Development of a Semifascicle Graft Technique to Bridge Peripheral Nerve Defect: A Case Report and Animal Study.

BACKGROUND: Autologous nerve grafting, the criterion standard for bridging peripheral nerves, can cause complications at the donor site. We investigated a novel approach to reconstruct the nerve gap with a split cross-sectional unmatched semifascicle autograft, which was harvested from the distal part of the injured nerve. METHODS: A patient diagnosed with left-sided frontal branch facial nerve dissection underwent nerve bridging emergency surgery using a semifascicle nerve graft. A sciatic nerve model was used to validate the feasibility and mechanism of this method. Male Sprague-Dawley rats (n = 36) were randomized into (A) intact fascicle, (B) semifascicle, and (C) semifascicle + conduit groups and further subdivided into 4- and 8-week groups for histological analysis of the neurotissue area, fibers, and Schwann cells. The 8-week groups underwent weekly pain and temperature tests; the wet weight of the gastrocnemius muscle was measured after euthanasia. RESULTS: The frontalis of the patient's injured side exhibited movement at 2 months postsurgery and recovered a symmetrical appearance at 13 months. Group A exhibited more neurotissue areas and fibers than groups B and C at week 4; group B had more neurotissue than group C. Group A had greater neurotissue areas than groups B and C at week 8; groups B and C exhibited no differences. The groups displayed no differences regarding nerve fiber, pain, and temperature analysis at week 8. Muscle wet weight of groups A and B exhibited no differences and was higher than that of group C. CONCLUSION: We demonstrated the clinical translational value of semifascicle nerve grafts; the injured site was both the donor and recipient, thereby avoiding donor site damage and associated complications.

Smartphone-imaged multilayered paper-based analytical device for colorimetric analysis of carcinoembryonic antigen.

Paper-based immunoassays are effective methods that employ microfluidic paper-based analytical devices (µPADs) for the rapid, simple, and accurate quantification of analytes in point-of-care diagnosis. In this study, we developed a wax-printed multilayered µPAD for the colorimetric detection of carcinoembryonic antigen (CEA), where the device contained a movable and rotatable detection layer to allow the µPAD to switch the state of the sample solutions, i.e., flowing or storing in the sensing zones. A smartphone with a custom-developed program served as an automated colorimetric reader to capture and analyze images from the µPAD, before calculating and displaying the test results. After optimizing the crucial conditions for the assay, the proposed method exhibited a wide linear dynamic range from 0.5 to 70 ng/mL, with a low CEA detection limit of 0.015 ng/mL. The clinical performance of this method was successfully validated using 50 positive and 40 negative human serum samples, thereby demonstrating the high sensitivity of 98.0% and specificity of 97.5% in the detection of CEA. The proposed method is greatly simplified compared with the cumbersome steps required for traditional immunoassays, but without any loss of accuracy and stability, as well as reducing the time needed to detect CEA. Complex and bulky instruments are replaced with a smartphone. The proposed detection platform could potentially be applied in point-of-care testing. Graphical abstract.

Use of quantum dot beads-labeled monoclonal antibody to improve the sensitivity of a quantitative and simultaneous immunochromatographic assay for neuron specific enolase and carcinoembryonic antigen.

Detection of multiplex tumor markers was of great importance for cancer diagnosis. Immunochromatographic test strip (ICTS) was the most frequently-used point-of-care detection means. Herein, a convenient and fast method for simultaneous quantitative detection of neuron specific enolase (NSE) and carcinoembryonic antigen (CEA) was developed based on ICTS using quantum dot beads (QBs) as marking material. Good monodispersity, high colloidal stability and carboxyl-modified (COOH-) QBs were used. For this method, two test lines were applied to the NC membrane for simultaneous analysis of CEA and NSE respectively. The ideal limit of CEA and NSE detection was 0.0378ng/mL and 0.0426ng/mL with scarcely any cross-reactivity. Moreover, the fluorescent signal intensity of the nitrocellulose membrane could be easily read out in the cooperation of the "Handing" system without professional operators. The possible clinical utilization of this platform was demonstrated by detecting 100 clinic human serums. The result showed that the platform had sensitivity of 99% and 97% for CEA and NSE, while the specificity was 97% and 100% respectively. Our results indicated that the QBs based ICTS not only owning the ability of sensitive and specific simultaneous detection of CEA and NSE, but also showing the potential in developing this ICTS into a routine part of early lung cancer diagnosis.

Carcinoembryonic antigen detection with "Handing"-controlled fluorescence spectroscopy using a color matrix for point-of-care applications.

In this study, we developed a power-free, accurate, and portable diagnostic platform called Handing based on embedded technology, which can rapidly detect fluorescent signals from quantum dots (QDs) on lateral flow test strips (LFTSs). The Handing system has three components: a hand-held test terminal, LFTS cartridge, and data server. The hand-held test terminal is the primary system component and it is integrated with tiny components using printed circuit board packaging for image acquisition, processing, and data handling by a specific program. A black smooth shell and three-dimensional printed test cartridge are used to facilitate the portability of the detection terminal, which provides a closed detection process as well as enhancing the anti-interference capacity. The functions of the data server comprise pre-editing, storage, range querying, and sharing with an international network. Multiple hand-held terminal devices can be linked simultaneously to the same data server. In this study, we detected the tumor marker carcinoembryonic antigen (CEA) using the QD-LFTS system, which allowed quantitative analysis in the range of 1-100ng/mL with an ideal detection limit of 0.049ng/mL. Thus, the system is suitable for detecting CEA in the clinically accepted range. We also detected 70 positive and 30 negative serum samples using the Handing system, which exhibited good specificity and sensitivity. Thus, Handing has the capacity for rapid quantitative detection with high stability and repeatability, so it could be used for in vitro diagnostics in the laboratory and in other conditions for various applications, e.g., food evaluation, disease screening, environmental monitoring, and drug testing.

Highly Fluorescent Ribonuclease-A-Encapsulated Lead Sulfide Quantum Dots for Ultrasensitive Fluorescence in Vivo Imaging in the Second Near-Infrared Window.

Ribonuclease-A (RNase-A) encapsulated PbS quantum dots (RNase-A@PbS Qdots) which emit in the second near-infrared biological window (NIR-II, ca. 1000-1400 nm) are rapidly synthesized under microwave heating. Photoluminescence (PL) spectra of the Qdots can be tuned across the entire NIR-II range by simply controlling synthesis temperature. The size and morphology of the Qdots are examined by transmission electron microscopy (TEM), atomic force microscopy (AFM), and dynamic light scattering (DLS). Quantum yield (Φf) measurement confirms that the prepared Qdots are one of the brightest water-soluble NIR-II emitters for in vivo imaging. Their high Φf (∼17.3%) and peak emission at ∼1300 nm ensure deep optical penetration to muscle tissues (up to 1.5 cm) and excellent imaging contrast at an extremely low threshold dose of ∼5.2 pmol (∼1 µg) per mouse. Importantly, this protein coated Qdot displays no signs of toxicity toward model neuron, normal, and cancer cells in vitro. In addition, the animal's metabolism results in thorough elimination of intravenously injected Qdots from the body within several days via the reticuloendothelial system (RES), which minimizes potential long-term toxicity in vivo from possible release of lead content. With a combination of attractive properties of high brightness, robust photostability, and excellent biocompatibility, this new NIR-II emitting Qdot is highly promising in accurate disease screening and diagnostic applications.

Facile synthesis of ß-lactoglobulin capped Ag2S quantum dots for in vivo imaging in the second near-infrared biological window.

Effective in vivo fluorescence imaging for cancer screening and diagnostics requires bright and biocompatible fluorophores whose emission can effectively penetrate biological tissues. Recent studies have confirmed that the second near-infrared window (NIR-II, 1000-1400 nm) is the most sensitive spectral range for in vivo imaging due to ultralow tissue absorption and autofluorescence. We report herein a facile synthesis of Ag2S quantum dots (QDs) that emit at ∼1100 nm using ß-lactoglobulin (ß-LG) as a biological template. The ß-LG protein coating improves water-solubility, faciliates rapid biodistribution and reduces in vivo toxicity of the QDs. Compared to other currently used NIR emitters, ß-LG capped Ag2S QDs exhibit superior photostability and biocompatibility, making them promising probes for in vivo NIR-II imaging.

Systematic safety evaluation on photoluminescent carbon dots.

Photoluminescent carbon dots (C-dots) were prepared using the improved nitric acid oxidation method. The C-dots were characterized by tapping-mode atomic force microscopy, and UV-vis absorption spectroscopy. The C-dots were subjected to systematic safety evaluation via acute toxicity, subacute toxicity, and genotoxicity experiments (including mouse bone marrow micronuclear test and Salmonella typhimurium mutagenicity test). The results showed that the C-dots were successfully prepared with good stability, high dispersibility, and water solubility. At all studied C-dot dosages, no significant toxic effect, i.e., no abnormality or lesion, was observed in the organs of the animals. Therefore, the C-dots are non-toxic to mice under any dose and have potential use in fluorescence imaging in vivo, tumor cell tracking, and others.

Biocompatibility of Graphene Oxide.

Herein, we report the effects of graphene oxides on human fibroblast cells and mice with the aim of investigating graphene oxides' biocompatibility. The graphene oxides were prepared by the modified Hummers method and characterized by high-resolution transmission electron microscope and atomic force microscopy. The human fibroblast cells were cultured with different doses of graphene oxides for day 1 to day 5. Thirty mice divided into three test groups (low, middle, high dose) and one control group were injected with 0.1, 0.25, and 0.4 mg graphene oxides, respectively, and were raised for 1 day, 7 days, and 30 days, respectively. Results showed that the water-soluble graphene oxides were successfully prepared; graphene oxides with dose less than 20 µg/mL did not exhibit toxicity to human fibroblast cells, and the dose of more than 50 µg/mL exhibits obvious cytotoxicity such as decreasing cell adhesion, inducing cell apoptosis, entering into lysosomes, mitochondrion, endoplasm, and cell nucleus. Graphene oxides under low dose (0.1 mg) and middle dose (0.25 mg) did not exhibit obvious toxicity to mice and under high dose (0.4 mg) exhibited chronic toxicity, such as 4/9 mice death and lung granuloma formation, mainly located in lung, liver, spleen, and kidney, almost could not be cleaned by kidney. In conclusion, graphene oxides exhibit dose-dependent toxicity to cells and animals, such as inducing cell apoptosis and lung granuloma formation, and cannot be cleaned by kidney. When graphene oxides are explored for in vivo applications in animal or human body, its biocompatibility must be considered.