A novel contact optimization algorithm for endomicroscopic surface scanning.

PURPOSE: Probe-based confocal laser endomicroscopy (pCLE) offers real-time, cell-level imaging and holds promise for early cancer diagnosis. However, a large area surface scanning for image acquisition is needed to overcome the limitation of field-of-view. Obtaining high-quality images during scanning requires maintaining a stable contact distance between the tissue and probe. This work presents a novel contact optimization algorithm to acquire high-quality pCLE images. METHODS: The contact optimization algorithm, based on swarm intelligence of whale optimization algorithm, is designed to optimize the probe position, according to the quality of the image acquired by probe. An accurate image quality assessment of total co-occurrence entropy is introduced to evaluate the pCLE image quality. The algorithm aims to maintain a consistent probe-tissue contact, resulting in high-quality images acquisition. RESULTS: Scanning experiments on sponge, ex vivo swine skin tissue and stomach tissue demonstrate the effectiveness of the contact optimization algorithm. Scanning results of the sponge with three different trajectories (spiral trajectory, circle trajectory, and raster trajectory) reveal high-quality mosaics with clear details in every part of the image and no blurred sections. CONCLUSION: The contact optimization algorithm successfully identifies the optimal distance between probe and tissue, improving the quality of pCLE images. Experimental results confirm the high potential of this method in endomicroscopic surface scanning.

OpenColab project: OpenSim in Google colaboratory to explore biomechanics on the web.

OpenSim is an open-source biomechanical package with a variety of applications. It is available for many users with bindings in MATLAB, Python, and Java via its application programming interfaces (APIs). Although the developers described well the OpenSim installation on different operating systems (Windows, Mac, and Linux), it is time-consuming and complex since each operating system requires a different configuration. This project aims to demystify the development of neuro-musculoskeletal modeling in OpenSim with zero configuration on any operating system for installation (thus cross-platform), easy to share models while accessing free graphical processing units (GPUs) on a web-based platform of Google Colab. To achieve this, OpenColab was developed where OpenSim source code was used to build a Conda package that can be installed on the Google Colab with only one block of code in less than 7 min. To use OpenColab, one requires a connection to the internet and a Gmail account. Moreover, OpenColab accesses vast libraries of machine learning methods available within free Google products, e.g. TensorFlow. Next, we performed an inverse problem in biomechanics and compared OpenColab results with OpenSim graphical user interface (GUI) for validation. The outcomes of OpenColab and GUI matched well (r≥0.82). OpenColab takes advantage of the zero-configuration of cloud-based platforms, accesses GPUs, and enables users to share and reproduce modeling approaches for further validation, innovative online training, and research applications. Step-by-step installation processes and examples are available at: https://simtk.org/projects/opencolab.

Multifunctional magnetic iron oxide nanoparticles: an advanced platform for cancer theranostics.

Multifunctional magnetic nanoparticles and derivative nanocomposites have aroused great concern for multimode imaging and cancer synergistic therapies in recent years. Among the rest, functional magnetic iron oxide nanoparticles (Fe3O4 NPs) have shown great potential as an advanced platform because of their inherent magnetic resonance imaging (MRI), biocatalytic activity (nanozyme), magnetic hyperthermia treatment (MHT), photo-responsive therapy and drug delivery for chemotherapy and gene therapy. Magnetic Fe3O4 NPs can be synthesized through several methods and easily surface modified with biocompatible materials or active targeting moieties. The MRI capacity could be appropriately modulated to induce response between T1 and T2 modes by controlling the size distribution of Fe3O4 NPs. Besides, small-size nanoparticles are also desired due to the enhanced permeation and retention (EPR) effect, thus the imaging and therapeutic efficiency of Fe3O4 NP-based platforms can be further improved. Here, we firstly retrospect the typical synthesis and surface modification methods of magnetic Fe3O4 NPs. Then, the latest biomedical application including responsive MRI, multimodal imaging, nanozyme, MHT, photo-responsive therapy and drug delivery, the mechanism of corresponding treatments and cooperation therapeutics of multifunctional Fe3O4 NPs are also be explained. Finally, we also outline a brief discussion and perspective on the possibility of further clinical translations of these multifunctional nanomaterials. This review would provide a comprehensive reference for readers to understand the multifunctional Fe3O4 NPs in cancer diagnosis and treatment.

Tetramodal Imaging and Synergistic Cancer Radio-Chemotherapy Enabled by Multiple Component-Encapsulated Zeolitic Imidazolate Frameworks.

The abundant species of functional nanomaterials have attracted tremendous interests as components to construct multifunctional composites for cancer theranostics. However, their distinct chemical properties substantially require a specific strategy to integrate them in harmony. Here, we report the preparation of a distinctive multifunctional composite by encapsulating small-sized semiconducting copper bismuth sulfide (CBS) nanoparticles and rare-earth down-conversion (DC) nanoparticles in larger-sized zeolitic imidazolate framework-8 (ZIF8) nanoparticles, followed by loading an anticancer drug, doxorubicin (DOX). Such composites can be used for tetramodal imaging, including traditional computed tomography and magnetic resonance imaging and, recently, for photoacoustic imaging and fluorescence imaging. With a pH-responsive release of the encapsulated components, synergistic radio-chemotherapy with a high (87.6%) tumor inhibition efficiency is achieved at moderate doses of the CBS&DC-ZIF8@DOX composite with X-ray irradiation. This promising strategy highlights the extending capacity of zeolitic imidazolate frameworks to encapsulate multiple distinct components for enhanced cancer imaging and therapy.

FRET-based colorimetric and ratiometric sensor for visualizing pH change and application for bioimaging in living cells, bacteria and zebrafish.

Acid-alkaline balance plays a crucial role in all biological processes. Accordingly, monitoring pH changes will help us to understand the functional status of these physiological and pathological processes. Though fluorescent probes may be a useful tool for detecting pH changes, and there are many limitations to currently available probes, such as background interference, potential cytotoxicity, and poor cell permeability, which call for a solution urgently. In this work, a rhodamine-derived colorimetric and ratiometric sensor (Rh-HN) was fabricated for monitoring pH change via the mechanism of fluorescence resonance energy transfer (FRET). Rh-HN has been shown to possess several advantages over other probes, such as high sensitivity, outstanding permeability, and low toxicity. Besides, the fluorescence intensity ratio (F526/F592) of Rh-HN displays a pH-sensitive response from 2.0 to 7.5 (pKa = 5.05) and linear response from pH 3.8 to 6.4, which was desirable for mapping pH change in the biological systems. Besides, the results indicated that Rh-HN generated a pH-dependent response regulated by switchable forms between closed and opened spirolactam ring. Overall, Rh-HN has accomplished sensing and mapping of pH in living cells, bacteria, and zebrafish. Those results demonstrated that the great potential of Rh-HN in sensing and visualizing pH in the living biosystem.

Highly efficient dye decontamination via microbial salecan polysaccharide-based gels.

Wastewater treatment materials that combine high decontamination performance, ease of use and economic production are highly desirable for practical applications. Herein, we fabricated a low-cost and recyclable bio-adsorbent based on a microbial polysaccharide (salecan) for efficient removal of methyl violet (MV) from wastewater. The success fabrication and the properties (such as thermal stability, microarchitecture, mechanical strength and water uptake) of the adsorbent had been investigated, and the hydrogels were found to have tunable properties by simple adjusting the salecan dose in hydrogel composition. Adsorption data displayed that the adsorption of MV followed the pseudo second-order kinetic model (R2 = 0.99015) and Freundlich isotherm model (R2 = 0.99221) with a maximum adsorption capacity of 178.9 mg/g. Moreover, salecan-based hydrogels showed a good reversibility in adsorption-desorption cycles. These features indicate that salecan-based bio-adsorbent may be a promising device for dye removal from dyeing waste water.

Construction of macroporous salecan polysaccharide-based adsorbents for wastewater remediation.

Adsorbents fabricated with biopolymer are extremely fascinating from the material design aspect, with numerous advantages like excellent biocompatibility, good biodegradability and availability at low cost. In this paper, a novel salecan polysaccharide-based biosorbent was designed for removal of Cd2+ ions from aqueous solutions. The resulting adsorbent was characterized by FTIR, XRD, TGA, SEM, rheology and swelling measurements. Adsorption of Cd2+ onto the salecan biosorbent was evaluated taking into account salecan amount, sorbent dosage, solution pH, initial Cd2+ concentration and contact time. Pseudo-second-order kinetic model and Weber-Morris intra-particle diffusion model well fitted the kinetic results, suggesting chemisorption and intra-particle diffusion as the most probable adsorption mechanism. Meanwhile, the equilibrium adsorption data was nicely described by Langmuir isotherm model with a maximum adsorption capacity of 170.1 mg Cd2+ per gram of sample. Finally, the salecan biosorbent exhibited an excellent reusability and 89.2% of the original sorption ability remained after 6 cycles. The present findings suggest that salecan-based biosorbents have potential for application as a wastewater remediation device.

Removal of copper ions from water using polysaccharide-constructed hydrogels.

Polysaccharides are an important class of materials that are often exploited in the fields of food, agriculture, biomedical engineering and wastewater treatment owing to their unique and tunable properties. In this work, we utilize an inexpensive and sustainable extracellular polysaccharide salecan (EPS), which is produced by bacterium Agrobacterium sp. ZX09, as a hydrogel matrix, poly(3-sulfopropyl methacrylate potassium salt) (PSM) as side chains to fabricate EPS-grafted-PSM adsorbents through a simple one-pot approach. Scanning electron microscope, X-ray diffraction, Fourier transformed infrared spectroscopy, rheometry and thermogravimetry were conducted to characterize the physicochemical properties of resultant adsorbents. We noticed that EPS not only served as the host chains of network to adjust the water uptake ability of adsorbents, but also endued them with tunable polarity. Further, the adsorption behaviors of developed adsorbents to copper ions (Cu2+) were explored: these gels present high absorption ability for Cu2+ through a chemical adsorption process which well described by Freundlich isotherm and pseudo-second-order kinetic models. In summary, the approach exhibited in this work opens a new avenue to design polysaccharide-based materials for Cu2+ adsorption.

A novel preparation method for ZnO/γ-Al2O3 nanofibers with enhanced absorbability and improved photocatalytic water-treatment performance by Ag nanoparticles.

A novel method for synthesizing ZnO/γ-Al2O3 nanofibers by electrospinning and subsequent calcination is reported. The prepared nanofibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The ZnO/γ-Al2O3 nanofibers exhibited excellent capacity for adsorbing organics with a negative zeta potential such as methyl orange (95.8%) and heavy metal ions such as Cr(vi) in aqueous solution. The mechanism of adsorption was investigated, and the adsorption results were fitted using the Langmuir and Freundlich models. Once silver nanoparticles (Ag NPs) were decorated on the surface of the nanofibers by photoreduction, the Ag/ZnO/γ-Al2O3 nanofibers manifested efficient photocatalytic degradation of methyl orange under UV-light illumination. Results confirmed that our Ag/ZnO/γ-Al2O3 nanofibers are a promising adsorbent for the removal of methyl orange and Cr(vi) ions and the adsorbent can be sustainably reused.

Stable multi-jet electrospinning with high throughput using the bead structure nozzle.

A modified bead structure nozzle for the electrospinning process was developed to improve the production efficiency of nanofibers and facilitate the cleaning of equipment. The effects of the flow rate, voltage and receiving distance on the number of jets were studied. The results indicate that the number of stable jets can be effectively controlled by spinning conditions. The rotating spinning phenomenon, which occurred during spinning, was subjected to force analysis. The COMSOL Multiphysics model was applied to simulate the electric field to show that the bead structured nozzle does not change the overall spinning electric field compared with traditional spinning. The results indicate that the bead structure nozzle can produce a stable multi-jet using a curved surface structure and improve the production efficiency of nanofibers. Compared with the high-voltage conditions of needleless spinning, the bead-type nozzle helps to save energy and facilitate cleaning, so as to avoid the production of waste in experimental research and industrial production.