Preliminary Investigation Into Prospective Applications of Nanosilver, Produced Using Teff (Eragostris Tef) Flour Extract

doi:10.21203/rs.3.rs-2595604/v1

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Preliminary Investigation Into Prospective Applications of Nanosilver, Produced Using Teff (Eragostris Tef) Flour Extract

https://doi.org/10.21203/rs.3.rs-2595604/v1

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Silver-based nanomaterials have etched an indelible mark in multiple domains. The green synthesis of silver nanoparticles has received significant attention in comparison to the conventional use of toxic chemicals and reagents in the preparatory stages. In this milieu, the work reported here highlights the use of an aqueous extract of teff (Eragostris tef) flour to prepare silver nanoparticles (TSNPs). The compositional abundance of various phytochemicals, sunlight-induced bio-reduction of silver ions, and subsequent stabilization of the nanostructures by teff’s biomolecules were adroitly exploited. UV-visible spectroscopic analysis was employed to track the evolution of the TSNPs over time and their month-long storage stability. Exhibiting λ_max at around 426 nm and energy gap (as revealed by Tauc’s plot) of 2.26 eV, the silver nanomaterial was employed for methylene blue dye degradation (50% degradation in less than 50 min) and DPPH scavenging (IC₅₀ = 243.42 μL containing 410 μg of TSNPs), attesting their catalytic and anti-oxidant potency. On the other hand, anticoagulant action and a concentration-dependent variation were noted for radicle length post germination of Cicer arientinum seeds, treated with the TSNPs. The TSNPs could have profound implications in multiple domains.

Nanoscience

Materials Chemistry

Food Science & Technology

Biotechnology and Bioengineering

Silver nanoparticles

Teff

UV-visible spectroscopy

DPPH scavenging

Dye-decolorization

Anticoagulant

Phytocompatibility

Teff (Eragrostis tef), the annual cereal grass (family Poaceae), grown for its tiny nutritious seeds is native to Ethiopia and Eritrea and serves as a staple food crop to millions of people. The recognition that teff is gluten-free has instigated tremendous research impetus in the food science domain (Homem et al., 2022; Girija et al., 2022). Consequently, scientific documentation on the nutritional composition, processing quality, and health benefits of teff is pacing up. The existing literature suggests that teff is composed of complex carbohydrates with slowly digestible starch. Teff has a similar protein content to other more common cereals like wheat, but is relatively richer than the latter in the essential amino acid, lysine. It is also a good source of essential fatty acids, fiber, minerals (especially calcium and iron), and phytochemicals such as polyphenols and phytates (Baye, 2014; Zhu, 2018; Girija et al., 2022; Yisak et al., 2022).

Pertinently, the compositional abundance of such biomolecules may be suitably exploited as prospective bioreductant and stabilizing agent in the green synthesis of nanomaterials such as silver nanoparticles. Besides high energy consumption, most of the conventional processes for generation of silver nanoparticles are slow and costly (Kaabipour and Hemmati, 2021). Moreover, colloidal dispersions of silver nanoparticles (Ag NPs) in water or organic solvents have been prepared through chemical reduction using various reductants like sodium borohydride, trisodium citrate, ascorbate, and dimethyl formamide, which pose an environmental burden. Furthermore, the prepared silver nanoparticles are often polydisperse, unstable and requires additional capping agent (Kaabipour and Hemmati, 2021). Although there exist numerous reports on phyto-mediated (plant-based) synthesis of nanoparticles (Konwarh et al., 2011, Bachheti et al., 2019; Dogra et al., 2023), it is relevant to mention that till date there exists very few reports on the use of teff in the domain of nanotechnology. High temperature and toxic reagents like H₂SO₄ and HCl have been used to prepare nanosilica from teff straw (Bageru et al., 2017). Similarly, response surface methodology (RSM) has been resorted to prepare teff straw-based silica nanoparticles in a recent work (Amibo et al., 2022). Barring this, not much has been delved into the use of this extremely prospective bioresource for nanotechnological applications in accordance to the dictates of ‘green nanotechnology’ which focuses on the resorting to preparation of nanomaterials under ambient conditions, use of less toxic reagents and lesser energy expense besides water as the reaction medium.

Dictated by the afore-stated information, we intended to develop an environmentally benign approach using water as the solvent and exploitation of the various biomolecules in aqueous extract of teff for the preparation and stabilization of silver nanoparticles for a range of applications. This stems from the following hypothesis: Teff seeds (Baye, 2014) are a source of both bound and free polyphenols such as catechin, ferulic, rosmarinic, protocatechuic, p-coumaric acids as well phytosterols and vitamins. High abundance of proteins, carbohydrates, fibers, and other minerals has been documented as mentioned above. The compositional abundance of various polyphenolic compounds and biomacromolecules in the aqueous extract of teff powder could be bracketed together with its plausible bioreductive potency to generate silver nanoparticles from silver salt as well as endowing of electrostatic and steric stability to the nanoparticles. Furthermore, a high surface to volume ratio of the prepared nanoparticles is envisaged, implying a highly active surface, dictated by shape-size-surface chemistry accord could be exploited for multiple applications like catalysis etc.

2.1. Teff based aqueous extract mediated reduction

3 g white teff flour (procured from local market), suspended in 100 mL of double distilled water was subjected to overnight stirring over a magnetic stirrer (the ambient temperature was ~ 25 ^oC) and subsequent filtration through a muslin cloth to prepare teff based aqueous extract. Aqueous solution of silver nitrate (AgNO₃) (Abron Chemicals) was subjected to reduction using the teff extract, added drop by drop, followed by gentle manual swirling of the contents in conical flasks (replicates of three for various experimental conditions). The reaction was carried out in a) a dark-chamber (the ambient temperature was ~ 23 ^oC), b) under ambient light of the laboratory (the ambient temperature was ~ 24.5 ^oC) and c) under sunlight (the ambient temperature was ~ 30 ^oC), using the reducing agent and the silver nitrate solution, adjusted to different v/v ratios (1:1, 1:2. 2:1) while the variations of the molarity of the silver nitrate solution were 0.01, 0.02, and 0.03 M. Monitoring the rapidity of visible colour-change (indicating the reduction of the silver ions and consequent formation of nanoparticles) and UV-visible spectral analysis assisted in choosing the reaction-conditions (dictated by the objective of preparing nanoparticles with narrow-size distribution/ lesser polydispersity). These initial studies had dictated us to select the parameters of 2:1 (v/v) reducing agent: silver salt (0.01 M) solution for the preparation of the nanoparticles under sunlight. The results reported in this work are for the nanoparticles prepared under these parameters.

2.2. UV-visible spectroscopic characterization

The time-course dependent formation as well as a month-long dependent storage stability of the TSNPs were monitored using BIOCHROM Libra UV-visible double-beam spectrophotometer (scanning range: 300–700 nm, path length: 10 mm, bandwidth: 1 nm, single- cycle). Tauc’s plot was used to calculate the band gap energy of the TSNPs. All the graphs were plotted and analyzed using the OriginPro 8 software.

2.3. Dye decolourization test (to check the prospective application as catalyst)

1 mg of methylene blue (MB) (Abron Chemical) was dissolved in 100 mL of distilled water and its absorbance was monitored spectrophotometrically. The experiment was conducted by adding 1 mL of freshly prepared 0.2 M NaBH₄ ((SRL Chemical) to 25 mL aqueous solution of MB at room temperature (~ 25 ^oC). To this 1 mL of TSNPs was added and the reactants were vortexed. At a regular interval of time, 250 µL of the reaction mixture was withdrawn and diluted with 2.75 mL distilled water. The absorption of the mixture was monitored periodically using UV–visible spectrophotometer. The degradation was also monitored without the TSNPs. The reaction kinetics were evaluated by assuming the concentration of reactive dyes obeying the pseudo-first order reaction, where the integrated form is expressed as follows:

lnA_t/A₀ = - kt [1]

where, A₀ is the absorbance at zero time, A_t is the absorbance at time t, and k is the rate constant

2.4. DPPH scavenging test (to check the prospective application as an anti-oxidant)

Antioxidant activity of the TSNPs was measured by using the modified DPPH method as reported previously (Konwarh et al., 2011). To examine the anti-oxidant potency, 200 µL, 400 µL, 600 µL, 800 µL and 1000 µL of the TSNPs were mixed with 2 mL of 100 µM DPPH (1′-1′ diphenyl picryl-hydrazyle) (SRL Chemical) solution. The samples were vortexed for around 15 s and allowed to scavenge DPPH in dark for 30 min. The absorbance of the samples was measured at 517 nm. In all the cases, measurements were done in triplicates. The scavenging percentage was calculated using the formula:

DPPH scavenging = (A_C−A_s)/ A_c × 100 [2]

where A_C and A_S are absorption of blank DPPH and DPPH subjected to interact with the TSNPs at 517 nm, respectively.

2.5. Anticoagulant activity assessment

The experimental protocol to test the anticoagulant activity of the TSNPs was adopted from previously published report (Raja et al., 2015). Briefly, blood was collected from a healthy volunteer (post receipt of appropriate written consent) in different vials (C, S, T) without any anticoagulant by medical personnel, stationed at AASTU health-center. Immediately, TSNPs and teff extract was added to the tube S and T respectively at 0.5% (v/v) and anticoagulant activity of the samples was assessed. EDTA-tube (marked as E) served as positive control while vial C served as negative control. This experiment was approved by the M.Sc. Project Proposal Evaluation Committee, Department of Biotechnology, AASTU.

2.6. Effect on seed germination (Phytocompatibility assessment)

Assessing the phytotoxicity of nanoparticles (Konwarh et al., 2011) was our next objective. For this, Cicer arientinum (chick pea) seeds were procured from the local market. The average germination rates of the Cicer arientinum seeds were greater than 95% as revealed in our initial experimentation. Seeds were kept in a dry and dark place at room temperature before use. These were surface sterilized in 1:1 volume of 3% hydrogen peroxide (SRL Chemicals) for 10 min, followed by rinsing thrice with distilled water. About 15 seeds were then soaked in distilled water (control) or nanoparticle suspension, taken in different concentrations for about 12 h. The soaking process resulted in imbibition and consequent swelling in all the seeds. The water and the nanoparticles suspension were drained off post soaking. The seeds were then, placed (with sufficient distance between each seed) on a piece of cotton filter-cloth (10 cm x 10 cm), taken on a Petri dish. The Petri dishes were incubated in the dark for 3 days (room temperature: ~ 26.5 ⁰C). Number of seeds germinated for each treatment as well as the length of the emanating radicles were noted. The experiment was conducted in replicates of three and the results were expressed as mean ± standard deviation. In conjunction to the above tests, the seeds were also soaked and incubated in the aqueous teff extract.

3.1. Preparation and UV-visible spectroscopic analysis

In the present study, the first objective was to use the aqueous extract of teff flour to prepare the TSNPs. The UV-visible spectra supported the successful green-route mediated generation of the silver nanoparticles. The optical properties of nanoparticles are sensitive to size, shape, concentration, agglomeration state, and refractive index near the nanoparticle surface, therefore, UV-visible/IR spectroscopy serve as tools of immense pertinence in identifying and characterizing these materials. No absorption peak was observed in UV-visible spectrum of Ag⁺ solution before reduction (Fig. 1). This is attributed to Ag⁺ ions’ d¹⁰ configuration (Konwarh et al., 2011).

In our pursuit to go green, we had resorted to the use of sunlight as catalyst for the generation of the nanoparticles. Initially, we had tried to reduce the silver salt under a) dark condition and b) ambient light condition of the laboratory at room temperature. Although, there was visible colour change (colourless to yellow, indicative of the reduction of the silver salt), it took considerably a long time (more than an hour) in both the cases. For the photo-assisted preparation, the gradual generation of silver nanoparticles, using 2: 1 ratio of the reducing agent and silver nitrate solution, was indicated by the progressive increase (till 22 min) in the absorbance intensity at around 420– 430 nm in the UV-visible spectra. This is attributable to silver’s surface plasmon resonance (SPR) (Fig. 1). The optical absorption of metal nanoparticles has been described traditionally and classically by Mie theory (Mie, 1908) as the localized surface plasmon resonance (LSPR). The optical absorption of metal nanoparticles can be described quantum mechanically due to intra- band excitations of conduction electrons by photon, mimicking the interactions of light on metal surface via the photoelectric absorption and Compton scattering. It is to be noted that the plasmonic coupling of metal nanoparticles with light augment a number of useful optical phenomena that finds application in ultra-sensitive biomolecular detection and lab-on-a-chip sensors. Furthermore, we had also assessed the prospects of preparing nanoparticles using solutions of varied ratios of the reducing agent and the silver salt. However, the preparation using 1:1 and 1:2 ratios led to considerably long time and appearance of a broad SPR peak, at around 450 nm, indicating considerably large particle size and polydisperse nanoparticles. Thus, we had resorted to proceed with the nanoparticles, prepared using 2:1 reducing agent to silver salt solution.

The rapid generation of the silver nanoparticles under the influence of sunlight (photo- induced bioreduction) could possibly be due to photo-induced homolytic cleavage of the O-H bond of the various bioreductants (example, amino acids) to form hydrogen radical that eventually transfers its electron to silver ion (Ag⁺)-generating silver nanoparticle. The oxygen radical part attains stabilization in the solution through extended conjugation. On the other hand, the compositional abundance of the biopolymers like starch in the teff extract is expected to confer steric stabilization to the nanoparticles (Fig. 2).

Based on the UV-visible spectral analysis, we then proceeded with the calculation of the band gap in the prepared TSNPs. Nanoparticles are larger than individual atoms and molecules but are smaller than bulk solid. They obey neither absolute quantum chemistry nor laws of classical physics and have properties that differ markedly from those expected. The effect of size quantization particularly in metals and semiconductors is profound. The size of a nanoparticle is comparable to the de Broglie wavelength of its charge carriers (i.e., electrons and holes). Due to the spatial confinement of the charge carriers, the edge of the valence and conduction bands split into discrete, quantized, electronic levels (Fig. 3). These electronic levels are similar to those in atoms and molecules. The spacing of the electronic levels and the bandgap increases with decreasing particle size. This is because the electron hole pairs are now much closer together and the Coulombic interaction between them can no longer be neglected giving an overall higher kinetic energy. This increase in bandgap can be observed experimentally by the blue-shift in the absorption spectrum or sometimes even visually by the colour of the samples. A larger bandgap means that more energy is required to excite an electron from the valance band to the conduction band and hence light of a higher frequency and lower wavelength would be absorbed.

The maximum absorbance wavelength is associated with the conduction band energy according to quantum theory of metal nanoparticles (Gharibshahi et al., 2017). The conduction band energy of Ag nanoparticles can be calculated indirectly from the absorption spectra by the following Tauc’s equation:

(αhν)² = B(hν − E_cb) [3]

where α is the absorption coefficient, hv is the photon energy, E_cb is the conduction band energy, and B is a constant. According to this equation, by plotting the (αhν)² versus energy and extrapolation of the linear part of the curve to the energy axis, the conduction band energy of Ag nanoparticles can be obtained as shown in Fig. 4. The Tauc plot shows that the band gap for the TSNPs was 2.26 eV. This is quite high compared to bulk silver (0 eV) and in lines with previously reported values for nanoparticles (Banerjee et al., 2008; Yukna, 2007; Yang et al., 1995; Gharibshahi et al., 2017).

We had also resorted to the UV-visible spectroscopic studies to understand the storage stability of the nanoparticles under room temperature (~ 23–26 ^OC). In our case, post storage of the TSNPs for a month, a slight shift of SPR peak (from 426 nm to 430 nm) was observed, however, the peak width remained the same (Fig. 5). The biomolecules present in the teff flour extract were envisaged to act both as the reducing and stabilizing agent, thereby preventing excess aggregation of the nanoparticles. It is pertinent to note that scattering from a sample is typically highly sensitive to the aggregation state of the sample, with scattering contribution augmenting with the increase in the aggregation of the particles.

The optical attributes of nanoparticles may be altered when particles aggregate and the conduction electrons (as in silver nanoparticles) near each particle surface become delocalized and are shared amidst the neighbouring particles. Occurrence of such events, leads to shifting of the SPR to lower energies, causing the absorption and scattering peaks to red-shift to longer wavelengths.

(Due to inaccessibility of other characterization tools (DLS, zeta potential, HRTEM etc.) during the execution of this B.Sc. project work in Ethiopia, we could not present a complete landscape of the physicochemical characterization of the nanoparticles. Nevertheless, the UV-visible spectroscopic analysis attested or at least indicated the successful preparation of the TSNPs. Thus, we proceeded with our investigation into their prospective applications and preliminary delving of their action at the bio-interface.)

3.2. Prospective Applications and nanobiointerfacial interactions

3.2.1. Dye decolourization (application as catalyst)

Use of various dyes in paper, plastic, leather, food, cosmetic and textile industries have led to multiple issues including skin irritation, liver, kidney damage as well as the widespread application could prove detrimental to the central nervous system and even result in mutation and cancer (Latha et al., 2019). The need of the hour is to economically and safely mitigate the various synthetic dyes in the environment. Amongst others, techniques such as carbon sorption, redox treatment, phyco-remediation, UV-light mediated degradation etc. have been explored (Latha et al., 2019). Use of nanoparticles for dye-abatement (Fairuzi et al., 2018) has been proposed as a rapid, low-cost methodology (without the formation of polycyclic products and oxidation of pollutants). In this regard, we had resorted to test the efficacy of the TSNPs for decolorization of methylene blue (MB), a common cationic dye. We found that the TSNPs functioned as an efficient catalyst (Fig. 6 [A]) in decolourizing aqueous MB in presence of NaBH₄. The decrease of absorbance at λ_max (664 nm) of MB with time was followed spectrophotometrically. The bar diagram depicts the percentage of MB degradation with exposure time (Fig. 6 [B]). The degradation-percentage (%) of the dye was calculated by using the formula:

Dye degradation (%) = (A₀ - A/A₀) x 100 [4]

where, A₀ is the initial concentration of MB solution and A is the concentration after t minutes of reaction.

In the absence of the nanocatalyst, the dye-decolourization was found to the negligible. Addition of the nanoparticles resulted in more than 50% decolourization in less than 20 min. The kinetic data were fitted to first order rate equations value (Fig. 6 [C]). The nanoparticles are envisaged to act as electron relay and initiate shifting of electron from BH⁴⁻ ion (donor B₂H₄/BH⁴⁻) to acceptor (acceptor LMB/MB), leading to reduction of the dye. Concomitant adsorption of the BH⁴⁻ ion on the surface of the nanoparticles is followed by electron transfer from the BH⁴⁻ ion into the dye via the the nanoparticles (Kumari et al., 2015).

3.2.2. DPPH scavenging (application as anti-oxidant)

The free radical scavenging of the TSNPs was evaluated in the present study. The percent scavenging of DPPH increased almost linearly with the increase in the concentration of the nanoparticles in the test samples. From the above plot, 50% DPPH scavenging was calculated for 243.42 µL of the TSNPs. Previously, we had reported DPPH based antioxidant activity of Colocasia esculenta based silver nanoparticles (Baruah et al., 2013). Similarly, we had also reported free radical scavenging using orange peel-based silver nanoparticles (Konwarh et al., 2011). Numerous anti-oxidants of the orange peel (pooled into the system during preparation and consequently surface-adsorbed) were proposed to act synergistically in that system. Furthermore, with a high surface area to volume ratio and an ambient electrostatic field with anti-oxidant bio-moieties on the surface, these silver nanoparticles were envisaged to develop a high tendency to interact with and reduce DPPH like species. In this work, although, a higher volume was required for our sample (in comparison to as reported by Konwarh et al. (2011), possibly due to lesser abundance of polyphenolic compounds in teff compared to orange peel) to display 50% scavenging, nevertheless, it raises the prospects of incorporating the prepared nanoparticles for developing of nanocomposite packaging materials with the facet of free radical scavenging. The nano-chemistry involved in this free radical scavenging attribute of the nanoparticles needs further investigation. However, this attribute of the TSNPs could have profound impact in the domain of nanomedicine as well.

3.2.3. Anticoagulant activity

Assessment of hemocompatibility of silver nanoparticles has been a prime focus in the domain of nanotoxicity. Amongst others, Krajewski et al. (2013) pointed out that silver nanoparticles, on contact with blood could modulate the coagulation cascade (the sequence of various biochemical events involved in coagulation) or the inflammatory response. Shrivastava et al. (2009) had proved the potential of antiplatelet and antithrombic effect of silver nanoparticles and concluded that the silver nanoparticles have innate antiplatelet property which prevents integrin-mediated platelet responses. Kim et al. (2013) demonstrated that the anticoagulant property of heparin was enhanced by the addition of earthworm extract mediated gold nanoparticles. In our study, the anticoagulant property of TSNPs was examined by the addition of TSNPs to freshly collected blood (Fig. 8). Blood clot was observed in the tube without any anti-coagulant. Blood collected in the EDTA-tube served as the control. On the other hand, no clot with prolonged stability was observed for the blood collected in vials, supplemented with the TSNPs. This confirmed that the TSNPs could serve as blood anticoagulant. This is in accordance with the results obtained by Jeyaraj et al., (2013) and Raja et al., (2015). However, the effect of the nanoparticles on the morphology, population and functionality of the other blood cells must be studied in details.

3.2.4. Effect on seed germination (Phytocompatibility assessment)

Exotics like nanoparticles can penetrate via the cell wall, primarily composed of polymeric carbohydrates, prior to membrane invagination in plant cells (Konwarh et al., 2011) and can lead to alteration in various physiological activities of the plants. In this backdrop, investigation of the modulation of the phyto-physiology, assessed in terms of seed germination due to the plausible penetration of the TSNPs was one of the propositions in this work (Fig. 9). Plant seeds showing emergence of radicle or cotyledon coming out of the seed coat were recorded as being germinated in the present experiment.

In our experiment, it was observed that the average germination rate remained unchanged for the treated seeds with respect to the control. However, significant difference was noted for the average radicle length post four days of incubation (Table 1).

Table 1

*Phytotoxicity assessment of the TSNPs - on germination and radicle length of Cicer arientinum*
Sample	Average germination rate (%) of the seeds	Average radicle length (cm) post four days of incubation
Control (Sample code: C)	98%	2.1 ± 0.3
TSNPs (25 µL in 50 mL distilled water, resulting in final concentration of 0.84 µg/mL TSNPs) (Sample code: 1)	100%	2.3 ± 0.2
TSNPs (100 µL in 50 mL distilled water, resulting in final concentration of 3.36 µg/mL TSNPs) (Sample code: 2)	100%	3.6 ± 0.3
TSNPs (200 µL in 50 mL distilled water, resulting in final concentration of 6.72 µg/mL TSNPs) (Sample code: 3)	98%	4 ± 0.2
TSNPs (300 µL in 50 mL distilled water, resulting in final concentration of 10.08 µg/mL TSNPs) (Sample code: 4)	99%	4.4 ± 0.2
TSNPs (400 µL in 50 mL distilled water, resulting in final concentration of 13.44 µg/mL TSNPs) (Sample code: 5)	100%	4.6 ± 0.2
TSNPs (500 µL in 50 mL distilled water, resulting in final concentration of 16.8 µg/mL TSNPs) (Sample code: 6)	99%	4.4 ± 0.1

There exist contrasting reports on the phytomodulatory effects of different nanoparticles. Shi et al., 2019 had reported the germination-inhibitory effect of gold nanoparticles on mung-bean (Phaseolus radiates). With increasing concentration of gold nanoparticles, chlorophyll and nitrogen contents in leaves decreased, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities in both shoot and root increased first and then decreased, while the malondialdehyde (MDA) contents increased. On the other hand, at the end of 60 days of cultivation, Timoteo et al., 2019 documented that the in vitro germination of Physalis peruviana L. is not affected by the presence of AgNPs and that at low concentrations (0.385 mg L ^− 1) it can promote an increase in seedlings biomass. However, higher concentration (15.4 mg L^− 1) was found to reduce the seedling size and root system, but no changes were observed in the seedlings’ antioxidant metabolism and anatomy. On similar veins, various tested concentrations of AgNPs (10, 20, 40 ppm) were found to promote both the shoot and root growth which was evident from the increased length and biomass of rice seedlings (Gupta et al., 2018). Exposure to AgNPs was also found to significantly increase the chlorophyll a and carotenoid contents. The molecular basis of these observation needs further investigation. Our preliminary investigation has shown that TSNPs do have a phytophysiology modulatory effect, as reflected in the differential radicle length. It is to be noted that the aqueous teff extract did not influence the seed-germination negatively and the results were in lines parallel to that of the control. Besides delving into the effect on the shoot length and survival percentage of the seedlings post transplantation, a number of questions have to addressed in future studies: Will the effect of the prepared samples and the consequences of the internalization and bio-distribution be same for both dicot and monocot plants? Does the penetration of Ag NPs into the root cells help the plants to ward off soil pathogens or lead to the loss of beneficial microflora peripheral to the roots? Furthermore, investigation is needed to clarify the contribution of dissolution to the toxicity of these metal-based nanoparticles.

This work mirrors the successful sunlight-induced rapid and efficient biogenic synthesis of silver nanoparticles using aqueous teff powder extract (without any additional chemical additive), for multiple applications. However, the complete physicochemical attributes of the nanoparticles have not been investigated. The work reported in this work brings the fact to light that a common raw material of the Ethiopian food- delicacy can be useful even in the domain of nanotechnology. The well-stabilized silver nanoparticles synthesized under the ambient conditions shows tremendous potential for applications in a number of niches. These nanoparticles endowed with the attributes of free radical scavenging, catalysis and anticoagulant potency as well as phytocompatibility may be exploited for various biomedical, agricultural and industrial applications. Furthermore, probing into the nanobiointerfacial actions at various levels could be the next level of study. To cite for evidence, effect of the silver nanoparticles on PCR amplification of genes of interest, understanding antimicrobial potency as well as in vivo effects could be the investigated.

ACKNOWLEDGMENT

A note of gratitude is forwarded to Addis Ababa Science and Technology University (AASTU), Ethiopia for supporting this B.Sc. project financially. The incessant support of the M.Sc. students (Alazar Yeshitla, Bethelehem Getachew, Simatsidk Haregu, Setegn Haile and Abate Ayele) merits special mention. A bouquet of gratefulness is extended to sister Semeret G/Sellasie for assisting in the anti-coagulant test at AASTU health centre.

CONFLICT OF INTEREST

The authors declare no conflict of interest

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Preliminary Investigation Into Prospective Applications of Nanosilver, Produced Using Teff (Eragostris Tef) Flour Extract

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Abstract

Figures

1. Introduction

2. Material And Methods

2.1. Teff based aqueous extract mediated reduction

2.2. UV-visible spectroscopic characterization

2.3. Dye decolourization test (to check the prospective application as catalyst)

2.4. DPPH scavenging test (to check the prospective application as an anti-oxidant)

2.5. Anticoagulant activity assessment

2.6. Effect on seed germination (Phytocompatibility assessment)

3. Results And Discussion

3.1. Preparation and UV-visible spectroscopic analysis

3.2. Prospective Applications and nanobiointerfacial interactions

3.2.1. Dye decolourization (application as catalyst)

3.2.2. DPPH scavenging (application as anti-oxidant)

3.2.3. Anticoagulant activity

3.2.4. Effect on seed germination (Phytocompatibility assessment)

4. Conclusion

Declarations

References

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