This work reports the incorporation of coordinated water into Ni-BTC nanorods (Ni-BTC-O) which induces their structural transformation to Ni-BTC nanofibres (Ni-BTC-F). The carbonization of the NiBTC nanofibres at 600 degrees C results in the formation of carbon nanotube (CNT)-decorated hierarchical porous nickel/carbon hybrid (labelled as Ni/C-600) with enlarged pores. In contrast, the Ni/C hybrid obtained from the carbonization of the original (unmodified) Ni-BTC nanorods (Ni-BTC-O) at 600 degrees C (labelled as Ni-BTC-O-600) exhibits smaller pore size and does not show the formation of CNTs. The Ni/C-600 hybrid derived from Ni-BTC-F shows a very high adsorption capacity of 686.8 mg g-1 toward methyl blue (MB) dye. This is approximately 4.8 times higher than the adsorption capacity of Ni-BTC-O-600 (144.1 mg g-1). The higher adsorption performance of Ni/C-600 relative to Ni-BTC-O-600 can be attributed to its larger pore volume, hierarchical porosity, and additional adsorption sites provided by the CNTs. In addition, the Ni/C-600 hybrid can maintain 90% of its adsorption capacity after 5 consecutive cycles, demonstrating its potential as an efficient and recyclable adsorbent for MB dye. (c) 2023 Elsevier Inc. All rights reserved.

Multiple sclerosis (MS) is a debilitating disease that requires prolonged treatment with often severe side effects. One experimental MS therapeutic currently under development is a single amino acid mutant of a plant peptide termed kalata B1, of the cyclotide family. Like all cyclotides, the therapeutic candidate [T20K]kB1 is highly stable as it contains a cyclic backbone that is cross-linked by three disulfide bonds in a knot-like structure. This stability is much sought after for peptide drugs, which despite exquisite selectivity for their targets, are prone to rapid degradation in human serum. In preliminary investigations, it was found that [T20K]kB1 retains oral activity in experimental autoimmune encephalomyelitis, a model of MS in mice, thus opening up opportunities for oral dosing of the peptide. Although [T20K]kB1 can be synthetically produced, a recombinant production system provides advantages, specifically for reduced scale-up costs and reductions in chemical waste. In this study, we demonstrate the capacity of the Australian native Nicotiana benthamiana plant to produce a structurally identical [T20K]kB1 to that of the synthetic peptide. By optimizing the co-expressed cyclizing enzyme, precursor peptide arrangements, and transgene regulatory regions, we demonstrate a [T20K]kB1 yield in crude peptide extracts of ~ 0.3 mg/g dry mass) in whole plants and close to 1.0 mg/g dry mass in isolated infiltrated leaves. With large-scale plant production facilities coming on-line across the world, the sustainable and cost-effective production of cyclotide-based therapeutics is now within reach.