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The present study deals with novel synthesizing method of TEMPO oxidized cellulose (extracted from bagasse) (TOC) amino acids (l-phenyl alanine (Phe) and l-tryptophan (Trp)) nano-composites as potential antimicrobial biocompatible agents. The produced nanocomposites were characterized via Fourier transform Infrared (FT-IR) spectroscopy, thermal analysis (TGA and DTGA), scanning electron microscope(SEM), and transmission electron microscope (TEM) which approved that the synthesis of composites in nano-scale in spherical shape with average particle size 72 and 44.37 nm for l-phenylalanine composite (Phe-TOC) and l-tryptophan composite (Trp-TOC) respectively. The antimicrobial studies were carried out on (i) Gram-negative bacteria: Escherichia coli (NCTC-10416) and Pseudomonas aeruginosa (NCID-9016); (ii) Gram-positive bacteria: Streptococcus aurous (NCTC-7447) and Bacillus subtilis (NCID-3610); (iii) unicellular fungi: namely, Candida albicans (NCCLS 11). The results were cleared that the both composites have high effective, rapid and broad-spectrum antimicrobial activity. The Trp-TOC showed slightly higher antimicrobial activity than Phe-TOC especially in time required of killing performance. The Phe-TOC has required 20 h for killing all microbial population while Trp-TOC required only 12 h. The MIC values were close in both nanocomposites with high clear zone measurements in the same concentration in the case of Trp-TOC., (Copyright © 2019 Elsevier B.V. All rights reserved.)

A series of cyclic peptides containing a number of tryptophan (W) and glutamic acid (E) residues were synthesized and evaluated as pH-sensitive agents for targeting of acidic tissue and pH-dependent cytoplasmic delivery of molecules. Biophysical studies revealed the molecular mechanism of peptides action and localization within the lipid bilayer of the membrane at high and low pHs. The symmetric, c[(WE)4WC], and asymmetric, c[E4W5C], cyclic peptides translocated amanitin, a polar cargo molecule of similar size, across the lipid bilayer and induced cell death in a pH- and concentration-dependent manner. Fluorescently-labelled peptides were evaluated for targeting of acidic 4T1 mammary tumors in mice. The highest tumor to muscle ratio (5.6) was established for asymmetric cyclic peptide, c[E4W5C], at 24 hours after intravenous administration. pH-insensitive cyclic peptide c[R4W5C], where glutamic acid residues (E) were replaced by positively charged arginine residues (R), did not exhibit tumor targeting. We have introduced a novel class of cyclic peptides, which can be utilized as a new pH-sensitive tool in investigation or targeting of acidic tissue.