Nanopartículas de prata com efeito medicinal biologicamente sintetizadas por actinomicetos de um fragmento de floresta tropical

Abstract

Nanotechnology is a science of nano-sized systems, comprised in a range of 10-9 m, which proposes to create a new organizational structure able to show different behaviors and properties of materials currently known and available. Through integration with biotechnology, the term "nanobiotechnology" may be used to define the use of microorganisms in studies concerning medical, pharmaceutical and cosmetics industries, among others. By virtue of their biotechnological potential for synthesizing antibacterial compounds, antifungal, antitumor, and antiparasitic compounds, beyond other substances of industrial interest, filamentous bacteria (actinomycetes) has potential for the development of drugs through biological synthesis of silver nanoparticles (AgNPS). This study aimed to evaluate the potential of AgNPs synthesis with antimicrobial activity against pathogenic bacteria and opportunistic fungi using as source of biomolecules species of actinomycetes. Ten samples of actinomycetes were selected from the collection Collection of Culture-DPUA and were subcultured and authenticated in ISP-2A (malt extract-yeast extract agar), based on morphological characteristics. The identification at the species level was performed by the technique of PCR (Polymerase Chain Reaction). For biogenic synthesis AgNPs, actinomycetes underwent submerged fermentation. The recovered crude extract and biosynthesized nanoparticles were used to determine the antimicrobial activity by agar diffusion method. The AgNPs that showed significant antagonistic action have been used to determine the MIC (Minimum Inhibitory Concentration), Cytotoxicity and characterized by different techniques, such as UV-Vis, DLS (Dynamic Light Scattering), XRD (diffraction X-ray) FTIR (Infrared Spectroscopy Fourier Transform), ICP-OES (Optical Emission Spectroscopy by Inductively Coupled Plasma) and TEM (Transmission Electron Microscopy). From these actinomycetes, 100% viable expressed morphological characteristics of Streptomyces. For the test of PCR the following species were identified Streptomyces parvulus (40%), Streptomyces bullii (10%), Streptomyces seoulensis (10%), Streptomyces owasiensis (10%), Streptomyces malasyensis (20%), Streptomyces lavendulae (10%). By the method agar block antimicrobial activity was confirmed and 80% of the bacteria inhibited S. aureus; 30% M. smegmatis and 40% the Candidas (albicans, atlantica and valderwaltii). Only 10% of actinomycetes inhibited the growth of E. coli. When tested across the crude extract to microorganisms test, 50% of the samples inhibited S. aureus; 30% M. smegmatis and 20% proved to be effective against C. albicans, C. atlantica and C. valderwaltii. In these tests the halo diameters varied on average 12 to 29 mm. As for the AgNPs, 100% inhibited the growth of S. aureus and E. coli with halos ranging from 12 to 34 mm. Data indicating the broad spectrum of these bioactive compounds. The AgNPs Streptomyces DPUA 1549, Streptomyces DPUA 1747 and Streptomyces DPUA 1748 showed antagonistic action for greater efficiency. Promising AgNPs showed spherical shape and sizes ranging from 1-40 nm. However, nanoparticles produced by Streptomyces sp. DPUA 1549 were the most efficient with MIC against S. aureus at low concentrations (1.95 μM). Through the images displayed in AFM was observed structural damage on cell membrane of S. aureus. In toxicity tests the AgNPs reduced the proliferation of NIH-3T3 cells. In addition, the cytotoxic activity of this nanomaterial is time dependent. These scientific evidences show the potential application of nanoparticles biosinthesyzed by Streptomyces DPUA 1549 on preparation of products for use in medical, cosmetic and pharmaceutical industries