The Effect of Nanofillers on the Functional Properties of Biopolymer-Based Films: A Review

Waste from non-degradable plastics is becoming an increasingly serious problem. Therefore, more and more research focuses on the development of materials with biodegradable properties. Bio-polymers are excellent raw materials for the production of such materials. Bio-based biopolymer films reinforced with nanostructures have become an interesting area of research. Nanocomposite films are a group of materials that mainly consist of bio-based natural (e.g., chitosan, starch) and synthetic (e.g., poly(lactic acid)) polymers and nanofillers (clay, organic, inorganic, or carbon nanostructures), with different properties. The interaction between environmentally friendly biopolymers and nanofillers leads to the improved functionality of nanocomposite materials. Depending on the properties of nanofillers, new or improved properties of nanocomposites can be obtained such as: barrier properties, improved mechanical strength, antimicrobial, and antioxidant properties or thermal stability. This review compiles information about biopolymers used as the matrix for the films with nanofillers as the active agents. Particular emphasis has been placed on the influence of nanofillers on functional properties of biopolymer films and their possible use within the food industry and food packaging systems. The possible applications of those nanocomposite films within other industries (medicine, drug and chemical industry, tissue engineering) is also briefly summarized

Using CdTe/ZnSe core/shell quantum dots to detect DNA and damage to DNA

CdTe/ZnSe core/shell quantum dot (QD), one of the strongest and most highly luminescent nanoparticles, was directly synthesized in an aqueous medium to study its individual interactions with important nucleobases (adenine, guanine, cytosine, and thymine) in detail. The results obtained from the optical analyses indicated that the interactions of the QDs with different nucleobases were different, which reflected in different fluorescent emission maxima and intensities. The difference in the interaction was found due to the different chemical behavior and different sizes of the formed nanoconjugates. An electrochemical study also confirmed that the purines and pyrimidines show different interactions with the core/shell QDs. Based on these phenomena, a novel QD-based method is developed to detect the presence of the DNA, damage to DNA, and mutation. The QDs were successfully applied very easily to detect any change in the sequence (mutation) of DNA. The QDs also showed their ability to detect DNAs directly from the extracts of human cancer (PC3) and normal (PNT1A) cells (detection limit of 500 pM of DNA), which indicates the possibilities to use this easy assay technique to confirm the presence of living organisms in extreme environments

Isolation of branched chain aminoacids (Valine, Leucine and Arginine) using maghemite particles

In this paper, we report the optimal conditions for the isolation and preconcentration of branched chain amino acids (BCAAs) - leucine, valine and arginine from different types of matrix, such as tissue, plasma, blood, bacteria or cells. Herein, we focused on the synthesis of paramagnetic particles able to isolate and immobilize amino acids and thus preconcentrate it for subsequent analysis on ion-exchange liquid chromatography with VIS detector. We modified nanomaghemite (-Fe2O3) by multi walled carbon nanotubes (MWCNT) and hyaluronic acid as the functional carriers providing excellent affinity properties. Our paramagnetic particles have potential for better isolation of BCAAs mainly from plasma or bacteria and in the future they can also be applied as a platform of delivery system

Antimicrobial activity of CdTe QDs modified with lanthanides on pseudomonas aeruginosa

The aim of this study is to obtain data based on an experimental procedure and check the effectiveness of some antibacterial agents against pathogenic bacteria. In the present experiment, two different nanoparticles (Cadmium Telluride Quantum dots with Lanthanides: Gadolinium and Terbium) were used to check their antibacterial properties on Pseudomonas aeruginosa. The Cadmium Telluride Quantum dots without the Lanthanides, Gadolinium nitrate and Terbium nitrate were also tested on those bacteria as control. In the present experiment, the following methods were employed: disc-diffusion test, the determination of the growth properties of the bacteria and comparison of absorbance after treatment with antimicrobial agent. From the results it has been found that the tested Cadmium Telluride Quantum dots with Lanthanides (Gadolinium and Terbium) have good antimicrobial effects. Additionally, GdQDs show stronger antibacterial effect than Tb QD and other tested compounds