Nanotechnology, a frontier in agricultural science, a novel approach in abiotic stress management and convergence with new age medicine-A review

Climate change imposes various environmental stresses which substantially impact plant growth and productivity. Salinity, drought, temperature extremes, heavy metals, and nutritional imbalances are among several abiotic stresses contributing to high yield losses of crops in various parts of the world, resulting in food insecurity. Many interesting strategies are being researched in the attempt to improve plants' environmental stress tolerance. These include the application of nanoparticles, which have been found to improve plant function under stress situations. Nanotechnology will be a key driver in the upcoming agri-tech and pharmaceutical revolution, which promises a more sustainable, efficient, and resilient agricultural and medical system Nano-fertilizers can help plants utilise nutrients more efficiently by releasing nutrients slowly and sustainably. Plant physiology and nanomaterial features (such as size, shape, and charge) are important aspects influencing the impact on plant growth. Here, we discussed the most promising new opportunities and methodologies for using nanotechnology to increase the efficiency of critical inputs for crop agriculture, as well as to better manage biotic and abiotic stress. Potential development and implementation challenges are highlighted, emphasising the importance of designing suggested nanotechnologies using a systems approach. Finally, the strengths, flaws, possibilities, and risks of nanotechnology are assessed and analysed in order to present a comprehensive and clear picture of the nanotechnology potentials, as well as future paths for nano-based agri-food applications towards sustainability. Future research directions have been established in order to support research towards the long-term development of nano-enabled agriculture and evolution of pharmaceutical industry.

Effect of gelatin nano-coating containing Gardenia pigment on the preservation of pork slices

The nano-coating composed of gelatin and Gardenia pigment (GP) was successfully prepared and showed strong antioxidant activity. The average particle sizes of the nano-coating containing 0.1% and 0.3% GP were 269.58 and 394.13 nm, respectively. The pork slices uncoated and coated with the nano-coating were preserved at 4 °C for 15 days. The pork slices' pH, total volatile basic nitrogen (TVB-N), total viable counts (TVC), water-binding capacity (WHC), and thiobarbituric acid reactive substances (TBARS) were measured to assess the preservation effect of the nano-coating. The results showed that the pork coated with the nano-coating had lower pH, TVC, TVB-N, TBARS, and higher WHC, significantly different (p < 0.05) than the uncoated pork. It is suggested that the proposed nano-coating can be used to effectively improve the pork's quality and shelf life during refrigeration storage.

A triple-coated ligament graft to facilitate ligament-bone healing by inhibiting fibrogenesis and promoting osteogenesis

Absence of ligament-bone healing due to poor bioactivity and hyperplasia of fibrous tissue caused by immune response severely impairs ligament grafts' functional duration in anterior cruciate ligament (ACL) reconstruction. While osteogenic modification is a popular technique for promoting ligament-bone integration, inadequate osseointegration remains a common experience, due to occupying fibrous hyperplasia and impaired osteogenesis potential. In the present study, a triple-nano-coating polyethylene terephthalate (PET) graft was developed by polydopamine self-assembly, chondroitin sulfate (CS) chemical-grafting and BMP-2 physical-immobilization to facilitate robust ligament-bone healing, The CS/polydopamine-modified PET (C-pPET) graft was demonstrated to inhibit fibrogenesis by regulating polarization of macrophages and promoting the secretion of anti-inflammatory factors. Moreover, the immunoregulatory function of CS cooperated with BMP-2 to facilitate osteogenic differentiation of stem cells, promoting the expression of ALP, Runx2, OCN and COL I. Bone regeneration was significantly enhanced at early-middle stage in the BMP-loaded pPET (B/pPET) group, while occurring at middle-late stage in the C-pPET group. Continuous new bone formation and optimal ligament-bone healing were observed in the B/C-pPET group via sequential and synergistic immune osteogenesis by CS and cytokine osteogenesis by BMP-2. Thus, the present study revealed a practical avenue for the promotion of ligament-bone healing through the development of a triple-nano-coating engineered ligament combining immunoregulatory anti-fibrogenesis and sequential-synergistic osteogenesis, which holds a great potential for improving the clinical efficacy of ligament graft in ACL reconstruction. STATEMENT OF SIGNIFICANCE: A triple-nano-coating polyethylene terephthalate (PET) graft was developed by polydopamine self-assembly, chondroitin sulfate (CS) chemical-grafting and BMP-2 physical-immobilization to facilitate robust ligament-bone healing. This study demonstrated that the multifunctional ligament grafts could reshape the local immune microenvironment by regulating macrophage phenotype and immune cytokine secretion to inhibit the fibrous hyperplasia and regulate stem cell towards osteogenic differentiation to promote bone regeneration. The present study demonstrates that efficient ligament-bone healing is achieved via the combination of immunoregulatory anti-fibrogenesis and dual osteogenesis of immunoregulation and cytokine induction.

Mechanical testing of antimicrobial biocomposite coating on metallic medical implants as drug delivery system

Post-operative infection often occurs following orthopedic and dental implant placement requiring systemically administered antibiotics. However, this does not provide long-term protection. Over the last few decades, alternative methods involving slow drug delivery systems based on biodegradable poly-lactic acid and antibiotic loaded hydroxyapatite microspheres were developed to prevent post-operative infection. In this study, thermally anodised and untreated Ti6Al4V discs were coated with Poly-Lactic Acid (PLA) containing Gentamicin (Gm) antibiotic-loaded coralline Hydroxyapatite (HAp) are investigated. Following chemical characterization, mechanical properties of the coated samples were measured using nanoindentation and scratch tests to determine the elastic modulus, hardness and bonding adhesion between film and substrate. It was found that PLA biocomposite multilayered films were around 400nm thick and the influence and effect of the substrate were clearly observed during the nanoindentation studies with heavier loads. Scratch tests of PLA coated samples conducted at ~160nm depth showed the minimal difference in the measured friction between Gm and non Gm containing films. It is also observed that the hardness values of PLA film coated anodised samples ranged from 0.45 to 1.9GPa (dependent on the applied loads) against untreated coated samples which ranged from 0.28 to 0.8GPa.

Photoelectrocatalytic decolorization of azo dyes with nano-composite oxide layers of ZnO nanorods decorated with Ag nanoparticles

Photoelectrocatalysis provides an excellent frame for the application of photocatalytic nanostructured materials on easy recoverable supports. This study reports the two-step synthesis of hierarchically nanostructured ZnO/Ag composite photoelectrodes. Wurtzite ZnO was selectively electronucleated as spheroidal seeds on fluor doped tin oxide substrates and nanodecorated with Ag nanoclusters under electrochemical control. Hierarchically organized nanorods were selectively chemically grown on the plane (002) perpendicular to the substrate from ZnO/Ag seeds. Solutions emulating dye effluents with the usual contents of 0.1 M of NaCl and a model azo dye (Methyl Orange) were decolorized using ZnO/Ag nanorods in different treatments. Photocatalysis attained discrete decolorizations of 8% whereas photoelectrocatalysis completely decolorized solutions after 60 min. The influence of the metal/semiconductor interface (ZnO/Ag) as introduced Schottky barrier is studied demonstrating a four-fold enhancement on decolorization kinetics respect bare ZnO nanorods. The influence of the seed growth control on the final photoelectrocatalytic response is reported to control the hierarchical organization of nanorods. This resulted in different decolorization kinetics as result of the differences on the efficient use of the delivered photons conditioned by the photoelectrode structure.

Layer-by-layer nanocoating of antibacterial niosome on orthopedic implant

The major clinical hindrance of orthopedic implants is the bacterial infection, which can lead to biofilm formation and ultimately results in implant rejection. In this research, layer-by-layer nanocoating consists of vancomycin/PLA/vancomycin-loaded niosomes was designed. Vancomycin-loaded niosomes were formulated by thin film hydration method and the attributes of niosomes in terms of size, zeta potential, drug loading and EE, were assessed. The size was 340.5 ± 2.95 nm with the zeta potential and %EE was 45.4 ± 0.77 mV and 50.47 ± 3.66% respectively. The dip coating technique was used to deposit a thin film, which was characterized morphologically under FE-SEM. Drug release from coated bone plates with and without vancomycin-loaded niosomes was also studied and results suggested that bone plates coated with vancomycin-loaded niosomes have accumulated more vancomycin than the control group and hence aided in the prolonged release up to two weeks. These niosomes-coated bone plates demonstrated superior antibacterial activity for longer time period, without exhibiting any cytotoxic effects towards normal cells (L929). These findings offer a promising approach to control the bacterial colonization and biofilms formation. This thin film nano-coating can also be utilized in coating of other medical devices, which are prone to infections.