Role of Functional Groups in Strengthening Polymer−Polymer Interfaces:  Random Copolymers with Hydrogen-Bonding Functionalities

1998 ◽  
Vol 10 (4) ◽  
pp. 994-1002 ◽  
Author(s):  
Brian D. Edgecombe ◽  
Jean M. J. Fréchet ◽  
Zhihua Xu ◽  
Edward J. Kramer
1998 ◽  
Vol 31 (4) ◽  
pp. 1292-1304 ◽  
Author(s):  
Brian D. Edgecombe ◽  
Jason A. Stein ◽  
Jean M. J. Fréchet ◽  
Zhihua Xu ◽  
Edward J. Kramer

2014 ◽  
Vol 43 (39) ◽  
pp. 14865-14875 ◽  
Author(s):  
Deepak Bansal ◽  
Gulshan Kumar ◽  
Geeta Hundal ◽  
Rajeev Gupta

Coordination complexes of amide-based ligands with appended heterocyclic rings create a hydrogen bonding cavity that effectively binds the substrate(s). Such cavity-based complexes function as reusable and heterogeneous catalysts for various organic transformations.


Author(s):  
Pierre Taberlet ◽  
Aurélie Bonin ◽  
Lucie Zinger ◽  
Eric Coissac

Chapter 10 “Environmental DNA for functional diversity” discusses the potential of environmental DNA to assess functional diversity. It first focuses on DNA metabarcoding and discusses the extent to which this approach can be used and/or optimized to retrieve meaningful information on the functions of the target community. This knowledge usually involves coarsely defined functional groups (e.g., woody, leguminous, graminoid plants; shredders or decomposer soil organisms; pathogenicity or decomposition role of certain microorganisms). Chapter 10 then introduces metagenomics and metatranscriptomics approaches, their advantages, but also the challenges and solutions to appropriately sampling, sequencing these complex DNA/RNA populations. Chapter 10 finally presents several strategies and software to analyze metagenomes/metatranscriptomes, and discusses their pros and cons.


Biosensors ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 246
Author(s):  
Patrick Severin Sfragano ◽  
Giulia Moro ◽  
Federico Polo ◽  
Ilaria Palchetti

Peptides represent a promising class of biorecognition elements that can be coupled to electrochemical transducers. The benefits lie mainly in their stability and selectivity toward a target analyte. Furthermore, they can be synthesized rather easily and modified with specific functional groups, thus making them suitable for the development of novel architectures for biosensing platforms, as well as alternative labelling tools. Peptides have also been proposed as antibiofouling agents. Indeed, biofouling caused by the accumulation of biomolecules on electrode surfaces is one of the major issues and challenges to be addressed in the practical application of electrochemical biosensors. In this review, we summarise trends from the last three years in the design and development of electrochemical biosensors using synthetic peptides. The different roles of peptides in the design of electrochemical biosensors are described. The main procedures of selection and synthesis are discussed. Selected applications in clinical diagnostics are also described.


Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2074
Author(s):  
Sara Tabandeh ◽  
Cristina Elisabeth Lemus ◽  
Lorraine Leon

Electrostatic interactions, and specifically π-interactions play a significant role in the liquid-liquid phase separation of proteins and formation of membraneless organelles/or biological condensates. Sequence patterning of peptides allows creating protein-like structures and controlling the chemistry and interactions of the mimetic molecules. A library of oppositely charged polypeptides was designed and synthesized to investigate the role of π-interactions on phase separation and secondary structures of polyelectrolyte complexes. Phenylalanine was chosen as the π-containing residue and was used together with lysine or glutamic acid in the design of positively or negatively charged sequences. The effect of charge density and also the substitution of fluorine on the phenylalanine ring, known to disrupt π-interactions, were investigated. Characterization analysis using MALDI-TOF mass spectroscopy, H NMR, and circular dichroism (CD) confirmed the molecular structure and chiral pattern of peptide sequences. Despite an alternating sequence of chirality previously shown to promote liquid-liquid phase separation, complexes appeared as solid precipitates, suggesting strong interactions between the sequence pairs. The secondary structures of sequence pairs showed the formation of hydrogen-bonded structures with a β-sheet signal in FTIR spectroscopy. The presence of fluorine decreased hydrogen bonding due to its inhibitory effect on π-interactions. π-interactions resulted in enhanced stability of complexes against salt, and higher critical salt concentrations for complexes with more π-containing amino acids. Furthermore, UV-vis spectroscopy showed that sequences containing π-interactions and increased charge density encapsulated a small charged molecule with π-bonds with high efficiency. These findings highlight the interplay between ionic, hydrophobic, hydrogen bonding, and π-interactions in polyelectrolyte complex formation and enhance our understanding of phase separation phenomena in protein-like structures.


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