We report the design and synthesis of a biocompatible small-peptide-based compound for the controlled and targeted delivery of encapsulated bioactive metal ions through transformation of the internal nanostructures of its complexes. A tyrosine-based short-peptide amphiphile (sPA) was synthesized and observed to self-assemble into β-sheet-like secondary structures. The self-assembly of the designed sPA was modulated by application of different bioactive transition-metal ions, as was confirmed by spectroscopic and microscopic techniques. These bioactive metal-ion-conjugated sPA hybrid structures were further used to develop antibacterial materials. As a result of the excellent antibacterial activity of zinc ions the growth of clinically relevant bacteria such as Escherichia coli was inhibited in the presence of zinc⋅sPA conjugate. Bacterial testing demonstrated that, due to high biocompatibility with bacterial cells, the designed sPA acted as a metal ion delivery agent and might therefore show great potential in locally addressing bacterial infections.

The rise of human populations and the growth of cities contribute to the depletion of natural resources, increase their cost, and create potential climatic changes. To overcome difficulties in supplying populations and reducing the resource cost, a search for alternative pharmaceutical, nanotechnology, and energy sources has begun. Among the alternative sources, microalgae are the most promising because they use carbon dioxide (CO2) to produce biomass and/or valuable compounds. Once produced, the biomass is ordinarily harvested and processed (downstream program). Drying, grinding, and extraction steps are destructive to the microalgal biomass that then needs to be renewed. The extraction and purification processes generate organic wastes and require substantial energy inputs. Altogether, it is urgent to develop alternative downstream processes. Among the possibilities, milking invokes the concept that the extraction should not kill the algal cells. Therefore, it does not require growing the algae anew. In this review, we discuss research on milking of diatoms. The main themes are (a) development of alternative methods to extract and harvest high added value compounds; (b) design of photobioreactors; (c) biodiversity and (d) stress physiology, illustrated with original results dealing with oleaginous diatoms.

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In search of new antibacterial agents and therapeutic strategies, during this antibiotic resistance crises, we developed a facile and effective antibacterial nanomaterial by using di‐phenylalanine based hydrophobized short peptide amphiphile (HsPA) and AuNPs. Such peptide amphiphile functionalised nanoparticles can provide a universal platform for medicinal applications owing to their unique physicochemical properties. The nanostructures of sPA and HsPA‐AuNPs hybrids were confirmed by spectroscopic and microscopy techniques. The antibacterial activity of these nanostructures were tested against clinically relevant bacteria such as Escherichia coli and found satisfactory. The HsPA acted as a model drug (Au(III) and AuNPs) delivery agent. Therefore such stimuli responsive, HsPA‐AuNPs system may open new therapeutic paradigms for emerging the theranostics.

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