Green nanotechnology is now accepted as an environmentally friendly and cost-effective advance with various biomedical applications. The cyanobacterium Synechocystis sp. is a unicellular spherical cyanobacterium with photo- and hetero-trophic capabilities. This study investigates the ability of this cyanobacterial species to produce silver nanoparticles (AgNPs) and the wound-healing properties of the produced nanoparticles in diabetic animals. Methods: UV–visible and FT-IR spectroscopy and and electron microscopy techniques investigated AgNPs’ producibility by Synechocystis sp. when supplemented with silver ion source. The produced AgNPs were evaluated for their antimicrobial, anti-oxidative, anti-inflammatory, and diabetic wound healing along with their angiogenesis potential. Results: The cyanobacterium biosynthesized spherical AgNPs with a diameter range of 10 to 35 nm. The produced AgNPs exhibited wound-healing properties verified with increased contraction percentage, tensile strength and hydroxyproline level in incision diabetic wounded animals. AgNPs treatment decreased epithelialization period, amplified the wound closure percentage, and elevated collagen, hydroxyproline and hexosamine contents, which improved angiogenesis factors’ contents (HIF-1α, TGF-β1 and VEGF) in excision wound models. AgNPs intensified catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities, and glutathione (GSH) and nitric oxide content and reduced malondialdehyde (MDA) level. IL-1β, IL-6, TNF-α, and NF-κB (the inflammatory mediators) were decreased with AgNPs’ topical application. Conclusion: Biosynthesized AgNPs via Synechocystis sp. exhibited antimicrobial, anti-oxidative, anti-inflammatory, and angiogenesis promoting effects in diabetic wounded animals.

To the best of our knowledge, cyanobacterial strains from the Arabian Gulf have never been investigated with respect to their potential for nanoparticle production. Lyngbya majuscula was isolated from the AlOqair area, Al-Ahsa Government, Eastern Province, Kingdom of Saudi Arabia. The cyanobacterium was initially incubated with 1500 mg/mL of HAuCl₄ for two days. The blue-green strain turned purple, which indicated the intracellular formation of gold nanoparticles. Prolonged incubation for over two months triggered the extracellular production of nanogold particles. UV-visible spectroscopy measurements indicated the presence of a resonance plasmon band at ~535 nm, whereas electron microscopy scanning indicated the presence of gold nanoparticles with an average diameter of 41.7 ± 0.2 nm. The antioxidant and anti-myocardial infarction activities of the cyanobacterial extract, the gold nanoparticle solution, and a combination of both were investigated in animal models. Isoproterenol (100 mg/kg, SC (sub cutaneous)) was injected into experimental rats for three days to induce a state of myocardial infarction; then the animals were given cyanobacterial extract (200 mg/kg/day, IP (intra peritoneal)), gold nanoparticles (200 mg/kg/day, IP), ora mixture of both for 14 days. Cardiac biomarkers, electrocardiogram (ECG), blood pressure, and antioxidant enzymes were determined as indicators of myocardial infarction. The results showed that isoproterenol elevates ST and QT segments and increases heart rate and serum activities of creatine phosphokinase (CPK), creatine kinase-myocardial bound (CP-MB), and cardiac troponin T (cTnT). It also reduces heart tissue content of glutathione peroxidase (GRx) and superoxide dismutase (SOD), and the arterial pressure indices of systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and mean arterial pressure (MAP). Gold nanoparticles alone or in combination with cyanobacterial extract produced an inhibitory effect on isoproterenol-induced changes in serum cardiac injury markers, ECG, arterial pressure indices, and antioxidant capabilities of the heart.

Chlorella vulgaris from Al-Ahsa, KSA was proved to be an active silver and gold nanoparticle producer. Nanogold and nanosilver particles were characterized using UV-visible spectroscopy, Fourier-transform infrared spectroscopy, and scanning electronmicroscopy. Both nanoparticles were used in the antimicrobial bioassay. The two nanoparticles showed antibacterial activities, with the silver nanoparticles being the most effective. To investigate the argumentative nature of their biosynthesis (i.e., whether it is a biotic or abiotic process), we isolated total ribonucleic acid RNA as an indicator of vitality. RNA was completely absent in samples taken after one week of incubation with silver nitrate and even after one or two days. However, successful extraction was only achievable in samples taken after incubation for one and four hours with silver nitrate. Most importantly, the gel image showed recognizable shearing of the nucleic acid after 4 h as compared to the control. An assumption can be drawn that the synthesis of nanoparticles may start biotically by the action of enzyme(s) and abiotically by action of reducing entities. Nonetheless, with prolonged incubation, excessive nanoparticle accumulation can be deadly. Hence, their synthesis continues abiotically. From the RNA banding profile, we suggest that nanosilver production starts both biotically and abiotically in the first few hours of incubation and then continues abiotically. Nanosilver particles proved to have more of an antimicrobial impact than nanogold and hence are recommended for different applications as antibacterial agents.

Background: Chemical plastics cause global environmental pollution and can take hundreds of years to be naturally removed from the environment; therefore, eco-friendly alternatives are sought. In that regard, marine algae are considered a promising source for bioplastics. However, macroscopic algae from the Arabian Gulf, despite being produced in massive quantities every year, have never been exploited for this purpose. Moreover, most of the available studies have been primarily based on the extraction of specific components of algae to prepare algal bioplastics, which is laborious and costly and does not allow the use of all biological products of algae. Therefore, the present study aimed at generating biodegradable bioplastic from the whole biomass of a marine green macroscopic alga from the Arabian Gulf, Saudi Arabia, using a simplified method.Materials and methods: The identity of this green alga was investigated using both morphological characteristics and molecular analysis. Different treatments from the literature were initially tried to yield a bioplastic blend, but did not work. The successful method included drying the green macroalgal biomass and grinding it until it becomes a fine powder, followed by sieving. The powder was placed in 100 ml water with other reagents and then autoclaved. The resulting mixture was further treated with glycerin. Several reagents were tested, but successful treatment was achieved with the combination of the ground seeds of Plantago ovata and the chemical plasticizer polyethylene glycol (PEG; M_w = 3,350). The algal biocomposite was effective in forming a tensile polymer whose properties were further enhanced by adding glycerin 1 day after making the blend. Spectrophotometric, thermal, and mechanical analyses of the blend were conducted, including Fourier transform infrared (FTIR) spectroscopy, dynamic mechanical analysis (DMA) for the mechanical properties, and thermogravimetric analysis (TGA) for thermal stability. The biodegradability of the blend was also examined in sandy soil for 3 months.Results: The green alga was identified as macroscopic green alga Ulva sp., which was confirmed by both morphological and molecular analyses. The combination of a plant-based plasticizer and algal biomass formed a polymer with excellent tensile properties and thermal stability. FTIR confirmed the formation of a starch-based blend whose functional groups, O–H, C–H, C=O, and C–O, indicate the formation of a starch bioplastic derived from both starch and cellulose in the green alga and in P. ovata. Biodegradability was proven as the blend lost nearly 40% of its biomass after the soil burial test.Discussion: Ulva sp. is a marine alga that is widespread in marine habitats. This particular alga is highly rich in carbohydrates including cellulose, hemicelluloses, starch, and ulvan, among other carbohydrates that constitute the major part of its dry weight. This alga and the plant plasticizer both contain starch as reserve food material. Both natural polysaccharides are excellent precursors for the formation of bioplastics and are completely biodegradable by soil microorganisms. PEG is also biodegradable by bacterial action. Therefore, the whole blend is not only biodegradable but also has suitable tensile strength and thermal stability.Conclusion: The present study describes an eco-friendly novel method that is mostly based on using the whole algal biomass in addition to a natural plant material as a plasticizer, thereby providing a sustainable blend for the manufacturing of bioplastics for use in a number of applications, including agriculture, as it is biodegradable and can be utilized for composting and fertilizing plants.

The harmful effect of salinity stress on crops needs to be mitigated. Therefore, the application of microbial inoculum in combination with nanomaterials and methyl salicylate was investigated. Initially, different seeds were exposed to salinity levels treated with variable microbial treatments using different modes of applications. The microbial treatments included application of cyanobacterial strain Cyanothece sp. and the rhizobacterium Enterobacter cloacae, alone or in combination with one another, and a final treatment using combined microbial inoculum supplied with methyl salicylate. Later, different nanomaterials were used, namely, graphene, graphene oxide, and carbon nanotubes in combination with biofertilizers on the highest salinity level. The nanomaterial with microbial treatment and methyl salicylate were applied partly as a mixture in soil and partly as capsules. Results showed that salinity stress had a drastic inhibitory effect on growth parameters, especially at −5 MPa level. Nonetheless, the microbial treatments significantly alleviated the deleterious effect of salinity stress, especially when combined with methyl salicylate. When the nanomaterials were added to biofertilizers at highest salinity level, the inhibitory effect of salinity was mostly alleviated. Smart use of synergistic biofertilizers alongside the right nanomaterial, both encapsulated and in soil, would allow for mitigation and alleviation of inhibitory effect of salinity.

Cyanothece sp., a coccoid, unicellular, nitrogen-fixing and hydrogen-producing cyanobacterium, has been used in this study to biosynthesize customized gold nanoparticles under certain chemical conditions. The produced gold nanoparticles had a characteristic absorption band at 525–535 nm. Two types of gold nanoparticle, the purple and blue, were formed according to the chemical environment in which the cyanobacterium was grown. Dynamic light scattering was implemented to estimate the size of the purple and blue nanoparticles, which ranged from 80 ± 30 nm and 129 ± 40 nm in diameter, respectively. The highest scattering of laser light was recorded for the blue gold nanoparticles, which was possibly due to their larger size and higher concentration. The appearance of anodic and cathodic peaks in cyclic voltammetric scans of the blue gold nanoparticles reflected the oxidation into gold oxide, followed by the subsequent reduction into the nano metal state. The two produced forms of gold nanoparticles were used to treat isoproterenol-induced myocardial infarction in experimental rats. Both forms of nanoparticles ameliorated myocardial infarction injury, with a slight difference in their curative activity with the purple being more effective. Mechanisms that might explain the curative effect of these nanoparticles on the myocardial infarction were proposed. The morphological, physiological, and biochemical attributes of the Cyanothece sp. cyanobacterium were fundamental for the successful production of “tailored” nanoparticles, and complemented the chemical conditions for the differential biosynthesis process. The present research represents a novel approach to manipulate cyanobacterial cells towards the production of different-sized gold nanoparticles whose curative impacts vary accordingly. This is the first report on that type of manipulated gold nanoparticles biosynthesis which will hopefully open doors for further investigations and biotechnological applications.