Precisely controlling the surface roughness of silica nanoparticles for enhanced functionalities and applications.

HYPOTHESIS: Colloids with rough topography demonstrate more complex interactions and tremendous potential in industrial applications. However, relevant studies suffer from a range of challenges, including cumbersome synthesis, complex characterization, and very limited functionalities. A comprehensive study of rough nanoparticles can not only broaden our understanding of rough colloids, but also help to avoid some of their detrimental impacts in real life (e.g., clogging and pumping failures in slurry processing). EXPERIMENTS: A facile route to precisely control the surface roughness of silica nanoparticles and a highly efficient method to characterize the surface roughness were developed respectively. The fabricated particles can be applied for the immobilization of metal nanostructures; their cytotoxic effects and the capability to be used as a drug-delivery vehicle were also evaluated. FINDINGS: Modifying the addition time of precursors (i.e., TEOS and MPTMS) can precisely control the surface roughness of silica nanoparticles. The developed characterization method based on TEM observations allows statistical analyses on a large number of particles, and therefore features very reasonable accuracy. These rough particles behave like microporous materials, where the loading strategy is closely related to their surface roughness. Medium rough particles are promising carriers of metal nanostructures, while the roughest ones are excellent candidate for doxorubicin delivery to cancer cells.

The imaging quantification of multiple organs by dynamic 18F-FDG PET/CT in discharged COVID-19 patients: A prospective pilot study.

Purpose: To early identify abnormal lesions by applying the 18F-FDG PET dynamic modeling approach for discharged patients recovering from COVID-19. Methods: Seven discharged COVID-19 patients (COVID-19 group), twelve healthy volunteers (control group 1), and eight cancer patients with normal pulmonary function (control group 2) were prospectively enrolled. Control group 1 completed static 18F-FDG PET/CT only; COVID-19 group and control group 2 completed 60-min dynamic 18F-FDG PET/CT. Among COVID-19 group and control group 2, the uptake of FDG on the last frame (at 55-60 min) of dynamic scans was used for static analysis. Prior to performing scans, COVID-19 patients provided negative real-time Reverse Transcription-Polymerase Chain Reaction (rRT-PCR) of SARS-CoV-2, normal lung functions test, and normal laboratory test. Organ-to-liver standard uptake ratio (OLR, i.e. SUVmax evaluated organ/ SUVmax liver) from conventional static data and Patlak analysis based on the dynamic modeling to calculate the 18F-FDG net uptake rate constant (Ki) were performed. Results: Compared to the control groups, COVID-19 patients at two to three months after discharge still maintained significantly higher Ki values in multiple organs (including lung, bone marrow, lymph nodes, myocardium and liver), although results for regular OLR measurements were normal for all discharged COVID-19 patients. Taking the image of lung as an example, the differences of SUVmax images between COVID-19 group and control group were hard to distinguish. In contrast, a high 18F-FDG signal of the lung among the COVID-19 group was observed for Ki images. Conclusion: The Ki from 18F-FDG PET/CT dynamic imaging quantification might contribute to identifying residual lesions for COVID-19 survivors. Trial registration: The trial is registered with ClinicalTrials.gov, number NCT04519255 (IRB-approved number, K52-1).

The Role of Pretreatment 18F-FDG PET/CT for Early Prediction of Neoadjuvant Chemotherapy Response in Patients with Locoregionally Advanced Nasopharyngeal Carcinoma.

INTRODUCTION: To evaluate the role of maximal standardized uptake values (SUVmax) and total lesion glycolysis (TLG) from serial 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for early prediction of neoadjuvant chemotherapy (NAC) response in locoregionally advanced nasopharyngeal carcinoma (LANPC). METHODS: A total of 121 LANPC patients who completed pretreatment 18F-FDG PET/CT between June 2017 and July 2020 were retrospectively included. The median age of all the participants was 50 years old (range: 19-74 years), with 94 (77.7%) males and 27 (22.3%) females. The SUVmax from the primary tumor site (SUVmax-PT) and the total lesion glycolysis from the primary tumor site (TLG-PT) were recorded. Tumor response was calculated according to the Response Evaluation Criteria in Solid Tumor (RECIST) 1.1 Criteria at two-week post-secondary NAC cycle. Patients who achieved an objectively partial or full reaction after two cycles of NAC were defined as 'responders', and patients who obtained stability or progression were classified as 'non-responders'. RESULTS: After two cycles of NAC, 96 patients were categorized as "responders" and 25 patients as "non-responders". The optimal thresholds of the SUVmax-PT were 11.8 and 38.5 for the TLG-PT. Non-responders were significantly associated with high SUVmax-PT (HR, 3.49; 95% CI, 1.17-10.36; p = 0.024) and TLG-PT (HR, 4.45; 95% CI, 1.44-13.78; p = 0.010) in multivariate analysis. Recursive partitioning analysis (RPA) categorized patients into three prognostic groups based on SUVmax-PT and TLG-PT: high-response group, intermediate-response group, and low-response group, with corresponding favorable response rates of 94%, 80%, and 55%, respectively. Moreover, a nomogram was created based on metabolic parameters that precisely projected an individual's response of NAC (C-index, 0.787; 95% CI, 0.533-1.000). CONCLUSION: Pretreatment 18F-FDG PET/CT to measure SUVmax-PT and TLG-PT could be a useful non-invasive method for early indication of NAC efficacy. The nomogram based on PET/CT parameters may potentially provide direction for treatment decisions based on NAC levels.

Strong field enhancement in individual Φ-shaped dielectric nanostructures based on anapole mode resonances.

Due to their ability to produce high electric field enhancements in relatively large nanoscale volumes with minimum absorption and nonradiating properties, anapole modes excited in high index dielectric nanostructures have attracted considerable attentions in these years. We propose a design strategy to simultaneously excite the anapole mode efficiently and maintain its resonant wavelength, which has been remained as a challenge in the conventional dielectric nanostructures. Based on analyzing the relationship between the field enhancement factor and scattering intensity of the electric and toroidal dipoles, we introduce two and four nanocuboids into the nil field intensity areas in the silicon disk system, respectively. The geometric volume of the system can be increased effectively and the electric field enhancement is boosted to be 190% and 250% while the resonant wavelength of the anapole mode is almost maintained constant. The systems combined with a slot in the strongest field intensity area also follow the same law, revealing that the design strategy can be easily extended to other geometric, material and frequency systems. Different from the design strategy to add new components into the areas with strong field intensity, the incorporations occurring at the minimum intensity area is another design scheme to engineer the properties of the resonant systems and can find broad applications in nano-device designs.

A high-efficiency dual-wavelength achromatic metalens based on Pancharatnam-Berry phase manipulation.

The application of metasurfaces requires the reduction or elimination of their chromatic aberration while maintaining a high efficiency. We propose a method for the design of dual-wavelength operating achromatic metalenses, which can focus two different wavelengths at the same position. Phase manipulation was achieved by crossing two crystalline Si nanorods on each pixel carrying phase information for wavelengths of 780 and 660 nm based on the principal of Pancharatnam-Berry (PB) phase. At 660 nm, chromatic aberration was reduced from 1.28 to 0.46 µm in numerical experiments. The focusing efficiency of the circularly polarized light reached 90.2% for 780 nm and 49.7% for 660 nm. This method can be extended to other wavelengths.