Fluorescent Mannose-Functionalized Hyperbranched Poly(amido amine)s: Synthesis and Interaction with E. coli

How the Length of Through-Space Conjugation Influences the Clusteroluminescence of Oligo(Phenylene Methylene)s

The length and mode of conjugation directly affect the molecular electronic structure, which has been extensively studied in through-bond conjugation (TBC) systems. Corresponding research greatly promotes the development of TBC-based luminophores. However, how the length and mode of through-space conjugation (TSC), one kind of weak interaction, influence the photophysical properties of non-conjugated luminophores remains a relatively unexplored field. Here, we unveil a non-linear relationship between TSC length and emission characteristics in non-conjugated systems, in contrast to the reported proportional correlation in TBC systems. More specifically, oligo(phenylene methylene)s (OPM[4]-OPM[7]) exhibit stronger TSC and prominent blue clusteroluminescence (CL) (≈440 nm) compared to shorter counterparts (OPM[2] and OPM[3]). OPM[6] demonstrates the highest solid-state quantum yield (40 %), emphasizing the importance of balancing flexibility and rigidity. Further theoretical calculations confirmed that CL of these oligo(phenylene methylene)s was determined by stable TSC derived from the inner rigid Diphenylmethane (DPM) segments within the oligomers instead of the outer ones. This discovery challenges previous assumptions and adds a new dimension to the understanding of TSC-based luminophores in non-conjugated systems.

Conductive Viologen Hydrogel Based on Hyperbranched Polyamidoamine for Multiple Stimulus-Responsive Drug Delivery

The emergence of precision medicine and personalized pharmacotherapy has led to the development of advanced drug delivery systems that can respond to multiple stimuli. Conductive hydrogels have excellent electrical signal responsiveness and drug storage capabilities; however, current conductive hydrogels suffer from poor mechanical properties, low ionic conductivity, and high voltage. Herein, a covalently crosslinked viologen hydrogel was prepared using electroactive hyperbranched polyamidoamine (EHP) as the crosslinking center in a polymeric network. Attributed to its unique molecular architecture, this hydrogel exhibits improved mechanical properties (high tensile strength and desirable stretchability up to 1280%). Approvable ionic conductivity, biocompatibility, antibacterial properties, and wearable strain-sensing performance were also disclosed, ascribed to the participation of versatile viologen groups in the hydrogel structure. This hydrogel exhibited high efficiency in drug release (81.6%) at a lower voltage of -1.2 V. Moreover, fascinating pH-stimulus drug release behavior was also demonstrated in both acidic and alkalescent environments owing to the dramatic conformational transition of EHP. This work provides a new design strategy for conductive hydrogels for multiple stimulus-responsive drug delivery systems.

Bio-inspired nacre-like composites with excellent mechanical properties, gas-barrier function and fire-retardant performances based on self-assembly between hyperbranched poly(amido amine)s and montmorillonite

The fabrication of mechanically robust multifunctional nanocomposite (NC) films using simple but effective strategies is a long-term challenge. Inspired by natural nacre, we designed and fabricated high-performance nacre-like NC films (Na-MTM/HBP) through the self-assembly of the hyperbranched poly(amido amine) (HBP) and montmorillonite (Na-MTM) using a vacuum filtration approach. The optimal Na-MTM/HBP NC film shows excellent mechanical strength (106 MPa), which can be attributed to the formation of numerous hydrogen bonds and the electrostatic interactions between hyperbranched HBP and Na-MTM nanosheets. Such films also exhibit excellent gas barrier and fire-fire-retardant owing to the high aspect ratio of the Na-MTM nanosheets. In this work, a class of high-performance NC films exhibiting good mechanical, gas barrier, and flame retardancy properties have been developed. These NC films have great potential in packing or coating materials.

Weakly Acidic pH and Reduction Dual Stimuli-Responsive Gel Particles

This paper reports the facile preparation of dual stimuli-responsive gel particles that simultaneously respond to weakly acidic and reducing stimuli and the application of these gel particles as a drug delivery carrier. The dual stimuli-responsive gel particles composed of a pH-responsive polymer network cross-linked with reduction stimuli-responsive disulfide cross-links, and biocompatible poly(ethylene glycol) cross-links were prepared by soap-free emulsion polymerization. The resulting gel particles were colloidally stable at physiological ionic strength and had a diameter of approximately 200 nm with a narrow size distribution. The resulting gel particles slightly swelled in an acidic environment. On the other hand, the gel particles drastically swelled under simultaneous weakly acidic and reducing conditions because of the ionization of tertiary amino groups in the gel network and a decrease in the cross-linking density resulting from cleavage of the disulfide cross-links. When cells were treated with the gel particles, they were taken up by cells via the endocytosis pathway and distributed in the cytosol after endosomal escape by the proton sponge effect. In addition, a hydrophobic drug, doxorubicin (Dox), was loaded into the gel particles through hydrophobic interactions. Dox was released from the gel particles under weakly acidic and reducing conditions, while the Dox release was inhibited at neutral pH. The weakly acidic pH- and reduction stimuli-responsive release of Dox from gel particles was attributed to the drastic swelling of these particles. The fascinating properties of the dual stimuli-responsive gel particles suggest that they can provide a useful platform for designing intracellular drug delivery carriers.

Recent Advances in Clusteroluminescence

Clusteroluminescence is a phenomenon whereby the aggregation or clustering of non-conjugated electron-rich units leads to the emission of light at long wavelengths. This phenomenon was first discovered in poly(amido amine) (PAMAM) dendrimers. In recent years, clusteroluminescence has attracted growing research interest and its photophysical properties and mechanism have been thoroughly studied. In this review, we first briefly introduce the development of different types of clusteroluminogens. Then we highlight recent developments in clusteroluminescence, including mechanistic studies, the disclosure of room-temperature phosphorescence, and the extension of emission to the longer-wavelength region. Lastly, we demonstrate a few applications in various fields. With advantages such as being earth-abundant, biocompatible and biodegradable, clusteroluminogens are envisioned to be commonplace in the future.

Fluorescence in "Nonfluorescent" Polymers

Recently, a great deal of research has been started on generating fairly strong photoluminescence from organic molecules without having any conjugated π-system or fluorophore. Discrete chromophores or auxochromophores termed as "subfluorophores" may undergo "space conjugation" via co-operative intramolecular conformation followed by intermolecular aggregation to generate fluorescence or sometimes phosphorescence emission. Polymeric materials are important in this regard as nonconjugated polymers self-assemble/aggregate in a moderately concentrated solution and also in the solid state, producing membranes, films, and so forth with good physical and mechanical properties. Therefore, promoting fluorescence in these commodity polymers is very much useful for sensing, organic light emitting diodes (OLED), and biological applications. In this perspective, we have discussed the aggregation-induced emission from four different types of architectures, for example, (i) dendrimers or hyperbranched polymers, (ii) entrapped polymeric micellar self-assembly, (iii) cluster formation, and (iv) stretching-induced aggregation, begining with the genesis of fluorescence from aggregation of propeller-shaped small organic molecules. The mechanism of induced fluorescence of polymers with subfluorophoric groups is also discussed from the theoretical calculations of the energy bands in the aggregated state. Also, an attempt has been made to highlight some useful applications in the sensing of surfactants, bacteria, cell imaging, drug delivery, gene delivery, OLED, and so forth.

Cationic Peptidopolysaccharide with an Intrinsic AIE Effect for Combating Bacteria and Multicolor Imaging

An antibacterial polymer peptidopolysaccharide (COS-AMP) that integrates antibacterial and detection functions is constructed with a simple synthetic method. The COS-AMP is constructed by simulating the structure of peptidoglycan of the bacterial cell wall with chitooligosaccharide with intrinsic aggregation-induced emission (AIE) effect as the main chain, as well as a peptide polymer grafted onto its amino group. Based on the AIE effect and excitation-dependent fluorescence of COS-AMP, it is tentatively applied to multicolor imaging and quantification of bacteria. This multicolor imaging helps to match different excitation sources of fluorescent instrument for straightforward imaging and detection. The structural similarity with the bacterial cell wall component facilitates the passage of COS-AMP across the cell wall and destroys the bacterial structure, thus it has a good broad-spectrum antibacterial activity. In addition, aromatic fluorophores are not needed, and excellent biocompatibility will make it have broad application prospects.

Light-Emitting Multifunctional Maleic Acid-co-2-(N-(hydroxymethyl)acrylamido)succinic Acid-co-N-(hydroxymethyl)acrylamide for Fe(III) Sensing, Removal, and Cell Imaging

The intrinsically fluorescent highly hydrophilic multifunctional aliphatic terpolymer, maleic acid (MA)-co-2-(N-(hydroxymethyl)acrylamido)succinic acid (NHASA)-co-N-(hydroxymethyl)acrylamide (NHMA), that is, 1, was designed and synthesized via C-C/N-C-coupled in situ allocation of a fluorophore monomer, that is, NHASA, composed of amido and carboxylic acid functionalities in the polymerization of two nonemissive MA and NHMA. The scalable and reusable intrinsically fluorescent biocompatible 1 was suitable for sensing and high-performance adsorptive exclusion of Fe(III), along with the imaging of Madin-Darby canine kidney cells. The structure of 1, in situ fluorophore monomer, aggregation-induced enhanced emission, cell-imaging ability, and superadsorption mechanism were studied via microstructural analyses using 1H/13C NMR, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, atomic absorption spectroscopy, ultraviolet-visible spectroscopy, thermogravimetric analysis, dynamic light scattering, high-resolution transmission electron microscopy, solid-state fluorescence, fluorescence lifetime, and fluorescence imaging, along with measuring kinetics, isotherms, and thermodynamic parameters. The location, electronic structures, and geometries of the fluorophore and absorption and emission properties of 1 were investigated using density functional theory and natural transition orbital analyses. The limit of detection and the maximum adsorption capacity were 2.45 × 10-7 M and 542.81 mg g-1, respectively.

Fluorescent Terpolymers via In Situ Allocation of Aliphatic Fluorophore Monomers: Fe(III) Sensor, High-Performance Removals, and Bioimaging

Herein, purely aliphatic intrinsically fluorescent terpolymers, i.e., 1 and 2, are synthesized through one-pot solution polymerization via N-H functionalized and multi C-C/C-N coupled in situ protrusion of fluorescent monomers using two nonemissive monomers. These scalable terpolymers are suitable for highly selective Fe(III) sensing, high-performance exclusion of Fe(III), logic function and the imaging of normal mammalian Madin-Darby canine kidney and human osteosarcoma cancer cell lines. The structures of terpolymers, in situ attachment of fluorescent monomers, clusteroluminescence, adsorption-mechanism, and cell-imaging abilities are understood via unadsorbed and/or adsorbed microstructural analyses using ¹ H/¹³ C NMR, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, UV-vis spectroscopy, atomic absorption spectroscopy, thermogravimetric analysis, high-resolution transmission electron microscopy, dynamic light scattering, fluorescence imaging, and fluorescence lifetime. The geometries, electronic structures, location of fluorophores, and singlet-singlet absorption and emission of terpolymers are examined using density functional theory (DFT) and time-dependent DFT. For the precise identification of fluorophores, transition from occupied natural transition orbitals (NTOs) to unoccupied NTOs is computed. For 1/2, limit of detection (LOD) values and adsorption capacities are 6.0 × 10^-7 /8.0 × 10^-7 m and 147.82/120.56 mg g^-1 at pH_i = 7.0 and 303 K, respectively. The overall properties of 1 are more advantageous compared to 2 in sensing, cell imaging, and adsorptive exclusion of Fe(III).

Bioreducible and acid-labile polydiethylenetriamines with sequential degradability for efficient transgelin-2 siRNA delivery

The transgelin-2 (TAGLN2) protein plays an important role in multidrug resistance in human breast cancer. siRNA mediated gene silencing of TAGLN2 is a promising strategy for paclitaxel resistance reversal in breast cancer. In this study, a series of bioreducible and acid-labile polydiethylenetriamines (PDs) with different proportions of cross-linkers were synthesized. TAGLN2 siRNA was condensed by PDs to form dual-responsive nanocomplexes, and these nanocomplexes were hypothesized to partially degrade in the acidic environment of endosomes, and then completely degrade in the reducing environment of the cytoplasm to release siRNA. It was found that PDs have good water solubility, acid-base buffering capacity, suitable degradability and high biocompatibility. Moreover, PDCKM can deliver TAGLN2 siRNA into MCF-7/PTX cells and inhibit the expression of TAGLN2 even better than PEI 25k. Besides, paclitaxel showed higher cytotoxicity in cells incubated with PDCKM/TAGLN2 siRNA nanocomplexes. These results suggested that PDs have great potential for safe and efficient siRNA delivery to reverse paclitaxel resistance in breast cancer.

A dual-responsive biosensor for blood lead detection

Simple and accurate detection of trace heavy metals in blood is very important. A novel dual-responsive electrochemical/fluorescent biosensor based on magnetic hyperbranched polyamide with heparin modification (MHPAM-H) for blood lead detection has been successfully developed. Upon conjugated with blood lead ions, dual-biosensor could not only display electrochemical signal but also fluorescence signal owing to the enriched amino groups, cavity structure, and good fluorescence properties of HPAM. Blood biocompatibility, construction of the dual-responsive biosensor, electrochemical/fluorescent detection of lead ions in water phase and blood condition, selectivity and stability of the dual-responsive biosensor were investigated in detail. The proposed dual-responsive biosensor displays good linear relationship (1.5 pM- 4.8 × 10³ pM for electrochemical detection and 0.5 pM-4.8 × 10³ pM for fluorescent detection) with low detection limit (4.4 pM for electrochemical detection and 1.0 pM for fluorescent detection) for blood lead, providing potential application for blood lead detection in the future.

Glutathione-Induced Structural Transform of Double-Cross-Linked PEGylated Nanogel for Efficient Intracellular Anticancer Drug Delivery

A glutathione-sensitive poly[methacrylic acid- co-poly(ethylene glycol) methyl ether methacrylate] (PMAA_BACy- co-PEGMA) nanogel with tunable stability has been fabricated through covalent and metal double-cross-linking strategies in response to the differential change of GSH concentration between the inside and outside of tumor cells. Herein, the size-controlled PMAA- co-PEGMA that possessed unique core-shell structure was first obtained via adjusting the length of PEGMA. Furthermore, N, N-bis(acryloyl)cystamine was introduced to endow PMAA- co-PEGMA with glutathione-sensitive property. The PMAA_BACy- co-PEGMA₉₅₀ nanogel exhibited reasonable particle size and desired hydrodynamic diameter that was further cross-linked by Fe(III) ions to obtain a double-cross-linked PMAA_BACy/Fe(III)- co-PEGMA₉₅₀ vehicle. In this double-cross-linked vehicle, the existence of metal cross-linked structure made this vehicle possess favorable structural stability to restrict the premature leakage of therapeutic drug. The introduction of covalent cross-linked structure synchronously imparted the vehicle with glutathione-sensitive property in response to the high intracellular glutathione concentrations in tumor cells to induce its structural transform for realizing the release of drug. Additionally, a series of in vitro evaluations demonstrated that PMAA_BACy/Fe(III)- co-PEGMA₉₅₀ displayed remarkable biocompatibility and glutathione-sensitive release toward anticancer drug in the simulated intracellular environment of tumor tissues. Notably, the drug-loaded PMAA_BACy/Fe(III)- co-PEGMA₉₅₀ exhibited excellent anticancer activity against tumor cells. The double-cross-linked PMAA_BACy/Fe(III)- co-PEGMA₉₅₀ nanogel therefore is expected to be a promising tumor microenvironment-sensitive platform for delivering chemotherapeutic drugs.

Label-Free Fluorescent Poly(amidoamine) Dendrimer for Traceable and Controlled Drug Delivery

Poly(amidoamine) dendrimer (PAMAM) is well-known for its high efficiency as a drug delivery vehicle. However, the intrinsic cytotoxicity and lack of a detectable signal to facilitate tracking have impeded its practical applications. Herein, we have developed a novel label-free fluorescent and biocompatible PAMAM derivative by simple surface modification of PAMAM using acetaldehyde. The modified PAMAM possessed a strong green fluorescence, which was generated by the C=N bonds of the resulting Schiff Bases via n-π* transition, while the intrinsic cytotoxicity of PAMAM was simultaneously ameliorated. Through further PEGylation, the fluorescent PAMAM demonstrated excellent intracellular tracking in human melanoma SKMEL28 cells. In addition, our PEGylated fluorescent PAMAM derivative achieved enhanced loading and delivery efficiency of the anticancer drug doxorubicin (DOX) compared to the original PAMAM. Importantly, the accelerated kinetics of DOX-encapsulated fluorescent PAMAM nanocomposites in an acidic environment facilitated intracellular drug release, which demonstrated comparable cytotoxicity to that of the free-form doxorubicin hydrochloride (DOX·HCl) against melanoma cells. Overall, our label free fluorescent PAMAM derivative offers a new opportunity of traceable and controlled delivery for DOX and other drugs of potential clinical importance.

Bio-inspired nitric-oxide-driven nanomotor

Current chemical-fuel-driven nanomotors are driven by gas (e.g. H₂, O₂, NH₃) which only provides motion ability, and can produce waste (e.g. Mg(OH)₂, Pt). Here, inspired by endogenous biochemical reactions in the human body involving conversion of amino acid L-arginine to nitric oxide (NO) by NO synthase (NOS) or reactive oxygen species (ROS), we report on a nanomotor made of hyperbranched polyamide/L-arginine (HLA). The nanomotor utilizes L-arginine as fuel for the production of NO both as driving force and to provide beneficial effects, including promoting endothelialisation and anticancer effects, along with other beneficial by-products. In addition, the HLA nanomotors are fluorescent and can be used to monitor the movement of nanomotors in vivo in the future. This work presents a zero-waste, self-destroyed and self-imaging nanomotor with potential biological application for the treatment of various diseases in different tissues including blood vessels and tumours.

Depletion of propellant in chemical-fuel-driven nanomotors is a limiting factor in device design and application. Here, the authors create a nitric-oxide-generating nanoparticle and explore cellular uptake and application of the nanomotors in nitric oxide treatments.

Specific Immobilization of Escherichia coli Expressing Recombinant Glycerol Dehydrogenase on Mannose-Functionalized Magnetic Nanoparticles

Mannose-functionalized magnetic nanoparticles were prepared for the immobilization of Escherichia coli cells harboring the recombinant glycerol dehydrogenase gene. Immobilization of whole E. coli cells on the carrier was carried out through specific binding between mannose on the nanoparticles and the FimH lectin on the E. coli cell surface via hydrogen bonds and hydrophobic interactions. The effects of various factors including cell concentration, pH, temperature, and buffer concentration were investigated. High degrees of immobilization (84%) and recovery of activity (82%) were obtained under the following conditions: cell/support 1.3 mg/mL, immobilization time 2 h, pH 8.0, temperature 4°C, and buffer concentration 50 mM. Compared with the free cells, the thermostability of the immobilized cells was improved 2.56-fold at 37 °C. More than 50% of the initial activity of the immobilized cells remained after 10 cycles. The immobilized cells were evaluated functionally by monitoring the catalytic conversion of glycerol to 1,3-dihydroxyacetone (DHA). After a 12 h reaction, the DHA produced by the immobilized cells was two-fold higher than that produced by the free cells. These results indicate that mannose-functionalized magnetic nanoparticles can be used for the specific recognition of gram-negative bacteria, which gives them great potential in applications such as the preparation of biocatalysts and biosensors and clinical diagnosis.

Nanoengineered Peptide-Grafted Hyperbranched Polymers for Killing of Bacteria Monitored in Real Time via Intrinsic Aggregation-Induced Emission

Facing the global health crisis caused by drug-resistant bacteria, antimicrobial peptides and their analogues offer exciting solutions to this widespread problem. Without additionally introducing a fluorescent probe, novel nanoengineered peptide-grafted hyperbranched polymers (NPGHPs) are constructed for their combined outstanding antimicrobial activity and sensitive bacterial detection in real time. Hyperbranched polyamide amine (H-PAMAM) that exhibits aggregation-induced emission (AIE) effects is synthesized. Then, NPGHPs are prepared by ring-opening polymerization of α-amino acid N-carboxyanhydrides on the periphery of the H-PAMAM. The NPGHPs exhibit high-efficiency antibacterial properties against a wide spectrum of bacteria, especially against Gram-negative bacteria. On the basis of the AIE effect of NPGHPs, the interaction between NPGHPs and Escherichia coli is explored and the fluorescence intensity of NPGHPs is dependent on the number of E. coli present. Thus, a method for monitoring E. coli concentration is developed, and the detection limit is 1 × 10⁴ CFU mL^-1. Furthermore, NPGHPs are used as fluorescent probes to visualize antibacterial process via lighting-up bacteria. NPGHPs can penetrate the membrane of bacteria and cause cell rupture and apoptosis. In addition, the excellent selectivity of NPGHPs toward bacteria over mammalian cells makes them bright prospects for clinical applications.

Fluorescence of Nonaromatic Organic Systems and Room Temperature Phosphorescence of Organic Luminogens: The Intrinsic Principle and Recent Progress

Following the development of photoluminescence systems with various compositions, some nontraditional structures, including nonaromatic organic systems as fluorophores and organic luminogens as the source of phosphorescence emission at room temperature, have attracted considerable attention for their advantages in biological and medical applications, and for the updated photophysical understandings in science. In this Review, the recent progress in understanding these organic compounds or polymers for fluorescence and phosphorescence is briefly summarized, with the aim of exploring the intrinsic principle of these novel photoluminescence systems and providing reasonable constructs for molecular design. Finally, some prospects are suggested for further development of this continually expanding area of research, with the coined concept of Molecular Uniting Set Identified Characteristic (MUSIC).

A Simple Mannose-Coated Poly (p-Phenylene Ethynylene) for Qualitative Bacterial Capturing

A mannose-functionalized poly (p-phenylene ethynylene) was rationally designed to achieve selective detection of bacteria. The polymer was constructed as a signaling unit and was modified by attaching aminoethyl mannose using the carboxylic acid group at the end of the linker. Incubation of Escherichia coli with the polymer yielded fluorescent bacteria aggregates through polyvalent interactions. The utility of the mannose functionalized polymer to detect E. coli expressing functional FimH mannose-specific lectin on their surface was also demonstrated. The sugar units displayed on the surface of the polymer retained their functional ability to interact with mannose-binding lectin. To determine the optimum binding time, we measured the fluorescence intensity of the polymer-bacteria suspension at intervals. Our results showed that binding in this system will reach an optimum level within 30 min of incubation. The polymer’s affinity for bacteria has been demonstrated and bacteria with a concentration of 10³ CFU mL⁻¹ can be detected by this system.

Autofluorescent Polymers: 1 H,1 H,2 H,2 H-Perfluoro-1-decanol Grafted Poly(styrene- b-acrylic acid) Block Copolymers without Conventional Fluorophore

Recently, although several unconventional luminescent polymers have been synthesized, it still remains a significant challenge to prepare various new fluorescent polymers by functionalization of nonfluorescent polymers. A nonfluorescent 1 H,1 H,2 H,2 H-perfluoro-1-decanol grafted to nonfluorescent polystyrene- b-poly(acrylic acid) block copolymers through simply esterification reaction can exhibit strong blue emission. On the basis of control experiments and theoretical simulation, we have proposed that the luminescence stems from interchain n → π* interaction between the lone pair (n) of hydroxyl O atoms of carboxyl units and empty π* orbital of ester carbonyl unit. In addition, the fluorescent polymers are successfully employed for fluorescence imaging in living HeLa cell.

Highly photostable nanogels for fluorescence-based theranostics

A novel photo-crosslinkable nanogel is prepared from a biodegradable polymer template with intrinsic photoluminescence and high photostability. The fluorescent nanogels display excellent biodegradability and cytocompatibility owed to the facile synthesis scheme involving a solvent-and surfactant-free one-pot reaction, derived entirely from biocompatible monomers citric acid, maleic acid, L-cysteine, and poly(ethylene glycol). The resultant nanogels are less than 200 nm in diameter with a narrow size distribution and monodispersity, and demonstrate long-term structural stability in biological buffer for two weeks. To gauge potential in theranostic applications, the fluorescent nanogels were surface functionalized with biologically active RGD peptides and encapsulated with active anti-cancer drug Doxorubicin, resulting in a pH-responsive controlled drug release in acidic pH resembling tumor environments. The strong fluorescence of the nanogels enabled tracking of targeted drug delivery, showing that drug-loaded nanogels homed into the cytoplasmic regions of prostate cancer cells to significantly induce cell death. These photo-crosslinkable and biodegradable nanogels pose as a strong candidate for theranostic medicine, demonstrating versatile functionalization, high stability in biological buffers, and capacity for real-time fluorescence-based monitoring of targeted drug delivery.

The Role of Galectin-1 in Cancer Progression, and Synthetic Multivalent Systems for the Study of Galectin-1

This review discusses the role of galectin-1 in the tumor microenvironment. First, the structure and function of galectin-1 are discussed. Galectin-1, a member of the galectin family of lectins, is a functionally dimeric galactoside-binding protein. Although galectin-1 has both intracellular and extracellular functions, the defining carbohydrate-binding role occurs extracellularly. In this review, the extracellular roles of galectin-1 in cancer processes are discussed. In particular, the importance of multivalent interactions in galectin-1 mediated cellular processes is reviewed. Multivalent interactions involving galectin-1 in cellular adhesion, mobility and invasion, tumor-induced angiogenesis, and apoptosis are presented. Although the mechanisms of action of galectin-1 in these processes are still not well understood, the overexpression of galectin-1 in cancer progression indicates that the role of galectin-1 is significant. To conclude this review, synthetic frameworks that have been used to modulate galectin-1 processes are reviewed. Small molecule oligomers of carbohydrates, carbohydrate-functionalized pseudopolyrotaxanes, cyclodextrins, calixarenes, and glycodendrimers are presented. These synthetic multivalent systems serve as important tools for studying galectin-1 mediated cancer cellular functions.

Guanidinylated bioresponsive poly(amido amine)s designed for intranuclear gene delivery

Guanidinylated poly(amido amine)s with multiple disulfide linkages (Gua-SS-PAAs) were designed and constructed as nonviral gene carriers. The main chains of these novel carriers were synthesized based on monomers containing guanidino groups (guanidine hydrochloride and chlorhexidine), which could avoid complicated side-chain-modification reactions while introducing the guanidino groups. The synthesized Gua-SS-PAAs polymers were characterized by ¹H nuclear magnetic resonance, molecular weight, and polydispersity. Furthermore, Gua-SS-PAAs polymers were complexed with pDNA, and the properties of the complexes were determined, including entrapment efficiency, particle size, ζ-potential, atomic force microscopy images, stability, DNA complexation ability, reduction sensitivity, cytotoxicity, and transfection efficiency. The new Gua-SS-PAAs carriers exhibited higher transfection efficiency and lower cytotoxicity compared with two widely used gene delivery carriers, polyethylenimine and lipofectamine 2000. Furthermore, the relationship between the side-chain structure and morphological/biological properties was extrapolated, and the results showed that guanidine in the side chain aids in the improvement of transfection efficiency. In addition, the introduction of guanidino group might confer the new carriers with nuclear localization function compared to carriers without it.

Histone-inspired biomimetic polymeric gene vehicles with excellent biocompatibility and enhanced transfection efficacy

Histone-inspired biomimetic polymeric gene vectors show great biocompatibility and enhanced transfection efficacy.

Facile one-pot synthesis of novel water-soluble fluorescent hyperbranched poly(amino esters)

Two kinds of water-soluble fluorescent hyperbranched poly(amino esters) were first synthesized by a convenient one-pot approach via the A₂ + B₃ Michael addition reaction of trimethylolpropane triacrylate and aliphatic diamines.

Hydrosoluble aliphatic tertiary amine-containing hyperbranched polysiloxanes with bright blue photoluminescence

Two hydrosoluble aliphatic tertiary amine-containing hyperbranched polysiloxanes are explored. The resulting conventional chromophore-free polymers, without any treatment, such as acidification or oxidation, can emit bright blue fluorescence.

Tough and strong nacre-like composites from hyperbranched poly(amido amine) and clay nanosheets cross-linked by genipin

Tough and strong nacre-like composite films were fabricated from hyperbranched poly(amido amine) (HPAMAM) and clay nanosheets with the aid of genipin crosslinking.