silicon and Colorectal-Neoplasms

The study is aimed at investigating the effect of the FLOT2 gene on invasion and metastasis of colorectal cancer (CRC) cells and the corresponding molecular mechanism by preparing polylysine-silicon nanoparticles. Specifically, polylysine was used to modify the silica nanoparticles prepared by the emulsification method to obtain polylysine-silicon nanoparticles. The characterization of polylysine-silicon nanoparticles was completed by nanoparticle size analyzer, laser particle size potentiometer, and transmission microscope. The influence of polylysine-silicon nanoparticles on the survival rate of CRC cell line HT-29 was detected using the method of 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT). The FLOT2-siRNA expression vector was constructed and transfected with HT-29. The HT-29 transfected with empty plasmid was used as the negative control (NC). Western Blot (WB) and reverse transcription-polymerase chain reaction (RT-PCR) were used to detect expression levels of FLOT2 gene and epithelial-mesenchymal transition- (EMT-) related genes. Transwell invasion assay, Transwell migration assay, and CCK8 assay were used to detect the cell invasion, migration, and proliferation. The results showed that the average particle size of polylysine-silicon nanoparticles was 30 nm, the potential was 19.65 mV, the particle size was 65.8 nm, and the dispersion coefficient was 0.103. At the same concentration, the toxicity of silicon nanoparticles to HT-29 was significantly lower than that of liposome reagent, and the transfection efficiency was 60%, higher than that of liposome reagent (40%). The mRNA level and protein expression of the FLOT2 gene in the FLOT2-siRNA group were significantly lower than those in the NC group (

Topics: Cell Line, Tumor; Cell Movement; Cell Proliferation; Colorectal Neoplasms; Gene Expression; Gene Expression Regulation, Neoplastic; Humans; Liposomes; Nanotechnology; Polylysine; RNA Interference; RNA, Messenger; RNA, Small Interfering; Silicon

Topics: Anti-Inflammatory Agents, Non-Steroidal; Colorectal Neoplasms; Cyclooxygenase Inhibitors; Diclofenac; HT29 Cells; Humans; Indoles; Organosilicon Compounds; Silicon

Metasurfaces with a strongly enhanced local field are envisioned as a powerful platform for ultrasensitive optical sensors to significantly amplify imperceptible differences between compatible bioanalytes. Through the use of phototunable silicon-based terahertz (THz) metasurfaces, we experimentally demonstrate ultrafast switchable sensing functions. It is found that the THz responses of the coupled-resonances in the metasurfaces shift from Lorentz-lattice mode to electromagnetism-induced transparency (EIT) mode under optical pumping within an ultrashort time of 32 ps, enabling an ultrafast sensitive sensor. For the Lorentz-lattice mode, the THz time-domain signal directly shows a highly sensitive response to detect tiny analytes without extra Fourier transformation as the mismatch between the two modes increases. Once the metasurfaces are switched to the EIT mode, the silicon-metal hybrid structure supports frequency-domain sensing ability due to strong field confinement with a sensitivity of 118.4 GHz/RIU. Both of the sensing configurations contribute to more subtle information and guarantee the accuracy of the sensor performance. Combined with the aforementioned advantages, the proposed metasurfaces have successfully identified colorectal cells between normal, adenoma, and cancer states in experiments. This work furnishes a new paradigm of constructing reliable and flexible metasurface sensors and can be extended to other optics applications.

Topics: Biosensing Techniques; Colorectal Neoplasms; Humans; Silicon

In this paper, a nanobiosensor with surface-enhanced Raman scattering (SERS) capability is introduced for highly sensitive miRNA detection in colorectal cancer. This sensor was designed and fabricated by employing a nanoshielding mechanism from nanopolystyrene beads to resist reactive ion etching and allow anisotropic electrochemical etching, producing high-aspect-ratio, surface-corrugated nanopillars (SiNPs) on a silicon wafer to create extensive hot spots along the nanopillars for improved SERS signals. SERS enhancements were correlated with nanorange roughness, indicating that hot spots along the pillars were the crucial factor to improve the SERS effect. We achieved the detection capability of a trace amount of R6G (10

Topics: Biosensing Techniques; Colorectal Neoplasms; Gold; Humans; Limit of Detection; Metal Nanoparticles; MicroRNAs; Silicon; Spectrum Analysis, Raman; Surface Properties

Indole derivatives are a structurally diverse group of compounds found in food, toxins, medicines, and produced by commensal microbiota. On contact with acidic stomach conditions, indoles undergo condensation to generate metabolites that vary in solubility, activity and toxicity as they move through the gut. Here, using halogenated ions, we map promising chemo-preventative indoles, i) 6-bromoisatin (6Br), ii) the mixed indole natural extract (NE) 6Br is found in, and iii) the highly insoluble metabolites formed in vivo using desorption/ionisation on porous silicon-mass spectrometry imaging (DIOS-MSI). The functionalised porous silicon architecture allowed insoluble metabolites to be detected that would otherwise evade most analytical platforms, providing direct evidence for identifying the therapeutic component, 6Br, from the mixed indole NE. As a therapeutic lead, 0.025 mg/g 6Br acts as a chemo-preventative compound in a 12 week genotoxic mouse model; at this dose 6Br significantly reduces epithelial cell proliferation, tumour precursors (aberrant crypt foci; ACF); and tumour numbers while having minimal effects on liver, blood biochemistry and weight parameters compared to controls. The same could not be said for the NE where 6Br originates, which significantly increased liver damage markers. DIOS-MSI revealed a large range of previously unknown insoluble metabolites that could contribute to reduced efficacy and increased toxicity.

Topics: Animals; Colorectal Neoplasms; Gastrointestinal Tract; Imaging, Three-Dimensional; Indoles; Male; Metabolome; Mice, Inbred C57BL; Porosity; Silicon; Solubility; Xenobiotics

Small peptides in serum are potential biomarkers for the diagnosis of cancer and other diseases. The identification of peptide biomarkers in human plasma/serum has become an area of high interest in medical research. However, the direct analysis of peptides in serum samples using mass spectrometry is challenging due to the low concentration of peptides and the high abundance of high-molecular-weight proteins in serum, the latter of which causes severe signal suppression. Herein, we reported that porous semiconductor-noble metal hybrid nanostructures can both eliminate the interference from large proteins in serum samples and significantly enhance the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) yields of peptides captured on the nanostructure. Serum peptide fingerprints with high fidelity can be acquired rapidly, and successful discrimination of colorectal cancer patients based on peptide fingerprints is demonstrated.

Topics: Amino Acid Sequence; Biomarkers; Colorectal Neoplasms; Equipment Design; Gold; Humans; Molecular Sequence Data; Nanostructures; Peptides; Porosity; Sensitivity and Specificity; Silicon; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

A series of silicon(IV) phthalocyanines with two axial isopropylidene-protected galactose moieties and one, two, or eight chloro group(s) on the periphery of the macrocycle have been synthesised and spectroscopically characterised. The photophysical properties and in vitro photodynamic activities of these compounds have been studied and compared with those of the nonchlorinated analogue. All the compounds, with the exception of the octachlorinated counterpart which has a limited solubility, are essentially nonaggregated in N,N-dimethylformamide. The fluorescence quantum yield decreases and the singlet oxygen quantum yield increases as the number of chloro substituent increases, which is in accord with the heavy-atom effect. The non-, mono-, and dichlorinated phthalocyanines formulated with Cremophor EL are all photodynamically active against HT29 human colon adenocarcinoma and HepG2 human hepatocarcinoma cells with IC(50) values ranging from 0.03 to 1.05 microM. The photocytotoxicity as well as the efficiency to generate intracellular reactive oxygen species decrease along this series because of the increase in aggregation tendency upon chloro substitution. The nonchlorinated analogue exhibits the highest potency and can target the lysosomes of HT29 cells, whereas the monochlorinated counterpart is not localised in the lysosomes.

Topics: Cell Line, Tumor; Chlorine; Colorectal Neoplasms; Dimethylformamide; Fluorescence; Formamides; Galactose; HT29 Cells; Humans; Indoles; Isoindoles; Organosilicon Compounds; Photosensitizing Agents; Silicon; Singlet Oxygen; Spectrum Analysis; Structure-Activity Relationship

This paper introduces a new substrate for reverse-phase protein microarray applications based on macroporous silicon. A key feature of the microarray substrate is the vastly surface enlarging properties of the porous silicon, which simultaneously offers highly confined microarray spots. The proof of principle of the reverse array concept was demonstrated in the detection of different levels of cyclin E, a possible cancer biomarker candidate which regulates G1-S transition and correlates with poor prognosis in different types of human cancers. The substrate properties were studied performing analysis of total cyclin E expression in human colon cancer cell lines Hct116 and SW480. The absence of unspecific binding and good microarray quality was demonstrated. In order to verify the performance of the 3-D textured macroporous surface for complex biological samples, lysates of the human tissue spiked to different levels with cell extract overproducing cyclin E (Hct116) were arrayed on the chip surface. The samples were spotted in a noncontact mode in 100 pL droplets with spots sizes ranged between 50 and 70 mum and spot-to-spot center distances 100 mum, allowing microarray spot densities up to 14 000 spots per cm(2). The different sample types of increasing complexities did not have any impact on the spot intensities recorded and the protein spots showed good homogeneity and reproducibility over the recorded microarrays. The data demonstrate the potential use of macroporous silicon as a substrate for quantitative determination of a cancer biomarker cyclin E in tissue lysates.

Topics: Biomarkers, Tumor; Blotting, Western; Cell Extracts; Cell Line, Tumor; Colorectal Neoplasms; Cyclins; Fluorescent Antibody Technique, Direct; HCT116 Cells; Humans; Immunoblotting; Microscopy, Confocal; Neoplasm Proteins; Sensitivity and Specificity; Silicon; Surface Properties; Tissue Array Analysis; Tissue Extracts