In this work, we reported the generation of a novel supramolecular hydrogelator from a peptide derivative which consisted of a structural motif (e.g., Fc-FF) for supramolecular self-assembly and a functional moiety (e.g., RGD) for integrin binding. Following self-assembly in water at neutral pH, this molecule first tended to form metastable spherical aggregates, which subsequently underwent a morphological transformation to form high-aspect-ratio nanostructures over 2 h when aged at room temperature. More importantly, because of the presence of nanoscale RGD clusters on the surface of nanostructures, the self-assembled nanomaterials (e.g., nanoparticles and nanofibers) can be potentially used as a biomimetic matrix for cell culture and as a vector for cell-targeting drug delivery via multivalent RGD–integrin interactions.Keywords: hydrogel; multivalence; peptide; self-assembly; supramolecular

Glycopeptide-based hydrogelators with well-defined molecular structures and varied contents of sugar moieties were prepared via in vitro peptide glycosylation reactions. With systematic glucose modification, these glycopeptide hydrogelators exhibited diverse self-assembling behaviors in water and formed supramolecular hydrogels with enhanced thermostability and biostability, in comparison with their peptide analogue. Moreover, because of high water content and similar structural morphology and composition to extracellular matrixes (ECM) in tissues, these self-assembled hydrogels also exhibited great potential to act as new biomimetic scaffolds for mammalian cell growth. Therefore, peptide glycosylation proved to be an effective means for peptide modification and generation of novel supramolecular hydrogelators/hydrogels with improved biophysical properties (e.g., high biostability, increased thermostability, and cell adhesion) which could promise potential applications in regenerative medicine.Keywords: glycopeptide; hydrogel; peptide; self-assembly; supramolecular

Here we report the generation of a novel gelator from a glycosylated amino acid derivative, which contained three structural units, an aromatic residue, a carbohydrate moiety and a tert-butyl group in a single molecule. These structural units can promote the supramolecular self-assembly of this gelator in both aprotic and protic solvents via coordinated π–π stacking, multiple hydrogen binding and van der Waals interactions. More importantly, due to their non-equilibrium natures, the organogels formed in DCM, chloroform and ethanol can undergo gel to crystal transition in storage, driven by unbalanced gelator–gelator and solvent–gelator interactions. In this process, the gelators were firstly trapped in a kinetically favorable gel state, and then transferred into a more thermodynamically stable crystal state upon ageing, with the generation of microcrystals in different morphologies.

We report the design and synthesis of a novel probe (1) for ALP assay by incorporating a self-immolative linker between a phosphate moiety and resorufin. Because of its good biocompatibility and rapid cell internalization, this probe also exhibited great potential for real-time monitoring of endogenous phosphatase activity in living cells.

We report the generation of a novel self-assembled platinum (Pt) prodrug from a short peptide derivative, which acted as a substrate for the phosphatase-catalyzed dephosphorylation reaction, and a Pt(IV) complex, which could undergo supramolecular self-assembly in the presence of alkaline phosphatase, and perform controlled release of the Pt(II) drug under the reductive conditions of tumor cells. This self-assembled prodrug showed significant antitumor growth effects on a breast cancer xenograft model based on 4T1 cells in vivo, but much lower toxicity towards the kidney, liver, spleen and other major organs than the free cisplatin drug in mice. Such improved antitumor efficacy could be ascribed to the localized and sustained release of the Pt(II) anticancer drug from the supramolecular self-assembly of the Pt(IV) prodrug, which was triggered by phosphatases in tumor sites.

Simple conjugation of tyrosine-phosphate with tetraphenylethylene generates a new amphiphile, which not only undergoes enzymatic dephosphorylation to generate a relative hydrophobic residue for alkaline phosphatase (ALP) detection with significant enhancement of the fluorescence signals, but also self-assembles in water to result in a novel supramolecular hydrogel with gelation-enhanced fluorescence emission features upon the changes of pH. In addition, the highly ordered micelle nanostructures self-assembled from this amphiphile exhibit the ability to serve as efficient templates to promote the nucleation and growth of calcium phosphate. Since amino acids and peptides are an important class of bioactive entities whose functions range from biomolecular recognition to supramolecular self-assembly, this study demonstrates the potential to generate an amphiphile with a novel molecular architecture from the TPE and amino acid conjugate with multifunctional properties.

We describe here a simple fluorometric assay for the highly sensitive detection of caspase-3 activities on the basis of the inner-filter effect of gold nanoparticles (AuNPs) on CdTe quantum dots (QDs). The method takes advantage of the high molar absorptivity of the plasmon band of gold nanoparticles as well as the large absorption band shift from 520 to 680 nm upon nanoparticle aggregation. When labeled with a peptide possessing the caspase-3 cleavage sequence (DEVD), the monodispersed Au-Ps (peptide-modified AuNPs) exhibited a tendency to aggregate when exposed to caspase-3, which induced the absorption band transition from 520 to 680 nm and turned on the fluorescence of the CdTe QDs for caspase-3 sensing. Under optimum conditions, a high sensitivity towards caspase-3 was achieved with a detection limit as low as 18 pM, which was much lower than the corresponding assays based on absorbance or other approaches. Overall, we demonstrated a facile and sensitive approach for caspase-3 detection, and we expected that this method could be potentially generalized to design more fluorescent assays for sensing other bioactive entities.Keywords: caspase-3; fluorescence; gold nanoparticle; inner-filter effect; quantum dot;

A facile and efficient catalytic system based on Pd nanoclusters generated in situ from Pd(acac)2 was developed for the synthesis of various aromatic azo compounds (AAzos) by hydrogenation of the corresponding nitroaromatics, using H2 as the sole reductant, under mild reaction conditions.

We report the design and synthesis of a novel probe (1) for ALP assay by incorporating a self-immolative linker between a phosphate moiety and resorufin. Because of its good biocompatibility and rapid cell internalization, this probe also exhibited great potential for real-time monitoring of endogenous phosphatase activity in living cells.

We report the generation of a novel self-assembled platinum (Pt) prodrug from a short peptide derivative, which acted as a substrate for the phosphatase-catalyzed dephosphorylation reaction, and a Pt(IV) complex, which could undergo supramolecular self-assembly in the presence of alkaline phosphatase, and perform controlled release of the Pt(II) drug under the reductive conditions of tumor cells. This self-assembled prodrug showed significant antitumor growth effects on a breast cancer xenograft model based on 4T1 cells in vivo, but much lower toxicity towards the kidney, liver, spleen and other major organs than the free cisplatin drug in mice. Such improved antitumor efficacy could be ascribed to the localized and sustained release of the Pt(II) anticancer drug from the supramolecular self-assembly of the Pt(IV) prodrug, which was triggered by phosphatases in tumor sites.

Simple conjugation of tyrosine-phosphate with tetraphenylethylene generates a new amphiphile, which not only undergoes enzymatic dephosphorylation to generate a relative hydrophobic residue for alkaline phosphatase (ALP) detection with significant enhancement of the fluorescence signals, but also self-assembles in water to result in a novel supramolecular hydrogel with gelation-enhanced fluorescence emission features upon the changes of pH. In addition, the highly ordered micelle nanostructures self-assembled from this amphiphile exhibit the ability to serve as efficient templates to promote the nucleation and growth of calcium phosphate. Since amino acids and peptides are an important class of bioactive entities whose functions range from biomolecular recognition to supramolecular self-assembly, this study demonstrates the potential to generate an amphiphile with a novel molecular architecture from the TPE and amino acid conjugate with multifunctional properties.