In Vivo Biosynthesis of Inorganic Nanomaterials Using Eukaryotes - A Review

Bionanotechnology, the use of biological resources to produce novel, valuable nanomaterials, has witnessed tremendous developments over the past two decades. This eco-friendly and sustainable approach enables the synthesis of numerous, diverse types of useful nanomaterials for many medical, commercial, and scientific applications. Countless reviews describing the biosynthesis of nanomaterials have been published. However, to the best of our knowledge, no review has been exclusively focused on the in vivo biosynthesis of inorganic nanomaterials. Therefore, the present review is dedicated to filling this gap by describing the many different facets of the in vivo biosynthesis of nanoparticles (NPs) using living eukaryotic cells and organisms—more specifically, live plants and living biomass of several species of microalgae, yeast, fungus, mammalian cells, and animals. It also highlights the strengths and weaknesses of the synthesis methodologies and the NP characteristics, bio-applications, and proposed synthesis mechanisms. This comprehensive review also brings attention to enabling a better understanding between the living organisms themselves and the synthesis conditions that allow their exploitation as nanobiotechnological production platforms as these might serve as a robust resource to boost and expand the bio-production and use of desirable, functional inorganic nanomaterials

Photochemical synthesis of gold and silver nanoparticles — a review

ABSTRACT: Nanomaterials have supported important technological advances due to their unique properties and their applicability in various fields, such as biomedicine, catalysis, environment, energy, and electronics. This has triggered a tremendous increase in their demand. In turn, materials scientists have sought facile methods to produce nanomaterials of desired features, i.e., morphology, composition, colloidal stability, and surface chemistry, as these determine the targeted application. The advent of photoprocesses has enabled the easy, fast, scalable, and cost- and energy-effective production of metallic nanoparticles of controlled properties without the use of harmful reagents or sophisticated equipment. Herein, we overview the synthesis of gold and silver nanoparticles via photochemical routes. We extensively discuss the effect of varying the experimental parameters, such as the pH, exposure time, and source of irradiation, the use or not of reductants and surfactants, reagents’ nature and concentration, on the outcomes of these noble nanoparticles, namely, their size, shape, and colloidal stability. The hypothetical mechanisms that govern these green processes are discussed whenever available. Finally, we mention their applications and insights for future developments

Green synthesis of selenium and tellurium nanoparticles : current trends, biological properties and biomedical applications

ABSTRACT: The synthesis and assembly of nanoparticles using green technology has been an excellent option in nanotechnology because they are easy to implement, cost-efficient, eco-friendly, risk-free, and amenable to scaling up. They also do not require sophisticated equipment nor well-trained professionals. Bionanotechnology involves various biological systems as suitable nanofactories, including biomolecules, bacteria, fungi, yeasts, and plants. Biologically inspired nanomaterial fabrication approaches have shown great potential to interconnect microbial or plant extract biotechnology and nanotechnology. The present article extensively reviews the eco-friendly production of metalloid nanoparticles, namely made of selenium (SeNPs) and tellurium (TeNPs), using various microorganisms, such as bacteria and fungi, and plants’ extracts. It also discusses the methodologies followed by materials scientists and highlights the impact of the experimental sets on the outcomes and shed light on the underlying mechanisms. Moreover, it features the unique properties displayed by these biogenic nanoparticles for a large range of emerging applications in medicine, agriculture, bioengineering, and bioremediation

Life Sciences at the University of Yachay Tech in Ecuador

Yachay Tech University, home for more than 900 students and growing, has entered a new era and made a step forward in its development and fulfillment of the hopes placed on it. Indeed, its Schools have launched their careers offering the students a wide range of choices among programs of high academic level. The School of Biological Sciences and Engineering has started its two careers. The first one, coined "Biology," is designed for students aiming to gain knowledge either in "Organisms, Ecology and Evolution" or "Molecular and Cellular Biology." The second path, referred to as "Biomedical Engineering", is the first program of its type in Ecuador and is intended for students wishing to apply the principles and problem-solving techniques of Engineering to Biology and Medicine. These students will be able to acquire knowledge at the interface between Biology and Medicine, on one side, and Natural Sciences, such as Physics and Chemistry, and Engineering sciences, such as Flow Dynamics, Informatics and Electronics, on the other side

Biosynthesis of Inorganic Nanoparticles: A Fresh Look at the Control of Shape, Size and Composition

Several methodologies have been devised for the design of nanomaterials. The “Holy Grail” for materials scientists is the cost-effective, eco-friendly synthesis of nanomaterials with controlled sizes, shapes and compositions, as these features confer to the as-produced nanocrystals unique properties making them appropriate candidates for valuable bio-applications. The present review summarizes published data regarding the production of nanomaterials with special features via sustainable methodologies based on the utilization of natural bioresources. The richness of the latter, the diversity of the routes adopted and the tuned experimental parameters have led to the fabrication of nanomaterials belonging to different chemical families with appropriate compositions and displaying interesting sizes and shapes. It is expected that these outstanding findings will encourage researchers and attract newcomers to continue and extend the exploration of possibilities offered by nature and the design of innovative and safer methodologies towards the synthesis of unique nanomaterials, possessing desired features and exhibiting valuable properties that can be exploited in a profusion of fields

Sol-Gel-Derived Materials for Production of Pin-Printed Reporter Gene Living-Cell Microarrays

We report the fabrication of three-dimensional living-cell microarrays via pin-printing of soft sol-gel-derived silica materials containing bacterial cells. Bacterial cells entrapped in the silica-glycerol microarray spots can express reporter genes and produce strong fluorescence signals. The signals responded to the presence and concentration of inducers or repressors as expected, indicating that the entrapped cells remained metabolically active. Microscopic imaging of individual microarray spots at different culture times suggests that the entrapped cells can grow and divide, phenomena further confirmed by experiments in bulk sol-gel materials that demonstrated the increases of entrapped cell density and fluorescence during incubation in culture media. The cell microarrays can also be printed into 96-well glass bottom microtiter plates in a multiplexed manner, and the fluorescence signals generated were able to quantitatively and selectively respond to the concentration of inducers, thus demonstrating the potential for multitarget biosensing and high-throughput/high-content cell-based screening. The signal levels of bacterial cells in silica were significantly higher than those in alginate arrays, presumably due to viability of the entrapped cells in silica sol-gels. Microarray stability assays proved that the entrapped cells retained their physiological activity after storage for four weeks. Given that a large number of fluorescent and luminescent protein-based cell assays have been developed, the reporter gene living-cell microarrays demonstrated in this paper are expected to be applicable to a wide variety of research areas ranging from bioanalysis and chemical biology to drug discovery and probing of cell-material interactions

Biosynthetic Conversion of Ag+ to highly Stable Ag0 Nanoparticles by Wild Type and Cell Wall Deficient Strains of Chlamydomonas reinhardtii

In the current study, two different strains of the green, freshwater microalga Chlamydomonas reinhardtii bioreduced Ag+ to silver nanoparticles (AgNPs), which have applications in biosensors, biomaterials, and therapeutic and diagnostic tools. The bioreduction takes place in cell cultures of C. reinhardtii at ambient temperature and atmospheric pressure, thus eliminating the need for specialized equipment, harmful reducing agents or the generation of toxic byproducts. In addition to the visual changes in the cell culture, the production of AgNPs was confirmed by the characteristic surface plasmon resonance (SPR) band in the range of 415–425 nm using UV-Vis spectrophotometry and further evolution of the SPR peaks were studied by comparing the peak intensity at maximum absorbance over time. X-ray diffraction (XRD) determined that the NPs were Ag0. Micrographs from transmission electron microscopy (TEM) revealed that 97 ± 2% AgNPs were <10 nm in diameter. Ag+ to AgNP conversion was determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The AgNPs were stable over time in the cell culture media, acetone, NaCl and reagent alcohol solutions. This was verified by a negligible change in the features of the SPR band after t > 300 days of storage at 4 °C

Individual and Combined Effects of Extracellular Polymeric Substances and Whole Cell Components of Chlamydomonas reinhardtii on Silver Nanoparticle Synthesis and Stability

The fresh water microalga Chlamydomonas reinhardtii bioreduced Ag+ to silver nanoparticles (AgNPs) via three biosynthetic routes in a process that could be a more sustainable alternative to conventionally produced AgNPs. The AgNPs were synthesized in either the presence of whole cell cultures, an exopolysaccharide (EPS)-containing cell culture supernatant, or living cells that had been separated from the EPS-containing supernatant and then washed before being suspended again in fresh media. While AgNPs were produced by all three methods, the washed cultures had no supernatant-derived EPS and produced only unstable AgNPs, thus the supernatant-EPS was shown to be necessary to cap and stabilize the biogenic AgNPs. TEM images showed stable AgNPs were mostly spherical and showed a bimodal size distribution about the size ranges of 3.0 ± 1.3 nm and 19.2 ± 5.0 nm for whole cultures and 3.5 ± 0.6 nm and 17.4 ± 2.6 nm for EPS only. Moreover, selected area electron diffraction pattern of these AgNPs confirmed their polycrystalline nature. FTIR of the as-produced AgNPs identified polysaccharides, polyphenols and proteins were responsible for the observed differences in the AgNP stability, size and shape. Additionally, Raman spectroscopy indicated carboxylate and amine groups were bound to the AgNP surface

Microalgae: An outstanding tool in nanotechnology

Microalgae are microorganisms of choice in biotechnology thanks to their wide range of potential bio-applications, such as over-expression of pigments, bioremediation, biofuel production and toxicity studies. Recently, microalgae have been gaining attention from materials scientists worldwide owing to their versatility, and the ease and the variety of procedures through which the biosynthesis of valuable nanomaterials is implemented. This has resulted mainly in the production of nanoparticles made of noble metals, alloys, oxides and chalcogenides. Although still burgeoning, the biosynthesis of nanomaterials based on the exploitation of microalgal resources may thrive and witness dramatic developments in the near future

Sonochemical synthesis of porous gold nano- and micro-particles in a Rosette cell for drug delivery applications

We report the synthesis of gold nano- and micro-particles that relies on α-D-glucose (C6H12O6) as the reducer and stabilizer in a Rosette cell under 20 kHz ultrasound irradiation. The chemical and physical effects of ultrasonic irradiation on the synthesis were investigated. The results showed that an optimum pH is required for the formation of insoluble Au(0) particles. Upon irradiation, low pH yielded gold nanoparticles while high pH resulted in microparticles. The Au surface capping by α-D-glucose hydroxyl and carbonyl groups was confirmed by Fourier transform infrared (FT-IR) spectroscopy. X-ray diffraction (XRD) analysis indicated that the Au particles crystallize within the face-centered-cubic (FCC) cell lattice. Moreover, intermittent sonication reduced larger amounts of the Au precursor compared to the continuous mode. Furthermore, tuning sonication time and mode influences the particle size and porosity as characterized by scanning and transmission electron microscopy. Our results shed a new light into the importance of the experimental and ultrasound parameters in obtaining gold particles of desired features through sonochemistry