CdSe Quantum Dots Synthesis Laboratory Course for High School Students

Cadmium selenide quantum dot is a fascinating subject for leading high school students to the quantum world. An 8-hour laboratory course for up to 12 high school students is proposed. The 8-hour course consist of two 4-hours sections. This laboratory course includes the quantum dot syntheses, absorption and emission characterization, and data analysis. The proposes process runs at relatively lower temperature which means safe and easy, and shows apparent experimental results

Self-healing materials for soft-matter machines and electronics

The emergence of soft machines and electronics creates new opportunities to engineer robotic systems that are mechanically compliant, deformable, and safe for physical interaction with the human body. Progress, however, depends on new classes of soft multifunctional materials that can operate outside of a hard exterior and withstand the same real-world conditions that human skin and other soft biological materials are typically subjected to. As with their natural counterparts, these materials must be capable of self-repair and healing when damaged to maintain the longevity of the host system and prevent sudden or permanent failure. Here, we provide a perspective on current trends and future opportunities in self-healing soft systems that enhance the durability, mechanical robustness, and longevity of soft-matter machines and electronics

Rheological, In Situ Printability and Cell Viability Analysis of Hydrogels for Muscle Tissue Regeneration

Advancements in additive manufacturing have made it possible to fabricate biologically relevant architectures from a wide variety of materials. Hydrogels have garnered increased attention for the fabrication of muscle tissue engineering constructs due to their resemblance to living tissue and ability to function as cell carriers. However, there is a lack of systematic approaches to screen bioinks based on their inherent properties, such as rheology, printability and cell viability. Furthermore, this study takes the critical first-step for connecting in-process sensor data with construct quality by studying the influence of printing parameters. Alginate-chitosan hydrogels were synthesized and subjected to a systematic rheological analysis. In situ print layer photography was utilized to identify the optimum printing parameters and also characterize the fabricated three-dimensional structures. Additionally, the scaffolds were seeded with C2C12 mouse myoblasts to test the suitability of the scaffolds for muscle tissue engineering. The results from the rheological analysis and print layer photography led to the development of a set of optimum processing conditions that produced a quality deposit while the cell viability tests indicated the suitability of the hydrogel for muscle tissue engineering applications

ANION INDUCED BLUE TO PURPLE TRANSITION IN BACTERIORHODOPSIN

Purple membrane (PM, λ role= presentation \u3eλmax role= presentation \u3emax 570 nm) of H. halobium on treatment with sulphuric acid changes its colour to blue (λ role= presentation \u3eλmax role= presentation \u3emax 608 nm). The purple chromophore can be regenerated from the blue chromophore by exogeneous addition of anions such as CI− role= presentation \u3e− and HPO42− role= presentation \u3e2−4. Chloride ion is found to be more effective than the dibasic phosphate ion in regenerating the purple chromophore. Nevertheless, one thing common to the anion regeneration is that both CI− role= presentation \u3e− and HPO42− role= presentation \u3e2−4 show marked pH effect. At pH 1.0 the efficiency of regeneration of the purple chromophore is greater than at pH 2.0, for the same anion concentration. Fluorescence and circular dichroic studies indicate that the proteins do not undergo drastic changes at the secondary\u27 or tertiary structure level and the native structure is preserved during this transition. However, chromophoric-site interactions between retinal and the apoprotein are affected during this colour transition. A molecular mechanism is advanced for this transition

A paper-based microbial fuel cell operating under continuous flow condition

Microbial fuel cells have gained popularity as a viable, environmentally friendly alternative for the production of energy. However, the challenges in miniaturizing the system for application in smaller devices as well as the short duration of operation have limited the application of these devices. Here, the capillary motion was employed to design a self-pumped paper-based microbial fuel cell operating under continuous flow condition. A proof-of-concept experiment ran approximately 5 days with no outside power or human interference required for the duration of operation. Shewanella oneidensis MR-1 was used to create a maximum current of 52.25 µA in a 52.5 µL paper-based microfluidic device. SEM images of the anode following the experiment showed biofilm formation on the carbon cloth electrode. The results showed a power density of approximately 25 W/m3 and proved unique capabilities of the paper-based microbial fuel cells to produce energy for an extended period of time

Clove essential oil and nanoclays-based active food packaging

Active food packaging materials enhance the shelf-life of food products while reducing food waste. The current study aims to develop a biodegradable active food packaging material. The food packaging material was developed with the incorporation of clove essential oil, sodium alginate, gelatin, and nanoclay films were prepared. The influences of nanoclay and clove on the surface, optical, mechanical, chemical, barrier, and pH-indicating properties were studied. The lightness and yellowness increased by 1.06 folds and 3.34 folds when compared to clove (control), respectively. The UV barrier property 0.08±0.01nm in all films, while 8.37 folds reduction in transparency has been observed as compared to clove films. The tensile strength was reduced by 62.25% while elongation at break increased by 2.23 folds when compared to NC (control) film. The surface roughness increased with the addition of NC. The hydrophobicity of the films has increased up to 85.64. Water vapour permeability increased by 8.25% and oxygen permeability increased by 67.61%. Complete E. coli and S. aureus inhibition at 24 hours in all films containing clove. Thus, the developed packaging film can be used as an active food packaging material that enhances food shelf-life