In this study, zinc oxide nanoparticles (ZnO NPs) in powder and in thin film were successfully synthesized first time using an eco-friendly, simple and cost effective green synthesis method mediated by corn husk (Zea mays) extract as an effective chelating agent, and zinc nitrate hexahydrate as precursor. Diverse characterizations techniques such as High Resolution – Scanning Electron Microscopy (HR-SEM), Energy Dispersive X- rays Spectroscopy (EDS), X-Rays Diffraction (XRD), and UV – Vis – NIR spectroscopy as well as Photoluminescence (PL) were investigated to confirm ZnO NPs nature. For the ZnO NPs powder, highly crystalline ZnO nanoparticles (ZnO NPs) annealed at 500°C which are 48.635 nm in particles size were characterised by HR-SEM and XRD analysis. The structure morphology and the constituents of the resultant ZnO powder were investigated respectively by HR-SEM and EDS. UV – Visible spectroscopy analysis was investigated on the optical band gap of ZnO NPs, which was calculated to be 3.31 eV. This result indicates that ZnO NPs can be used in metal oxide semiconductor-based devices. For the ZnO NPs thin film, XRD patterns of hexagonal wurtzite structure with c/a ratio about of 1.60 and μ – parameter of 0.38 were obtained. PL measurements showed a broad emission band in the 380 – 800 nm range, centred at 481 nm. ZnO NPs thin film yielded relatively more intense photoluminescence spectra than the ZnO NPs powder. The intrinsic point defects and defect level transitions responsible for the broad emission are discussed.

Bio-reduction agents are being explored to synthesised nanoparticles to minimize the effects of toxic chemicals. The present study was focused on green approach for the synthesis of zinc oxide nanoparticles using aqueous seeds extract of Papaver somniferum. The biosynthesised ZnO NPs (27.8nm) were characterized by using of spectroscopy and microscopy instruments. The surface morphology and the structural analysis confirms the formation of hexagonal nanostructure and a pure zincite nature of ZnO nanoparticles (NPs) respectively. The EDS spectrum confirms pure ZnO NPs were synthesised. From electrochemical properties, the CV indicates both anodic and cathodic sweep are quasi-reversible properties whose intensity increases with the scan rates. The bode plot shows the maximum angles of 74o which is an indication of a higher conductivity of ZnO NPs.

Most of the photochemical activity of bacterial photosynthetic apparatuses occurs in the reaction center, a transmembrane protein complex which converts photons into charge-separated states across the membrane with a quantum yield close to unity, fuelling the metabolism of the organism. Integrating the reaction center from the bacterium Rhodobacter sphaeroides onto electroactive surfaces, it is possible to technologically exploit the efficiency of this natural machinery to generate a photovoltage upon Near Infra-Red illumination, which can be used in electronic architectures working in the electrolytic environment such as electrolyte-gated organic transistors and bio-photonic power cells. Here, photovoltage generation in reaction center-based bio-hybrid architectures is investigated by means of chronopotentiometry, isolating the contribution of the functionalisation layers and defining novel surface functionalization strategies for photovoltage tuning.

Enzymes can be a renewable source of catalytic agents and thus be interesting for sustainable approaches to create and modify functional materials. Here, thin hydrogel layers were prepared as thin coatings on hard substrates by immobilized horseradish peroxidase. Hydrophilic 4-arm star shaped telechelics from oligo(ethylene glycol) bearing on average 55% end groups derived from aromatic amino acids served as monomers and enzymatic substrates. Shifts of the contact angle from 84° to 62° for the wetting process and of zeta potential towards the neutral range illustrated an alteration of physicochemical properties of the model surfaces by a hydrophilic shielding. Time-of-flight secondary ion mass spectrometry (ToF-SIMS), quartz crystal microbalance and atomic force microscopy (AFM) experiments enabled the qualitative and quantitative proof of hydrogel deposition at the interface with thicknesses in the medium nanometer size range. Conceptually, as the immobilized enzyme becomes entrapped in the hydrogel and the crosslinking mechanism bases on a radical reaction after enzymatic activation of the monomers with a limited diffusivity and lifetime, the formed network material can be assumed to be inhomogeneous on the molecular level. On the macroscale, however, relative homogeneity of the coating was observed via ToF-SIMS and AFM mapping. As an exemplary functional evaluation in view of bioanalytical applications, the thrombogenicity of the coating was studied in static tests with human blood from several donors. In the future, this “coating-from” approach may be explored for cell culture substrate coatings, for protein/biofilm repellence in technical applications, or in bioanalytical devices.

This work reports on the synthesis and the main physical and chemical properties of ZnO nanoparticles synthesized by an entirely green Bio-physical-chemical process using natural dye extract from Adansonia digitata leaves as an efficient reduction/oxidizing agent. Their structural and surfaces properties by electron microscopy, X-rays diffraction, Raman and TGA, as well as gas adsorption analysis are reported.

The effects of Ag nanoparticles on microorganisms and the antimicrobial mechanism has recently been validated for different microbiological strains, as well as their cytotoxic effect in in vitro cellular models. In this work we report the synthesis of Ag nanoparticles using the extract of Eichhornia crassipes as reducing agent, and evaluated its antimicrobial activity with Escherichia coli. The morphology, size and inhibition properties of the nanoparticles as a function of the reduction time in the chemical synthesis were analyzed. The characterization was carried out by UV-Vis spectrophotometry and transmission electron microscopy. Nanoparticles with average diameters of 40 nm ± 10 nm were obtained and their antimicrobial activity with higher inhibition in Escherichia coli was recorded with the nanoparticle samples obtained at 120 min. These results suggest that Ag nanoparticles can be used as effective growth inhibitors in various microorganisms, making them applicable to various medical devices and antimicrobial control systems by modifying their concentration.

The chemical decoration of biosilica shells (frustules) from microalgae with several classes of organic molecules is a convenient, scalable biotechnological route to silica nanostructures with applications ranging from photonics to biomedicine. Here we report for the first time the in vivo staining of Thalassiosira weissflogii diatoms with a two photon red emitting triphenylamine-based fluorescent dye bearing a triethoxysilyl functional group (tPhA-Silane). In vivo staining of the cells has been investigated with confocal microscopy and hybrid silica structures comprising the dye embedded into the biosilica have been isolated by proper protocols able to remove the organic protoplasm.

In this contribution we report on the synthesis of n-type Bismuth vanadate (BiVO4) nanorods prepared via the use of aqueous extracts of Callistemon viminalis. X-ray diffraction analysis confirmed the formation of highly crystalline monoclinic BiVO4 nanorods post annealing of the Bismuth vanadate precursor powder at 500 °C. Scanning Electron Microscopy and High Resolution Transmission Electron Microscopy showed that BiVO4 nanorods have a high aspect ratio. Using UV-Vis absorption measurements the optical band gap of the nanorods is estimated to be 2.4 eV which makes the bio-synthesized BiVO4 powder a good candidate for sunlight driven photocatalysis.

Extracellular Matrix (ECM), a natural biomaterials, have recently garnered attention in tissue engineering for their high degree of cell proliferative capacity, biocompatibility, biodegradability, and tenability in the body. Decellularization process offers a unique approach for fabricating ECM-based natural scaffold for tissue engineering application by removing intracellular contents in a tissue that could cause any adverse host responses. The effects of Supercritical carbon dioxide (Sc-CO2) treatment on the histological and biochemical properties of the decellularized extracellular matrix (de-ECM) were evaluated and compared with de-ECM from conventional decellularization process to see if it offers significantly reduced treatment times, complete decellularization, and well preserved extracellular matrix structure. The study has shown that a novel method of using supercritical fluid extraction system indeed removed all unnecessary residues and only leaving ECM. The potential of Sc-CO2 de-ECM progressed as a promising approach in tissue repair and regeneration.

Hydrostatic pressure is an essential physical parameter for studying the structure, dynamics, phase behavior, and free-energy landscape of biomolecular systems. High pressure is an important feature of certain natural environments, and pressure effects on biosystems are of increasing interest for biotechnological applications. Here, we focus on the pressure-dependent activity of enzymes in different environments, from bulk solution to various interfaces. Results were obtained using a high-pressure stopped-flow methodology and high-pressure total internal reflection fluorescence spectroscopy. We highlight that pressure can enhance enzyme activity in various environments, contributing to the fundamental understanding of life under extreme conditions, and elucidate new ways to optimize biotechnological processes.

A high-throughput crystallographic investigation on several crystals of photosynthetic reaction center covalently bound to an ad-hoc synthesized artificial antenna (AE600) is presented. The investigation did not show a preferential binding site of the antenna molecule AE600 to the reaction center in the solid phase. An accurate crystallographic study allowed identifying a lysine residue sitting on periplasmic side of the protein as one of the bioconjugation sites. The residue sits on subunit M of the protein, in close proximity to the bacteriochlorophylls of the reaction center involved in the light absorption and conversion processes. Distances obtained from the crystallographic structure confirm that energy transfer between the antenna and the protein proceed with the Förster resonance mechanism.

Organic biological hybrid systems, accessible by covalent functionalization of photosynthetic proteins with molecular antennas, represent a promising novelty to enhance natural photosynthesis. In this paper, we present the successful bioconjugation of a commercial fluorophore, fluorescein isothiocyanate (FITC), to the photosynthetic reaction center RC from the bacterium Rhodobacter sphaeroides strain R26. The resulting hybrid outperforms the pristine protein in hole-electron couple generation yield, exclusively at wavelengths where the fluorophore absorbs while the protein does not.

Covalent functionalization of reduced graphene oxide (rGO) with the photosynthetic reaction center (RC) from Rhodobacter sphaeroides R26 via click chemistry reaction has been performed. The hybrid system was characterized by flash photolysis and infrared spectroscopy and the RC was found to retain its photoactivity and structural integrity. The strategy is applicable for the fabrication of hybrid bio-electronic devices capable of absorbing and converting solar energy.

Differences on physicochemical properties of poly(pentadecanolide), PPDL, synthesized by enzymatic ring opening polymerization at two different temperatures, 70 C and 90 C, using Novozyme-430 were assessed. PPDL synthesized at 90°C presents lower molecular weight and crystallinity than the one prepared at 70°C. It was detected by FTIR that PPDL synthesized at 90°C presents a large amorphous phase with more terminal OH groups. A difference in the melting and crystallization behavior was detected by differential scanning calorimetry, DSC, where the melting of the PPDL synthesized at 90°C presents multiple melting and crystallization events at lower temperature than those exhibit by PPDL synthesized at 70°C which presents a well defined single melting and crystallization event. The differences in melting behavior are attributed to the presence of a larger amorphous phase in PPDL synthesized at 90°C due to increased number of terminal OH groups that disrupt the crystalline structure. Thermal stability is also higher in PPDL synthesized at 70°C since the onset of decomposition starts 50°C above that observed in PPDL obtained at 70°C.

The formation of injectable implants in the presence of cells or solutes has previously been conceptualized to be based on the selectivity of bioorthogonal chemical reactions. As an alternative approach, hydrogel network synthesis by enzymatic reactions with a typically high inherent substrate specificity and low toxicity have been repeatedly proposed, e.g. using commercial mushroom tyrosinase (MTyr), which specifically catalyzes phenol oxidation. In this study, it should be explored whether MTyr is compatible with therapeutic peptides that may be delivered from such hydrogels in the future. Based on the specificity of MTyr to phenol residues, no modification of peptides lacking the amino acid tyrosine would be expected. One example of such peptides is gramicidin S (GS), a potent antimicrobial peptide. However, when GS was incubated with commercial MTyr, peptide degradation occurred as observed by HPLC analysis. Several fragments of the peptide were detected by MALDI-TOF. Contamination of MTyr with peptidases was proven as the source of undesired peptide cleavage, which needs to be considered when preparing enzymatically crosslinked hydrogels for biomedical applications.

Silver nanoparticle (AgNP) is one of the elegant material because its uses in various fields. In this study, AgNPs have been prepared by using Peltophorum pterocarpum (PP) flower extract as reducing and capping agent and aqueous silver nitrate (aq.AgNO3) as silver precursor. The synthesized nanoparticles were characterized using Ultra Violet - Visible (UV-Vis) spectroscopy, High Resolution Transmission Electron Microscope (HR-TEM) and Fourier Transform Infrared Spectroscopy (FT-IR), which reveals the formation of nanosized particles. The UV-Vis spectrum shows an absorption peak around 430nm. HR-TEM images of AgNPs with clear morphology and well dispersed prepared AgNPs.

Copper nanoparticles are synthesized successfully through chemical reduction of different copper salts stabilized by Ocimum Sanctum Leaf extract, a natural biopolymer. The resulting copper nanoparticles are characterized by using UV Visible Absorption Spectrometer, X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Small Angle X-ray Scattering (SAXS) and Fourier Transform Infrared Spectroscopy (FTIR) experiments. Copper nanoparticles prepared display an absorption peak at around 558 nm. X-ray diffraction analysis shows that the particles are FCC crystalline. SEM and TEM display the formation of copper nanoparticles with an average size of 10 nm. The SAXS studies demonstrate the formation of spherical nanoparticles with bimodal size distribution. The FTIR spectrum analysis has confirmed the presence of functional groups of stabilizer Ocimum Sanctum leaf extract in capping the copper nanoparticles.

The covalent functionalization of photosynthetic proteins with properly tailored organic molecular antennas represents a powerful approach to build a new generation of hybrid systems capable of exploiting solar energy. In this paper the strategy for the synthesis of the tailored aryleneethynylene organic fluorophore (AE) properly designed to act as light harvesting antenna is presented along with its successful bioconjugation to the photosynthetic reaction center RC from the bacterium Rhodobacter sphaeroides .

Watson and Crick’s discovery of the structure of DNA in 1953 and the near-simultaneous advent of the first silicon transistor in 1954 spurred parallel historic advances over the following decades in molecular biology and materials technology. As these two expansive fields of research have progressed, important areas of overlap have included the extensive use of materials innovations in biological research, such as in microscopy and measurement systems, while materials research has benefited from efforts to mimic design principles utilized in nature. Until relatively recently, however, the molecular mechanisms that underpin nature’s biological orchestra have remained largely outside the purview of materials research. Now, with new abilities to harness and modify biomolecular and cellular systems, evidence is mounting that biology can be fruitfully utilized to directly engineer technological materials. This article aims to highlight the importance of DNA-driven routes to new materials while providing a brief overview of the genetic engineering platforms that make these routes possible. Emphasis is placed on the fact that it is now possible to genetically evolve materials technologies in a manner that mimics the genetic evolution of biominerals in nature.

The one pot-synthesis and use of monolithic biohybrid foams in a continuous flow device reported inhere presents the advantages of covalent stabilization of the enzymes, together with a low steric hindrance between proteins and substrates, an optimized mass transport due to the interconnected macroporous network and a rather simplicity in regard of the column in-situ synthetic path. Those features, concerning transesterification (biodiesel production) enzyme- based catalyzed reaction, provide high enzymatic activity addressed with bio-hybrid catalysts bearing unprecedented endurance of continuous catalysis for a two months period of time.