Peptide Glycosylation Generates Supramolecular Assemblies from Glycopeptides as Biomimetic Scaffolds for Cell Adhesion and Proliferation

Understanding the gelation properties of the fluorophenyl glycosides of arabinoside gelators: experimental and theoretical studies

In supramolecular gelation, fluorinated gelators are important due to the unique properties displayed by these compounds that arise out of the presence of fluorine atoms. Generally, incorporation of fluorine leads to higher mechanical strength of the gels compared to their non-fluorinated counterparts and this property is enhanced with increasing the number of fluorine atoms. Herein, we show that the incorporation of fluorine into the phenyl ring of phenyl arabinoside allows the molecule to act as a gelator, unlike the non-fluorinated compound. We also show that the mechanical strength and stiffness of the gels is not only dependent on the positions of the fluorine atoms but also guided by their number. Detailed experimental studies, supported by computational studies, allowed us to rationalize the observed supramolecular interactions and propose reasons based on the conformational preferences of these compounds that allow additional hydrogen bonds and π-π interactions which guide the self-assembly, in addition to the primary H-bonding interactions. This, in turn, affects the mechanical behavior of these gels.

Concentration- and Solvent-Induced Chiral Tuning by Manipulating Non-Proteinogenic Amino Acids in Glycoconjugate Supra-Scaffolds: Interaction with Protein, and Streptomycin Delivery

We showed solvent- and concentration-triggered chiral tuning of the fibrous assemblies of two novel glycoconjugates Z-P(Gly)-Glu and Z-F(4-N)-Glu made by chemical attachment of Cbz-protected [short as Z)] non-proteinogenic amino acids L-phenylglycine [short as P(Gly)] and 4-Nitro-L-phenylalanine [short as F(4-N)] with D-glucosamine [short as Glu]. Both biomimetic gelators can form self-healing and shape-persistent gels with a very low critical gelator concentration in water as well as in various organic solvents, indicating they are ambidextrous supergelators. Detailed spectroscopic studies suggested β-sheet secondary structure formation during anisotropic self-aggregation of the gelators which resulted in the formation of hierarchical left-handed helical fibers in acetone with an interlayer spacing of 2.4 nm. After the physical characterization of the gels, serum protein interaction with the gelators was assessed, indicating they may be ideal for biomedical applications. Further, both gelators are benign, non-immunogenic, non-allergenic, and non-toxic in nature, which was confirmed by performing the blood parameters and liver function tests on Wister rats. Streptomycin-loaded hydrogels showed efficacious antibacterial activity in vitro and in vivo as well. Finally, cell attachment and biocompatibility of the hydrogels were demonstrated which opens a newer avenue for promising biomedical and therapeutic applications.

Glycopeptide-Based Supramolecular Hydrogels Induce Differentiation of Adipose Stem Cells into Neural Lineages

We applied a bottom-up approach to develop biofunctional supramolecular hydrogels from an aromatic glycodipeptide. The self-assembly of the glycopeptide was induced by either temperature manipulation (heating-cooling cycle) or solvent (DMSO to water) switch. The sol-gel transition was salt-triggered in cell culture media and resulted in gels with the same chemical compositions but different mechanical properties. Human adipose derived stem cells (hASCs) cultured on these gels under basal conditions (i.e., without differentiation factors) overexpressed neural markers, such as GFAP, Nestin, MAP2, and βIII-tubulin, confirming the differentiation into neural lineages. The mechanical properties of the gels influenced the number and distribution of the adhered cells. A comparison with gels obtained from the nonglycosylated peptide showed that glycosylation is crucial for the biofunctionality of the hydrogels by capturing and preserving essential growth factors, e.g., FGF-2.

Designing ECM-inspired supramolecular scaffolds by utilizing the interactions between a minimalistic neuroactive peptide and heparin

Short bioactive peptide-based supramolecular hydrogels are emerging as interesting candidates for developing scaffolds for tissue engineering applications. However, proteins and peptides represent only a single class of molecules present in the native ECM, thus, recapitulating the complete ECM microenvironment via only peptide-based biomaterials is extremely challenging. In this direction, complex multicomponent-based biomaterials have started gaining importance for achieving the biofunctional complexity and structural hierarchy of the native ECM. Sugar-peptide complexes can be explored in this direction as they provide essential biological signaling required for cellular growth and survival in vivo. In this direction, we explored the fabrication of an advanced scaffold by employing heparin and short bioactive peptide interactions at the molecular level. Interestingly, the addition of heparin into the peptide has significantly modulated the supramolecular organization, nanofibrous morphology and the mechanical properties of the scaffold. Additionally, the combined hydrogels demonstrated superior biocompatibility as compared to the peptide counterpart at certain ratios. These newly developed scaffolds were also observed to be stable under 3-D cell culture conditions and supported cellular adhesion and proliferation. Most importantly, the inflammatory response was also minimized in the case of combined hydrogels as compared to heparin. We expect that this approach of using simple non-covalent interactions between the ECM-inspired small molecules to fabricate biomaterials with improved mechanical and biological properties could advance the current knowledge on designing ECM mimetic biomaterials. Such an attempt would create a novel, adaptable and simplistic bottom-up strategy for the invention of new and more complex biomaterials of ECM origin with advanced functions.

Nanostructured multifunctional stimuli-responsive glycopolypeptide-based copolymers for biomedical applications

Inspired by natural resources, such as peptides and carbohydrates, glycopolypeptide biopolymer has recently emerged as a new form of biopolymer being recruited in various biomedical applications. Glycopolypeptides with well-defined secondary structures and pendant glycosides on the polypeptide backbone have sparked lots of research interest and they have an innate ability to self-assemble in diverse structures. The nanostructures of glycopolypeptides have also opened up new perspectives in biomedical applications due to their stable three-dimensional structures, high drug loading efficiency, excellent biocompatibility, and biodegradability. Although the development of glycopolypeptide-based nanocarriers is well-studied, their clinical translation is still limited. The present review highlights the preparation and characterization strategies related to glycopolypeptides-based copolymers, followed by a comprehensive discussion on their biomedical applications with a specific focus on drug delivery by various stimuli-responsive (e.g., pH, redox, conduction, and sugar) nanostructures, as well as their beneficial usage in diagnosis and regenerative medicine.

Modular Platform of Carbohydrates-modified Supramolecular Polymers Based on Dendritic Peptide Scaffolds

Glycopeptide supramolecular polymers displaying multivalent carbohydrates are particularly suitable for immune-relevant biomaterials, due to the important functions of carbohydrates in mediating cell-cell communication and modulating immune responses. However, the diversity and complexity of carbohydrates limited the generation of glycopeptide supramolecular monomers. Thereby, a modular platform of presenting various carbohydrates, especially more complex oligosaccharides, is highly desirable but remains underexplored. Here, we first prepared the linear amphiphilic glycopeptides that self-assembled into spherical nanoparticles and worm-like nanoparticles. Furthermore, the dendritic glycopeptides that self-assembled into uniform nanorods were designed to generate modular supramolecular polymers with variable functionality, via redesigning the molecular backbone. With various functional oligosaccharide-modified supramolecular polymers, the in vitro studies further indicated that these polymers were not cytotoxic to macrophages, and significantly modulated the production of proinflammatory cytokines. These findings provide a promising platform to develop supramolecular glycopeptide biomaterials with potential applications in immunomodulation and immunotherapy.

Supramolecular glycopolymers: How carbohydrates matter in structure, dynamics, and function

Supramolecular glycopolymers exhibiting inherent dynamicity, tunability, and adaptivity allow us to arrive at a deeper understanding of multivalent carbohydrate-carbohydrate interactions and carbohydrate-protein interactions, both being essential to key biological events. The impacts of the carbohydrate segments in these supramolecular glycopolymers towards their structure, dynamics, and function as biomaterials are addressed in this minireview. Bottlenecks and challenges are discussed, and we speculate about possible future directions.

Exploring the TEMPO-Oxidized Nanofibrillar Cellulose and Short Ionic-Complementary Peptide Composite Hydrogel as Biofunctional Cellular Scaffolds

Multicomponent self-assembly is an emerging approach in peptide nanotechnology to develop nanomaterials with superior physical and biological properties. Inspired by the multicomponent nature of the native extracellular matrix (ECM) and the well-established advantages of co-assembly in the field of nanotechnology, we have attempted to explore the noncovalent interactions among the sugar and peptide-based biomolecular building blocks as an approach to design and develop advanced tissue scaffolds. We utilized TEMPO-oxidized nanofibrillar cellulose (TO-NFC) and a short ionic complementary peptide, Nap-FEFK, to fabricate highly tunable supramolecular hydrogels. The differential doping of the peptide into the TO-NFC hydrogel was observed to tune the surface hydrophobicity, microporosity, and mechanical stiffness of the scaffold. Interestingly, a differential cellular response was observed toward composite scaffolds with a variable ratio of TO-NFC versus Nap-FEFK. Composite scaffolds having a 10:1 (w/w) ratio of TO-NFC and the Nap-FEFK peptide showed enhanced cellular survival and proliferation under two-dimensional cell culture conditions. More interestingly, the cellular proliferation on the 10:1 matrix was found to be similar to that of Matrigel in three-dimensional culture conditions, which clearly indicated the potential of these hydrogels in advanced tissue engineering applications. Additionally, these composite hydrogels did not elicit any significant inflammatory response in Raw cells and supported their survival and proliferation, which further emphasized their ability to form versatile scaffolds for tissue regeneration. This multicomponent assembly approach to construct biomolecular composite hydrogels to access superior physical and biological properties within the scaffold is expected to improve the scope for designing novel ECM-mimicking biomaterials for regenerative medicine.

Cooperative Metal Ion Coordination to the Short Self-Assembling Peptide Promotes Hydrogelation and Cellular Proliferation

Non-covalent interactions among short peptides and proteins led to their molecular self-assembly into supramolecular packaging, which provides the fundamental basis of life. These biomolecular assemblies are highly susceptible to the environmental conditions, including temperature, light, pH, and ionic concentration, thus inspiring the fabrication of a new class of stimuli-responsive biomaterials. Here, we report for the first time the cooperative effect of the divalent metal ions to promote hydrogelation in the short collagen inspired self-assembling peptide for developing advanced biomaterials. Introduction of the biologically relevant metal ions (Ca²⁺ /Mg²⁺ ) to the peptide surpasses its limitation to self-assemble into a multi-scale structure at physiological pH. In particular, in presence of metal ions, the negatively charged peptide showed a distinct shift in its equilibrium point of gelation and demonstrated conversion from sol to gel and thus enabling the scope of fabricating an advanced biomaterial for controlling cellular behaviour. Interestingly, tunable mechanical strength and improved cellular response were observed within ion-coordinated peptide hydrogels compared to the peptide gelator. Microscopic analyses, rheological assessment, and biological studies established the importance of utilizing a novel strategy by simply using metal ions to modulate the physical and biological attributes of CIPs to construct next-generation biomaterials. This article is protected by copyright. All rights reserved.

Organic/inorganic hydrogels by simultaneous self-assembly and mineralization of aromatic short-peptides

Hybrid hydrogels with a tunable structure–function relationship were prepared by simultaneous self-assembly and mineralization of aromatic short-peptides. Sub-stoichiometric Ca concentrations resulted in nanoapatite oriented along the peptide fiber.

Development of an Amino Sugar-Based Supramolecular Hydrogelator with Reduction Responsiveness

Stimuli-responsive supramolecular hydrogels are a newly emerging class of aqueous soft materials with a wide variety of bioapplications. Here we report a reduction-responsive supramolecular hydrogel constructed from a markedly simple low-molecular-weight hydrogelator, which is developed on the basis of modular molecular design containing a hydrophilic amino sugar and a reduction-responsive nitrophenyl group. The hydrogel formation ability differs significantly between glucosamine- and galactosamine-based self-assembling molecules, which are epimers at the C4 position, and only the glucosamine-based derivative can act as a hydrogelator.

Carbohydrate-Based Macromolecular Biomaterials

Carbohydrates are the most abundant and one of the most important biomacromolecules in Nature. Except for energy-related compounds, carbohydrates can be roughly divided into two categories: Carbohydrates as matter and carbohydrates as information. As matter, carbohydrates are abundantly present in the extracellular matrix of animals and cell walls of various plants, bacteria, fungi, etc., serving as scaffolds. Some commonly found polysaccharides are featured as biocompatible materials with controllable rigidity and functionality, forming polymeric biomaterials which are widely used in drug delivery, tissue engineering, etc. As information, carbohydrates are usually referred to the glycans from glycoproteins, glycolipids, and proteoglycans, which bind to proteins or other carbohydrates, thereby meditating the cell-cell and cell-matrix interactions. These glycans could be simplified as synthetic glycopolymers, glycolipids, and glycoproteins, which could be afforded through polymerization, multistep synthesis, or a semisynthetic strategy. The information role of carbohydrates can be demonstrated not only as targeting reagents but also as immune antigens and adjuvants. The latter are also included in this review as they are always in a macromolecular formulation. In this review, we intend to provide a relatively comprehensive summary of carbohydrate-based macromolecular biomaterials since 2010 while emphasizing the fundamental understanding to guide the rational design of biomaterials. Carbohydrate-based macromolecules on the basis of their resources and chemical structures will be discussed, including naturally occurring polysaccharides, naturally derived synthetic polysaccharides, glycopolymers/glycodendrimers, supramolecular glycopolymers, and synthetic glycolipids/glycoproteins. Multiscale structure-function relationships in several major application areas, including delivery systems, tissue engineering, and immunology, will be detailed. We hope this review will provide valuable information for the development of carbohydrate-based macromolecular biomaterials and build a bridge between the carbohydrates as matter and the carbohydrates as information to promote new biomaterial design in the near future.

Glycosylation of a Nonfibrillizing Appendage Alters the Self-Assembly Pathway of a Synthetic β-Sheet Fibrillizing Peptide

Owing to their biocompatibility and biodegradability, short synthetic peptides that self-assemble into elongated β-sheet fibers (i.e., peptide nanofibers) are widely used to create biomaterials for diverse medical and biotechnology applications. Glycosylation, which is a common protein post-translational modification, is gaining interest for creating peptide nanofibers that can mimic the function of natural carbohydrate-modified proteins. Recent reports have shown that glycosylation can disrupt the fibrillization of natural amyloid-forming peptides. Here, using transmission electron microscopy, fluorescence microscopy, and thioflavin T spectroscopy, we show that glycosylation at a site external to the fibrillization domain can alter the self-assembly pathway of a synthetic fibrillizing peptide, NSGSGQQKFQFQFEQQ (NQ11). Specifically, an NQ11 variant modified with N-linked N-acetylglucosamine, N(GlcNAc)SGSG-Q11 (GQ11), formed β-sheet nanofibers more slowly than NQ11 in deionized water (pH 5.8), which correlated to the tendency of GQ11 to form a combination of short fibrils and nonfibrillar aggregates, whereas NQ11 formed extended nanofibers. Acidic phosphate buffer slowed the rate of GQ11 fibrillization and altered the morphology of the structures formed yet had no effect on NQ11 fibrillization rate or morphology. The buffer ionic strength had no effect on the fibrillization rate of either peptide, while the diphosphate anion had a similar effect on the rate of fibrillization of both peptides. Collectively, these data demonstrate that a glycan moiety located external to the β-sheet fibrillizing domain can alter the pH-dependent self-assembly pathway of a synthetic peptide, leading to significant changes in the fibril mass and morphology of the structures formed. These observations add to the understanding of the effect of glycosylation on peptide self-assembly and should guide future efforts to develop biomaterials from synthetic β-sheet fibrillizing glycopeptides.

Electroactive peptide-based supramolecular polymers

The electroactivity as a supramolecular feature of intelligently designed self-assembled systems stimulates a wide interest in development of new stimuli-responsive biomaterials. A diverse set of nanostructures are fabricated through programmed self-assembly of molecules for functional materials. Electroactive groups are conjugated as a functional moiety for organic semiconductor applications. In this review, we present recent examples of self-assembling peptide molecules and electroactive units for supramolecular functional electronic ​and optical materials with potential biomedical and bioelectronics applications.

Antimicrobial and Amyloidogenic Activity of Peptides. Can Antimicrobial Peptides Be Used against SARS-CoV-2?

At present, much attention is paid to the use of antimicrobial peptides (AMPs) of natural and artificial origin to combat pathogens. AMPs have several points that determine their biological activity. We analyzed the structural properties of AMPs, as well as described their mechanism of action and impact on pathogenic bacteria and viruses. Recently published data on the development of new AMP drugs based on a combination of molecular design and genetic engineering approaches are presented. In this article, we have focused on information on the amyloidogenic properties of AMP. This review examines AMP development strategies from the perspective of the current high prevalence of antibiotic-resistant bacteria, and the potential prospects and challenges of using AMPs against infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Pathway-Dependent Preferential Selection and Amplification of Variable Self-Assembled Peptide Nanostructures and Their Biological Activities

We demonstrate the formation of diverse peptide nanostructures, which are "out of equilibrium" based on a single dipeptide gelator. These structures represent the differential energy states of the free energy landscape, which are accessed by differential energy inputs provided by variable self-assembly pathways, that is, heat-cool method or ultrasonication. A higher energy input by the heat-cool method created a thermodynamically favored long entangled nanofibrillar network, while twisted ribbonlike structures were prevalent by ultrasonication. Interestingly, the nanofibrillar network representing the global thermodynamic minima could be accessed by simply melting the kinetically trapped structures as indicated by the thermoreversibility studies. The impact on the material strength was remarkable; gels with an order of magnitude difference in mechanical properties could be fabricated by simply modulating the self-assembly pathways. Interestingly, the thermodynamically favored nanofibrous network promoted cellular adhesion and survival, while a significant number of cells fail to adhere on the kinetically trapped twisted ribbons. Thus, nonequilibrium nanostructures open up new directions to develop advanced functional materials with diverse functions.

Recent trends in the development of peptide and protein-based hydrogel therapeutics for the healing of CNS injury

Traumatic brain injury (TBI) and spinal cord injury (SCI) cause millions of deaths and permanent or prolonged physical disabilities around the globe every year. It generally happens due to various incidents, such as accidents during sports, war, physical assault, and strokes which result in severe damage to brain and spinal cord. If this remains untreated, traumatic CNS injuries may lead to early development of several neurodegenerative diseases like Alzheimer's, Parkinson, multiple sclerosis, and other mental illnesses. The initial physical reaction, which is also termed as the primary phase, includes swelling, followed by inflammation as a result of internal haemorrhage causing damage to indigenous tissue, i.e., axonal shear injury, rupture of blood vessels, and partial impaired supply of oxygen and essential nutrients in the neurons, thereby initiating a cascade of events causing secondary injuries such as hypoxia, hypotension, cognitive impairment, seizures, imbalanced calcium homeostasis and glutamate-induced excitotoxicity resulting in concomitant neuronal cell death and cumulative permanent tissue damage. In the modern era of advanced biomedical technology, we are still living with scarcity of the clinically applicable comparative non-invasive therapeutic strategies for regeneration or functional recovery of neurons or neural networks after a massive CNS injury. One of the key reasons for this scarcity is the limited regenerative ability of neurons in CNS. Growth-impermissive glial scar and the lack of a synthetic biocompatible platform for proper neural tissue engineering and controlled supply of drugs further retard the healing process. Injectable or implantable hydrogel materials, consisting majorly of water in its porous three-dimensional (3D) structure, can serve as an excellent drug delivery platform as well as a transplanted cell-supporting scaffold medium. Among the various neuro-compatible bioinspired materials, we are limiting our discussion to the recent advancement of engineered biomaterials comprising mainly of peptides and proteins due to their growing demand, low immunogenicity and versatility in the fabrication of neuro regenerative medicine. In this article, we try to explore all the recent scientific avenues that are developing gradually to make peptide and peptide-conjugated biomaterial hydrogels as a therapeutic and supporting scaffold for treating CNS injuries.

Prebiotic Peptides: Molecular Hubs in the Origin of Life

The fundamental roles that peptides and proteins play in today's biology makes it almost indisputable that peptides were key players in the origin of life. Insofar as it is appropriate to extrapolate back from extant biology to the prebiotic world, one must acknowledge the critical importance that interconnected molecular networks, likely with peptides as key components, would have played in life's origin. In this review, we summarize chemical processes involving peptides that could have contributed to early chemical evolution, with an emphasis on molecular interactions between peptides and other classes of organic molecules. We first summarize mechanisms by which amino acids and similar building blocks could have been produced and elaborated into proto-peptides. Next, non-covalent interactions of peptides with other peptides as well as with nucleic acids, lipids, carbohydrates, metal ions, and aromatic molecules are discussed in relation to the possible roles of such interactions in chemical evolution of structure and function. Finally, we describe research involving structural alternatives to peptides and covalent adducts between amino acids/peptides and other classes of molecules. We propose that ample future breakthroughs in origin-of-life chemistry will stem from investigations of interconnected chemical systems in which synergistic interactions between different classes of molecules emerge.

A review on recent advances in polymer and peptide hydrogels

In this review, we focus on the very recent developments on the use of the stimuli responsive properties of polymer hydrogels for targeted drug delivery, tissue engineering, and biosensing utilizing their different optoelectronic properties. Besides, the stimuli-responsive hydrogels, the conducting polymer hydrogels are discussed, with specific attention to the energy generation and storage behavior of the xerogel derived from the hydrogel. The electronic and ionic conducting gels have been discussed that have applications in various electronic devices, e.g., organic field effect transistors, soft robotics, ionic skins, and sensors. The properties of polymer hybrid gels containing carbon nanomaterials have been exemplified here giving attention to applications in supercapacitors, dye sensitized solar cells, photocurrent switching, etc. Recent trends in the properties and applications of some natural polymer gels to produce thermal and acoustic insulating materials, drug delivery vehicles, self-healing material, tissue engineering, etc., are discussed. Besides the polymer gels, peptide gels of different dipeptides, tripeptides, oligopeptides, polypeptides, cyclic peptides, etc., are discussed, giving attention mainly to biosensing, bioimaging, and drug delivery applications. The properties of peptide-based hybrid hydrogels with polymers, nanoparticles, nucleotides, fullerene, etc., are discussed, giving specific attention to drug delivery, cell culture, bio-sensing, and bioimaging properties. Thus, the present review delineates, in short, the preparation, properties, and applications of different polymer and peptide hydrogels prepared in the past few years.

Construction of self-assembled nanostructure-based tetraphenylethylene dipeptides: supramolecular nanobelts as biomimetic hydrogels for cell adhesion and proliferation

A novel TPE-YY peptide hydrogelator self-assembled to form twisted nanobelts at neutral pH, upon cultured with 3A6 cells showed selective cell adhesion and growth.

Minimalistic supramolecular proteoglycan mimics by co-assembly of aromatic peptide and carbohydrate amphiphiles

A modular two-component supramolecular hydrogel composed of a peptide core and carbohydrate shell as a minimalistic mimic of proteoglycans.

We report the co-assembly of aromatic carbohydrate and dipeptide amphiphiles under physiological conditions as a strategy to generate minimalistic proteoglycan mimics. The resulting nanofibers present a structural, fluorenylmethoxycarbonyl-diphenylalanine (Fmoc-FF) core and a functional carbohydrate (Fmoc-glucosamine-6-sulfate or -phosphate) shell. The size, degree of bundling and mechanical properties of the assembled structures depend on the chemical nature of the carbohydrate amphiphile used. In cell culture medium, these nanofibers can further organize into supramolecular hydrogels. We demonstrate that, similar to proteoglycans, the assembled gels prolong the stability of growth factors and preserve the viability of cultured cells. Our results demonstrate that this approach can be applied to the design of extracellular matrix (ECM) substitutes for future regenerative therapies.

Commercially Relevant Orthogonal Multi-Component Supramolecular Hydrogels for Programmed Cell Growth

This study reports the ability of synthetically simple, commercially viable sugar-derived 1,3:2,4-dibenzylidenesorbitol-4',4"-diacylhydrazide (DBS-CONHNH₂ ) to support cell growth. Simple mixing and orthogonal self-sorting can formulate heparin, agarose, and heparin-binding micelles into these gels-easily incorporating additional function. Interestingly, the components used in the gel formulation, direct the ability of cells to grow, meaning the chemical programming of these multi-component gels is directly translated to the biological systems in contact with them. This simple approach has potential for future development in regenerative medicine.

Glucosamine-Based Supramolecular Nanotubes for Human Mesenchymal Cell Therapy

Herein, we demonstrate an example of glucosamine-based supramolecular hydrogels that can be used for human mesenchymal cell therapy. We designed and synthesized a series of amino acid derivatives based on a strategy of capping d-glucosamine moiety at the C-terminus and fluorinated benzyl group at the N-terminus. From a systematic study on chemical structures, we discovered that the glucosamine-based supramolecular hydrogel [pentafluorobenzyl (PFB)-F-Glu] self-assembled with one-dimensional nanotubular structures at physiological pH. The self-assembly of a newly discovered PFB-F-Glu motif is attributed to the synergistic effect of π-π stacking and extensive intermolecular hydrogen bonding network in aqueous medium. Notably, PFB-F-Glu nanotubes are proven to be nontoxic to human mesenchymal stem cells (hMSCs) and have been shown to enhance hMSC proliferation while maintaining their pluripotency. Retaining of pluripotency capabilities provides potentially unlimited source of undifferentiated cells for the treatment of future cell therapies. Furthermore, hMSCs cultured on PFB-F-Glu are able to secrete paracrine factors that downregulate profibrotic gene expression in lipopolysaccharide-treated human skin fibroblasts, which demonstrates that PFB-F-Glu nanotubes have the potential to be used for wound healing applications. Overall, this article addresses the importance of chemical design to generate supramolecular biomaterials for stem cell therapy.

Circular dichroism studies of low molecular weight hydrogelators: The use of SRCD and addressing practical issues

Circular dichroism (CD) spectroscopy has been used extensively for the investigation of the conformation and configuration of chiral molecules, but its use for evaluating the mode of self-assembly in soft materials has been limited. Herein, we report a protocol for the study of such materials by electronic CD spectroscopy using commercial/benchtop instruments and synchrotron radiation (SR) using the B23 beamline available at Diamond Light Source. The use of the B23 beamtime for SRCD was advantageous because of the unique enhanced spatial resolution achieved because of its highly collimated and small beamlight cross section (ca. 250 μm) and higher photon flux in the far UV region (175-250 nm) enhancing the signal-to-noise ratio relative to benchtop CD instruments. A set of low molecular weight (LMW) hydrogelators, comprising two Fmoc-protected enantiomeric monosaccharides and one Fmoc dipeptide (Fmoc-FF), were studied. The research focused on the optimization of sample preparation and handling, which then enabled the characterization of sample conformational homogeneity and thermal stability. CD spectroscopy, in combination with other spectroscopic techniques and microscopy, will allow a better insight into the self-assembly of chiral building blocks into higher order structural architectures.

The effect of carbohydrate structures on the hydrogelation ability and morphology of self-assembled structures of peptide-carbohydrate conjugates in water

We describe the construction of peptide-carbohydrate conjugates, namely glycopeptides, capable of self-assembling in water. We found that disaccharide structures (epimer or glycosidic-bond geometry) appended to the glycopeptides have a noticeable effect on the hydrogel formation ability as well as the morphology of the self-assembled structures. The soft materials consisting of self-assembled structures with carbohydrates on their surface and various types of morphologies might be useful as matrices to investigate the function of carbohydrates in biological events.

Enzymatic Formation of an Injectable Hydrogel from a Glycopeptide as a Biomimetic Scaffold for Vascularization

The construction of functional vascular networks in regenerative tissues is a crucial technology in tissue engineering to ensure the sufficient supply of nutrients. Although natural hydrogels are highly prevalent in fabricating three-dimensional scaffolds to induce neovascular growth, their widespread applicability was limited by the potential risk of immunogenicity or pathogen transmission. Therefore, developing hydrogels with good biocompatibility and cell affinity is highly desirable for fabricating alternative matrices for tissue regeneration applications. Herein, we report the generation of a new kind of hydrogel from supramolecular assembling of a synthetic glycopeptide to mimic the glycosylated microenvironment of extracellular matrix. In the presence of a tyrosine phosphate group, this molecule can undergo supramolecular self-assembling and gelation triggered by alkaline phosphatase under physiological conditions. Following supramolecular self-assembling, the glycopeptide gelator tended to form nanofilament structures displaying a high density of glucose moieties on their surface for endothelial cell adhesion and proliferation. On further incorporation with deferoxamine (DFO), the self-assembled hydrogel can serve as a reservoir for sustainably releasing DFO and inducing endothelial cell capillary morphogenesis in vitro. After subcutaneous injection in mice, the glycopeptide hydrogel encapsulating DFO can work as an effective matrix to trigger the generation of new blood capillaries in vivo.

Tuning carbohydrate density enhances protein binding and inhibition by glycosylated β-sheet peptide nanofibers

The efficacy of glycosylated β-sheet peptide nanofibers for inhibiting carbohydrate-binding proteins can be increased by tuning carbohydrate density to maximize protein binding affinity.

Potentiating the immune response of MUC1-based antitumor vaccines using a peptide-based nanovector as a promising vaccine adjuvant

We utilize the supramolecular self-assembling peptide of Nap-G^DF^DF^DY^DK to construct chemically programmed, self-assembling and self-adjuvant MUC1-based antitumor vaccines.

Temperature and ion dual responsive biphenyl-dipeptide supramolecular hydrogels as extracellular matrix mimic-scaffolds for cell culture applications

Illustration of the gelation process of a new aromatic short peptide gelator based on biphenyl and its application in cell culture.

Synthesis and characterization of amide linked triazolyl glycolipids as molecular hydrogelators and organogelators

Eighteen new glycolipids were synthesized and characterized. All eighteen are effective molecular gelators for at least one solvent and eleven are hydrogelators at concentrations of 0.15–1.0 wt%. The hydrogels are suitable carriers for sustained release of chloramphenicol.

Glucose-bearing biodegradable poly(amino acid) and poly(amino acid)-poly(ester) conjugates for controlled payload release

The glucoseamine-initiated ring-opening polymerisation of amino acid N-carboxyanhydrides and O-carboxanhydrides to yield amphiphilic block copolymers that are capable of self-assembly in aqueous solution to form well-defined, glucose-presenting, particles is reported.