Extraction,Optical Properties and Bio-Imaging of Fluorescent Composition From Moso Bamboo Shoots

A novel fluorescent composition was firstly isolated from natural winter fresh Moso bamboo shoots,and its optical properties were fully investigated by fluorescence spectroscopy.It could emit strong blue light both in solid and solution state,providing high fluorescence intensity in ethanol.The solution’s concentration and addition of water greatly affected the fluorescence intensity,high concentration and addition of much water could quench fluorescence.Apoptosis results showed that the fluorescent extract(0-25 mg/L)could not induce apoptosis of Hela cells.Confocal fluorescent microscopic imaging in human hepatocellular carcinoma cells(HepG2)was realized using the fluorescent extract,it could dye the whole cell well which was different from 4',6-diamidino-2-phenylindole(DAPI)only dying cell nucleus.The fluorescent extract may be candidate for future natural fluorescent bio-imaging agent.

Digital liver biopsy:Bio-imaging of fatty liver for translational and clinical research

The rapidly growing field of functional, molecular and structural bio-imaging is providing an extraordinary new opportunity to overcome the limits of invasive liver biopsy and introduce a "digital biopsy" for in vivo study of liver pathophysiology. To foster the application of bio-imaging in clinical and translational research, there is a need to standardize the methods of both acquisition and the storage of the bio-images of the liver. It can be hoped that the combination of digital, liquid and histologic liver biopsies will provide an innovative synergistic tri-dimensional approach to identifying new aetiologies, diagnostic and prognostic biomarkers and therapeutic targets for the optimization of personalized therapy of liver diseases and liver cancer. A group of experts of different disciplines(Special Interest Group for Personalized Hepatology of the Italian Association for the Study of the Liver, Institute for Biostructures and Bio-imaging of the National Research Council and Bio-banking and Biomolecular Resources Research Infrastructure) discussed criteria, methods and guidelines for facilitating the requisite application of data collection. This manuscript provides a multi-Author review of the issue with special focus on fatty liver.

A H_(2)S-triggered two-photon ratiometric fluorescent theranostic prodrug for bio-imaging

Hydrogen sulfide(H_(2) S) is a signaling molecule that plays important roles in biological systems.The exploration of H_(2) S as a new drug release trigger and its related fluorescent theranostic system is crucial for cancer bio-imaging and therapy.Herein,we designed a new two-photon ratiometric fluorescent theranostic prodrug(compound 1) and studied its spectroscopic properties and application in in vivo imaging.Compound 1 specifically reacted with H_(2) S and released the free active therapeutic component of 7-ethyl-10-hydroxycamptothecin,which was accompanied with a red-shift fluorescence emission signal from 460 nm to 545 nm.The exogenous and endogenous H_(2) S in living cells were imaged by compound 1 under one-photon and two-photon excitation.Furthermore,compound 1 monitored the H_(2) S concentration changes in Caenorhabditis elegans by fluorescence imaging.Additionally,it showed effective drug release activation in situ tumor with exogenous and endogenous H_(2) S as the trigger.The H_(2) S-sensitive activation and drug-release properties highlight the potential of theranostic compound 1 in future cancer treatment and therapy.

Novel in situ biosynthesized fluorescent zinc nanoclusters for specific cellular bio-imaging

It is well known that zinc ions play an indispensable role in the structure and function of a large number of biological process and relevant bio-macromolecules. When some cancers occurred, the relevant concentration of zinc ions considerably decreased. Since cancer cells have a completely different redox homeostasis from normal cells, in this contribution, we have explored the possibility of bio-imaging or labeling of cancer cells through the in situ biosynthesized zinc nanoclusters by cancerous cells. The results demonstrate that we can readily realize the in vivo fluorescent bio-imaging of cancer cells through the in situ biosynthesis of the biocompatible zinc nanoclusters from cancerous cells （i.e., Hela cervical carcinoma cell line and others） when target cells cultured with micromolar zinc gluconate solutions.

A multi-functional nanoplatform for efficacy tumor theranostic applications

Nanomaterials with multiple functions have become more and more popular in the domain of cancer research. MoS2 has a great potential in photothermal therapy, X-ray/CT imaging and drug delivery. In this study, a water soluble MoS2 nanosystem(MoS2-PEG) was synthesized and explored in drug delivery, photothermal therapy(PTT) and X-ray imaging.Doxorubicin(DOX) was loaded onto MoS2-PEG with a high drug loading efficiency(~69%)and obtained a multifunctional drug delivery system(MoS2-PEG/DOX). As the drug delivery, MoS2-PEG/DOX could efficiently cross the cell membranes, and escape from the endosome via NIR light irradiation, lead to more apoptosis in MCF-7 cells, and afford higher antitumor efficacy without obvious toxic effects to normal organs owing to its prolonged blood circulation and 11.6-fold higher DTX uptake of tumor than DOX. Besides, MoS2-PEG/DOX not only served as a drug delivery system, but also as a powerful PTT agent for thermal ablation of tumor and a strong X-ray contrast agent for tumor diagnosis. In the in vitro and in vivo studies, MoS2-PEG/DOX exhibited excellent tumor-targeting efficacy, outstanding synergistic anti-cancer effect of photothermal and chemotherapy and X-ray imaging property,demonstrating that MoS2-PEG/DOX had a great potential for simultaneous diagnosis and photothermal-chemotherapy in cancer treatment.

Recent advances in nonlinear optics for bio‐imaging applications

Nonlinear optics,which is a subject for studying the interaction between intense light and materials,has great impact on various research fields.Since many structures in biological tissues exhibit strong nonlinear optical effects,nonlinear optics has been widely applied in biomedical studies.Especially in the aspect of bio-imaging,nonlinear optical techniques can provide rapid,label-free and chemically specific imaging of biological samples,which enable the investigation of biological processes and analysis of samples beyond other microscopy techniques.In this review,we focus on the introduction of nonlinear optical processes and their applications in bio-imaging as well as the recent advances in this filed.Our perspective of this field is also presented.

Novel Hybrid SiO2/ZnS Coated CdTe/CdS Quantum Dots and Their Bioapplications

Novel CdTe/CdS quantum dots(QDs)coated with a hybrid of SiO_2 and ZnS were fabricated through a simple two-step approach.The hybrid SiO_2/ZnS coated CdTe/CdS quantum dots was characterized by transmission electron microscopy(TEM),UV and fluorescence spectrometer.Results indicated that the core-shell structure gave the QDs outstanding photoluminescence properties,includinganarrowphotoluminescencespectrum,high photoluminescence(PL)quantum yield and long emission lifetime(average PL lifetime of increased from 26.4 ns to 49.1 ns).Cellular studies showed the QDs had good cytocompatibility with Hela cells as determined by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide(MTT)assay after coating SiO_2/ZnS,and also proved the feasibility of using the hybrid SiO_2/ZnS coated QDs as optical probes for in vitro cell imaging.The synthesis method of QDs is highly promising for the production of robust and functional optical probes for bio-imaging and sensing applications.

Research Progress on the Application of Graphene in the Field of Biomedicine

Graphene is the thinest nanomaterial known in the world,which has unique electronic mobility,super specific surface area,high mechanical strength,excellent corrosion resistance and surface chemical structure.Due to its special nanostructure and excellent physical and chemical properties,graphene has a broad application prospect in the fields of electronics,optics,magnetism,biomedicine,catalysis,energy storage and sensors.In order to better develop and utilize graphene data,this paper reviewed the structural characteristics of graphene,as well as its research progress in biosensors,bio-imaging,aerogel and other biomedical fields,hoping to provide scientific basis for better development of graphene and the development of graphene pharmaceutical products.

Recent developments of fluorescence imaging technology in the second near-infrared window

Background:Fluorescence bio-imaging in the second near-infrared window(NIR-II FL,1000-1700nm)has great potential in clinical theranostics,which is of great importance providing precise locations of lesions and molecular dynamic actions simultaneously in a single nanoprobe.Methods:T here has been an upsurge of multidisciplinary research focusing on developing functional types of inorganic and organic nanoprobes that can be used for NIR-II FL with the high spatiotemporal resolution,deep tissue penetration,and negligible auto-fluorescence.Results:In this mini-review,we summarize recent progress in inorganic/organic NIR-II FL nanoprobes.We introduce the design and properties of inorganic and organic nanoprobes,in the order of single-walled carbon nanotubes,quantum dots,rare-earth-doped nanoparticles,metal nanoclusters and organic fluorophores,expect to realize precise diagnosis and efficient image-guided therapy.Conclusion:Meanwhile,to elucidate the problems and perspectives,we aim to offer diverse biological applications of inorganic/organic NIR-II FL nanoprobes and accelerate the clinical transformation progress.

Achieving purely organic room temperature phosphorescence in aqueous solution

Purely organic room temperature phosphorescence(RTP)materials have aroused increasing interests in recent years and have been widely applied in anticounterfeiting,biological imaging,sensing,etc.Currently,these materials can be efficiently developed in crystalline states and amorphous polymer-doped systems.However,achieving organic RTP in solution,especially in water solution,is still a formidable challenge.Recently,reports on aqueous phase RTP have been increasing and some feasible design strategies have been proposed;however,related investigations are still limited and there is a lack of systematic reviews.Therefore,we summarized the recent cases of aqueous phase organic RTP emission with primarily focusing on the RTP properties and efficient design strategies(e.g.,forming nanoparticles from phosphorescent molecules and macrocyclic supramolecular assembly).Moreover,promising applications of the aqueous phase organic RTP emission in bio-imaging and sensing were discussed.Some detailed perspectives concerning materials design and application were provided with the hope to provide inspiration for the future development of aqueous phase organic RTP.

Resolution enhancement with deblurring by pixel reassignment

Improving the spatial resolution of a fluorescence microscope has been an ongoing challenge in the imaging community.To address this challenge,a variety of approaches have been taken,ranging from instrumentation development to image postprocessing.An example of the latter is deconvolution,where images are numerically deblurred based on a knowledge of the microscope point spread function.However,deconvolution can easily lead to noise-amplification artifacts.Deblurring by postprocessing can also lead to negativities or fail to conserve local linearity between sample and image.We describe here a simple image deblurring algorithm based on pixel reassignment that inherently avoids such artifacts and can be applied to general microscope modalities and fluorophore types.Our algorithm helps distinguish nearby fluorophores,even when these are separated by distances smaller than the conventional resolution limit,helping facilitate,for example,the application of single-molecule localization microscopy in dense samples.We demonstrate the versatility and performance of our algorithm under a variety of imaging conditions.

Luminescent metal nanoclusters for biomedical applications

Luminescent metal nanoclusters (NCs) have recently emerged as a novel class of luminescent nanomaterials and hold significant potential in biomedicine owing to their ultrasmall (<2nm) size,excellent photostability,and good biocompatibility.The recent rapid advances in the synthesis and functionalization of luminescent metal NCs have enabled scientists to develop colorful nanomaterials and nanodevices for a wide range of biomedical applications.In this review,we summarize the characteristics and advantages of luminescence from metal NCs,and highlight their applications in biomedicine.We focus on the research in biomedical detection,bio-imaging,drug delivery,and therapy,especially for the advances in the last five years.Luminescent metal NCs display a series of unique superiorities in biomedical applications,and the recent achievements have brought a lot of benefits to the diagnosis and treatment of clinical diseases,especially for tumors and cancers.Finally,we put forward the main challenges that currently still hinder the basic science studies and the practical development of luminescent metal NCs in biomedical applications.Overall,we expect that luminescent metal NCs will play a much more important role in future biomedicine and clinical applications.

Biosynthesis of Biocompatible Cadmium Telluride Quantum Dots Using Yeast Cells

We demonstrate a simple and efficient biosynthesis method to prepare easily harvested biocompatible cadmium telluride(CdTe)quantum dots(QDs)with tunable fluorescence emission using yeast cells.Ultraviolet-visible(UV-vis)spectroscopy,photoluminescence(PL)spectroscopy,X-ray diffraction(XRD),and transmission electron microscopy(TEM)confirm that the CdTe QDs are formed via an extracellular growth and subsequent endocytosis pathway and have size-tunable optical properties with fluorescence emission from 490 to 560 nm and a cubic zinc blende structure with good crystallinity.In particular,the CdTe QDs with uniform size(2-3.6 nm)are protein-capped,which makes them highly soluble in water,and in situ bio-imaging in yeast cells indicates that the biosynthesized QDs have good biocompatibility.This work provides an economic and environmentally friendly approach to synthesize highly fluorescent biocompatible CdTe QDs for bio-imaging and bio-labeling applications.

Recent Advances in Super-Resolution Fluorescence Imaging and Its Applications in Biology

Fluorescence microscopy has become an essential tool for biological research because it can be minimally invasive, acquire data rapidly, and target molecules of interest with specific labeling strategies. However, the diffraction-limited spatial resolution, which is classically limited to about 200 nm in the lateral direction and about 500 nm in the axial direction, hampers its application to identify delicate details of subcellular structure. Extensive efforts have been made to break diffraction limit for obtaining high-resolution imaging of a biological specimen. Various methods capable of obtaining super-resolution images with a resolution of tens of nanometers are currently available. These super-resolution techniques can be generally divided into three primary classes： （1） patterned illumination- based super-resolution imaging, which employs spatially and temporally modulated illumination light to reconstruct sub-diffraction structures; （2） single-molecule localization-based super-resolution imaging, which localizes the profile center of each individual fluo- rophore at subdiffraction precision; （3） bleaching/blinking-based super-resolution imaging. These super-resolution techniques have been utilized in different biological fields and provide novel insights into several new aspects of life science. Given unique technical merits and commercial availability of super-resolution fluorescence microscope, increasing applications of this powerful technique in life science can be expected.

Recent developments and progress of inorganic photo-stimulated phosphors

Photo-stimulated luminescence(PSL) is the process in which trapped charges are released by photons and produce luminescence through recombination. The variegated optical characteristics of photostimulated phosphors(PSPs) have drawn increasing attention and a large body of work encompassing mechanism and application of PSPs has been addressed. The optical data storage capacity resulting from abundant defect states enables PSPs to be applied to information storage. Moreover, PSPs provide potential application for anti-counterfeiting, as color changes due to the tunneling process. Recently, near infrared(NIR) light PSPs have been developed, exhibiting enormous potential for in vivo bio-imaging, as the stable and high noise-signal ratio characteristic of PSL. In this review, we devote to introducing the development and process of PSPs, and the challenge and future advance have also been demonstrated.

Fluorescent silicon nanoparticles-based nanotheranostic agents for rapid diagnosis and treatment of bacteria-induced keratitis

Recommended as a medical emergency,infectious keratitis with an acute and rapid disease progression can lead to serious damage of vision and even blindness.Herein,we present a kind of theranostic agents,which are made of vancomycin(Van)-modified fluorescent silicon nanoparticles(SiNPs-Van),enabling rapid and non-invasive diagnosis and treatment of Gram-positive bacteria-induced keratitis in a simultaneous manner.Typically,the resultant SiNPs-Van nanoagents have an ability of imaging bacteria in a short time both in vitro(5 min)and in vivo(10 min),making them an efficacious diagnostic agent for the detection of bacterial keratitis.In addition,the SiNPs-Van feature distinct antimicrobial activity,with superior activity of 92.5%at a concentration of 0.5 ng/mL against Staphylococcus aureus(S.aureus);comparatively,the antimicrobial rate of free vancomycin is 23.3%at the same concentration.We further explore the SiNPs-Van agents as eye drops for therapy of S.aureus-induced bacterial keratitis on rat model.Represented by slit-lamp scores,the keratitis severity of SiNPs-Van-treated corneas is 3.4,which is 59.6%and 77.3%slighter than vancomycin-(8.2 score)and PBS-treated corneas(15.0 score),respectively.The infected corneas recover to normal(1 score)after 7-d of SiNPs-Van treatment.Above results suggest that the SiNPs-Van could serve as a new kind of high-quality nanotheranostic agents,especially suitable for simultaneous diagnosis and therapy of Gram-positive bacteria keratitis.

Poly(α-L-lysine)-based nanomaterials for versatile biomedical applications:Current advances and perspectives

Poly(α-L-lysine)(PLL)is a class of water-soluble,cationic biopolymer composed ofα-L-lysine structural units.The previous decade witnessed tremendous progress in the synthesis and biomedical applications of PLL and its composites.PLL-based polymers and copolymers,till date,have been extensively explored in the contexts such as antibacterial agents,gene/drug/protein delivery systems,bio-sensing,bio-imaging,and tissue engineering.This review aims to summarize the recent advances in PLL-based nanomaterials in these biomedical fields over the last decade.The review first describes the synthesis of PLL and its derivatives,followed by the main text of their recent biomedical applications and translational studies.Finally,the challenges and perspectives of PLL-based nanomaterials in biomedical fields are addressed.

Effects of the molluscicide can didate PPU06 on alkaline phosphatase in the golden apple snails determined using a near-infrared fluorescent probe

We constructed a reaction-based near-infrared fluorescent probe(Niap) to specifically identify alkaline phosphatase(ALP) with fast red fluorescence enhancement.Based on the positive concentrationdependent manner between the fluorescent intensity of the Niap and ALP,probe Niap was used to study the ALP enrichment and variation in golden apple snails(Pomacea canaliculata) exposed to the molluscicide candidate PPU06.After treatment with different concentrations of PPU06 over various times,three organs of the surviving snails,liver,stomach and plantaris,were frozen and sectioned for fluorescent imaging experiments.With increased PPU06 concentration,red fluorescence substantially increased in the liver and reached a maximum within 24 h when the PPU06 co ncentration was 0.75 mg/L.No obvious changes in the stomach or foot plantaris were found.It showed PPU06 caused liver injury and stimulated the increase of ALP in the liver of P.canaliculata.This study demonstrates a rapid ALP fluorescent identification method that can be used to study the effects of PPU06 on P.canaliculata.It also provides optical evidence that may aid in the discovery of new chemistry for snail control.

Naphthalene diimide based near-infrared luminogens with aggregation-induced emission characteristics for biological imaging and high mobility ambipolar transistors

Organic conjugated materials combining high conductivity with strong solid-state emission are highly desired for organic electronic applications,yet still rather rare.Herein,a novel luminogen(TEN)comprised by linking naphthalene diimides and triphenyl ethylene with vinyl bridges is reported.TEN exhibits aggregation-induced emission(AIE)behavior of a strong nearinfrared fluorescence over 700 nm and the efficiency above 60.5%in the solid state,while also shows promising application in vivo bio-imaging with good permeability and extremely low background.Single crystal of TEN reveals intra-and intermolecular C–H…O hydrogen bonds,contributing to an inclined molecular stacking along the a-axis of the cell,creating a 1 D charge carrier transporting channel under a shortπ-πinteraction distance of 3.42?,which might benefit the solid emission and charge transport ability simultaneously.Solution processed bottom contact,top gate organic field effect transistors based on TEN reveal a high ambipolar charge transport ability with the hole mobility up to 0.13 cm2 V-1 s-1 and electron mobility up to0.010 cm2 V-1 s-1.Further atomic force microscopy and X-ray diffraction analysis on TEN thin film confirm the existence of the1 Dπ-πstacking channel,suggesting the stacking geometry revealed in crystal crucial for facilitating high charge carrier mobility while preserving the strong solid emission at the same time.

The potential clinical applications of radionuclide labeled/doped gold-based nanomaterials

Radionuclides have been widely used for multimodal imaging and radioisotope therapy of cancer.Various nanomaterials have been developed as excellent nanocarriers of radionuclides for the targeted delivery into tumors,in order to minimize the unnecessary side effect and enhance the therapeutic efficacy of radiotherapy.Among those nanomaterials,gold nanomaterials with tunable morphologies,easy modification,good biological safety,and radiation sensitization capability are excellent candidates for cancer theranostics.Given the superior performance of gold-based nanomaterials in biomedicine,we summary the recent advance of radionuclide labeled/doped gold-based nanomaterials for cancer theranostics.In this review article,we will discuss the methods for labelling or doping radionuclides onto gold nanomaterials,their applications for nuclear imaging and Cerenkov luminescence(CL)imaging,as well as the radioisotope therapy of cancer,and finally the toxicity evaluation of radionuclide labeled/doped gold-based nanomaterials.We hope that our review article would provide guidance for non-experts to design the radiolabeled nanomaterials for cancer imaging guided therapy.