Antimicrobial peptides are sequences of amino acids, which present activity against microorganisms. These peptides were discovered over 70 years ago, and are abundant in nature from soil bacteria, insects, amphibians to mammals and plants. They vary in amino acids number, the distance between amino acids within individual peptide structure, net charge, solubility and other physical chemical properties as well as differ in mechanism of action. These peptides may provide an alternative treatment to conventional antibiotics, which encounter resistance such as the peptide nisin applied in treating methicillin resistant Staphylococcus aureus (MRSA) or may behave synergistically with known antibiotics against parasites for instance, nisin Z when used in synergy with ampicillin reported better activity against Pseudomonas fluorescens than when the antibiotic was alone. AMPs are known to be active against viruses, bacteria, fungi and protozoans. Nanotechnology is an arena which explores the synthesis, characterization and application of an array of delivery systems at a one billionth of meter scale. Such systems are implemented to deliver drugs, proteins, vaccines, and peptides. The role of nanotechnology in delivering AMPs is still at its early development stage. There are challenges of incorporating AMPs into drug delivery system. This review intends to explore in depth, the role of nanotechnology in delivering AMPs as well as presenting the current advances and accompanying challenges of the technology.

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Antimicrobial Peptides and Nanotechnology, Recent Advances and Challenges.

Graphene quantum dots (GQDs) have been prepared for the first time using raw plant leaf extracts of Neem (Azadirachta indica) and Fenugreek (Trigonella foenum-graecum) by a facile, hydrothermal method at 300 °C for 8 hours in water, without the need of any passivizing, reducing agents or organic solvents. High resolution transmission electron microscope studies showed that the average sizes of the GQDs from Neem (N-GQDs) and Fenugreek (F-GQDs) were 5 and 7 nm respectively. N-GQDs and F-GQDs exhibit high quantum yields of 41.2% and 38.9% respectively. Moreover, the GQDs were utilized to prepare a white light converting cap based on the red-green-blue (RGB) color mixing method.

Plant leaf-derived graphene quantum dots and applications for white LEDs

Interactions of hemin with bovine serum albumin and human hemoglobin: A fluorescence quenching study

Interactions of porphyrin derivatives 5,10,15,20-tetrakis(N-methylpyridinium-4-yl)-21H,23H-porphyrin (TMPyP4) and 5,10,15,20-tetrakis(N-propylpyridinium-4-yl)-21H,23H-porphyrin (TPrPyP4) with human telomeric AG3(T2AG3)3G-quadruplex DNAs in 150 mM K+-containing buffer in the presence or absence of 40% molecular crowding agent poly(ethylene glycol) (PEG 200) were studied by absorption titration fitting and time-resolved fluorescence spectroscopy. The results show that two TMPyP4 (or TPrPyP4) molecules bind to antiparallel/parallel hybrid structure of AG3(T2AG3)3G-quadruplex by end-stacking and outside groove binding modes in the absence of PEG. Interestingly, in the presence of PEG one porphyrin molecule is stacked between two parallel AG3(T2AG3)3 G- quadruplexes to form a sandwich structure, another porphyrin molecule is bound to the groove of the G-quadruplex. The interactions of TMPyP4 with different structures of AG3(T2AG3)3G-quadruplex are non cooperative, the binding constants of two independent binding sites are 1.07 × 106 and 4.42 × 108 M−1 for an antiparallel/parallel hybrid structure of AG3(T2AG3)3, 8.67 × 105 and 2.26 × 108 M−1 for parallel-stranded AG3(T2AG3)3G-quadruplex. Conversely, the two binding sites are cooperative for TPrPyP4, the apparent association constants are 5.58 × 106 and 1.24 × 107 M−1 for parallel-stranded and antiparallel/parallel hybrid structures of AG3(T2AG3)3G-quadruplex, respectively.

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Magdalena Makarska-Bialokoz

Papers

Interactions of hemin with bovine serum albumin and human hemoglobin: A fluorescence quenching study

Study of the binding interactions between uric acid and bovine serum albumin using multiple spectroscopic techniques

Investigation of the binding affinity in vitamin B12-Bovine serum albumin system using various spectroscopic methods.

Analysis of the binding interaction in uric acid - Human hemoglobin system by spectroscopic techniques

Fluorescence quenching effect of guanine interacting with water-soluble cationic porphyrin