2015 Impact Factor: 1.043
Enzyme-instructed self-assembly (EISA) offers a facile approach to explore the supramolecular assemblies of small molecules in cellular milieu for a variety of biomedical applications. One of the commonly used enzymes is phosphatase, but the study of the substrates of phosphatases mainly focuses on the phosphotyrosine containing peptides. In this work, we examine the EISA of phosphoserine containing small peptides for the first time by designing and synthesizing a series of precursors containing only phosphoserine or both phosphoserine and phosphotyrosine. Conjugating a phosphoserine to the C-terminal of a well-established self-assembling peptide backbone, (naphthalene-2-ly)-acetyl-diphenylalanine (NapFF), affords a novel hydrogelation precursor for EISA. The incorporation of phosphotyrosine, another substrate of phosphatase, into the resulting precursor, provides one more enzymatic trigger on a single molecule, and meanwhile increases the precursors’ propensity to aggregate after being fully dephosphorylated. Exchanging the positions of phosphorylated serine and tyrosine in the peptide backbone provides insights on how the specific molecular structures influence self-assembling behaviors of small peptides and the subsequent cellular responses. Moreover, the utilization of D-amino acids largely enhances the biostability of the peptides, thus providing a unique soft material for potential biomedical applications.
Shape memory polymers (SMPs) are smart materials that can change their shape in a pre-defined manner under a stimulus. The shape memory functionality has gained considerable interest for biomedical applications, which require materials that are biocompatible and sometimes biodegradable. There is a need for SMPs that are prepared from renewable sources to be used as substitutes for conventional SMPs. In this paper, advances in SMPs based on synthetic monomers and bio-compounds are discussed. Materials designed for biomedical applications are highlighted.
Functionalising surfaces using polymeric thin films is an industrially important field. One technique for achieving nanoscale, controlled surface functionalization is plasma deposition. Plasma deposition has advantages over other surface engineering processes, including that it is solvent free, substrate and geometry independent, and the surface properties of the film can be designed by judicious choice of precursor and plasma conditions. Despite the utility of this method, the mechanisms of plasma polymer growth are generally unknown, and are usually described by chemical (i.e., radical) pathways. In this review, we aim to show that plasma physics drives the chemistry of the plasma phase, and surface-plasma interactions. For example, we show that ionic species can react in the plasma to form larger ions, and also arrive at surfaces with energies greater than 1000 kJ?mol–1 (>10 eV) and thus facilitate surface reactions that have not been taken into account previously. Thus, improving thin film deposition processes requires an understanding of both physical and chemical processes in plasma.
Great interests have arisen over the last decade in the development of hierarchically porous materials. The hierarchical structure enables materials to have maximum structural functions owing to enhanced accessibility and mass transport properties, leading to improved performances in various applications. Hierarchical porous materials are in high demand for applications in catalysis, adsorption, separation, energy and biochemistry. In the present review, recent advances in synthesis routes to hierarchically porous materials are reviewed together with their catalytic contributions.
Natural products and their derivatives represent a rich source for the discovery and development of new cancer therapeutic drugs. Bioactive components derived from natural sources including marine compounds have been shown to be effective agents in the clinic or in preclinical settings. In the present review, we present a story of discovery, synthesis and evaluation of three synthetic tricyclic pyrroloquinone (TPQ) alkaloid analogs as cancer therapeutic agents. Chemical synthesis of these compounds (BA-TPQ, TBA-TPQ, and TCBA-TPQ) has been accomplished and the mechanisms of action (MOA) and structure-activity relationships (SAR) have been investigated. In the past, the complexity of chemical synthesis and the lack of well-defined MOA have dampened the enthusiasm for the development of some makaluvamines. Recent discovery of novel molecular targets for these alkaloids (unrelated to inhibition of Topoisomerase II) warrant further consideration as clinical candidates in the future. In addition to the establishment of novel synthetic approaches and demonstration of in vitro and in vivo anticancer activities, we have successfully demonstrated that these makaluvamines attack several key molecular targets, including the MDM2-p53 pathway, providing ample opportunities of modulating the compound structure based on SAR and the use of such compounds in combination therapy in the future.
Over the past few decades, cell penetrating peptides (CPPs) have become an important class of drug carriers for small molecules, proteins, genes and nanoparticle systems. CPPs represent a very diverse set of short peptide sequences (10?30 amino acids), generally classified as cationic or amphipathic, with various mechanisms in cellular internalization. In this review, a more comprehensive assessment of the chemical structural characteristics, including net cationic charge, hydrophobicity and helicity was assembled for a large set of commonly used CPPs, and compared to results from numerous in vivo drug delivery studies. This detailed information can aid in the design and selection of effective CPPs for use as transport carriers in the delivery of different types of drug for therapeutic applications.