Recent progress of nano-drugs in neutron capture therapy.

As a developing radiation treatment for tumors, neutron capture therapy (NCT) has less side effects and a higher efficacy than conventional radiation therapy. Drugs with specific isotopes are indispensable counterparts of NCT, as they are the indespensable part of the neutron capture reaction. Since the creation of the first and second generations of boron-containing reagents, NCT has significantly advanced. Notwithstanding, the extant NCT medications, predominantly comprised of small molecule boron medicines, have encountered challenges such monofunctionality, inadequate targeting of tumors, and hypermetabolism. There is an urgent need to promote the research and development of new types of NCT drugs. Bio-nanomaterials can be introduced into the realm of NCT, and nanotechnology can give conventional medications richer functionality and significant adaptability. This can complement the advantages of each other and is expected to develop more new drugs with less toxicity, low side effects, better tumor targeting, and high biocompatibility. In this review, we summarized the research progress of nano-drugs in NCT based on the different types and sources of isotopes used, and introduced the attempts and efforts made by relevant researchers in combining nanomaterials with NCT, hoping to provide pivotal references for promoting the development of the field of tumor radiotherapy.

Biosafety assessments of hexafluoropropylene trimer derivative as a fluorinated cooling fluid for electronics.

The Internet Data Center (IDC) is one of the most important infrastructures in the field of information technology. The cooling system for heat dissipation of IDC is indispensable due to it generates a large amount of heat during its calculation process, which may potentially harm its normal operation. Electronic fluorinated fluids have been widely used in cooling systems of IDC with stable physical and chemical properties. However, the biological toxicity of electronic fluorinated fluids has not been fully evaluated and there is a lack of unified safety standards, which may pose potential risks to the environment and human health. Here, hexafluoropropylene terpolymer (HFPT) as an example has been systematically studied, fully considering the application scenarios of data centers. Also, the emergency effects of fluorinated coolants in mammalian models from the perspectives of inhalation, skin contact, accidental entry into eyes, accidental ingestion, and chronic toxicity, are evaluated. Multiple in vivo experiments have proven that HFPT not only has stable physical and chemical properties, that can maintain the safe operation of IDC, but also has low physiological toxicity to mammals and can provide health benefits to data center staff and the assurance of surrounding environment. This study proves the good biological safety of electronic fluorinated fluids and provides a reference for environmental assessment and risk management of liquid cooling technology in IDC. Supplementary Information: The online version contains supplementary material available at 10.1007/s43188-024-00234-3.

DNA Nanoparticle Based 2D Biointerface to Study the Effect of Dynamic RGD Presentation on Stem Cell Adhesion and Migration.

The native extracellular matrix (ECM) undergoes constant remodeling, where adhesive ligand presentation changes over time and in space to control stem cell function. As such, it is of interest to develop 2D biointerfaces able to study these complex ligand stem-cell interactions. In this study, a novel dynamic bio interface based on DNA hybridization is developed, which can be employed to control ligand display kinetics and used to study dynamic cell-ligand interaction. In this approach, mesoporous silica nanoparticles (MSN) are functionalized with single-strand DNA (MSN-ssDNA) and spin-coated on a glass substrate to create the 2D bio interface. Cell adhesive tripeptide RGD is conjugated to complementary DNA strands (csDNA) of 9, 11, or 20 nucleotides in length, to form csDNA-RGD. The resulting 3 csDNA-RGD conjugates can hybridize with the ssDNA on the MSN surface, presenting RGD with increased ligand dissociation rates as DNA length is shortened. Slow RGD dissociation rates led to enhanced stem cell adhesion and spreading, resulting in elongated cell morphology. Cells on surfaces with slow RGD dissociation rates also exhibited higher motility, migrating in multiple directions compared to cells on surfaces with fast RGD dissociation rates. This study contributes to the existing body of knowledge on dynamic ligand-stem cell interactions.

Coupling of surface plasmon resonance and mass spectrometry for molecular interaction studies in drug discovery.

Various analytical technologies have been developed for the study of target-ligand interactions. The combination of these technologies gives pivotal information on the binding mechanism, kinetics, affinity, residence time, and changes in molecular structures. Mass spectrometry (MS) offers structural information, enabling the identification and quantification of target-ligand interactions. Surface plasmon resonance (SPR) provides kinetic information on target-ligand interaction in real time. The coupling of MS and SPR complements each other in the studies of target-ligand interactions. Over the last two decades, the capabilities and added values of SPR-MS have been reported. This review summarizes and highlights the benefits, applications, and potential for further research of the SPR-MS approach.

Quantification of MicroRNA in a Single Living Cell via Ionic Current Rectification-Based Nanopore for Triple Negative Breast Cancer Diagnosis.

Accurate analysis of microRNAs (miRNAs) at the single-cell level is extremely important for deeply understanding their multiple and intricate biological functions. Despite some advancements in analyzing single-cell miRNAs, challenges such as intracellular interferences and insufficient detection limits still remain. In this work, an ultrasensitive nanopore sensor for quantitative single-cell miRNA-155 detection is constructed based on ionic current rectification (ICR) coupled with enzyme-free catalytic hairpin assembly (CHA). Benefiting from the enzyme-free CHA amplification strategy, the detection limit of the nanopore sensor for miRNA-155 reaches 10 fM and the nanopore sensor is more adaptable to complex intracellular environments. With the nanopore sensor, the concentration of miRNA-155 in living single cells is quantified to realize the early diagnosis of triple-negative breast cancer (TNBC). Furthermore, the nanopore sensor can be applied in screening anticancer drugs by tracking the expression level of miRNA-155. This work provides an adaptive and universal method for quantitatively analyzing intracellular miRNAs, which will greatly improve our understanding of cell heterogeneity and provide a more reliable scientific basis for exploring major diseases at the single-cell level.

Rapid detection of non-normal teeth on dental X-ray images using improved Mask R-CNN with attention mechanism.

PURPOSE: Dental health has been getting increased attention. Timely detection of non-normal teeth (caries, residual root, retainer, teeth filling, etc.) is of great importance for people's health, well-being, and quality of life. This work proposes a rapid detection of non-normal teeth based on improved Mask R-CNN, aiming to achieve comprehensive screening of non-normal teeth on dental X-ray images. METHODS: An improved Mask R-CNN based on attention mechanism was used to develop a non-normal teeth detection method trained on a high-quality annotated dataset, which can segment the whole mask of each non-normal tooth on the dental X-ray image immediately. RESULTS: The average precision (AP) of the proposed non-normal teeth detection was 0.795 with an intersection-over-union of 0.5 and max detections (maxDets) of 32, which was higher than that of the typical Mask R-CNN method (AP = 0.750). In addition, validation experiments showed that the evaluation metrics (AP, recall, precision-recall (P-R) curve) of the proposed method were superior to those of the Mask R-CNN method. Furthermore, the experimental results indicated that proposed method exhibited a high sensitivity (95.65%) in detecting secondary caries. The proposed method took about 0.12 s to segment non-normal teeth on one dental X-ray image using the laptop (8G memory, NVIDIA RTX 3060 graphics processing unit), which was much faster than conventional manual methods. CONCLUSION: The proposed method enhances the accuracy and efficiency of abnormal tooth diagnosis for practitioners, while also facilitating early detection and treatment of dental caries to substantially lower patient costs. Additionally, it can enable rapid and objective evaluation of student performance in dental examinations.

Ultrasmall Bi/Cu Coordination Polymer Combined with Glucose Oxidase for Tumor Enhanced Chemodynamic Therapy by Starvation and Photothermal Treatment.

Multi-modal combination therapy for tumor is expected to have superior therapeutic effect compared with monotherapy. In this study, a super-small bismuth/copper-gallic acid coordination polymer nanoparticle (BCN) protected by polyvinylpyrrolidone is designed, which is co-encapsulated with glucose oxidase (GOX) by phospholipid to obtain nanoprobe BCGN@L. It shows that BCN has an average size of 1.8 ± 0.7 nm, and photothermal conversion of BCGN@L is 31.35% for photothermal imaging and photothermal therapy (PTT). During the treatment process of 4T1 tumor-bearing nude mice, GOX catalyzes glucose in the tumor to generate gluconic acid and hydrogen peroxide (H2 O2 ), which reacts with copper ions (Cu2+ ) to produce toxic hydroxyl radicals (•OH) for chemodynamic therapy (CDT) and new fresh oxygen (O2 ) to supply to GOX for further catalysis, preventing tumor hypoxia. These reactions increase glucose depletion for starvation therapy , decrease heat shock protein expression, and enhance tumor sensitivity to low-temperature PTT. The in vitro and in vivo results demonstrate that the combination of CDT with other treatments produces excellent tumor growth inhibition. Blood biochemistry and histology analysis suggests that the nanoprobe has negligible toxicity. All the positive results reveal that the nanoprobe can be a promising approach for incorporation into multi-modal anticancer therapy.

Gelatinase-responsive biodegradable targeted microneedle patch for abscess wound treatment of S. aureus infection.

Abscess wound caused by bacterial infection is usually difficult to heal, thus greatly affect people's quality of life. In this study, a biodegradable drug-loaded microneedle patch (MN) is designed for targeted eradication of S. aureus infection and repair of abscess wound. Firstly, the bacterial responsive composite nanoparticle (Ce6@GNP-Van) with a size of about 182.6 nm is constructed by loading the photosensitizer Ce6 into gelatin nanoparticle (GNP) and coupling vancomycin (Van), which can specifically target S. aureus and effectively shield the phototoxicity of photosensitizer during delivery. When Ce6@GNP-Van is targeted and enriched in the infected regions, the gelatinase secreted by the bacteria can degrade GNP in situ and release Ce6, which can kill the bacteria by generating ROS under laser irradiation. In vivo experiments show that the microneedle is basically degraded in 10 min after inserting into skin, and the abscess wound is completely healed within 13 d after applying Ce6@GNP-Van-loaded MN patch to the abscess wound of the bacterial infected mice with laser irradiation, which can simultaneously achieve the eradication of biofilm and subsequent wound healing cascade activation, showing excellent synergistic antibacterial effect. In conclusion, this work establishes a synergistic treatment strategy to facilitate the repair of chronic abscess wound.

Endogenous Protease-Activatable Nanosensor Based on PNA-Peptide-DNA Engineering for AND-Gated and Dual-Model Detection of MicroRNA in Single Living Tumor Cells.

The in situ detection of low-content cancer biomarkers by an endogenous activator instead of an exogenous initiator in vitro remains a great challenge, leaving a gap in the development of a tumor-specific nanosensor with an endogenous protease-activatable manner. Herein, we proposed an endogenous protease-activatable nanosensor (PA-NS) guided by peptide nucleic acid-peptide-DNA copolymers to realize AND-gated and dual-model sensing of miRNA-21 (miR-21) by combining electrochemical detection with optical imaging in living tumor cells, without an additional introduction of an exogenous activator or nanomaterials. Moreover, the PA-NS can only be activated by "dual keys" (overexpressed miR-21 and cathepsin B protease in tumor cells) simultaneously, which enables effective improvement of the tumor-to-healthy cells ratio. The fluorescence intensity measured in single tumor cells was ∼3.5-fold higher than that in single healthy cells, and the electrochemical response decreased ∼30% in the presence of target miRNA. Furthermore, studies on regulation of the protease activity and miR-21 fluctuation under external stimulation have contributed to our understanding of the biological processes and drug screenings underlying disease development. This specific endogenous protease-mediated manner for dual-model detection of miRNA guarantees excellent tumor-selective capability, which offers new opportunities to study cell heterogeneity and provides more reliable fundamentals for the diagnosis and treatment of cancer down to the single-cell level.

Carbon quantum dot fluorescent probe for labeling and imaging of stellate cell on liver frozen section below freezing point.

The targeted labeling imaging of stellate cells on liver frozen section by immunofluorescence is a very promising visualization technique to study the distribution of stellate cells in the liver. In this study, water soluble carbon quantum dots that can emit blue, green and yellow fluorescence are synthesized by the hydrothermal method, and their sizes are 3.2, 3.7, and 4.3 nm, respectively. The three carbon quantum dots have good fluorescence stability, and the quantum yields are 36.1%, 26.3% and 21%, respectively. When the mass fraction of KCl in the blue carbon quantum dot dispersion system is 13%, it still maintains the liquid state at -30 °C. The final fluorescent probe is obtained after the carbon quantum dots are coupled with the secondary antibody, spectral characterizations confirm that the conjugate probe still maintains protein immunoactivity and has good stability. Cell experiments prove that the probe has good biocompatibility, the rabbit anti-mouse Desmin antibody is used as the primary antibody, the results of cellular immunofluorescence imaging and flow cytometry show that the probe can specifically label hepatic stellate cell at -20 °C. The results of liver frozen section experiments show that hepatic stellate cell can be specifically targeted and labeled by the fluorescent probe. This labeling technology provides an important technical means for elucidating the structure and function of the liver at the cellular level, exploring the liver pathological change, and designing and developing drug.

Poly(ethylene glycol) diacrylate based hydrogel filled micropore with enhanced sensing capability.

Ionic current rectification (ICR) phenomena conventionally occurs in nanopores which dimensions are comparable to the thickness of their electrical double layers. However, the microscale ICR in a micropore can also exist under some conditions. Here, the charged hydrogel filled conical micropore was constructed to realize microscale ICR. To better understand the micropore ICR, the influences of space charge density of the hydrogel, micropore geometry, the hydrogel filling length as well as the electrolyte concentration and pH were investigated. Furthermore, we developed a PEGDA-based hydrogel filled micropore sensing platform which sensing performance was enhanced due to the weakly charged PEGDA. The promyelocytic leukemia (PML)/retinoic acid receptor alpha (RARA) fusion genes and adenosine triphosphate (ATP) were respectively used as model analytes and the measured detection limits of 0.1 pM were achieved. The successful realization of microscale ICR in a homogenous and functional hydrogel filled micropore suggests that the fabrication, characterization and operation of ICR based devices can be more robust and facilitated for the wider applications.

Ionic mononuclear [Fe] and heterodinuclear [Fe,Ru] bis(diphenylphosphino)alkane complexes: Synthesis, spectroscopy, DFT structures, cytotoxicity, and biomolecular interactions.

Iron(II) and Ru(II) half-sandwich compounds encompass some promising pre-clinical anticancer agents whose efficacy may be tuned by structural modification of the coordinated ligands. Here, we combine two such bioactive metal centres in cationic bis(diphenylphosphino)alkane-bridged heterodinuclear [Fe2+, Ru2+] complexes to delineate how ligand structural variations modulate compound cytotoxicity. Specifically, Fe(II) complexes of the type [(η5-C5H5)Fe(CO)2(κ1-PPh2(CH2)nPPh2)]{PF6} (n = 1-5), compounds 1-5, and heterodinuclear [Fe2+, Ru2+] complexes, [(η5-C5H5)Fe(CO)2(µ-PPh2(CH2)nPPh2))(η6-p-cymene)RuCl2]{PF6} (n = 2-5) (compounds 7-10), were synthesized and characterised. The mononuclear complexes were moderately cytotoxic against two ovarian cancer cell lines (A2780 and cisplatin resistant A2780cis) with IC50 values ranging from 2.3 ± 0.5 µM to 9.0 ± 1.4 µM. For 7-10, the cytotoxicity increased with increasing Fe⋅⋅⋅Ru distance, consistent with their DNA affinity. UV-visible spectroscopy suggested the chloride ligands in heterodinuclear 8-10 undergo stepwise substitution by water on the timescale of the DNA interaction experiments, probably affording the species [RuCl(OH2)(η6-p-cymene)(PRPh2)]2+ and [Ru(OH)(OH2)(η6-p-cymene)(PRPh2)]2+ (where PRPh2 has R = [-(CH2)5PPh2-Fe(C5H5)(CO)2]+). One interpretation of the combined DNA-interaction and kinetic data is that the mono(aqua) complex may interact with dsDNA through nucleobase coordination. Heterodinuclear 10 reacts with glutathione (GSH) to form stable mono- and bis(thiolate) adducts, 10-SG and 10-SG2, with no evidence of metal ion reduction (k1 = 1.07 ± 0.17 × 10-1 min-1 and k2 = 6.04 ± 0.59 × 10-3 min-1 at 37 °C). This work highlights the synergistic effect of the Fe2+/Ru2+ centres on both the cytotoxicity and biomolecular interactions of the present heterodinuclear complexes.

Simultaneous labeling and multicolor fluorescence imaging of multiple immune cells on liver frozen section by polychromatic quantum dots below freezing points.

A method for simultaneous labeling and multicolor fluorescence imaging of different hepatic immune cells below freezing point is established based on quantum dots. In the experiment, carbon quantum dots with emission wavelength of 435 nm, CdTe@CdS quantum dots at 542 nm and CdSe@ZnS quantum dots at 604 nm are synthesized respectively, it is found that when the mass fractions of KCl (as antifreeze) are 12 %, 14 %, and 12 %, respectively, the three quantum dot dispersion systems remain liquid state at -20 °C. After they are conjugated with the corresponding secondary antibodies, agarose gel electrophoresis, circular dichroism and capillary electrophoresis confirm the effectiveness of conjugation. By indirect immunofluorescence method, the above three quantum dot fluorescent probes are used to simultaneously and specifically target a variety of liver immune cells, and the multi-color simultaneous imaging of different liver immune cells is realized under the same excitation wavelength, it is found that hepatic macrophages are arranged radially in the liver, hepatic stellate cells present punctate distribution, and hepatic sinusoidal endothelial cells present circular distribution, which is consistent with the results of H&E staining and ultrathin section TEM. This study provides an important technical means for elucidating the structure and function of the liver.

State-of-the-Art Fluorescent Probes: Duplex-Specific Nuclease-Based Strategies for Early Disease Diagnostics.

Precision healthcare aims to improve patient health by integrating prevention measures with early disease detection for prompt treatments. For the delivery of preventive healthcare, cutting-edge diagnostics that enable early disease detection must be clinically adopted. Duplex-specific nuclease (DSN) is a useful tool for bioanalysis since it can precisely digest DNA contained in duplexes. DSN is commonly used in biomedical and life science applications, including the construction of cDNA libraries, detection of microRNA, and single-nucleotide polymorphism (SNP) recognition. Herein, following the comprehensive introduction to the field, we highlight the clinical applicability, multi-analyte miRNA, and SNP clinical assays for disease diagnosis through large-cohort studies using DSN-based fluorescent methods. In fluorescent platforms, the signal is produced based on the probe (dyes, TaqMan, or molecular beacon) properties in proportion to the target concentration. We outline the reported fluorescent biosensors for SNP detection in the next section. This review aims to capture current knowledge of the overlapping miRNAs and SNPs' detection that have been widely associated with the pathophysiology of cancer, cardiovascular, neural, and viral diseases. We further highlight the proficiency of DSN-based approaches in complex biological matrices or those constructed on novel nano-architectures. The outlooks on the progress in this field are discussed.

Detection of Matrix Metalloproteinase-1 in Human Saliva Based on a Pregnancy Test Strip Platform.

Matrix metalloproteinase (MMP) is closely correlated with tumorigenesis and progression. Establishing a low-cost, simple, rapid, and sensitive method for its detection is highly desired for the broad-spectrum screening of oral cancer. Herein, we combine the MMP-specific cleavage ability with magnetic separation technology and a commercial test strip to construct a sensitive biosensor to detect MMP-1 conveniently for the first time. The method involves two DNA probes, peptide-DNA1 and hCG-DNA2, where DNA1 and DNA2 are complementary sequences, and the peptide labeled with biotin can bind streptavidin-modified magnetic nanoparticles stably. The human chorionic gonadotropin (hCG) is the target of the pregnancy test strip. The cleavage reaction mediated by MMP-1 releases peptide-DNA1 and the hybridized hCG-DNA2 into the solution, and the hCG probe in the solution can develop color on the test strip for the determination of MMP-1 after magnetic separation. This method utilizes the high specificity of MMP-1's proteolytic cleavage and the high sensitivity of the test strip to the target probe, achieving a sensitive detection of MMP-1 with a visual detection limit of 65.5 pg/mL. The method shows better anti-interference and sensitivity than the enzyme-linked immunosorbent assay in the application of a biological sample matrix, suggesting its great potential for clinical diagnosis, especially for broad-spectrum oral cancer screening.

A self-assembled bilayer polypeptide-engineered hydrogel for spatiotemporal modulation of bactericidal and anti-inflammation process in osteomyelitis treatment.

BACKGROUND: Drug resistance of pathogens and immunosuppression are the main causes of clinical stagnation of osteomyelitis. The ideal treatment strategy for osteomyelitis is to achieve both efficient antibacterial and bone healing through spatiotemporal modulation of immune microenvironment. METHODS: In this study, a bilayer hydrogel based on genetically engineered polypeptide AC10A and AC10ARGD was prepared by self-assembly. Ag2S QDs@DSPE-mPEG2000-Ce6/Aptamer (AD-Ce6/Apt) was loaded in the top layer AC10A hydrogel (AA) for antibacterial, and bone marrow-derived mesenchymal stem cells (BMSCs) were loaded in the lower layer AC10ARGD hydrogel (MAR) for bone healing. The AD-Ce6/Apt can be released from the AA hydrogel to target S. aureus before bacterial biofilm formation and achieved significant bactericidal effect under irradiation with a 660 nm laser. Moreover, AD-Ce6/Apt can induce M1 type polarization of macrophages to activate the immune system and eliminate residual bacteria. Subsequently, BMSCs released from the MAR hydrogel can differentiate into osteoblasts and promote the formation of an anti-inflammatory microenvironment by regulating the M2 type polarization of macrophages. The bilayer AA-MAR hydrogel possessed good biocompatibility. RESULTS: The in vitro and in vivo results showed that the AA-MAR hydrogel not only realized efficient photodynamic therapy of S. aureus infection, but also promoted the transformation of immune microenvironment to fulfill the different needs of each stage, which ultimately improved bone regeneration and mechanical properties post-surgery. CONCLUSION: This work presents an approach for spatiotemporal modulation of immune microenvironment in the treatment of osteomyelitis.

Biomimetic material degradation for synergistic enhanced therapy by regulating endogenous energy metabolism imaging under hypothermia.

Inefficient tumour treatment approaches often cause fatal tumour metastases. Here, we report a biomimetic multifunctional nanoplatform explicitly engineered with a Co-based metal organic framework polydopamine heterostructure (MOF-PDA), anethole trithione (ADT), and a macrophage membrane. Co-MOF degradation in the tumour microenvironment releases Co2+, which results in the downregulation of HSP90 expression and the inhibition of cellular heat resistance, thereby improving the photothermal therapy effect of PDA. H2S secretion after the enzymatic hydrolysis of ADT leads to high-concentration gas therapy. Moreover, ADT changes the balance between nicotinamide adenine dinucleotide/flavin adenine dinucleotide (NADH/FAD) during tumour glycolysis. ATP synthesis is limited by NADH consumption, which triggers a certain degree of tumour growth inhibition and results in starvation therapy. Potentiated 2D/3D autofluorescence imaging of NADH/FAD is also achieved in liquid nitrogen and employed to efficiently monitor tumour therapy. The developed biomimetic nanoplatform provides an approach to treat orthotopic tumours and inhibit metastasis.

Terminal deoxynucleotidyl transferase associated with split G-quadruplex/hemin deoxyribozyme amplification detection for various contaminants in milk based on pregnancy test strip platform.

Contaminant residue analysis in milk can provide essential assistance for safety quality and contamination level management of milk production, which is critical for safeguarding public health. In this study, the pregnancy test strip is employed to achieve multiple analytes detection based on the specific recognition of aptamer and terminal deoxynucleotidyl transferase associated with split G-quadruplex/hemin deoxyribozyme system. Through the subsequent enzyme catalyzed reaction, the detection signal can be further amplified to improve the sensitivity. The method does not need to assemble test strip, prepare and purify antibodies/haptens, nor design complex probe sequences. By coupling human chorionic gonadotrophin with DNA probes and combining magnetic separation technology, the targets can be determined via the test strip. Under the optimized conditions, the visual detection limits for mercury ion, bisphenol A, and penicillin are 1, 0.1 and 0.05 nM, respectively. The detection results show that the method displays good accuracy and practicability in spiked milk sample. The method presents a simple scheme, low cost as well as good design versatility, which demonstrates great application prospect for the sensitive, low-cost, and convenient detection of food matrices.

Multifunctional nanocarrier with self-catalytic production of nitric oxide for photothermal and gas-combined therapy of tumor.

Single treatment often faces the problem that it cannot completely eradicate tumor and inhibit the tumor metastasis. In order to overcome this shortcoming, multi-modal tumor treatment has attracted widespread attention. In the present article, based on ascorbyl palmitate (PA) and l-arginine (l-Arg), a multifunctional nanocarrier is designed for synergetic treatment of tumor with photothermal and nitric oxide (NO) gas therapy. Firstly, PA and l-Arg were self-assembled to form novel functional micelles, PL, with high biosafety using electrostatic interaction and hydrogen bonding. The functional micelles could self-catalyze to produce NO at the tumor site. Then, Ag2S quantum dots having fluorescence imaging and photothermal properties were encapsulated to obtain the nanocarrier, A@PL. The results show that A@PL had a hydrated size of around 78 nm and presented good stability within 30 d. Moreover, in vitro studies indicate that it was efficient with regards to NO self-generating capacity, whereas the photothermal conversion efficiency was as high as 34% under near-infrared light irradiation. The cytotoxicity results show that, when the concentration of A@PL was as high as 2 mM, the survival rate of 3 T3 cells was still 78.23%, proving that the probe has good safety characteristics. Fluorescence imaging results show that its maximum enrichment can be achieved at the tumor site after tail vein injection for 3 h, and out of the body after 24 h, indicating good internal circulation. The in vivo studies show that the rate of inhibition of tumor using the nanocarrier was as high as 98%, and almost overcame the problem of tumor recurrence caused by single treatment, thus presenting a significant tumor treatment effect. This new multifunctional nanocarrier with self-catalytic production of NO provides a new idea for the efficient treatment of tumors.

A simple fluorescent strategy for liver capillary labeling with carbon quantum dot-lectin nanoprobe.

Taking the hepatic sinusoid (HS) as the main delivery area of liver nutrients and metabolic waste, recognizing its structure is important for a deep understanding of liver function. In this paper, based on lycopersicon esculentum lectin (LEL), with targeting ability for endothelial cells, and carbon quantum dots (CQDs), with high biosafety, an LEL-coupled CQD immunofluorescence probe (CQD@LEL) that can label microvessels is designed and used for the fluorescence labeling and imaging of HS in liver tissue sections. The CQD size is approximately 2 nm. Blue fluorescence is emitted under excitation; its optimal excitation wavelength is 400 nm while the emission is at about 450 nm. Gel electrophoresis and capillary electrophoresis confirm that glutaraldehyde can couple LEL to CQD, and the obtained CQD@LEL retains the fluorescence property and has good stability. Optimization experiments show that its labeling effect is positively correlated with time and probe concentration for dyeing the blood vessels of mouse liver slices. In order to improve the effect further, a probe concentration of 0.17 mg mL-1 and incubation time of 3 h were chosen to label the liver tissue sections. The results show that the liver microvessels are formed by interstitial structures among the hepatic cords, and the HS presents a granular or patchy appearance. H&E and ultrathin section TEM show that the microvascular wall of the liver is composed of discontinuous endothelial cells, and there are Kupffer cells and other cells in the tubes, proving that our probe can clearly label the structure and morphology of liver microvessels. This work is of great significance for the visualization of HS.