Deep Learning Insights into the Dynamic Effects of Photodynamic Therapy on Cancer Cells.

Photodynamic therapy (PDT) shows promise in tumor treatment, particularly when combined with nanotechnology. This study examines the impact of deep learning, particularly the Cellpose algorithm, on the comprehension of cancer cell responses to PDT. The Cellpose algorithm enables robust morphological analysis of cancer cells, while logistic growth modelling predicts cellular behavior post-PDT. Rigorous model validation ensures the accuracy of the findings. Cellpose demonstrates significant morphological changes after PDT, affecting cellular proliferation and survival. The reliability of the findings is confirmed by model validation. This deep learning tool enhances our understanding of cancer cell dynamics after PDT. Advanced analytical techniques, such as morphological analysis and growth modeling, provide insights into the effects of PDT on hepatocellular carcinoma (HCC) cells, which could potentially improve cancer treatment efficacy. In summary, the research examines the role of deep learning in optimizing PDT parameters to personalize oncology treatment and improve efficacy.

Low breast density and peritumoral edema on MR predict worse overall survival of breast cancer patients after neoadjuvant chemotherapy.

OBJECTIVES: To investigate the relationship of pre-treatment MR image features (including breast density) and clinical-pathologic characteristics with overall survival (OS) in breast cancer patients receiving neoadjuvant chemotherapy (NAC). METHODS: This retrospective study obtained an approval of the institutional review board and the written informed consents of patients were waived. From October 2013 to April 2019, 130 patients (mean age, 47.6 ± 9.4 years) were included. The univariable and multivariable Cox proportional hazards regression models were applied to analyze factors associated with OS, including MR image parameters and clinical-pathologic characteristics. RESULTS: Among the 130 included patients, 11 (8.5%) patients (mean age, 48.4 ± 11.8 years) died of breast cancer recurrence or distant metastasis. The median follow-up length was 70 months (interquartile range of 60-85 months). According to the Cox regression analysis, older age (hazard ratio [HR] = 1.769, 95% confidence interval [CI]): 1.330, 2.535), higher T stage (HR = 2.490, 95%CI:2.047, 3.029), higher N stage (HR = 1.869, 95%CI:1.507, 2.317), low breast density (HR = 1.693, 95%CI:1.391, 2.060), peritumoral edema (HR = 1.408, 95%CI:1.078, 1.840), axillary lymph nodes invasion (HR = 3.118, 95%CI:2.505, 3.881) on MR were associated with worse OS (all p < 0.05). CONCLUSIONS: Pre-treatment MR features and clinical-pathologic parameters are valuable for predicting long-time OS of breast cancer patients after NAC followed by surgery. Low breast density, peritumoral edema and axillary lymph nodes invasion on pre-treatment MR images were associated with worse prognosis.

Low-dose X-ray radiodynamic therapy solely based on gold nanoclusters for efficient treatment of deep hypoxic solid tumors combined with enhanced antitumor immune response.

Background: Radiodynamic therapy (RDT) is an emerging novel anti-cancer treatment based on the generation of cytotoxic reactive oxygen species (ROS) at the lesion site following the interaction between low-dose X-ray and a photosensitizer (PS) drug. For a classical RDT, scintillator nanomaterials loaded with traditional PSs are generally involved to generate singlet oxygen (1O2). However, this scintillator-mediated strategy generally suffers from insufficient energy transfer efficiency and the hypoxic tumor microenvironment, and finally severely impedes the efficacy of RDT. Methods: Gold nanoclusters were irradiated by low dose of X-ray (called RDT) to investigate the production of ROS, killing efficiency of cell level and living body level, antitumor immune mechanism and biosafety. Results: A novel dihydrolipoic acid coated gold nanoclusters (AuNC@DHLA) RDT, without additional scintillator or photosensitizer assisted, has been developed. In contrast to scintillator-mediated strategy, AuNC@DHLA can directly absorb the X-ray and exhibit excellent radiodynamic performance. More importantly, the radiodynamic mechanism of AuNC@DHLA involves electron-transfer mode resulting in O2 -• and HO•, and excess ROS has been generated even under hypoxic conditions. Highly efficient in vivo treatment of solid tumors had been achieved via only single drug administration and low-dose X-ray radiation. Interestingly, enhanced antitumor immune response was involved, which could be effective against tumor recurrence or metastasis. Negligible systemic toxicity was also observed as a consequence of the ultra-small size of AuNC@DHLA and rapid clearance from body after effective treatment. Conclusions: Highly efficient in vivo treatment of solid tumors had been achieved, enhanced antitumor immune response and negligible systemic toxicity were observed. Our developed strategy will further promote the cancer therapeutic efficiency under low dose X-ray radiation and hypoxic conditions, and bring hope for clinical cancer treatment.

Dynamic real-time imaging of living cell traction force by piezo-phototronic light nano-antenna array.

Dynamic mapping of the cell-generated force of cardiomyocytes will help provide an intrinsic understanding of the heart. However, a real-time, dynamic, and high-resolution mapping of the force distribution across a single living cell remains a challenge. Here, we established a force mapping method based on a "light nano-antenna" array with the use of piezo-phototronic effect. A spatial resolution of 800 nm and a temporal resolution of 333 ms have been demonstrated for force mapping. The dynamic mapping of cell force of live cardiomyocytes was directly derived by locating the antennas' positions and quantifying the light intensities of the piezo-phototronic light nano-antenna array. This study presents a rapid and ultrahigh-resolution methodology for the fundamental study of cardiomyocyte behavior at the cell or subcellular level. It can provide valuable information about disease detection, drug screening, and tissue engineering for heart-related studies.

Super-efficient in Vivo Two-Photon Photodynamic Therapy with a Gold Nanocluster as a Type I Photosensitizer.

Photodynamic therapy (PDT) is a clinically approved, minimally invasive therapeutic technique that can induce the regression of targeted lesions via generating excess cytotoxic reactive oxygen species. However, due to the limited penetration depth of visible excitation light and the intrinsic hypoxia microenvironment of solid tumors, the efficacy of PDT in the treatment of cancer, especially deep-seated or large tumors, is unsatisfactory. Herein, we developed an efficient in vivo PDT system based on a nanomaterial, dihydrolipoic acid coated gold nanocluster (AuNC@DHLA), that combined the advantages of large penetration depth in tissue, extremely high two-photon (TP) absorption cross section (σ2 ∼ 106 GM), efficient ROS generation, a type I photochemical mechanism, and negligible in vivo toxicity. With AuNC@DHLA as the photosensitizer, highly efficient in vivo TP-PDT has been achieved.

A facile synthesis of biocompatible, glycol chitosan shelled CdSeS/ZnS QDs for live cell imaging.

We here report a facile synthesis of chitosan shelled quantum dot (QD/fGC) that holds essential properties requisite for biological applications, such as excellent water solubility, super colloidal stability, and low nonspecific adsorption as well as ease of functionalization. In this method, the amphiphilic glycol chitosan fragment (MW 1.0-1.7 kDa) was assembled on the top of CdSeS/ZnS nanocrystal through hydrophobic interaction in aqueous solution, without displacing the native coordinating ligands, which result in a higher quantum yield of about 0.26, 46% of the uncoated CdSeS/ZnS QDs in chloroform (0.57). In addition, the prepared QD/fGC composes an individual semiconductor core and presents an extremely small size of about 6.03 ± 1.50 nm (n = 399) in diameter. By conjugation with bioactive amines via 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-based hydroxyl activation approach, the functionalized QD/fGC presented excellent recognition of specific cells in fluorescent imaging. Our work provides a new general method of chitosan modification of hydrophobic nanoparticles for biomedical applications.

[Analysis of Growth Curve Type in Pulmonary Nodules with
Different Characteristics].

BACKGROUND: Background and objective Follow up by computed tomography (CT) and growth evaluation are routine methods for the differential diagnosis of indeterminate pulmonary nodules in clinical practice. Pulmonary nodules with diverse biological behaviors may show different growth patterns and velocities. The aim of this study is to identify the volume growth curve of both benign and malignant pulmonary nodules. This work also intends to determine these nodules' growth patterns and provide evidence for the establishment of a follow-up strategy. METHODS: The CT data of 111 pulmonary nodules (54 solid, 57 subsolid) were retrospectively evaluated using 3D volumetric software. All of these nodules have been followed up at least twice. Of these nodules, 35 were confirmed as lung cancers, whereas 5 were confirmed as benign by pathology or histology. Moreover, 71 nodules showed no growth in more than 2 years. Stable nodules were defined as low-risk nodules, as confirmed by reevaluation from experts. On the basis of their densities and diameters, the nodules were classified into four types: benign/low-risk solid nodules, malignant solid nodules (diameter ≤1 cm and >1 cm), benign/low-risk subsolid nodules, and malignant subsolid nodules (diameter ≤1 cm and >1 cm). The follow-up interval time (d) were plotted on the x-axis, and the nodules' volume (mm3) and logarithmic volume were plotted on the y-axis. Two radiologists subjectively determined the type of growth curve. Chi-square test was performed to compare the growth curves of benign/low-risk and malignant nodules. RESULTS: Of 18 solid cancers, 12 cases (66%) were found with steep ascendant growth curves. Those of 3 cases (16.7%) were flat ascendant, 2 cases (11.1%) slowly ascendant, and 1 (5.56%) case flat. Of 17 subsolid cancers, 8 cases (47.1%) manifested steep ascendant growth curves. Those of 4 cases (23.5%) were slowly ascendant, 3 (17.6%) flat, and 2 (11.8%) descendant-ascendant. Of 36 benign/low-risk solid nodules, 5 cases (13.9%) manifested descendant growth curves, 17 cases (47.2%) flat, 8 cases (21.6%) slowly ascendant, and 6 cases (16.7%) undulate. Of 40 benign/low-risk subsolid nodules, 4 cases (10%) manifested descendant growth curves, 21 cases (52.5%) flat, 9 cases (22.5%) slowly ascendant, and 6 cases (15%) undulate. The distribution of growth curve types significantly differed between benign/low-risk and malignant nodules (χ2=42.4, P<0.01). CONCLUSIONS: The growth curves of lung cancers are heterogeneous. A steep ascendant curve is the main type for lung cancer, with the exception of flat, slowly ascendant, or even descendant curve. A slowly ascendant curve cannot exclude the diagnosis of lung cancer, especially for subsolid nodules.
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Nanoprobes for two-photon excitation time-resolved imaging of living animals: In situ analysis of tumor-targeting dynamics of nanocarriers.

Great challenges remain in the noninvasive luminescence imaging analysis of tumor-targeting dynamics of nanocarriers in living animals which is of significance for the development of anti-cancer nanomedicine. In this work, luminescent nanoparticles Eu(tta)3bpt@SMA (dav = 15 nm), which exhibited good water dispersion stability and high yields of red Eu-luminescence under near-infrared two-photon excitation, were prepared by a modified microfluidic mixing method in the absence of surfactants. Tumor-targeting agents, Arg-Gly-Asp-D-Phe-Lys (cRGD) polypeptide or transferrin (Tf), were then anchored on the nanoparticle surfaces to form the desired nanocarriers Eu@SMA-RGD or Eu@SMA-Tf. The tumor-targeting processes of the prepared nanocarriers in intact living mice were analyzed on a home-built two-photon excitation time-resolved (TPE-TR) imaging apparatus having a wide view filed. The TPE-TR strategy could effectively suppress the interference from biological autofluorescence, which allowed the targeted domains to be visualized with a high signal-to-noise ratio. It was found that the tumor-tissue trapping efficacy of Eu@SMA-RGD was much higher than that of Eu@SMA-Tf, and the desorption process from the tumor tissues of Eu@SMA-RGD was slower than that of Eu@SMA-Tf. The methods developed in this work pave a way to investigate the in vivo tumor-targeting dynamics of nanocarriers by noninvasive luminescence imaging of living animals.

[Three Dimensional Volumetric Analysis of Solid Pulmonary Nodules on Chest CT: 
Cancer Risk Assessment].

BACKGROUND: The management of pulmonary nodules relies on cancer risk assessment, in which the only widely accepted criterion is diameter. The development of volumetric computed tomography (CT) and three-dimensional (3D) software enhances the clarity in displaying the nodules' characteristics. This study evaluated the values of the nodules' volume and 3D morphological characteristics (edge, shape and location) in cancer risk assessment. METHODS: The CT data of 200 pulmonary nodules were retrospectively evaluated using 3D volumetric software. The malignancy or benignity of all the nodules was confirmed by pathology, histology or follow up (>2 years). Logistic regression analysis was performed to calculate the odds ratios (ORs) of the 3D margin (smooth, lobulated or spiculated/irregular), shape (spherical or non-spherical), location (purely intraparenchymal, juxtavascular or pleural-attached), and nodule volume in cancer risk assessment for total and sub-centimeter nodules. The receiver operating characteristic (ROC) curve was employed to determine the optimal threshold for the nodule volume. RESULTS: Out of 200 pulmonary nodules, 78 were malignant, whereas 122 were benign. The Logistic regression analysis showed that the volume (OR=3.3; P<0.001) and the 3D margin (OR=13.4, 9.8; both P=0.001) were independent predictive factors of malignancy, whereas the location and 3D shape exhibited no total predictive value (P>0.05). ROC analysis showed that the optimal threshold for malignancy was 666 mm³. For sub-centimeter nodules, the 3D margin was the only valuable predictive factor of malignancy (OR=60.5, 75.0; P=0.003, 0.007). CONCLUSIONS: The volume and 3D margin are important factors considered to assess the cancer risk of pulmonary nodules. Volumes larger than 666 mm³ can be determined as high risk for pulmonary nodules; by contrast, nodules with lobulated, spiculated, or irregular margin present a high malignancy probability.

Intracellular Temperature Sensing: An Ultra-bright Luminescent Nanothermometer with Non-sensitivity to pH and Ionic Strength.

Luminescence thermometry usually suffer from cellular complexity of the biochemical environment (such as pH and ionic strength), and thus the accuracy and reliability of the determined intracellular temperature are directly affected. Herein, a photoluminescent nanothermometer composed of polymer encapsulated quantum dots (P-QD) has been developed. And the prepared nanothermometer exhibits some advantages: such as non-sensitivity to pH and ionic strength, as well as high detection sensitivity and ultrahigh reversibility. The intracellular temperature was accurately determined under physiological conditions with different pH and ionic strength, and direct measurement of thermogenesis in individual cells has been achieved.

New photostable naphthalimide-based fluorescent probe for mitochondrial imaging and tracking.

Monitoring mitochondria morphological changes temporally and spatially exhibits significant importance for diagnosing, preventing and treating various diseases related to mitochondrial dysfunction. However, the application of commercially available mitochondria trackers is limited due to their poor photostability. To overcome these disadvantages, we designed and synthesized a mitochondria-localized fluorescent probe by conjugating 1,8-naphthalimide with triphenylphosphonium (i.e. NPA-TPP). The structure and characteristic of NPA-TPP was characterized by UV-vis, fluorescence spectroscopy, (1)HNMR, (13)CNMR, FTIR, MS, etc. The photostability and cell imaging were performed on the laser scanning confocal microscopy. Moreover, the cytotoxicity of NPA-TPP on cells was evaluated using (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. The results showed that NPA-TPP not only has high sensitivity and specificity to mitochondria, but also exhibits super-high photostability, negligible cytotoxicity and good water solubility. In short, NPA-TPP indicates great potential for targeting mitochondria and enables a real-time and long-term tracking mitochondrial dynamics changes.

Extremely high brightness from polymer-encapsulated quantum dots for two-photon cellular and deep-tissue imaging.

Materials possessing high two photon absorption (TPA) are highly desirable for a range of fields, such as three-dimensional data storage, TP microscopy (TPM) and photodynamic therapy (PDT). Specifically, for TPM, high TP excitation (TPE) brightness (σ × Ï•, where σ is TPA cross-sections and ϕ is fluorescence quantum yield), excellent photostability and minimal cytotoxicity are highly desirable. However, when TPA materials are transferred to aqueous media through molecule engineering or nanoparticle formulation, they usually suffer from the severely decrease of quantum yield (QY). Here, we report a convenient and efficient method for preparing polymer-encapsulated quantum dots (P-QD). Interestingly, the QY was considerably enhanced from original 0.33 (QDs in THF) to 0.84 (P-QD in water). This dramatic enhancement in QY is mainly from the efficiently blocking nonradiative decay pathway from the surface trap states, according to the fluorescence decay lifetimes analysis. The P-QD exhibits extremely high brightness (σ × Ï• up to 6.2 × 10(6) GM), high photostability, excellent colloidal stability and minimal cytotoxicity. High quality cellular TP imaging with high signal-to-background ratio (> 100) and tissue imaging with a penetration depth of 2200 µm have been achieved with P-QD as probe.

High surface-enhanced Raman scattering performance of individual gold nanoflowers and their application in live cell imaging.

Molecular imaging techniques based on surface-enhanced Raman scattering (SERS) face a lack of reproducibility and reliability, thus hampering its practical application. Flower-like gold nanoparticles have strong SERS enhancement performance due to having plenty of hot-spots on their surfaces, and this enhancement is not dependent on the aggregation of the particles. These features make this kind of particle an ideal SERS substrate to improve the reproducibility in SERS imaging. Here, the SERS properties of individual flower-like gold nanoparticles are systematically investigated. The measurements reveal that the enhancement of a single gold nanoparticle is independent of the polarization of the excitation laser with an enhancement factor as high as 10(8) . After capping with Raman signal molecules and folic acid, the gold nanoflowers show strong Raman signal in the living cells, excellent targeting properties, and a high signal-to-noise ratio for SERS imaging.

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 fluorophore 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.

Polyvalent lactose-quantum dot conjugate for fluorescent labeling of live leukocytes.

Oligosaccharides play crucial roles in many biorecognition processes by the so-called "cluster glycosidic effect". We here report a facile synthesis of lactose-CdSeS/ZnS quantum dot conjugate (Lac-QDs) by use of 1-thiol-beta-D-lactose via ligand exchange, which exhibits significantly high affinity and specificity to leukocytes in contrast to the monovalent lactose. Structural analyses indicate that there are about 132 lactosyl molecules assembled on single QDs and the hydrodynamic diameter is small, close to 8.2 nm. Further, Lac-QDs display good fluorescence and physicochemical stability in physiological conditions, as well as extremely low cytotoxicity. These properties facilitate the use of Lac-QDs in fluorescent labeling of live leukocytes.

A facile synthesis of small-sized, highly photoluminescent, and monodisperse CdSeS QD/SiO(2) for live cell imaging.

In recent years, silica coating has been extensively investigated to fabricate the biocompatible interface of quantum dots (QDs) for biomedical applications. We here describe a facile and efficient method of synthesizing high-quality silica-coated CdSeS QDs (CdSeS QD/SiO(2)), where an immediate photoluminescence-favorable microenvironment is first created by assembling amphiphilic molecules around the CdSeS core, and a thin silica shell is further introduced to protect this hydrophobic interlayer. The prepared CdSeS QD/SiO(2) exhibits excellent properties such as good water solubility, low cytotoxicity, and high quantum yield (QY, up to 0.49) as well as the resistance of photobleaching in aqueous solution. Also, the CdSeS QD/SiO(2) nanoparticles homogeneously comprise single CdSeS cores and hold a comparatively small size up to about 11 nm in diameter. Particularly, this method leads to a significant increase in QY as compared to the uncoated CdSeS QDs ( approximately 109% of the initial QY), though only thin silica shells formed in the CdSeS QD/SiO(2) structure. By coupling with folic acids, the CdSeS QD/SiO(2) conjugates were successfully used for tumor cell labeling. Our results demonstrated a robust hydrophobic QDs-based approach for preparing highly photoluminescent, biocompatible QD/SiO(2) through creation of a stable hydrophobic interlayer surrounding the QD cores, which could be also suitable for silica coating of other kinds of hydrophobic nanoparticles.