Identification and drug resistance of pathogen of ulcerative skin disease and its immune responses and protective efficacy after vaccination in a giant spiny frog, Quasipaa spinosa.

OBJECTIVE: In order to explore the pathogen of the ulcerative skin disease in giant spiny frog (Quasipaa spinosa), and to provide theoretical basis for the prevention and control of the disease in practical production, this study was carried out to isolate and identify the pathogenic bacteria from the sick frogs suffering from rotting skin disease and to carry out the immunization test of the inactivated vaccine. METHODS: Physiological and biochemical characterization, and molecular biology of the pathogenic bacteria were identified, and drug screening and immunization responses were also carried out. RESULTS: The dominant bacterium QS01 was isolated from the lesions of diseased giant spiny frogs, which was confirmed to be the causative agent of the rotting skin disease of giant spiny frogs by artificial regression infection test. Based on the fact that the pathogen is a gram-negative short bacterium, its phenotypic characteristics and 16S rRNA and gyrB gene sequences were analyzed, and the bacterium was determined to be Citrobacter freundii. The results of the drug sensitivity test showed that the bacterium was sensitive to 11 antibiotics, including Enrofloxacin, Fleroxacin and Ciprofloxacin, including three non-polluting drugs such as Florfenicol, Roxithromycin and Thiamphenicol, as well as three Chinese herbal medicines such as Rheum officinale Baill, Coptis chinensis Franch and Scutellaria baicalensis Georgi. Most non-specific immune responses could go to recovery in 24h. The frogs were vaccinated with QS01 formaldehyde inactivated vaccine by injection, immersion and spraying, and the serum antibody potency of the three immunized groups with the average potency reached the peak at the 20th d after immunization, and the serum antibody potency of the injected immunized group was at the highest ratio of 1:64-128 (101.6), while the immersed group and the spraying group attained the ratio of 1:16-32 (20.2) and 1:16-32 (16) respectively, and lasted until the 30th d. The control group that was not immunized had the highest serum antibody potency of 1:16-32 (20.2) and 1:16-32 (16), and continued until the 30th d. The control group that was not immunized was not immunized. The serum antibody potency of the unimmunized control group was 1:2 to 2(2). The immunoprotection rates after takedown were 100 %, 85.71 % and 71.43 %, respectively. CONCLUSION: C. freundii is the pathogen of the disease in this farm, and the vaccination by immersion and spraying can effectively prevent and control the rotting skin disease in frogs. These results revealed pathogenicity of C. freundii and its activation of host immune response, which will provide a scientific reference for the aquaculture and disease prevention in Q. spinosa culture.

Choline phosphate lipid-hitchhiked near-infrared BODIPY nanoparticles for enhanced phototheranostics.

Phototheranostics integrating optical imaging and phototherapy has attracted extensive attention. Achieving nanophototherapeutics with near infrared (NIR)-light synchronously triggered photodynamic therapy (PDT) and photothermal therapy (PTT) is challenging. Herein, we develop a multifunctional theranostic nanoplatform prepared from the co-assembly of NIR boron dipyrromethene (BODIPY) with a cooperative D-π-A structure of a thiophene-BODIPY core and benzene-diethylamino, and a choline phosphate lipid. The as-fabricated nanoparticles (DBNPs) exhibited desirable NIR absorption, uniform spherical morphology and good colloidal stability. The elaborate molecular design and supramolecular assembly endowed DBNPs with desirable PDT and PTT activities. Upon 808 nm laser irradiation, the DBNPs efficiently generated active singlet oxygen and regional hyperpyrexia, with a photothermal conversion efficiency of 37.6%. The excellent PDT and PTT performance of DBNPs boosted the potent in vitro and in vivo anti-tumor effects. In addition, these nanoparticles manifested their good capability of NIR fluorescence imaging of tumors. Overall, the DBNPs provide a paradigm for delivering hydrophobic phototherapy molecules with phospholipids for enhanced tumor treatment and imaging.

Biomimetic nanoprodrugs from fatty acid modified camptothecin and albumin for enhanced pharmacotherapy.

Design of nanovectors inspired by nature is a short cut to improve the efficacy and bioavailability of chemotherapeutic agents, while reduce the toxicity. In this work, strongly hydrophobic camptothecin (CPT) was modified with different chain length of fatty acid (C4, C9 and C18) to synthesize CPT4C, CPT9C and CPT18C, respectively. CPT4C, CPT9C and CPT18C could complex with human serum albumin (HSA) readily to prepare CPT4C-HSA, CPT9C-HSA and CPT18C-HSA nanoagents. In vitro MTT assays demonstrated CPT18C-HSA possessed the highest cell killing capacity, due to the elevated cellular uptake that resulted from albumin-mediated transportation. In vivo tumor inhibition experiments verified that CPT18C-HSA had the most remarkable antitumor efficiency with distinctly lowered physiological toxicity. It could be used in large doses without obvious side effects. We believe this albumin-mediated transportation mode has great potential for efficient delivery of hydrophobic and/or physiologically unstable drugs.

Ultra-small NIR J-aggregates of BODIPY for potent phototheranostics.

Cancer phototheranostics that combines diagnosis with phototherapy has emerged as a new mode of precise treatment. Nevertheless, taking highly effective phototheranostics into consideration, it is still a tremendous challenge to design multifunctional photothermal agents (PTAs) that combine the features of intensive near-infrared (NIR) absorption/emission, high photothermal conversion efficiency (PCE) and preferable tumor accumulation. Herein, seeking a convenient method to facilitate absorption red-shift, promote the accumulation of drugs in tumors and heighten the PCE appears to be particularly important for cancer theranostics. In this work, heavy-atom-free boron dipyrromethene (BODIPY) was assembled with F127 to fabricate ultra-small J-aggregated nanoparticles (named as BNPs). Compared to free BODIPY, BNPs exhibited 63 nm redshifted absorption, deep-tissue fluorescence imaging, enhanced cellular uptake, preferable tumor accumulation, elevated PCE, excellent photothermal stability and water dispersibility. In vivo experiments demonstrated that BNPs could behave as high-performance tumor fluorescent imaging probes and antitumor PTAs to conduct NIR imaging-guided PTT. This work offers a novel J-aggregated framework on developing robust diagnostic and therapeutic agents.

Nanoscale porphyrin assemblies based on charge-transfer strategy with enhanced red-shifted absorption.

Charge-transfer assemblies (CTAs) represent a new class of functional material due to their excellent optical properties, and show great promise in the biomedical field. Porphyrins are widely used photosensitizers, but the short absorption wavelengths may restrict their practical applications. To obtain porphyrin phototherapeutic agents with red-shifted absorption, charge-transfer nanoscale assemblies (TAPP-TCNQ NPs) of 5,10,15,20-tetrakis(4-aminophenyl) porphyrin (TAPP) and 7,7,8,8­tetracyanoquinodimethane (TCNQ) were prepared via optimizing the stoichiometric ratios of donor-acceptor. The as-prepared TAPP-TCNQ NPs exhibit red-shifted absorption to the near-infrared (NIR) region and enhanced absorbance because of the charge-transfer interactions. In especial, TAPP-TCNQ NPs possess the capacity of both photodynamic and photothermal therapy, thus effectively killing the bacteria upon 808 nm laser irradiation. This modular assembly method provides an alternative strategy to enhance the application of the phototherapeutic agents.

Facile Preparation of a Thienoisoindigo-Based Nanoscale Covalent Organic Framework with Robust Photothermal Activity for Cancer Therapy.

The covalent organic frameworks (COFs) so far are usually built with small aromatic subunits, which makes their absorption spectra mainly located in the high-energy part of the visible region. In this work, we have developed a COF with a low band gap by integrating electron-deficient thienoisoindigo and electron-rich triphenylamine. The intramolecular charge-transfer effect combining the extended length of the π-conjugated backbone of COF endow it with broad absorption even to the second near-infrared region. After optimizing the solvent, a uniform size and colloidal stable COF is obtained. Benefiting from the coplanar structure of the monomer, this COF achieves a considerable photothermal conversion efficiency (PCE) of 48.2%. With these advantages, it displays convincing cancer cell killing effect upon laser irradiation in vitro or in vivo. This work provides a simple and practical method to acquire promising a COF-based phototherapy reagent that is applied in biomedicine field.

Deep Tumor Penetrating Gold Nano-Adjuvant for NIR-II-Triggered In Situ Tumor Vaccination.

Local tumor photothermal treatment with the near-infrared light at the second window (NIR-II) is a promising strategy in triggering the in situ tumor vaccination (ISTV) for cancer therapy. However, limited penetration of photothermal agents within tumors seriously limits their spatial effect in generating sufficient tumor-associated antigens, a key factor to the success of ISTV. In this study, a nano-adjuvant system is fabricated based on the NIR-II-absorbable gold nanostars decorated with hyaluronidases and immunostimulatory oligodeoxynucleotides CpG for ISTV. The nano-adjuvant displays a deep tumor penetration capacity via loosening the dense extracellular matrix of tumors. Upon NIR-II light irradiation, the nano-adjuvant significantly inhibits the tumor growth, induces a cascade of immune responses, generates an obvious adaptive immunity against the re-challenged cancers, boosts the abscopal effect, and completely inhibits the pulmonary metastases. The study highlights an advanced nano-adjuvant formulation featuring deep tumor penetration for NIR-II-triggered ISTV.

Multifunctional BODIPY for effective inactivation of Gram-positive bacteria and promotion of wound healing.

Bacterial infectious diseases and antimicrobial resistance seriously endanger human health, so alternative therapies for bacterial infections are urgently needed. Recently, photodynamic therapy against bacteria has shown great potential because of its high efficiency and low acquired resistance. Here, we design and synthesize a dipyrromethene boron difluoride (BODIPY) photosensitizer containing a guanidine group LIBDP for combating bacterial infections. The positively charged guanidine can destroy the bacterial membrane and inhibit the proliferation of bacteria to a certain extent. Upon light irradiation, LIBDP can produce reactive oxygen species (ROS), which can destroy the pre-formed biofilm and induce potent antibacterial activity. In addition, the guanidine of LIBDP can be oxidized to nitric oxide (NO) by the generated ROS, which can not only improve the antibacterial effect, but also promote wound healing. The strategy in this work paves the way for synthesizing high-performance antibacterial materials.

Leveraging BODIPY nanomaterials for enhanced tumor photothermal therapy.

In the past ten years, photothermal therapy (PTT) has attracted widespread attention in tumor treatment due to its non-invasiveness and little side effects. PTT utilizes heat produced by photothermal agents under the irradiation of near-infrared light to kill tumor cells. Boron-dipyrromethene (BODIPY), an organic phototherapy agent, has been widely used in tumor phototherapy due to its higher molar extinction coefficient, robust photostability and good phototherapy effect. However, there are some issues in the application of BODIPY for tumor PTT, such as low photothermal conversion efficiency and short absorption wavelength. In this review, we focus on the latest development of BODIPY nanomaterials for overcoming the above problems and enhancing the PTT effect.

Near-Infrared absorbing J-Aggregates of boron dipyrromethene for high efficient photothermal therapy.

Constructing bioactive materials remains a big challenge through the aggregates of molecules. Herein, a boron dipyrromethene (BODIPY) derivative containing three nitro groups (BDP-(NO2)3) was synthesized, which displays the characteristic of J-aggregate with pronounced red-shifted absorption in nonpolar solvent and aqueous media. The bathochromic shift from 635 to 765 nm facilitates photothermal transition upon the irradiation of near-infrared (NIR) light. Interestingly, BDP-(NO2)3 nanoparticles (NPs) fabricated from BDP-(NO2)3 and poly(oxyethylene)-poly(oxypropylene) copolymer (F-127), still exhibit obvious J-aggregate, which possess the merits of hydrophilicity, NIR absorption, high photothermal conversion efficiency, excellent biosafety, and can behave as unique candidates for photothermal therapy. In vitro and in vivo experiments validate that BDP-(NO2)3 NPs can effectively suppress the proliferation of cancer cells and lead to tumor ablation. This assembly method would be a generic and efficient mode for reasonable design of functional nanomaterials, and could inspire more study on aggregates of organic molecules.

Vaginal drug delivery approaches for localized management of cervical cancer.

Cervical cancer or cervical intraepithelial neoplasia (CIN) remain a major public health problem among women globally. Traditional methods such as surgery are often associated with possible complications which may impact future pregnancies and childbirth especially for young female patients. Vagina with a high contact surface is a suitable route for the local and systemic delivery of drugs but its abundant mucus in continuous exchange presents a barrier for the popularization of conventional vaginal formulations including suppositories, gel, patch, creams and so on. So the development of new pharmaceutical forms based on nanotechnology became appealing owing to its several advantages such as mucosa penetration, bioadhesion, controlled drug release, and decreased adverse effects. This review provided an overview of the development of topical treatment of cervical cancer or CIN through vaginal drug delivery ranging from conventional vaginal formulations to new nanocarriers to the newly developed phototherapy and gene therapy, analyzing the problems faced by current methods used, and advising the developing trend in future. The methods of establishing preclinical animal model are also discussed.

Merocyanine-paclitaxel conjugates for photothermal induced chemotherapy.

Small molecular nanomedicines that integrate the flexibility of self-assembly strategies and the advantages of a precise molecular structure, a high drug content and controlled drug release are effective diagnostic and therapeutic modalities. Herein, merocyanine-paclitaxel conjugates (MC-PTX) were developed and fabricated by using the degradable ester bonds as the linker. The as-prepared MC-PTX could self-assemble into nanoparticles (MC-PTX NPs) using the non-covalent molecular interaction via the nanoprecipitation method. MC-PTX NPs possess a favorable biological stability and can efficiently release the paclitaxel (PTX) activated by the heat of the photoactive material merocyanine under light illumination, as monitored using dynamic light scattering. The obtained MC-PTX NPs could be endocytosed into cancer cells and release PTX under laser irradiation in the cytoplasm, thus eliciting a satisfactory anticancer effect. Photothermal triggered degradation upon light illumination could enhance the chemotherapeutic efficacy of paclitaxel. The fluorescent nature of the NPs could visualize the internalization process. We believe that this robust nanomedicine offers a novel strategy to facilitate clinical translation for use as a small molecular chemotherapy nanomedicine.

Mitochondria-Targeting Organic Nanoparticles for Enhanced Photodynamic/Photothermal Therapy.

Organelle-targeting techniques have been proved to be promising approaches for enhanced cancer treatment, especially phototherapy, because it can greatly improve the efficiency of photosensitizers. In this work, we designed and synthesized a mitochondria-targeting diketopyrrolopyrrole-based photosensitizer (DPP2+) for synergistic photodynamic/photothermal therapy upon irradiation. The obtained mitochondria-targeting nanoparticles (DPP2+ NPs) could produce thermal energy and singlet oxygen under 635 nm laser irradiation with ideal cytocompatibility. Importantly, DPP2+ NPs are more likely to enter the cells and target mitochondria. In in vitro and in vivo antitumor experiments, DPP2+ NPs showed highly effective antitumor effects, suggesting that mitochondria-targeting photosensitizers have potential for cancer treatment. The present work provides an alternative strategy to mitochondria-targeting molecular engineering and highlights the potential of organic nanomaterials in biomedical fields and cancer treatment.

Highly efficient near-infrared BODIPY phototherapeutic nanoparticles for cancer treatment.

BODIPYs are highly potential photoactive agents for cancer theragnostics. The rational design of BODIPY-based photoactive nanodrugs with high efficiency and near-infrared (NIR) absorption is imperative. Herein, we developed a donor-acceptor-donor (D-A-D) organic photosensitizer (PS) (BODIPY, named NBB), which possessed strong absorption in the NIR region due to the multi-intersection of intramolecular charge transfer (ICT), photoinduced electron transfer (PET), and heavy atom effects. Through a nanoprecipitation method, NBB nanoparticles (NPs) were facilely prepared. The as-prepared NBB NPs exhibited favorable water-stability and photostability. In particular, the outstanding photon absorption capacity endows the NPs with high photothermal conversion efficiency (η = 53.8%) and active singlet oxygen (1O2) generation ability upon 808 nm laser irradiation, and promotes their tumour inhibition efficiency via the combination of photothermal/photodynamic therapy (half-maximal inhibitory concentration IC50 = 8.11 and 7.77 µM for HeLa and HepG2 cells, respectively). Together with the favorable synthetic yield and excellent antitumour effect, we envision that this exploration can provide beneficial guidance for the clinical translation of BODIPY-based PSs for phototherapy.

Integration of metal-organic framework with a photoactive porous-organic polymer for interface enhanced phototherapy.

Porphyrin-based porous organic polymers are highly potential candidates for cancer theranostics. However, un-controllable particle size and unclear photoactive mechanisms have been deemed to be "Achilles' heels" for their biomedical application. Herein, a facile self-template strategy has been applied to integrate two types of porous materials to build the MOF@POP-PEG nanocomposite (named HUC-PEG). As-synthesized HUC-PEG exhibited controllable particle shape and size, good biocompatibility, and better colloidal stability. Importantly, synergy "0 + 1 > 1" interface effects have been demonstrated to simultaneously enhance both the generation of more singlet oxygen (1O2) for photodynamic therapy (PDT) and local hyperthermia for photothermal therapy (PTT), thus to achieve favorable proliferation inhibition of tumor cell both in vitro and in vivo. Moreover, the strong X-ray attenuating ability of Hf element and excellent photothermal conversion efficacy endow this nanocomposite with computed tomography (CT)/photothermal imaging functions. We believe that our ingenious design may open a new horizon for the preparation of nanoscale POP-based therapeutic agents and also realize a paradigm shift in the understanding of photoactive mechanism in porous materials.

Engineering pH-Responsive BODIPY Nanoparticles for Tumor Selective Multimodal Imaging and Phototherapy.

It is a challenge to develop multifunctional theranostic agents in one molecule, which simultaneously possesses tumor imaging ability with a high signal-to-noise ratio and excellent therapeutic activity. In this work, we synthesized and screened a series of BODIPY (BDP) with various absorption and fluorescence. The interplay of the molecular structure, pH-sensitive absorption and emission, and photodynamic and photothermal activities was well studied in detail. Photoinduced electron transfer, intramolecular charge transfer, and heavy atom effect were leveraged to engineer BDP with tumor imaging and therapeutic functions. The BDP nanoparticle formulations possessed multifunctional biological features, including selective treatment of cancer cells, near-infrared fluorescence, photoacoustic and computed tomography imaging, and photodynamic and photothermal therapy, as validated by cellular and animal experiments. These results not only give a new horizon to multifunctional BDP for biological applications but also show a new way to design the organic dye for tumor imaging and phototherapy.

The neural stem cell/carnitine malnutrition hypothesis: new prospects for effective reduction of autism risk?

Autism spectrum disorders (ASDs) are developmental neuropsychiatric disorders with heterogeneous etiologies. As the incidence of these disorders is rising, such disorders represent a major human health problem with escalating social cost. Although recent years witnessed advances in our understanding of the genetic basis of some dysmorphic ASDs, little progress has been made in translating the improved understanding into effective strategies for ASD management or minimization of general ASD risk. Here we explore the idea, described in terms of the neural stem cell (NSC)/carnitine malnutrition hypothesis, that an unappreciated risk factor for ASD is diminished capacity for carnitine-dependent long-chain fatty acid ß-oxidation in neural stem cells of the developing mammalian brain. The basic premise is that fetal carnitine status is a significant metabolic component in determining NSC vulnerability to derangements in their self-renewal program and, therefore, to fetal ASD risk. As fetal carnitine status exhibits a genetic component that relates to de novo carnitine biosynthesis and is sensitive to environmental and behavioral factors that affect maternal circulating carnitine levels, to which the fetus is exposed, we propose that reduced carnitine availability during gestation is a common risk factor that lurks beneath the genetically complex ASD horizon. One major prediction of the NSC/carnitine malnutrition hypothesis is that a significant component of ASD risk might be effectively managed from a public policy perspective by implementing a carnitine surveillance and dietary supplementation strategy for women planning pregnancies and for women in their first trimester of pregnancy. We argue that this prediction deserves serious clinical interrogation.

Self-quenching synthesis of coordination polymer pre-drug nanoparticles for selective photodynamic therapy.

The design and preparation of a photoactive coordination polymer nanoplatform with tumor-related stimuli-activatability and biodegradability is highly desirable for achieving highly precise photodynamic therapy (PDT). Herein, novel "pre-photodynamic" nanoparticles (Fe-IBDP NPs) with a tumor microenvironment (TME)-activatable PDT and good biodegradability were synthesized by carrying out facile coordination assembly of an IBDP photosensitizer with an Fe3+ quenching agent. After being taken up by cancer cells, our "inactive" Fe-IBDP NPs were activated by the TME and as a result decomposed and released the photoactive carboxyl-functionalized diiodo-substituted BODIPY (IBDP) photosensitizer, which generated cytotoxic singlet oxygen (1O2) under light irradiation. By contrast, these NPs showed relatively low cytotoxicity in normal cells. This work also provided a feasible method for preparing the next generation of photoactive nanomedicines for use in precise phototherapy.

Self-destructive PEG-BODIPY nanomaterials for photodynamic and photothermal therapy.

Photoactive nanoparticles are an important platform for multimodal imaging and phototherapy of tumors. Herein, amphiphilic photosensitizers were made from boron dipyrromethene (BODIPY) and poly(ethylene glycol) (PEG2k) by using a thioketal linker, which is reactive oxygen species-responsive. The photosensitizers could form stable nanoparticles in aqueous solution. The resulting nanoparticles could simultaneously produce heat and reactive oxygen species upon irradiation to achieve combined photothermal and photodynamic therapy. The produced singlet oxygen could destroy the thioketal linker, and accelerate the destruction of nanoparticles. In addition, the near-infrared fluorescence and photoacoustic imaging ability of nanoparticles can reflect the biodistribution and destiny of nanoparticles. This work highlights the application of integrated diagnostic and therapeutic photosensitizers in carriers.

Comparative study of two near-infrared coumarin-BODIPY dyes for bioimaging and photothermal therapy of cancer.

Near-infrared (NIR) responsive agents for cancer bioimaging and photothermal therapy are available and significant. Herein, we employed two easily available dyes, boron-dipyrromethane and coumarin, to synthesize a pair of coumarin-borondipyrromethane dyes with different conjugate degrees (BDC and BSC). The difference in conjugate degree made their photophysical properties poles apart. After the self-assembling of BDC and BSC, the newly constructed nanoparticles (BDC NPs and BSC NPs) demonstrated good biocompatibility. Moreover, BDC NPs exhibited a good photothermal effect under irradiation of 808 nm laser, which could effectively inhibit the growth of HeLa cells, and BSC NPs could quickly show a conspicuous fluorescence in the HeLa cells. The exploration demonstrates that the two organic dyes prepared with different conjugation degrees could provide new options for photothermal therapy of cancer and rapid bioimaging.