Perylene-cored star-shaped polycations for fluorescent gene vectors and bioimaging

Efficient gene delivery by multifunctional star poly (β-amino ester)s into difficult-to-transfect macrophages for M1 polarization

Gene delivery to macrophages holds great promise for cancer immunotherapy. However, traditional gene delivery methods exhibit low transfection efficiency in macrophages. The star-shaped topological structure of polymers is known to encapsulate genes inside their cores, thereby facilitating sustained release of the genetic material. Herein, combining the structural advantages of star polymers and the transfection advantages of poly (β-amino ester)s (PAEs), we developed a novel linear oligomer grafting-onto strategy to synthesize a library of multi-terminal star structured PAEs (SPAEs), and evaluated their gene delivery efficiency in various tissue cells. The transfection with human hepatocellular carcinoma cells (HepG2, HCC-LM3 cells and MHCC-97H cells), rat normal liver cells (BRL-3 A cells), human ovarian cancer cells (A2780 cells), African green monkey kidney cells (Vero cells), human cervical cancer cells (HeLa cells), human chondrosarcoma cells (SW1353 cells), and difficult-to-transfect human epidermal keratinocytes (HaCaT cells) and normal human fibroblast cells (NHF cells) showed that SPAEs exhibited superior transfection profile. The GFP transfection efficiency of top-performing SPAEs in HeLa cells (96.1%) was 2.1-fold, and 3.2-fold higher compared to jetPEI and Lipo3000, respectively, indicating that the star-shaped topological structure can significantly enhance the transfection efficiency of PAEs. More importantly, the top-performing SPAEs could efficiently deliver Nod2 DNA to difficult-to-transfect RAW264.7 macrophages, with a high transfection efficiency of 33.9%, which could promote macrophage M1 polarization and enhanced CD8+ T cell response in co-incubation experiments. This work advances gene therapy by targeting difficult-to-transfect macrophages and remodeling the tumor immune microenvironment.

Protein Recognition Based on Temperature-Stimulated Multiparameter Response Virtual Array Sensing Strategy

In the field of array sensing, researchers are committed to miniaturizing array sensing systems while ensuring the acquisition of multiple sensing information. Here, a new strategy called "stimulus responsive array sensing" was presented to obtain virtual multiple sensing without constructing multiple physical sensing units. Based on bioluminescence resonance energy transfer, where luciferase acts as the donor and temperature stimulus response polymers act as the receptors, by using only one sensing unit to output multiple stimulus responsive sensing signals in temperature dimension, an equivalent array sensing could be achieved. This strategy can distinguish and quantify a variety of proteins. More importantly, glucose responsive monomers were doped in polymers; thus, more virtual sensing units can be further increased to obtain more sensing signals, greatly increasing the accuracy of protein recognition, and it can also be used to differentiate several compositions of protein under different glucose concentrations in urine caused by different renal diseases. The results show the potential of the "stimulus responsive array sensing" for analyzing molecular compositions in complex biological systems and show a new tack in array sensing.

Unlocking the Potential of Carbon Quantum Dots for Cell Imaging, Intracellular Localization, and Gene Expression Control in Arabidopsis thaliana (L.) Heynh

Utilizing carbon quantum dots (CQDs) as biomaterials for delivering small substances has gained significant attention in recent research. However, the interactions and mechanisms of action of CQDs on plants have received relatively little focus. Herein, we investigated the transportation of CQDs into various organs of Arabidopsis thaliana (L.) Heynh. via the vessel system, leading to the epigenetic inheritance of Argonaute family genes. Our findings reveal that CQDs may interact with microRNAs (miRNAs), leading to the repression of post-transcriptional regulation of target genes in the cytoplasm. Transcriptome and quantitative PCR analyses demonstrated consistent gene expression levels in offspring. Moreover, microscopic observations illustrated rapid CQD localization on cell membranes and nuclei, with increased nuclear entry at higher concentrations. Notably, our study identified an alternative regulatory microRNA, microRNA172D, for the Argonaute family genes through methylation analysis, shedding light on the connection between CQDs and microRNAs.

Fluorescent detection of emerging virus based on nanoparticles: From synthesis to application

The spread of COVID-19 has caused huge economic losses and irreversible social impact. Therefore, to successfully prevent the spread of the virus and solve public health problems, it is urgent to develop detection methods with high sensitivity and accuracy. However, existing detection methods are time-consuming, rely on instruments, and require skilled operators, making rapid detection challenging to implement. Biosensors based on fluorescent nanoparticles have attracted interest in the field of detection because of their advantages, such as high sensitivity, low detection limit, and simple result readout. In this review, we systematically describe the synthesis, intrinsic advantages, and applications of organic dye-doped fluorescent nanoparticles, metal nanoclusters, up-conversion particles, quantum dots, carbon dots, and others for virus detection. Furthermore, future research initiatives are highlighted, including green production of fluorescent nanoparticles with high quantum yield, speedy signal reading by integrating with intelligent information, and error reduction by coupling with numerous fluorescent nanoparticles.

Efficient polymer-mediated delivery system for thiocyclam: Nanometerization remarkably improves the bioactivity toward green peach aphids

The unscientific application of synthetic pesticides has brought various negative effects on the environment, hindering the sustainable development of agriculture. Nanoparticles can be applied as carriers to improve pesticide delivery, showing great potential in the development of pesticide formulation in recent years. Herein, a star polymer (SPc) was constructed as an efficient pesticide nanocarrier/adjuvant that could spontaneously assemble with thiocyclam or monosultap into a complex, through hydrophobic association and hydrogen bonding, respectively, with the pesticide-loading contents of 42.54% and 19.3%. This complexation reduced the particle sizes of thiocyclam from 543.54 to 52.74 nm for pure thiocyclam, and 3 814.16 to 1 185.89 nm for commercial preparation (cp) of thiocyclam. Interestingly, the introduction of SPc decreased the contact angles of both pure and cp thiocyclam on plant leaves, and increased the plant uptake of cp thiocyclam to 2.4-1.9 times of that without SPc. Meanwhile, the SPc could promote the bioactivity of pure/cp thiocyclam against green peach aphids through leaf dipping method and root application. For leaf dipping method, the 50% lethal concentration decreased from 0.532 to 0.221 g/L after the complexation of pure thiocyclam with SPc, and that decreased from 0.390 to 0.251 g/L for cp thiocyclam. SPc seems a promising adjuvant for nanometerization of both pure and cp insecticides, which is beneficial for improving the delivery efficiency and utilization rate of pesticides.

Advances in nanocarriers to improve the stability of dsRNA in the environment

RNAi technology, known as a revolutionary technology in the history of pesticides, has been identified as a very promising novel approach for crop protection, which is of great significance for achieving the sustainable agricultural development of the United Nations Food and Agriculture Organization. Although many studies have shown that RNA biopesticides have strong application prospects, its stability seriously restricts the commercial use. As the core component of RNAi, double-stranded RNA (dsRNA) is unstable in its natural form. Therefore, how to ensure the stability of dsRNA is one of the most significant challenges in realizing the commercial use of RNA biopesticides. Nanomaterials such as cationic polymers and lipofectamine can improve the stability of dsRNA in the environment, which has been proved. This paper reviews the recent research progress of nanomaterials that can be used to improve the environmental stability of dsRNA, and discusses the advantages and limitations of different nanomaterials combined with dsRNA, which provides reference for the selection of dsRNA nanoformulations.

Recent Advances in the Development and Applications of Conjugated Polymer dots

Conjugated polymer dots or semiconducting polymer nanoparticles (Pdots) are nanoparticles prepared based on organic polymers. Pdots have the advantages of lower cost, simple preparation process, good biocompatibility, excellent stability, easy...

Perylene diimide-based treatment and diagnosis of diseases

Integrated treatment using imaging technology to monitor biological processes for the precise treatment and diagnosis of diseases to improve treatment outcomes is becoming a hot topic. Accordingly, perylene diimide (PDI) has excellent photothermal conversion and photostability, which can be used as a good material for disease treatment and diagnosis. Herein, we review the latest research progress on the real-time diagnosis of related diseases based on perylene diimide probes in the aspects of bioimaging, detection of biomarkers and determination of the pH in living cells. Furthermore, perylene diimide-based multifunctional nano-delivery systems are particularly emphasized, showing great therapeutic potential in the field of image-guided combination therapy in tumor therapy. Finally, the great opportunities and challenges still faced by perylene diimide before entering the clinic are comprehensively analyzed.

Simple Osthole/Nanocarrier Pesticide Efficiently Controls Both Pests and Diseases Fulfilling the Need of Green Production of Strawberry

The application of botanical pesticides is a good choice in organic agriculture. However, most botanical pesticides have limitations of slow action and short persistence for pest and disease management, which constrain their further application. With the objective of exploring a green pesticide for controlling strawberry pests and diseases simultaneously, a star polymer (SPc) with a low production cost was synthesized as a pesticide nanocarrier through simple reactions. The SPc complexed with osthole quickly through electrostatic interaction and hydrophobic association, which decreased the particle size of osthole down to the nanoscale (17.66 nm). With the help of SPc, more nano-sized osthole was delivered into cytoplasm through endocytosis, leading to the enhanced cytotoxicity against insect cells. As a green botanical pesticide, the control efficacy of the osthole/SPc complex was improved against main strawberry pests (green peach aphid and two-spotted spider mite) and disease (powdery mildew), which fulfilled the need of both pest and disease management in sustainable production of strawberry. Meanwhile, the introduction of SPc not only improved plant-uptake but also decreased the residue of osthole due to the higher degradation rate. Furthermore, the application of the osthole/SPc complex exhibited no influence on the strawberry fruit quality and nontarget predators. To our knowledge, it is the first success to control plant pests and diseases simultaneously for sustainable agriculture by only one pesticidal formulation based on nanoparticle-delivered botanical pesticides.

Fluorescein-bridged Perylene Bisimide Dimer for Use as Liquid Crystal: Studies on Mesomorphic and Fluorescence Properties

A novel fluorescein-bridged perylene bisimide (PBI) dimer for liquid crystal (LC) with geometrically symmetric structure was developed. The mesomorphic results indicated that the energetically stable and unstable conformers of fluorescein fragments could lead to the transformation of mesophases from a hexagonal columnar mesophase to an uncertain phase at 136.9 °C in heating, whilst a stable hexagonal columnar mesophase maintained between 175.6 °C and 58.6 °C in cooling. The selectively excited fluorescence characters in THF solution demonstrated that the fluorescence resonance energy transfer (FRET) effect between fluorescein fragments and PBI unites could provide a means to effectively impose strong fluorescence of the dimeric PBIs modified with suitable chromophore at the N-imide position, which alternatively serves as a platform for the further study of multi-functional PBI-based LCs.

Folded Perylene Diimide Loops as Mechanoresponsive Motifs

A supramolecular mechanophore that can be integrated into polymers and indicates deformation by a fluorescence color change is reported. Two perylene diimides (PDIs) were connected by a short spacer and equipped with peripheral atom transfer polymerization initiators. In the idle state, the motif folds into a loop and its emission is excimer dominated. Poly(methyl acrylate) (PMA) chains were grown from the motif and the mechanophore-containing polymer was blended with unmodified PMA to afford materials that display a visually discernible fluorescence color change upon deformation, which causes the loops to unfold. The response is instant, and correlates linearly with the applied strain. Experiments with a reference polymer containing only one PDI moiety show that looped mechanophores that display intramolecular excimer formation offer considerable advantages over intermolecular dye aggregates, including a concentration-independent response, direct signaling of mechanical processes, and a more pronounced optical change.

Nanometerization of thiamethoxam by a cationic star polymer nanocarrier efficiently enhances the contact and plant-uptake dependent stomach toxicity against green peach aphids

BACKGROUND

The utilization efficiency of conventional insecticides is comparatively low in agricultural production, which leads to their excessive application and environmental pollution. Insecticide nanometerization by polymers and polymeric materials has advantages, particularly increased utilization efficiency and reduced insecticide application.

RESULTS

To increase the utilization efficiency of insecticides, a star polycation (SPc) was selected as a drug carrier that could be complexed with thiamethoxam through electrostatic interaction. Formation of the complex decreased the particle size of thiamethoxam from 575.77 to 116.16 nm in aqueous solution. Plant uptake of SPc-delivered thiamethoxam was increased 1.69-1.84 times compared with thiamethoxam alone. Nano-sized thiamethoxam/SPc complexes showed enhanced contact and stomach toxicity against green peach aphids.

CONCLUSION

SPc is a promising insecticide adjuvant for insecticide nanometerization, and is beneficial in improving insecticidal activity and decreasing the application amounts and application rates of conventional insecticides. © 2020 Society of Chemical Industry.

[12]aneN3-based multifunctional compounds as fluorescent probes and nucleic acids delivering agents

A series of multifunctional compounds (MFCs) 1a-1e based on 1,8-naphthalimide and [12]aneN3 building blocks were designed and synthesized. They were used as not only fluorescent probes for recognition of Cu2+ ions but also as non-viral gene vectors for DNA and RNA delivery. Furthermore, their complexes with Cu2+ (1-Cu) could also selectively stain lysosome in HeLa cells. In order to achieve high performance multifunctional materials, structure-performance relationship of MFCs 1a-1e was studied. It was found that MFCs 1a-1e exhibited highly selective fluorescence turn-off for Cu2+, without interference by other metal ions in aqueous solution. The fluorescence emission of 1a-1e was quenched by a factor of 10-fold, 47-fold, 6-fold, 64-fold, and 15-fold respectively in the presence of Cu2+ ions. Due to high sensitivity, good water solubility, and low cytotoxicity, MFCs 1a-1d were successfully applied in the recognition of Cu2+ and selectively staining lysosome in HeLa cells. Most importantly, MFCs 1a and 1b had excellent HeLa cell selectivity in RNA delivery, and their performances were far better than lipofectamine 2000 and 25 kDa PEI.

Improving RNAi efficiency for pest control in crop species

The application of RNAi promotes the development of novel approaches toward plant protection in a sustainable way. Genetically modified crops expressing dsRNA have been developed as commercial products with great potential in insect pest management. Alternatively, some nontransformative approaches, including foliar spray, irrigation and trunk injection, are favorable in actual utilization. In this review, we summarize the recent progress and successful cases of RNAi-based pest management strategy, explore essential implications and possibilities to improve RNAi efficiency by delivery of dsRNA through transformative and nontransformative approaches, and highlight the remaining challenges and important issues related to the application of this technology.

From Dyestuff Chemistry to Cancer Theranostics: The Rise of Rylenecarboximides

Fighting cancer with the means of chemistry remains a tremendous challenge and defines a pressing societal need. Compounds based on synthetic organic dyes have long been recognized as vital tools for cancer diagnosis and therapy (theranostics). Fluorescence and photoacoustic imaging of cancer as well as cancer treatment protocols such as photodynamic and photothermal therapy are all photobased technologies that require chromophores. However, a serious drawback of most chromophoric molecules is photobleaching over the course of their use in biological environments, which severely compromises the desired theranostic effects. At this point, rylenecarboximide (RI) dyes with ultrahigh photostability hold enormous promise. RI stands for a homologous series of dyes consisting of an aromatic core and carboximide auxochromic groups. They possess high molar extinction coefficients and finely tunable photophysical properties. RIs such as perylenebiscarboxylic acid monoimide (PMI), perylenetetracarboxylic acid diimide (PDI), terrylenetetracarboxylic acid diimide (TDI), and quaterrylene tetracarboxylic acid diimide (QDI) have attracted great scientific attention as colorants, components of organic photovoltaics and organic field-effect transistors, as well as tools for biological applications. PDI has appeared as one of the most widely studied RI dyes for fluorescence bioimaging. Our recent breakthroughs including chemotherapy with PDI-based DNA intercalators and photothermal therapy guided by photoacoustic imaging using PDI, TDI, or QDI, define urgent needs for further scientific research and clinical translation. In this Account, we tackle the relationship between chemical structures and photophysical and pharmacologic properties of RIs aiming at new contrast and anticancer agents, which then lay the ground for further biomedical applications. First, we introduce the design concepts for RIs with a focus on their structure-property relationships. Chemical structure has an enormous impact on the fluorescent, chemotoxic, photodynamic, and photothermal performance of RIs. Next, based on the resulting performance criteria, we employ RIs for fluorescence and photoacoustic cancer imaging as well as cancer therapies. When carrying electron donating substituents, PDIs and PMIs possess high fluorescence quantum yield and red-shifted emission which qualifies them for use in cancer fluorescence imaging. Also, some fluorescent PDIs are combined with chemodrugs or developed into DNA intercalators for chemotherapy. PDI-based photosensitizers are prepared by "heavy atom" substitution, showing potential for photodynamic therapy. Further, photothermal agents using PDI, TDI, and QDI with near-infrared absorption and excellent photothermal conversion efficiency offer high promise in photothermal cancer therapy monitored by photoacoustic imaging. Finally, looking jointly at the outstanding properties of RIs and the demands of current biomedicine, we offer an outlook toward further modifications of RIs as a powerful and practical platform for advanced cancer theranostics as well as treatment of other diseases.

Star-shaped poly(2-aminoethyl methacrylate)s as non-viral gene carriers: Exploring structure-function relationship

Gene therapy shows much promise in treating many inheritable and acquired diseases, but challenges remain in the design of gene vectors with low cytotoxicity and high transfection efficiency. Elucidating the structure-function relationship of non-viral polymer-based gene carriers is crucial for improving the design and performance of safe and effective gene therapy approaches. The cationic poly(2-aminoethyl methacrylate) (PAEM) containing primary amino side groups is an attractive carrier for gene delivery. This study focuses on four PAEM-based polycations with well-defined molecular weight and chain architecture. The polymers include three cyclodextrin (CD)-cored star-shaped PAEM polycations (s-PAEM), synthesized by atom transfer radical polymerization (ATRP), and a linear PAEM polycation (l-PAEM), synthesized via activators regenerated by electron transfer (ARGET) ATRP. All four polycations could condense plasmid DNA (pDNA) into spherical polyplexes with small sizes (<200 nm). The polyplexes showed excellent stability during storage and were able to resist electrostatic destabilization. The cytotoxicity of these polycations was depended on dose and target cell type and was influenced by molecular weight and chain architecture, yet the polyplexes showed little cytotoxicity regardless of the type of polymer used. The transfection efficiency of PAEM polycations was highly dependent upon molecular weight, molecular architecture (star versus linear) and target cell type. In most cases, polyplexes formed by high-molecular-weight s-PAEM performed the best. Moreover, at a specific N/P ratio, the transfection efficiency mediated by s-PAEM was higher in MCF-7 breast cancer cells than in COS-7 fibroblast-like cells, but such cell-type dependence was not obvious for l-PAEM. These findings indicate that the star-shaped PAEM polycations could be promising gene carriers for gene therapy applications.

Luminescent Rhenium(I)-Polypyridine Complexes Appended with a Perylene Diimide or Benzoperylene Monoimide Moiety: Photophysics, Intracellular Sensing, and Photocytotoxic Activity

This communication reports novel luminescent rhenium(I)-polypyridine complexes appended with a perylene diimide (PDI) or benzoperylene monoimide (BPMI) moiety through a non-conjugated linker. The photophysical and photochemical properties originating from the interactions of the metal polypyridine and perylene units were exploited to afford new cellular reagents with thiol-sensing capability and excellent photocytotoxic activity.

Design and synthesis of a fluorescent amino poly(glycidyl methacrylate) for efficient gene delivery

A fluorescent amino poly(glycidyl methacrylate) (PGOHMA) was synthesized by atom transfer radical polymerization (ATRP) and post-polymerization. PGOHMA has low cytotoxicity and high DNA delivery efficiency.

Aggregation-Induced Emission and White Luminescence from a Combination of π-Conjugated Donor-Acceptor Organic Luminogens

Two new star-shaped phenyl- and triazine-core based donor-acceptor (D-A) type conjugated molecules bearing triphenylamine end-capped arms were synthesized and characterized as imminent organic optoelectronic materials. Photophysical properties of the compounds were explored systematically via spectroscopic and theoretical methods. Because of the presence of donor-acceptor interactions, these luminogens display multifunctional properties, for instance, high extinction coefficient, large stokes shift, and pronounced solvatochromic effect. The compounds also exhibited phenomenon known as aggregation-induced emission on formation of nano-aggregates in the tetrahydrofuran-water mixture. The aggregate formation was confirmed by transmission electron microscopy, scanning electron microscopy, and dynamic light scattering analyses. Moreover, by controlling the electron withdrawing ability of the acceptor, complementary emissive fluorophores (blue and yellow) were achieved. These two complementary colors together span the entire range of visible spectrum (400-800 nm) and therefore when mixed in a requisite proportion generate white light in solution phase. These findings have potential for the progress of new organic white light radiating materials for applications in lighting and display devices.

Perylene bisimide with diphenylacrylonitrile on side-chain: strongly fluorescent liquid crystal with large pseudo Stokes shift based on AIE and FRET effect

A novel perylene bisimide (PBI) derivative with an AIE-active diphenylacrylonitrile unit positioned at the terminal N-imide position through a flexible spacer has been synthesized and characterized. The DSC, POM and XRD studies confirmed that it could self-assemble into a stable hexagonal columnar liquid-crystalline phase between 56 °C and 160 °C. This PBI derivative also exhibited strong fluorescence in solution, thin film and mesophase based on the cooperative mechanism of AIE and FRET between the diphenylacrylonitrile group and perylene moiety. The pseudo Stokes shift was as large as 283 nm, and the fluorescence quantum yields were as high as 0.62-0.79 in solution and 0.68-0.86 in solid state. This study provides a good strategy for converting the columnar liquid crystal with ACQ effect to one with the AIE effect, successfully filling the gap between the excellent columnar mesomorphic properties and strong fluorescence in solid state.

Synthesis and Self-Assembly of Bay-Substituted Perylene Diimide Gemini-Type Surfactants as Off-On Fluorescent Probes for Lipid Bilayers

Interest in bay-substituted perylene-3,4:9,10-tetracarboxylic diimides (PDIs) for solution-based applications is growing due to their improved solubility and altered optical and electronic properties compared to unsubstituted PDIs. Synthetic routes to 1,12-bay-substituted PDIs have been very demanding due to issues with steric hindrance and poor regioselectivity. Here we report a simple one-step regioselective and high yielding synthesis of a 1,12-dihydroxylated PDI derivative that can subsequently be alkylated in a straightforward fashion to produce nonplanar 1,12-dialkoxy PDIs. These PDIs show a large Stokes shift, which is specifically useful for bioimaging applications. A particular cationic PDI gemini-type surfactant has been developed that forms nonfluorescent self-assembled particles in water ("off state"), which exerts a high fluorescence upon incorporation into lipophilic bilayers ("on state"). Therefore, this probe is appealing as a highly sensitive fluorescent labelling marker with a low background signal for imaging artificial and cellular membranes.

Comparative Transcriptome Analyses Uncover Key Candidate Genes Mediating Flight Capacity in Bactrocera dorsalis (Hendel) and Bactrocera correcta (Bezzi) (Diptera: Tephritidae)

Flight capacity is important for invasive pests during entry, establishment and spreading. Both Bactroceradorsalis Hendel and Bactroceracorrecta Bezzi are invasive fruit flies but their flight capacities differ. Here, a tethered flight mill test demonstrated that B. dorsalis exhibits a greater flight capacity than B. correcta. RNA-Seq was used to determine the transcriptomic differences associated with the flight capacity of two Bactrocera species. Transcriptome data showed that 6392 unigenes were differentially expressed between the two species in the larval stage, whereas in the adult stage, 4104 differentially expressed genes (DEGs) were identified in females, and 3445 DEGs were observed in males. The flight capacity appeared to be correlated with changes in the transcriptional levels of genes involved in wing formation, flight muscle structure, energy metabolism, and hormonal control. Using RNA interference (RNAi) to verify the function of one DEG, the epidermal growth factor receptor (EGFR), we confirmed the role of this gene in regulating wing development, and thereby flight capacity, in both species. This work reveals the flight mechanism of fruit flies and provides insight into fundamental transcriptomics for further studies on the flight performance of insects.

In situ polymerization of supramolecular nanorods assembled from polymerizable perylene bisimide

Dimethacryl amide functionalized perylene bisimide monomer was synthesized, in-situ free radical polymerization was then performed in the organized state to maintain the assembly structures.

Supramolecular assembly of fluorogenic glyco-dots from perylenediimide-based glycoclusters for targeted imaging of cancer cells

Supramolecular self-assembly between perylenediimide-based glycoclusters and a red-emitting fluorophore produces structurally uniform and stable glyco-dots amenable to targeted fluorogenic imaging of liver and triple-negative breast cancer cells.

Synthesis of platinum(ii) complex end functionalized star polymers: luminescence enhancements and unimolecular micelles in solvents of weakened quality

Platinum(ii) complex end functionalized star polymers have been synthesized by reacting K₂PtCl₄ with star ligands ended with 2,6-bis(benzimidazol-2′-yl)pyridine. They show luminescence enhancements and form unimolecular micelles in solvents of weakened quality.

Mesoporous Bamboo Charcoal Nanoparticles as a New Near-Infrared Responsive Drug Carrier for Imaging-Guided Chemotherapy/Photothermal Synergistic Therapy of Tumor

Near-infrared-(NIR)-light-triggered photothermal nanocarriers have attracted much attention for the construction of more smart and effective therapeutic platforms in nanomedicine. Here, a multifunctional drug carrier based on a low cost, natural, and biocompatible material, bamboo charcoal nanoparticles (BCNPs), which are prepared by the pyrolysis of bamboo followed by physical grinding and ultrasonication is reported. The as-prepared BCNPs with porous structure possess not only large surface areas for drug loading but also an efficient photothermal effect, making them become both a suitable drug carrier and photothermal agent for cancer therapy. After loading doxorubicin (DOX) into the BCNPs, the resulting DOX-BCNPs enhance drug potency and more importantly can overcome the drug resistance of DOX in a MCF-7 cancer cell model by significantly increasing cellular uptake while remarkably decreasing drug efflux. The in vivo synergistic effect of combining chemotherapy and photothermal therapy in this drug delivery system is also demonstrated. In addition, the BCNPs enhance optoacoustic imaging contrast due to their high NIR absorbance. Collectively, it is demonstrated that the BCNP drug delivery system constitutes a promising and effective nanocarrier for simultaneous bioimaging and chemo-photothermal synergistic therapy of cancer.

Star Polymers

Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

Cell-Targeting Cationic Gene Delivery System Based on a Modular Design Rationale

En route to target cells, a gene carrier faces multiple extra- and intracellular hurdles that would affect delivery efficacy. Although diverse strategies have been proposed to functionalize gene carriers for individually overcoming these barriers, it is challenging to generate a single multifunctional gene carrier capable of surmounting all these barriers. Aiming at this challenge, we have developed a supramolecular modular approach to fabricate a multifunctional cationic gene delivery system. It consists of two prefunctionalized modules: (1) a host module: a polymer (PCD-SS-PDMAEMA) composed of poly(β-cyclodextrin) backbone and disulfide-linked PDMAEMA arms, expectedly acting to compact DNA and release DNA upon cleavage of disulfide linkers in reductive microenvironment; and (2) a guest module: adamantyl and folate terminated PEG (Ad-PEG-FA), expectedly functioning to reduce nonspecific interactions, improve biocompatibility, and provide folate-mediated cellular targeting specificity. Through the host-guest interaction between β-cyclodextrin units of the "host" module and adamantyl groups of the "guest" module, the PCD-SS-PDMAEMA-1 (host) and Ad-PEG-FA (guest) self-assemble forming a supramolecular pseudocopolymer (PCD-SS-PDMAEMA-1/PEG-FA). Our comprehensive analyses demonstrate that the functions preassigned to the two building modules are well realized. The gene carrier effectively compacts DNA into stable nanosized polyplexes resistant to enzymatic digestion, triggers DNA release in reducing environment, possesses significantly improved hemocompatibility, and specifically targets folate-receptor positive cells. Most importantly, endowed with these predesigned functions, the PCD-SS-PDMAEMA-1/PEG-FA supramolecular gene carrier exhibits excellent transfection efficacy for both pDNA and siRNA. Thus, this work represents a proof-of-concept example showing the efficiency and convenience of an adaptable, modular approach for conferring multiple functions to a single supramolecular gene carrier toward effective in vivo delivery of therapeutic nucleic acids.

Fluorescent supramolecular micelles for imaging-guided cancer therapy

A novel smart fluorescent drug delivery system composed of a perylene diimide (PDI) core and block copolymer poly(d,l-lactide)-b-poly(ethyl ethylene phosphate) is developed and named as PDI-star-(PLA-b-PEEP)8. The biodegradable PDI-star-(PLA-b-PEEP)8 is a unimolecular micelle and can self-assemble into supramolecular micelles, called as fluorescent supramolecular micelles (FSMs), in aqueous media. An insoluble drug camptothecin (CPT) can be effectively loaded into the FSMs and exhibits pH-responsive release. Moreover, the FSMs with good biocompatibility can also be employed as a remarkable fluorescent probe for cell labelling because the maximum emission of PDI is beneficial for bio-imaging. The flow cytometry and confocal laser scanning microscopy analysis demonstrate that the micelles are easily endocytosed by cancer cells. In vitro and in vivo tumor growth-inhibitory studies reveal a better therapeutic effect of FSMs after CPT encapsulation when compared with the free CPT drug. The multifunctional FSM nanomedicine platform as a nanovehicle has great potential for fluorescence imaging-guided cancer therapy.

Development of an Amino Acid-Functionalized Fluorescent Nanocarrier to Deliver a Toxin to Kill Insect Pests

Large-scale cultivation of Bacillus thuringiensis Berliner (Bt) crops has led to the rapid development of drug resistance. Herein, a fluorescent star poly(amino acid) is synthesized with l-isoleucine functionalization for the efficient delivery of either positively or negatively charged exogenous proteins into live cells. Poly(amino acid)s (P1)/Cry1Ab complexes greatly increase the cytotoxicity of the Bt toxin, Cry1Ab, and efficiently kill Bt-resistant pests.

Drosophotoxicology: An Emerging Research Area for Assessing Nanoparticles Interaction with Living Organisms

The rapid development of nanotechnology allowed the fabrication of a wide range of different nanomaterials, raising many questions about their safety and potential risks for the human health and environment. Most of the current nanotoxicology research is not standardized, hampering any comparison or reproducibility of the obtained results. Drosophotoxicology encompasses the plethora of methodological approaches addressing the use of Drosophila melanogaster as a choice organism in toxicology studies. Drosophila melanogaster model offers several important advantages, such as a relatively simple genome structure, short lifespan, low maintenance cost, readiness of experimental manipulation comparative to vertebrate models from both ethical and technical points of view, relevant gene homology with higher organisms, and ease of obtaining mutant phenotypes. The molecular pathways, as well as multiple behavioral and developmental parameters, can be evaluated using this model in lower, medium or high throughput type assays, allowing a systematic classification of the toxicity levels of different nanomaterials. The purpose of this paper is to review the current research on the applications of Drosophila melanogaster model for the in vivo assessment of nanoparticles toxicity and to reveal the huge potential of this model system to provide results that could enable a proper selection of different nanostructures for a certain biomedical application.

Facile synthesis of core–shell magnetic-fluorescent nanoparticles for cell imaging

In this work, we present a novel type of magnetic-fluorescent bifunctional nanoparticle (NP).

Water-soluble perylenediimides: design concepts and biological applications

Water-soluble perylenediimides (PDIs) with high fluorescence intensity, photostability and biocompatibility have been successfully prepared and applied in the biological field.