silicon and Parkinson-Disease

Multiplexed detection of Parkinson's disease (PD) biomarkers is of great significance for early diagnosis and personalized treatment. In this study, we fabricated a robust surface-enhanced Raman scattering-enabled lab-on-a-chip (LoC-SERS) platform for simultaneous quantification of α-synuclein, phosphorylated tau protein 181, osteopontin, and osteocalcin. Herein, the antibody-DNA conjugate was designed to introduce the catalytic hairpin self-assembly (CHA) amplification into the protein detection. Au nano-stars (AuNSs) modified with Raman reporter molecules and hairpin-structure DNA 1 were applied as the SERS nanotags. Au-coated silicon nanocone array (Au/SiNCA) fabricated based on the maskless plasma etching-prepared high-density Si nanocone array (SiNCA) and surface ion sputtering was used as the capture substrate after the modification of hairpin-structure DNA 2. Benefitting from the antibody-DNA conjugate-induced CHA amplification, numerous AuNSs can be connected to the Au/SiNCA surface, which significantly amplify the plasmonic coupling effect for ultrasensitive SERS detection, and the limit of detection was less than the pg/mL level. The application of highly uniform Au/SiNCA and antibody-DNA conjugate endows the LoC-SERS platform excellent analytical performance, including superior reproducibility, satisfactory universality, and high sensitivity. In addition, a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice model was established, and satisfactory results were obtained in real sample analysis with the LoC-SERS platform, which may be enlightening for exploiting protein biomarkers in PD monitoring.

Topics: Animals; Biomarkers; Gold; Limit of Detection; Metal Nanoparticles; Mice; Parkinson Disease; Reproducibility of Results; Silicon; Spectrum Analysis, Raman; tau Proteins

Carbon nanoparticles are becoming promising agents in treating Parkinson's disease (PD) by preventing the folding and aggregation of α-synuclein, i.e., amyloid formation. Herein, for the first time, highly tunable graphene and carbon nanotubes (CNTs) have been doped using biocompatible silicon atoms for preventing Parkinson's disease. In this study, the conformational changes induced by these nanoparticles, the compactness of nanoparticles, the number of hydrogen bonds, the stability of α-synuclein in the presence of nanoparticles, and the interaction energies between α-synuclein and nanoparticles were investigated using microsecond coarse-grained and all-molecular-atom simulations. Although the nanoparticles considered in this study could induce desirable changes in α-synuclein conformations, Si-graphene (silicon-doped graphene) demonstrated the best performance. Si-graphene showed the highest interaction energy with α-synuclein compared to other nanoparticles, induced the most hydrogen bonds, was the least compact, and showed the most unstable α-synuclein conformation, resulting in the highest capability to prevent the folding and aggregation of α-synuclein. Our results displayed that 2D hexagonal structures, such as graphene and Si-graphene, possess better performance than tubular structures in inducing conformational changes in the α-synuclein protein. Furthermore, it was observed that the doping of silicon in graphene and CNT results in better folding and aggregation of α-synuclein prevention. This molecular investigation offers a nanostructure method in PD treatment.

Topics: alpha-Synuclein; Graphite; Humans; Nanotubes, Carbon; Parkinson Disease; Silicon

We have developed Si-based agent which can generate a large amount of hydrogen. Si-based agent continues generating hydrogen for more than 24 h by the reaction with water under conditions similar to those in bowels, i.e., pH8.3 and 36 °C, and generates ~400 mL hydrogen. To investigate beneficial effects for diseases associated with oxidative stress, Si-based agent is administered to remnant kidney rats and Parkinson's disease mice. Rats are fed with control or Si-based agent-containing diet for 8 weeks. Si-based agent is found to greatly suppress the development of renal failure and the parameters of oxidative stress. Treatment with Si-based agent in a mouse model of hemi-Parkinson's disease induced by 6-hydroxydopamine attenuated degeneration of dopaminergic neurons and prevented impairment of motor balance and coordination. These findings indicate that the Si-based agent shows renoprotective and neuroprotective effects presumably via suppression of oxidative stress by generation of hydrogen.

Topics: Animals; Disease Models, Animal; Hydrogen; Kidney; Male; Mice; Neuroprotective Agents; Oxidative Stress; Parkinson Disease; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Renal Insufficiency, Chronic; Rotarod Performance Test; Silicon; Tyrosine 3-Monooxygenase

Parkinson's disease (PD) is a neurodegenerative disorder that is characterized by symptoms such as rigor, tremor and bradykinesia. A reliable and early diagnosis could improve the development of early therapeutic strategies before death of dopaminergic neurons leads to the first clinical symptoms. The sFIDA (surface-based fluorescence intensity distribution analysis) assay is a highly sensitive method to determine the concentration of α-synuclein (α-syn) oligomers which are presumably the major toxic isoform of α-syn and potentially the most direct biomarker for PD. Oligomer-based diagnostic tests require standard molecules that closely mimic the native oligomer. This is particularly important for calibration and assessment of inter-assay variation. In this study, we generated a standard in form of α-syn coated silica nanoparticles (α-syn-SiNaPs) that are in the size range of α-syn oligomers and provide a defined number of α-syn epitopes. The preparation of the sFIDA assay was realized on an automated platform to allow handling of high number of samples and reduce the effects of human error. The assay outcome was analyzed by determination of coefficient of variation and linearity for the applied α-syn-SiNaPs concentrations. Additionally, the limit of detection and lower limit of quantification were determined yielding concentrations in the lower femtomolar range.

Topics: alpha-Synuclein; Biomarkers; Calibration; Epitopes; Humans; Immunologic Tests; Limit of Detection; Molecular Mimicry; Nanoparticles; Parkinson Disease; Protein Multimerization; Silicon

Twenty-six metals and the oxidative status in 71 patients affected by Parkinson's disease and 44 healthy individuals were compared in order to identify potential biomarkers of the disease. In the patients, the following significant imbalances were found (p < or = 0.05): i) in serum, an increment of Ca, Mg, Ni, Si and V, and a decrement of Cd, Co, Fe, Li, Sn, Zn and Zr; ii) in blood, raised levels of Co, Li, Ni and Si and decreased of Al, Be, Ca, Cd, Fe, Mg, Mo, Sn, Zn and Zr; iii) increased formation of oxidant species and lowered anti-oxidant capacity (p < or = 0.001 for both). Barium, Bi, Cr, Cu, Hg, Mn, Pb, Sb, Sr, Tl and W did not change with the disease. The best discriminating variables between patients and controls were Cd, Co, Fe, Ni and Si in serum (91.2% of cases correctly classified), and Al, Cd, Co, Fe, Mo and Si in blood (98.2% of cases properly classified).

Topics: Aged; Antiparkinson Agents; Female; Humans; Male; Mass Spectrometry; Metals; Middle Aged; Oxidative Stress; Parkinson Disease; Silicon

The aetiology of Parkinson's disease (PD) is still unknown, but some hypotheses have focused on the imbalances in body levels of metals as co-factors of risk. To assess whether hair could be a reliable marker of possible changes, calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), silicon (Si) and zinc (Zn) were determined in hair from 81 patients affected by PD and 17 age-matched controls. Care was taken to eliminate external contamination of the hair by thorough washing. Digestion of the matrix was achieved by an acid-assisted microwave procedure. Quantification of the elements was performed by inductively coupled plasma atomic emission spectrometry. Results indicated significantly lower levels of Fe in the hair of patients (p=0.018) compared with controls. Ca and Mg levels were slightly lower while Zn levels were higher in patients, although these differences were not significant; neither were variations in Cu and Si. Ca and Mg were at least 1.5 times higher in females than in males in both controls and patients. In addition, Ca correlated positively with Mg in both groups and in both sexes (p-value always less than 0.03), and negatively with age in patients (p<0.01). Finally, element levels did not correlate with either the duration or the severity of the disease or with anti-Parkinson treatment.

Topics: Age Factors; Aged; Calcium; Chemistry Techniques, Analytical; Copper; Female; Hair; Humans; Iron; Magnesium; Male; Middle Aged; Parkinson Disease; Sex Factors; Silicon; Spectrophotometry, Atomic; Trace Elements; Zinc

Topics: Aluminum; Amyotrophic Lateral Sclerosis; Calcium; Dementia; Guam; Hippocampus; Histocytochemistry; Humans; Neurons; Parkinson Disease; Silicon