Xinru Jia

A dual-targeting nanocarrier based on poly(amidoamine) dendrimers conjugated with transferrin and tamoxifen for treating brain gliomas

A pH-sensitive dual-targeting drug carrier (G4-DOX-PEG-Tf-TAM) was synthesized with transferrin (Tf) conjugated on the exterior and Tamoxifen (TAM) in the interior of the fourth generation PAMAM dendrimers for enhancing the blood-brain barrier (BBB) transportation and improving the drug accumulation in the glioma cells. It was found that, on average, 7 doxorubicine (DOX) molecules, over 30 PEG(1000) and PEG(2000) chains and one Tf group were bonded on the periphery of each G4 PAMAM dendrimer, while 29 TAM molecules were encapsulated into the interior of per dendrimer. The pH-triggered DOX release was 32% at pH 4.5 and 6% at pH 7.4, indicating a comparatively fast drug release at weak acidic condition and stable state of the carrier at physiological environment. The in vitro assay of the drug transport across the BBB model showed that G4-DOX-PEG-Tf-TAM exhibited higher BBB transportation ability with the transporting ratio of 6.06% in 3 h. The carrier was internalized into C6 glioma cells upon crossing the BBB model by the coactions of TfR-mediated endocytosis and the inhibition effect of TAM to the drug efflux transports. Moreover, it also displayed the in vitro accumulation of DOX in the avascular C6 glioma spheroids made the tumor volume effectively reduced.

PEGylated Poly(amidoamine) dendrimer-based dual-targeting carrier for treating brain tumors

A dual-targeting drug carrier (PAMAM-PEG-WGA-Tf) based on the PEGylated fourth generation (G = 4.0) PAMAM dendrimer with transferrin (Tf) and wheat germ agglutinin (WGA) on the periphery and doxorubicin (DOX) loaded in the interior was synthesized and its BBB penetration and tumor targeting properties were explored. DLS and TEM measurements revealed the size of PAMAM-PEG-WGA-Tf was in the range of 14-20 nm. It reduced the cytotoxicity of DOX to the normal cells greatly, while efficiently inhibited the growth rate of the C6 glioma cells. The assay of transport across the BBB showed that PAMAM-PEG-WGA-Tf delivered 13.5% of DOX in a period of 2 h, demonstrating an enhanced transport ratio as compared to the ratio of 8% for PAMAM-PEG-WGA, 7% for PAMAM-PEG-Tf and 5% for free DOX in the same period of time. The accumulation of DOX in the tumor site was increased due to the targeting effects of both Tf and WGA, leading to the complete breakage of the avascular C6 glioma spheroids in vitro.

Reversible Tuning Luminescent Color and Emission Intensity: A Dipeptide‐Based Light‐Emitting Material

A smart luminescent material whose emission color and emission intensity can be separately modulated by external force is demonstrated. The rational manipulation of rich noncovalent interactions and fluorophore packing style promotes an in-depth understanding between supramolecular structure and photophysical property and offers an effective strategy to modulate the light-emitting property in a predicative way.

Mechanically Induced Multicolor Switching Based on a Single Organic Molecule

Asserting its independence: A single organic molecule containing pyrene and rhodamine B chromophores separated by a peptide spacer formed a mechanochromic material whose fluorescence could be switched from blue to bluish-green and reddish by grinding. Modulation of the overlapped packing pattern of the pyrene excimer for blue emission was crucial for the reversible tricolored switching observed.

A Mechanochromic Single Crystal: Turning Two Color Changes into a Tricolored Switch

The single crystal of M-4-B was obtained by attaching the boron of BH3 to the amine linker between a tetraphenylethylene (TPE) unit and rhodamine B. M-4-B showed a novel sequential tricolor switching from dark blue to bluish-green and to a reddish color upon grinding. The boron atom played a key role in developing the single crystal.

A Dipeptide‐Based Multicolored‐Switching Luminescent Solid Material: When Molecular Assemblies Meet Mechanochemical Reaction

Color schemes: A mechanochromic material composed of two types of peptides bearing a pyrene group and rhodamine B moieties, respectively, displays multiluminescent colors, such as blue, green, and reddish in one sample (see picture). The mechanochromic behavior is based on a combined switching of molecular assemblies and chemical structure.

Glycine-glutamic-acid-based organogelators and their fluoride anion responsive properties

Novel low-molecular-weight organogelators (LMOGs) 1 and 2 derived from glycine-glutamic-acids (GGA) based dipeptide were synthesized. The difference on the chemical structures between 1 and 2 resulted in some interesting variations on their gelling behavior and fluoride anion (F−) responsive properties. Gelator 1 could gel aromatic solvents effectively, while gelator 2 possessed excellent gelation ability in protic solvents. Upon the addition of 0.5 equiv. F−, the toluene gel of 1 transformed into solution due to the disruption of the intermolecular hydrogen-bonding, whereas the alcohol gel of 2 was stable and preserved even by introducing 20 equiv. F−. Interestingly, 2 could be regarded as an efficient receptor for F− in acetonitrile (MeCN) solution. After the addition of F−, the fluorescent emission band of 2 red-shifted from 360 to 420 nm with the emission intensity enhanced drastically; the intensity of the CD signal decreased and almost disappeared after addition of 2 equiv. F−. These changes were due to the conformational change and hydrogen-bonding interaction between urea groups and F−. The results indicated that GGA-based 1 and 2 might represent potential sensor materials for the naked-eye detection of F−.

A Novel Mechanochromic and Photochromic Polymer Film: When Rhodamine Joins Polyurethane

A rhodamine-based molecule, Rh-OH, is synthesized. Rh-OH exhibits a reversible mechanochromic luminescent character but a passivating response to UV light. An elastomeric polymer film based on polyurethane with embedded Rh-OH is prepared via a polycondensation reaction. The film shows mechanochromic and photochromic properties with reversible color change, which originates from the isomerization of the Rh-OH molecule from a twisted spirolactam in the ring-closed form to a planarized zwitterionic structure in the ring-open state.

Fine-tuning the mechanofluorochromic properties of benzothiadiazole-cored cyano-substituted diphenylethene derivatives through D–A effect

We synthesized three new benzothiadiazole-cored cyano-substituted diphenylethene derivatives (PT-OMe, PT-H, and PT-CF3) with different methoxy, hydrogen, and trifluoromethyl end groups, and the synthesis confirmed by standard spectroscopic methods. These end groups endowed them with different donor–acceptor (D–A) effects, and they provide them with a peculiar and completely opposite mechanofluorochromic property. Red-shifted mechanofluorochromic features were found in the PT-OMe and PT-H compounds, while on the contrary, PT-CF3 showed blue-shifted mechanofluorochromic behavior. The mechanofluorochromic mechanism was explored and attributed to the metastable state of the ground compounds and the crystalline-amorphous phase transformation between the original and ground states. Moreover, these derivatives showed reversible significant mechanofluorochromic properties and reproducibility between ground and annealed states, making them promising stimuli-responsive and smart luminescent materials for mechanosensors, fluorescence switches and light-emitting device applications. The introduction of the D–A effect strategy demonstrated in this work would provide a new path to fine tune the optical features of mechanofluorochromic materials with unique and diverse fluorescent properties.

A Novel Poly(amido amine)‐Dendrimer‐Based Hydrogel as a Mimic for the Extracellular Matrix

The extracellular matrix is mimicked by a novel dendrimer-based hydrogel, which exhibits a highly interconnected porous network, enhanced mechanical stiffness, and a low swelling ratio. The hydrogel system supports the proliferation and differentiation of mesenchymal stem cells without any cytotoxic effects. This dendrimer-based hydrogel may serve as a model for developing new advanced materials with applications in tissue engineering.