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Open bone fractures are not only difficult to heal but also are at a high risk of infections. Annual cases of fractures which result from osteoporosis amount to approximately 9 million. Endogenously released nitric oxide (NO) has been shown to play a role in osteogenic differentiation in addition to eradicating infection against a wide variety of pathogens. In the current work, antimicrobial NO releasing 3D bone scaffolds were fabricated using S-nitroso-N-acetyl-penicillamine (SNAP) as the NO donor. During fabrication, nano-hydroxyapatite (nHA) was added to each of the scaffolds in the concentration range of 10-50 wt % in nHA-starch-alginate and nHA-starch-chitosan scaffolds. The mechanical strength of the scaffolds increased proportionally to the concentration of nHA and 50 wt % nHA-starch-alginate possessed the highest load bearing capacity of 203.95 ± 0.3 N. The NO flux of the 50 wt % nHA-starch-alginate scaffolds was found to be 0.50 ± 0.06 × 10 -10 mol/min/mg initially which reduced to 0.23 ± 0.02 × 10 -10 over a 24 h period under physiological conditions. As a result, a 99.76% ± 0.33% reduction in a gram-positive bacterium, Staphylococcus aureus and a 99.80% ± 0.62% reduction in the adhered viable colonies of gram-negative bacterium, Pseudomonas aeruginosa were observed, which is a significant stride in the field of antibacterial natural polymers. The surface morphology and pore size were observed to be appropriate for the potential bone cell growth. The material showed no toxic response toward mouse fibroblast cells. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1068-1078, 2019., (© 2018 Wiley Periodicals, Inc.)

Insects sustain the invading bacterial pathogens by inducing the production of lectin which participates in surveillance of non-self molecules. The antibacterial property of lectin is an inevitable aspect of innate immune system especially for the insects feeding the detritus organic matter. β-galactoside binding lectin possessing antibacterial property was detected and purified from the hemolymph of larvae of caddisfly, Stenopsyche kodaikanalensis using affinity chromatography. The purified lectin exhibited highest hemagglutination titer value against buffalo erythrocytes and has affinity to lactose and fetuin which contains β-galactoside linkages. It was found to be calcium independent, EDTA insensitive and heat labile. These reveal the characteristics features of S-Lac lectin. The molecular weight of lectin was 360 kDa with five distinct subunits such as 95, 90, 66, 62 and 47 kDa. The sequences acquired through MALDI-TOF-MS analysis shared homologies to the putative conserved region of leguminous lectin. Antibacterial studies were carried out with native soil bacterial isolates. It revealed that the lectin possessed the specific modes of action against bacteria that it can agglutinate the Bacillus subtilis and lyse the Bacillus flexus., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Biodegradable composite membranes with antimicrobial properties consisting of nanocellulose fibrils (CNFs), chitosan, and S-nitroso-N-acetyl-d-penicillamine (SNAP) were developed and tested for food packaging applications. As a nitric oxide donor, SNAP was encapsulated into completely dispersed chitosan in 100 mL of 0.1 N acetic acid and was thoroughly mixed with CNFs to produce a composite membrane. The fabricated membranes had a uniform dispersion of chitosan and SNAP within the CNFs, which was confirmed through scanning electron microscopy (SEM) micrographs and a chemiluminescence nitric oxide analyzer. The membranes prepared without SNAP showed lower water vapor permeability than that of the membranes with SNAP. The addition of SNAP resulted in a decrease in Young's modulus for both two- and three-layer membrane configurations. Antimicrobial property evaluation of SNAP-incorporated membranes showed an effective zone of inhibition against bacterial strains of Enterococcus faecalis, Staphylococcus aureus, and Listeria monocytogenes and demonstrated its potential applications for food packaging.