Development of Biopolymer Composite Films Using a Microfluidization Technique for Carboxymethylcellulose and Apple Skin Particles.

Biopolymer films based on apple skin powder (ASP) and carboxymethylcellulose (CMC) were developed with the addition of apple skin extract (ASE) and tartaric acid (TA). ASP/CMC composite films were prepared by mixing CMC with ASP solution using a microfluidization technique to reduce particle size. Then, various concentrations of ASE and TA were incorporated into the film solution as an antioxidant and an antimicrobial agent, respectively. Fourier transform infrared (FTIR), optical, mechanical, water barrier, and solubility properties of the developed films were then evaluated to determine the effects of ASE and TA on physicochemical properties. The films were also analyzed for antioxidant effect on 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and antimicrobial activities against Listeria monocytogenes, Staphylococcus aureus, Salmonella enterica, and Shigella flexneri. From the results, the ASP/CMC film containing ASE and TA was revealed to enhance the mechanical, water barrier, and solubility properties. Moreover, it showed the additional antioxidant and antimicrobial properties for application as an active packaging film.

A combined top-down/bottom-up approach to structuring multi-sensing zones on a thin film and the application to SPR sensors.

The development of a thin film with well-defined metallic micro/nanostructures, diverse surface functionalities, and superior electronic/optical properties has been a great challenge to researchers seeking an efficient method for the detection of various analytes in chemical and biological sensing applications. Herein, we report a facile and effective approach to the fabrication of an ordered gold island pattern on a glass substrate with contrasted chemical functionalities, which can provide spatially separated sensing zones for multi-detection. In the proposed method, the combination between the micro/nano-imprint lithography and sequential self-assembly approaches exhibited synergistic effects that allowed well-defined structuring and easy surface functionalization in separated sensing zones. Via imprint lithography, the uniform gold islands/glass structure was successfully fabricated from a readily available gold-coated glass film. In addition, a sequential self-assembling strategy and specific chemical-substrate interactions, such as thiol-gold and silane-glass, enabled the surfaces of gold islands and exposed portions of the glass substrate with contrasting chemical functionalities-SH-functionalized gold islands and NH2-functionalized glass substrate. A proof-of-concept experiment for the multi-detection of heavy metal ions (Hg(2+) and Cu(2+)) in an aqueous media was also successfully conducted using the dual-functionalized gold islands/glass structure and surface plasmon resonance measurements. The SH groups on the gold islands and the NH2 groups on the glass substrate functioned as spatially separated and selective receptors for Hg(2+) and Cu(2+) ions, respectively. Therefore, both the detection and quantification of Hg(2+) and Cu(2+) ions could be achieved using a single sensing substrate.

Apple peel and carboxymethylcellulose-based nanocomposite films containing different nanoclays.

UNLABELLED: Biodegradable packaging films were developed from polymeric blends of apple peel powder (APP) and carboxymethylcellulose (CMC), into which different nanoclays were incorporated to produce a nanocomposite film. After first estimating the barrier and mechanical properties of 4 different biopolymer films (CMC, methylcellulose, gelatin, and polylactide), CMC was chosen as the best film-forming solution. Three different nanoclays (Cloisite Na(+) , 30B, and 20A) were subsequently dispersed in a CMC film solution to improve the barrier and physical properties of the final CMC nanocomposite films. The structures of the exfoliated CMC nanocomposite films were characterized using X-ray diffraction (XRD) to determine the most efficient nanoclay type, with Cloisite Na(+) addition being found to demonstrate the greatest improvement in the barrier and mechanical properties of the film. Finally, the CMC and Cloisite Na(+) solution were thoroughly blended with APP using a high-pressure homogenization (HPH) process to develop biopolymer nanocomposite films, which were then characterized using XRD and Fourier transform infrared spectroscopy. The HPH treatment significantly improved the film-forming ability by increasing the dispersity of APP in the CMC nanocomposites, as well as having various other effects on the physical properties. These nanocomposite films can be viewed as an alternative solution for the use of agricultural biomass in developing environmentally friendly packaging materials. PRACTICAL APPLICATION: Cloisite Na(+) nanoclay noticeably improved the barrier and elongation properties of a biopolymer film. High-pressure homogenization successfully blended apple peel powder with carboxymethylcellulose to develop a nanocomposite film. The apple peel and CMC-based nanocomposite films that were developed could be used as a novel biodegradable packaging material.