications, no significant differences in larval mortalities were observed between the 250 mg and 500 mg kg^?1 feed applications. The percentage mortality of larvae accomplished as a result of using a combination of 250 mg kg^?1Bti feed and 2 g L^?1 spray applications was equivalent to that obtained as a result of combining 500 mg kg^?1Bti and 1g L^?1 spray applications. Treatment with Bti caused significant reductions in the emergence (up to 74%) of house fly adults compared to the control. The fact that the emergence of adult house flies was affected by Bti treatments implies that Bti has sublethal effects on house fly larvae. The cost–benefit analysis (expressed in terms of mortality of larvae growing) indicated that the most effective combination for house fly larvae and adult house fly emergence control was the 500 mg kg^?1 of feed and 2 g L^?1 spray application combination that resulted in 67% larval mortality and a 74% decrease in adult house fly emergence. This study presents commercial users with various alternatives for possible combinations of the two Bti formulations.