Non-invasive detection of bladder cancer via microfluidic immunoassay of the protein biomarker NMP22.

Bladder cancer (BC) is a malignant tumor that occurs in the bladder mucosa and has a high morbidity and mortality rate. Early diagnosis means that cystoscopy-aided imaging is invasive and pricey. Microfluidic immunoassay enables noninvasive detection of early BC. However, its clinical applications are limited due to the poor internal design and hydrophobic surface of polydimethylsiloxane (PDMS) chip. This study aims to design a PDMS chip with right-moon capture arrays and prepare a hydrophilic surface by APTES with different concentrations (PDMS-three-step: O2 plasma-5-98% APTES), which facilitates early detection of BC with enhanced sensitivity. Simulations showed that the right-moon arrays in the capture chamber reduced the flow velocity and shear stress of the target molecule NMP22, improving the capture performance of the chip. PDMS-three-step surface was measured by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), contact angle, and antibody immobilization. The results displayed that the contact angle of PDMS-three-step remained in the range of 40° to 50° even after 30 days of exposure to air, leading to a more stable hydrophilic surface. The effectiveness of the PDMS chip was assessed via the quantitative immunoassay of the protein marker NMP22 and its sensitivity analysis to urine. After the assessment, the LOD of NMP22 was 2.57 ng mL-1, and the sensitivity was 86.67%, which proved that the PDMS chip was effective. Thus, this study provided a novel design and modification method of the microfluidic chip for the early detection of BC.

Rapid preparation of surface-enhanced Raman substrate in microfluidic channel for trace detection of amoxicillin.

A high sensitive surface-enhanced Raman scattering (SERS) substrate based on the Ag dendrite in a T-type microfluidic device was constructed by a simple and rapid strategy. According to the simulated results by COMSOL Multiphysics, the microfluidic-SERS sensor was fabricated by simultaneously introducing into 40 mmol·L-1 silver nitrate solution and 0.2 mol·L-1 sodium nitrate solution for about 15 min with the flow velocity at 20 µL·min-1 at room temperature, respectively. The analytical performance of this sensor was investigated with different concentrations of amoxicillin aqueous solution, and the detection limit was up to 1.0 ng·mL-1. And the semi-quantitation was obtained from the relationship between the Raman intensity and the logarithm of the amoxicillin concentration. This method can be employed to fabricate high sensitive microfluidic-SERS sensors as well as realize many lab-on-a-chip applications with the integration of other microfluidic networks.

Promotion of Neuronal Guidance Growth by Aminated Graphene Oxide via Netrin-1/Deleted in Colorectal Cancer Signaling.

Promotion of neurite outgrowth and synapse formation is a key step for nervous tissue regeneration. It is important for finding a new biomaterial to guide neuron growth to target neurons. Aminated graphene oxide (NH2-GO) displays electrical properties and dispersibility, which may change the surface charge of neurons and further activate neuronal excitement. However, the molecular guidance mechanism of NH2-GO on neurite outgrowth is seldom reported. In this study, we compared the role of NH2-GO on the spinal cord neurons and cortical neurons. Results indicated that the proper concentrations were at 2 and 4 µg/mL as determined by the CCK-8 assay. Notably, NH2-GO (2 and 4 µg/mL) improved the dispersibility and strengthened the effect of the composite material. In addition, it enables biocompatibility and efficient guidance of growth performance, which is not neurotoxic for neuronal outgrowth under these two concentrations. More interestingly, NH2-GO at 2 µg/mL induced both marked neurite elongation and increased branches in cortical neurons, but there is no significant change of neurite length and branches in spinal cord neurons. Further, the fluorescence intensity and mRNA level of Netrin-1 and DCC (Deleted in Colorectal Cancer) were both enhanced by NH2-GO at 2 µg/mL. Moreover, the function of Netrin-1 and DCC were activated more significantly by NH2-GO at 2 µg/mL in cortical neurons than that of spinal cord neurons. When RhoA was inhibited by the C3 exoenzyme, phosphorylated Rac1 and Cdc42 expression decreased significantly. Thus, NH2-GO at 2 µg/mL could influence Netrin-1/DCC signaling and the downstream RhoGTPase pathway, which may be preferred to guide the neurite growth in cortical neurons. It will provide a promising approach for the development of novel therapeutic methods of nerve regeneration.

Effect of different-sizes of hydroxyapatite on the water resistance of magnesium oxychloride cement for bone repair.

Magnesium oxychloride cement (MOC) has recently attracted significant attention due to its excellent mechanical properties and biological behavior. However, the applications of MOC have been limited by its poor water resistance. To solve this problem, micro-sized hydroxyapatite (µ-HA) and nano-sized hydroxyapatite (n-HA) were used to improve the water resistance of MOC. The microstructure, mechanical strength and tissue responses of three types of MOC were investigated. The results demonstrated that the lost strength of MOC-0, MOC/µ-HA and MOC/n-HA were 0.92 ± 0.04, 0.81 ± 0.02 and 0.55 ± 0.01 after immersing in SBF for 28 days. The contact angles of MOC-0, MOC/µ-HA and MOC/n-HA were 42.5 ± 4.76°, 50.3 ± 5.63° and 70.4 ± 6.59°, respectively. Compared to MOC-0 and MOC/µ-HA, the filling role of the n-HA in the cement was more favorable for the formation of 5 Mg(OH)2·MgCl2·8H2O (phase 5) and a dense microstructure. In addition, the histological evaluation displayed that MOC/n-HA enhanced the efficiency of new bone formation. It also showed good biocompatibility and biodegradability in vivo. And MOC/n-HA had better osteogenic performance. Therefore, MOC/n-HA could be used as a potential bone void filler for irregular bone defects in clinical applications.

Synthesis and characterization of nano-hydroxyapatite/polyamide 66 biocomposites reinforced with multi-walled carbon nanotubes.

In this work, we investigate the enhanced mechanical properties of nano-hydroxyapatite/polyamide 66 (nHA/PA66) composites reinforced with multi-walled carbon nanotubes (MWCNTs) by means of the blending method. The MWCNTs-nHA/PA66 composites were characterized by various techniques, and the obtained results indicated that the MWCNTs were evenly distributed in the composite and that good interfacial bonding was formed between MWCNTs and PA66. The addition of MWCNTs improved the crystallinity of PA66, while it had little or no effect either on the composition or on the crystal structure of the composites. Moreover, the addition of MWCNTs in nHA/PA66 significantly improved the mechanical strength, and the tensile and compressive strengths attained maximum values of 90.3 and 126.8 MPa, respectively, with the addition of 0.1 wt% MWCNTs, whereas the bending strength attained a maximum value of 105.5 MPa with the addition of 0.05 wt% MWCNTs. Finally, L929 cells co-cultured with the MWCNTs-nHA/PA66 composite exhibited comparatively uninhibited cell growth, indicating that the addition of MWCNTs had negligible effect on the cytocompatibility of the original nHA/PA66 composite.