921X (2020) Peptide-based gel in environmental remediation: removal of toxic organic dyes and hazardous Pb2+ and Cd2+ ions from wastewater and oil spill recovery. Langmuir, 36 (43). pp. 12942-12953.

Here we present a series of peptide amphiphiles which form hydrogels based on beta-sheet nanofibril networks, several of which have very promising anti-microbial and anti-parasitic activities, in particular against multiple...

Newly synthesized blue-emitting few-atom copper nanoclusters (CuNCs) have been successfully utilized for catalyzing C­(sp2)–C­(sp2) and C­(sp2)–N­(sp3) bond formations. Various substituted biphenyls and 2° aromatic amines have been synthesized in good yield using this copper catalyst at facile reaction conditions in dimethyl sulfoxide. The amount of required nanocatalysts is as low as merely 2 mol % for carrying out these reactions. These types of copper nanoclusters are promising as potential and cheap catalysts for replacing conventional metal nanoparticles and heavy-metal-ion-based organic catalysts. The optimized structure of Cu6(GS)2 [GS = C10H16N3O6S] from computational studies revealed the perfect arrangements of Cu atoms in CuNCs and their interactions with stabilizing ligands. It is evident from the structure that some free Cu sites are available in the nanocluster species. These kinds of coordinatively unsaturated sites are highly active toward the catalytic reactions. Matrix-assisted laser desorption ionization–time-of-flight (MALDI–TOF) analysis also supports the computational hypothesis. Interestingly, matrix-assisted laser desorption ionization–time-of-flight mass spectrometry (MALDI–TOF MS) and computational studies revealed the formation of several reaction key intermediates in catalyzing C­(sp2)–C­(sp2) bond formation.

A histidine-based amphiphilic peptide (P) has been found to form an injectable transparent hydrogel in phosphate buffer solution over a pH range from 7.0 to 8.5 with an inherent antibacterial property. It also formed a hydrogel in water at pH = 6.7. The peptide self-assembles into a nanofibrillar network structure which is characterized by high-resolution transmission electron microscopy, field-emission scanning electron microscopy, atomic force microscopy, small-angle X-ray scattering, Fourier-transform infrared spectroscopy, and wide-angle powder X-ray diffraction. The hydrogel exhibits efficient antibacterial activity against both Gram-positive bacteria Staphylococcus aureus (S. aureus) and Gram-negative bacteria Escherichia coli (E. coli). The minimum inhibitory concentration of the hydrogel ranges from 20 to 100 μg/mL. The hydrogel is capable of encapsulation of the drugs naproxen (a non-steroidal anti-inflammatory drug), amoxicillin (an antibiotic), and doxorubicin, (an anticancer drug), but, selectively and sustainably, the gel releases naproxen, 84% being released in 84 h and amoxicillin was released more or less in same manner with that of the naproxen. The hydrogel is biocompatible with HEK 293T cells as well as NIH (mouse fibroblast cell line) cells and thus has potential as a potent antibacterial and drug releasing agent. Another remarkable feature of this hydrogel is its magnification property like a convex lens.

A dipeptide‐appended perylenediimide (PDI‐CFF) fluorescent molecule was designed, synthesized, and characterized. Though the molecule does not dissolve in any individual solvent, it dissolves well in an organic/water mixed solvent system such as tetrahydrofuran/water. This new fluorescent molecule was self‐assembled in a tetrahydrofuran/water mixture to form both nanofibrous network structures and a nano ring structure. It has shown nanofibril morphology by the interactions with ferric ions (PDI‐CFF/Fe3+ system) with diminishing fluorescent property. Interestingly, L‐ascorbic acid (LAA) interacts with the PDI‐CFF/Fe3+ system, showing turn‐on fluorescence. Another interesting feature is that the minimum detection limits for Fe3+ ions and LAA are at the submicromolar levels of 6.2 × 10−8 and 3 × 10−8 M, respectively. Moreover, the fluorescent (10 μM) signals can be monitored by the naked eye under handheld UV lamp irradiation at 365 nm, and this is very convenient for the real application. In this study, the molecule offers the opportunity for processing these sequential fluorescence responses in order to fabricate a implication logic gate that includes NOT, AND, and OR simple logic gates using chemical stimuli (ferric ions and LAA) as inputs and fluorescence emission at 536 nm as output. The detailed mechanism of interactions of Fe3+ with PDI‐CFF and LAA with the PDI‐CFF/Fe3+ system is vividly studied by using Fourier transform infrared (FT‐IR) analysis and fluorescence. Moreover, this new molecule was reusable for several times without significant loss of its activity. The construction of logic gates using biologically important molecules/ions holds future promise for the design and development of new bio‐logic gates.