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

Chiral Bay-Alkynylated Tetraazaperylenes: Photophysics and Chiroptical Properties

Fully bay-alkynylated octaazaperopyrene dioxide (OAPPDO) derivatives were accessible through Stille cross coupling reaction of the corresponding bay-chlorinated derivatives. This steric congestion of the bay area led to helically chiral fluorophores, and chiral resolution of two derivatives allowed the investigation of their chiroptical properties as well as their kinetics of enantiomerization and the related thermodynamic parameters depending on the size of the terminal alkynyl substituent. An increase of the latter resulted in stable OAPPDO atropisomers at room temperature. The dynamics of the photoexcited states of two of the OAPPDO derivatives were investigated by transient absorption (TA) and time-resolved photoluminescence (tr-PL) spectroscopy.

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.

Depending on different apoptosis pathways, the effector Cscaspase-3 in Chilo suppressalis exposed to temperature and parasitic stress was induced

Apoptosis is a form of programmed cell death (PCD) that is largely triggered by caspases through both the mitochondria-dependent and mitochondria-independent pathways. The rice stem borer, Chilo suppressalis, serves as an economically important pest of rice, which is often suffered by temperature and parasitic stress under natural conditions. In the present study, effector Cscaspase-3 encoding caspase was obtained from the rice pest Chilo suppressalis. CsCaspase-3 possesses p20 and p10 subunits, two active sites, four substrate-binding sites, and two cleavage motifs. Real-time quantitative PCR showed that Cscaspase-3 was expressed at maximal levels in hemocytes; furthermore, transcription was most highly in female adults. Expression of Cscaspase-3 was induced by hot and cold temperatures, with the highest expression at 39 °C. Cscaspase-3 expression was also significantly induced at 10 h, 2 d, 5 d, and 7 d of parasitism. Flow cytometry results showed that both temperature and parasitism trigger apoptosis, but only parasitism induces apoptosis via the mitochondrial apoptosis pathway in C. suppressalis. RNAi-mediated silencing of Cscaspase-3 expression reduced C. suppressalis survival at -3 °C. This study provides a foundation for further studies of caspases in insects during biotic and abiotic stress.

A fluorescent nano vector for early diagnosis and enhanced Interleukin-33 therapy of thoracic aortic dissection

Thoracic aortic dissection (TAD) is the most devastating complication of vascular disease. The accuracy of the clinical diagnosis and treatment of TAD at the early stage is still limited. Herein, we report a nano-delivery strategy for early diagnosis and the first case of interleukin-33 (IL-33) based therapy for the effective intervention of TAD. A targeted fluorescent nano vector (FNV) is designed to co-assemble with IL-33, which protects IL-33 and prolongs its half-life. With specific targeting ability to the thoracic aorta, FNV can diagnose TAD at its early stage through fluorescent imaging. FNV@IL-33 nanocomplex presents better therapeutic effects on mice TAD progression compared with that of IL-33 alone by reducing smooth muscle apoptosis. Administration of FNV@IL-33 two weeks before onset, the development of TAD is greatly intervened. Our study provides a novel approach for early diagnosis and effective IL-33 therapy of TAD, which opens attractive opportunities for clinical prevention of cardiovascular diseases.

Induced heat shock protein 70 confers biological tolerance in UV-B stress-adapted Myzus persicae (Hemiptera)

As an environmental stress factor, ultraviolet-B (UV-B) radiation directly affects insect growth, development, and reproduction. Heat shock protein 70s kDa (Hsp70s) plays an important role in the environmental adaptation of insects. To determine the role of MpHsp70s in the UV-B tolerance of Myzus persicae (Sulzer), we identified the complete complementary DNA sequences of seven MpHsp70s. They were found to be ubiquitously expressed during different developmental stages and were highly expressed in second-instar nymphs and wingless adults. The expression levels of the MpHsp70s were significantly upregulated when exposed to different durations of UV-B stress. Nanocarrier-mediated dsMpHsp70 suppressed the expression of the MpHsp70s and reduced the body length, weight, survival rate, and fecundity of M. persicae under UV-B exposure. When the combinational RNAi approach was adopted, the effects on the survival rate and fecundity were greater under UV-B stress, except for MpHsc70-4. These results suggest that MpHsp70s are essential for the resistance of M. persicae to UV-B stress.

A Preparation Method of Nano-Pesticide Improves the Selective Toxicity toward Natural Enemies

Various nano-delivery systems have been designed to deliver synthetic/botanical pesticides for improved bioactivity. However, the enhanced toxicity of nanocarrier-loaded pesticides may injure the natural enemies, and their selective toxicity should be evaluated before the large-scale application. In this context, a star polymer (SPc)-based cyantraniliprole (CNAP) nano-delivery system was constructed, and its selective toxicity was evaluated using pest Frankliniella occidentalis (WFT) and predator Orius sauteri. The amide NH of CNAP could assemble with carbonyl groups or tertiary amines of SPc through hydrogen bonds to form CNAP/SPc complex spontaneously. The above self-assembly decreased the particle size of CNAP from 808 to 299 nm. With the help of SPc, the lethal concentration 50 (LC₅₀) values of CNAP decreased from 99 to 54 mg/L and 230 to 173 mg/L toward WFTs and O. sauteri due to the enhancement of broad-spectrum bioactivity. Interestingly, the toxicity selective ratio (TSR) of CNAP increased from 2.33 to 3.23 with the help of SPc, revealing the higher selectivity of SPc-loaded CNAP. To our knowledge, it was the first successful exploration of the selective toxicity of nanocarrier-loaded pesticides, and the higher selective toxicity of SPc-loaded CNAP was beneficial for alleviating the negative impacts on predators.

Visualization of the process of a nanocarrier-mediated gene delivery: stabilization, endocytosis and endosomal escape of genes for intracellular spreading

Nanoparticles have been widely applied as gene carrier for improving RNA interference (RNAi) efficiency in medical and agricultural fields. However, the mechanism and delivery process of nanoparticle-mediated RNAi is not directly visualized and elucidated. Here we synthesized a star polymer (SPc) consisted of a hydrophilic shell with positively-charged tertiary amine in the side chain, which was taken as an example to investigate the mechanism in gene delivery. The SPc could assemble with dsRNA spontaneously through electrostatic force, hydrogen bond and van der Waals force. Interestingly, the SPc could protect dsRNA from degradation by RNase A and insect hemolymph, thus remarkably increasing the stability of dsRNA. Meanwhile, the SPc could efficiently promote the cellular uptake and endosomal escape for intracellular spreading of dsRNA. Transcriptome analysis revealed that the SPc could up-regulate some key genes such as Chc, AP2S1 and Arf1 for activating clathrin-mediated endocytosis. Furthermore, the suppression of endocytosis hindered the cellular uptake of SPc-delivered dsRNA in vitro, and the subsequent RNAi effect was also disappeared in vivo. To our knowledge, our study is the first direct visualization of the detailed cellular delivery process and mechanism of nanocarrier-mediated gene delivery. Above mechanism supports the application of nanocarrier-based RNAi in gene therapy and pest management.

Field application of nanoliposomes delivered quercetin by inhibiting specific hsp70 gene expression against plant virus disease

BACKGROUND

The annual economic loss caused by plant viruses exceeds 10 billion dollars due to the lack of ideal control measures. Quercetin is a flavonol compound that exerts a control effect on plant virus diseases, but its poor solubility and stability limit the control efficiency. Fortunately, the development of nanopesticides has led to new ideas.

RESULTS

In this study, 117 nm quercetin nanoliposomes with excellent stability were prepared from biomaterials, and few surfactants and stabilizers were added to optimize the formula. Nbhsp70er-1 and Nbhsp70c-A were found to be the target genes of quercetin, through abiotic and biotic stress, and the nanoliposomes improved the inhibitory effect at the gene and protein levels by 33.6 and 42%, respectively. Finally, the results of field experiment showed that the control efficiency was 38% higher than that of the conventional quercetin formulation and higher than those of other antiviral agents.

CONCLUSION

This research innovatively reports the combination of biological antiviral agents and nanotechnology to control plant virus diseases, and it significantly improved the control efficiency and reduced the use of traditional chemical pesticides.

NCs-Delivered Pesticides: A Promising Candidate in Smart Agriculture

Pesticides have been used extensively in the field of plant protection to maximize crop yields. However, the long-term, unmanaged application of pesticides has posed severe challenges such as pesticide resistance, environmental contamination, risk in human health, soil degradation, and other important global issues. Recently, the combination of nanotechnology with plant protection strategies has offered new perspectives to mitigate these global issues, which has promoted a rapid development of NCs-based pesticides. Unlike certain conventional pesticides that have been applied inefficiently and lacked targeted control, pesticides delivered by nanocarriers (NCs) have optimized formulations, controlled release rate, and minimized or site-specific application. They are receiving increasing attention and are considered as an important part in sustainable and smart agriculture. This review discussed the limitation of traditional pesticides or conventional application mode, focused on the sustainable features of NCs-based pesticides such as improved formulation, enhanced stability under harsh condition, and controlled release/degradation. The perspectives of NCs-based pesticides and their risk assessment were also suggested in this view for a better use of NCs-based pesticides to facilitate sustainable, smart agriculture in the future.

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.

Green Strategies of Powdery Mildew Control in Hop: From Organic Products to Nanoscale Carriers

Humulus lupulus L. is a long-lived, perennial, herbaceous, and dioecious climbing plant. The foremost producers in the European Union are Germany, the Czech Republic, Poland, Slovenia, and Spain. The Spanish cultivated area is concentrated in the province of León. Powdery mildew, caused by Podosphaera macularis, menaces hop production and quality in all hop growing regions located in the Northern hemisphere, colonizing leaves, petioles, inflorescences, and finally cones. In this work, powdery mildew control was monitored, comparing nine fungicide strategies: five organics, two integrated disease management (IDM)-based, with and without Nutragreen^® nanoscale carrier, and two conventional treatments (CON) with and without Nutragreen^® nanoscale carrier. The organic treatments were able to diminish P. macularis on leaves, but no effect was observed in cones. CON treatments reduced the infection on leaves and cones and increased the cone quantity and quality. Likewise, IDM-based treatments provided satisfactory results as they diminished powdery mildew on leaves and cones. Finally, dose reduction using a Nutragreen^® nanoscale carrier showed beneficial effects in the control of powdery mildew compared to the commercial dose. Hence, the use of nanoscale carries permits a 30% reduction in pesticide dose, which optimizes yield and hop quality, reduces risks linked to pesticides, and aids in compliance with public and international policy demands.

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.

Self-assembled bovine serum albumin nanoparticles as pesticide delivery vectors for controlling trunk-boring pests

BACKGROUND

Trunk-boring pests (TBPs) are an important type of forest pest, TBPs not only feed on the branches and trunks of trees, but also spread quarantine diseases in forests. However, because the larvae of TBPs live inside the trunk and are well concealed, prevention and control are difficult. The lack of effective control methods leads to the death of many trees in forests. In this study, a novel nanopesticide featuring high bioactivity and slow-release properties was developed to control TBPs. Thiacloprid (THI), which is commonly used to control Coleoptera species, was used as a model pesticide.

RESULTS

The oleophobic properties of bovine serum albumin (BSA) were exploited to encapsulate the hydrophobic pesticide THI by self-assembly, and the size of the obtained nanoparticles, THI@BSA·NPs, was approximately 23 nm. The loading efficiency reached 70.4%, and THI@BSA·NPs could be released continuously for over 15 days, with the cumulative release reaching 93.5%. The fluorescein isothiocyanate (FITC)-labeled nanoparticles were evenly distributed in the digestive tract and body surface of a typical TBPs, M. alternatus, and the stomach and contact toxicities increased by 33.7% and 25.9%, respectively, compared with those of free THI. Furthermore, the results showed that the transport efficiency of THI@BSA·NPs was highest at a concentration of 50 μg/mL, and the THI@BSA·NPs content in the trunk, from to lower to higher layers, was 8.8, 8.2, 7.6, and 5.8 μg/g. At the same time, THI@BSA·NPs also exhibited high transport efficiency in dead trees.

CONCLUSION

The transport efficiency and toxicity of the active ingredients are the key factors for the control of TBPs. This work provided idea for the application of biological delivery system encapsulated hydrophobic pesticides. The novel self-assembled THI@BSA·NPs have promising potential for sustainable control of TBPs.

pH-responsive perylenediimide nanoparticles for cancer trimodality imaging and photothermal therapy

Organic chromophores have been well developed for multimodality imaging-guided photothermal therapy (PTT) due to their outstanding optical properties and excellent designability. However, the theranostic efficiencies of most currently available organic chromophores are restricted intrinsically, owing to their poor photostability or complex synthesis procedures. These drawbacks not only increase their cost of synthesis, but also cause side effects in PTT. Method: We presented a facile strategy for constructing a near-infrared (NIR)-absorbing perylenediimide structured with pH-responsive piperazine ring at the bay region. The chromophore was conjugated with carboxyl-end-capped PEG as side chains that can self-assemble into nanoparticles (NPs) in aqueous solution. The NIR optical properties and photothermal conversation ability of PPDI-NPs were investigated. We then studied the imaging-guided PTT of PPDI-NPs under NIR light illumination in 4T1 cells and mice respectively. Results: The excellent photostable PPDI-NPs had near-infrared fluorescence (NIRF) emission and high photothermal conversion efficiency in acidic microenvironment. Importantly, PPDI-NPs can be utilized for the precise detection of tumors by NIRF/photoacoustic/thermal trimodality imaging. Efficient PTT of PPDI-NPs was applied in vitro and in vivo with high biosafety. Conclusion: In summary, we developed pH-responsive perylenediimide nanoparticles as multifunctional phototheranostic agent with high stability and simple synthesis procedures. This study offers a promising organic chromophore for developing phototheranostics in cancer therapy.

Progress and prospects of arthropod chitin pathways and structures as targets for pest management

Chitin is a structural component of the arthropod cuticular exoskeleton and the peritrophic matrix of the gut, which play crucial roles in growth and development. In the past few decades, our understanding of the composition, biosynthesis, assembly, degradation, and regulation of chitinous structures has increased. Many chemicals have been developed that target chitin biosynthesis (benzoyphenyl ureas, etoxazole), chitin degradation (allosamidin, psammaplin), and chitin regulation (benzoyl hydrazines), thus resulting in molting deformities and lethality. In addition, proteins that disrupt chitin structures, such as lectins, proteases, and chitinases have been utilized to halt feeding and induce mortality. Chitin-degrading enzymes, such as chitinases are also useful for improving the efficacy of bio-insecticides. Transgenic plants, baculoviruses, fungi, and bacteria have been engineered to express chitinases from a variety of organisms for control of arthropod pests. In addition, RNA interference targeting genes involved in chitin pathways and structures are now being investigated for the development of environmentally friendly pest management strategies. This review describes the chemicals and proteins used to target chitin structures and enzymes for arthropod pest management, as well as pest management strategies based upon these compounds, such as plant-incorporated-protectants and recombinant entomopathogens. Recent advances in RNA interference-based pest management, and how this technology can be used to target chitin pathways and structures are also discussed.

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.

A polymer/detergent formulation improves dsRNA penetration through the body wall and RNAi-induced mortality in the soybean aphid Aphis glycines

BACKGROUND

It is difficult to efficiently silence gene expression in some insects, probably because of the degradation of dsRNA by enzymes present in the gut and hemolymph post-oral feeding or body injecting of dsRNA. We previously developed a nanocarrier delivery system that can systemically deliver dsRNA into chewing mouthpart insects by oral feeding and efficiently silence gene expression. For the purpose of pest control in the field, there is a great demand to develop a spray method to apply dsRNA formulation.

RESULTS

A formulation of the nanocarrier/dsRNA/detergent was developed and could be easily applied just by dropping it on the notum of the aphid. The formulation penetrated the body wall into the hemocoel and then spread into various tissues within 1 h. The delivered dsRNA efficiently silenced the target gene expression at a high knockdown effect (95.4%) and the aphid population was largely suppressed (80.5%).

CONCLUSION

A novel dsRNA formulation was developed with the help of a nanocarrier and detergent that can quickly penetrate the insect body wall and efficiently silence gene expression. The formulation may provide a fast and easy tool for gene silence in some tough insects and for pest control in the field. © 2019 Society of Chemical Industry.

Substrate-Assisted Visualization of Surfactant Micelles via Transmission Electron Microscopy

The visualization of the micellar morphological evolution for surfactant has drawn much attention due to its self-assemble ability to fold into various structures. However, the direct observation of the soft materials with low atomic number has been hampered because of the poor scattering contrast and complex staining process by the traditional transmission electron microscopy (TEM) techniques. Herein, we reported a novel strategy to the visualization of surfactant micelles with the assistance of layered double hydroxides (LDHs) via TEM. Owing to the uniformly distributed metal ions and positive charges in the LDHs, the surfactant at the micelle-water interface reacted with LDHs to form a stabilized architecture through electrostatic and hydrogen-bond interactions. The morphologies of the surfactant can be clearly observed through the surfactant-LDHs architectures, exhibiting high contrast by TEM techniques. Significantly, the micellar evolutions involving the spherical, rodlike, and wormlike shapes were successfully distinguished. Our results may provide great possibilities and inspirations for the visualization for morphology of soft matters.

Nano-based smart pesticide formulations: Emerging opportunities for agriculture

The incorporation of nanotechnology as a means for nanopesticides is in the early stage of development. The main idea behind this incorporation is to lower the indiscriminate use of conventional pesticides to be in line with safe environmental applications. Nanoencapsulated pesticides can provide controlled release kinetics, while efficiently enhancing permeability, stability, and solubility. Nanoencapsulation can enhance the pest-control efficiency over extended durations by preventing the premature degradation of active ingredients (AIs) under harsh environmental conditions. This review is thus organized to critically assess the significant role of nanotechnology for encapsulation of AIs for pesticides. The smart delivery of pesticides is essential to reduce the dosage of AIs with enhanced efficacy and to overcome pesticide loss (e.g., due to leaching and evaporation). The future trends of pesticide nanoformulations including nanomaterials as AIs and nanoemulsions of biopesticides are also explored. This review should thus offer a valuable guide for establishing regulatory frameworks related to field applications of these nano-based pesticides in the near future.

A perylenediimide-based nanocarrier monitors curcumin release with an “off–on” fluorescence switch

A perylenediimide-based nanocarrier (PPL-B) is constructed and used for monitoring curcumin release through an “off–on” fluorescence switch.

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.

Monolayer Nanosheets with an Extremely High Drug Loading toward Controlled Delivery and Cancer Theranostics

2D nanomaterials have attracted considerable research interest in drug delivery systems, owing to their intriguing quantum size and surface effect. Herein, Gd³⁺ -doped monolayered-double-hydroxide (MLDH) nanosheets are prepared via a facile bottom-up synthesis method, with a precisely controlled composition and uniform morphology. MLDH nanosheets as drug carrier are demonstrated in coloading of doxorubicin and indocyanine green (DOX&ICG), with an ultrahigh drug loading content (LC) of 797.36% and an encapsulation efficiency (EE) of 99.67%. This is, as far as it is known, the highest LC level at nearly 100% of EE among previously reported 2D drug delivery systems so far. Interestingly, the as-prepared DOX&ICG/MLDH composite material shows both pH-controlled and near-infrared-irradiation-induced DOX release, which holds a promise in stimulated drug release. An in vivo dual-mode imaging, including near-infrared fluorescence and magnetic resonance imaging, enables a noninvasive visualization of distribution profiles at the tumor site. In addition, in vitro and in vivo therapeutic evaluations demonstrate an excellent trimode synergetic anticancer activity and superior biocompatibility of DOX&ICG/MLDH. Therefore, MLDH nanosheets provide new perspectives in the design of multifunctional nanomedicine, which shows promising applications in controlled drug delivery and cancer theranostics.

Perylenediimide chromophore as an efficient photothermal agent for cancer therapy

Photothermal agents with improved bioavailabilities can generate heat from near-infrared light, which has been efficiently used for in vivo photothermal therapy (PTT) for cancer, with minimum tissue invasion. Strategies for developing organic near-infrared-absorbing molecules for photothermal cancer therapy have drawn intensive attention among academic investigators. However, conventional organic near-infrared-absorbing molecules may not only have complex synthesis procedures, but also easily suffer from photobleaching under light irradiation. These drawbacks might lead to an increase in the synthesis cost, and elicit a risk of side effects in PTT. Thus, it is essential to devise an organic photothermal agent with stable photothermal capacity, which involves a facile synthesis process. In this study, incorporating a secondary amine group (donor) in the bay regions of perylenediimides (PDIs) could lead to a 150-nm bathochromic shift of the absorption maximum. Next, a modification of poly(ethylene glycol) (PEG) at the periphery of the chromophore renders the targeted macromolecule PDI-PEG highly water-soluble, and capable of intense absorption in the near-infrared region. The self-assembled PDI-based nanoparticles (PDI-NPs) have a size of 55 nm in aqueous solutions. PDI-NPs with excellent photostability possess a high photothermal conversion efficiency of up to 43% ± 2%. Finally, PDI-NPs allow for efficient in vitro and in vivo photothermal cancer therapy. Meanwhile, PDI-NPs exhibit quite low cytotoxicity and no biotoxicity on major organs in vivo. Thus, these easily-manufactured PDI-NPs can serve as extremely stable photothermal agents for efficient photothermal cancer therapy.

Multifunctional Core@Shell Magnetic Nanoprobes for Enhancing Targeted Magnetic Resonance Imaging and Fluorescent Labeling in Vitro and in Vivo

Core@shell magnetic nanoparticles (core@shell MNPs) are attracting widespread attention due to their enhancement properties for potential applications in hyperthermia treatment, magnetic resonance imaging (MRI), diagnostics, and so forth. Herein, we developed a facile thermal decomposition method for controllable synthesis of a superparamagnetic, monodispersed core@shell structure (Co@Mn = CoFe₂O₄@MnFe₂O₄) with uniform size distribution (σ < 5%, d_c ≈ 15 nm). The CoFe₂O₄ core could enhance magnetic anisotropy, and the MnFe₂O₄ shell could improve the magnetization value. The Co@Mn MNPs were transferred into aqueous solution with an amphiphilic polymer (labeled 2% TAMRA) and functionalized with PEG_2k and target molecules (folic acid, FA) to fabricate multifunctional PMA_TAMRA-Co@Mn-PEG_2k-FA nanoprobes. The obtained PMA_TAMRA-Co@Mn-PEG_2k-FA nanoprobes exhibit good biocompatibility, high T₂ relaxation values, and long-term fluorescence stability (at least 6 months). Our results demonstrate that the synthesized PMA_TAMRA-Co@Mn-PEG_2k-FA nanoprobes can effectively enhance the targeted MRI and fluorescent labeling in vitro and in vivo. The research outcomes will contribute to the rational design of new nanoprobes and provide a promising pathway to promote core@shell nanoprobes for further clinical contrast MRI and photodynamic therapy in the near future.

Terrylenediimide-Based Intrinsic Theranostic Nanomedicines with High Photothermal Conversion Efficiency for Photoacoustic Imaging-Guided Cancer Therapy

Activatable theranostic nanomedicines involved in photothermal therapy (PTT) have received constant attention as promising alternatives to traditional therapies in clinic. However, the theranostic nanomedicines widely suffer from instability and complicated nanostructures, which hamper potential clinical applications. Herein, we demonstrated a terrylenediimide (TDI)-poly(acrylic acid) (TPA)-based nanomedicine (TNM) platform used as an intrinsic theranostic agent. As an exploratory paradigm in seeking biomedical applications, TDI was modified with poly(acrylic acid)s (PAAs), resulting in eight-armed, star-like TPAs composed of an outside hydrophilic PAA corona and an inner hydrophobic TDI core. TNMs were readily fabricated via spontaneous self-assembly. Without additional vehicle and cargo, the as-prepared TNMs possessed a robust nanostructure and high photothermal conversion efficiency up to approximately 41%. The intrinsic theranostic properties of TNMs for use in photoacoustic (PA) imaging by a multispectral optoacoustic tomography system and in mediating photoinduced tumor ablation were intensely explored. Our results suggested that the TNMs could be successfully exploited as intrinsic theranostic agents for PA imaging-guided efficient tumor PTT. Thus, these TNMs hold great potential for (pre)clinical translational development.

Fluorescent Poly(glycerol-co-sebacate) Acrylate Nanoparticles for Stem Cell Labeling and Longitudinal Tracking

The stable presence of fluorophores within the biocompatible and biodegradable elastomer poly(glycerol-co-sebacate) acrylate (PGSA) is critical for monitoring the transplantation, performance, and degradation of the polymers in vivo. However, current methods such as physically entrapping the fluorophores in the polymer matrix or providing a fluorescent coating suffer from rapid leakage of fluorophores. Covalent conjugation of fluorophores with the polymers and the subsequent core-cross-linking are proposed here to address this challenge. Taking rhodamine as the model dye and PGSA nanoparticles (NPs) as the model platform, we successfully showed that the synthesized rhodamine-conjugated PGSA (PGSAR) NPs only released less than 30% rhodamine at day 28, whereas complete release of dye occurred for rhodamine-encapsulated PGSA (PGSA-p-R) NPs at day 7 and 57.49% rhodamine was released out for the un-cross-linked PGSAR NPs at day 28. More excitingly, PGSAR NPs showed a strong quantum yield enhancement (26.24-fold) of the fluorophores, which was due to the hydrophobic environment within PGSAR NPs and the restricted rotation of (6-diethylamino-3H-xanthen-3-ylidene) diethyl group in rhodamine after the conjugation and core-cross-linking. The stable presence of dye in the NPs and enhanced fluorescence allowed a longitudinal tracking of stem cells both in vitro and in vivo for at least 28 days.

Self-Assembly and Disassembly of Amphiphilic Zwitterionic Perylenediimide Vesicles for Cell Membrane Imaging

Animal cells have complicated dynamics of cell membrane structures which require desirable dyes for in vivo imaging. Here, an asymmetric amphiphilic zwitterionic perylenediimide (ZP) derivative has been constructed by introducing an octyl chain and a zwitterionic head to each imide position of perylenediimide chromophore. ZP could self-assemble into vesicles in aqueous solution. The aggregated ZP vesicles have been explored to image cell inner or surface membrane structures by a controlled disassembly process. After being taken up into cells, ZP vesicles disassemble into monomers and then incorporate into cell inner membranes. The vesicles can also disassemble in acid food and incorporate into cell surface membrane of gut cells. The research provides a new tool to label the complicated cell membrane structures with up to 3 days long-term labeling for life science applications.