Green Synthesis of Silver Nanoparticles Using Pecan Nut (Carya illinoinensis) Shell Extracts and Evaluation of Their Antimicrobial Activity.

Nowadays, the increase in bacteria resistant to multiple antibiotics has become a real threat to the human health, forcing researchers to develop new strategies. Silver nanoparticles (AgNPs) may be a viable solution to this problem. The green synthesis of AgNPs is considered a green, ecological and low-priced process that provides small and biocompatible nanostructures with antimicrobial activity with a potential application in medicine. In this work, pecan nut shell extracts were analyzed in order to determine their viability for the production of AgNPs. These NPs were synthesized using an extract rich in bioactive molecules, varying the reaction time and silver nitrate (AgNO3) concentration. AgNPs production was confirmed by FT-IR, UV-Vis and EDX spectroscopy, while their morphology and size were determined by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The antibacterial activity of AgNPs was evaluated by the agar diffusion method against Salmonella typhi, Staphylococcus aureus and Proteus mirabilis. The results showed that it is possible to obtain nanoparticles from an extract rich in antioxidant molecules with a size between 39.9 and 98.3 nm with a semi-spherical morphology. In addition, it was shown that the reaction time and the concentration of the precursor influence the final nanoparticles size. Antimicrobial tests showed that there is greater antimicrobial inhibition against Gram-negative than Gram-positive microorganisms, obtaining inhibition zone from 0.67 to 5.67 mm.

No Solid Colloidal Carriers: Aspects Thermodynamic the Immobilization Chitinase and Laminarinase in Liposome.

The present review describes the basic properties of colloidal and vesicular vehicles that can be used for immobilization of enzymes. The thermodynamic aspects of the immobilization of enzymes (laminarinase and chitinase) in liposomes are discussed. These systems protect enzymes against environmental stress and allow for a controlled and targeted release. The diversity of colloidal and vesicular carriers allows the use of enzymes for different purposes, such as mycolytic enzymes used to control phytopathogenic fungi.