Preparation of 3D flexible SERS substrates by mixing gold nanorods in hydrogels for the detection of malachite green and crystal violet.

A simple and cost-effective fabrication method of gold nanorods (AuNRs) nanoparticles hybridized with polyvinyl alcohol hydrogel (AuNR/PVA) for SERS substrate is described. The AuNR/PVA achieves the control of inter-particle nanogap by modulating the density of gold nanorods, and inter-particle nanogap by the spatial deformation of the hydrogel, and the reduction of the gap between the AuNRs deposited on hydrogel makes the SERS enhancement. In addition, the AuNR/PVA substrate maintains high SERS activity after more than 100 cycles of bending and storage in air for 30 days, and the substrate possesses high sensitivity and high reproducibility. Combining a flexible and transparent surface-enhanced Raman spectroscopy (SERS) substrate for in situ detection with a small portable Raman can be applied to scenarios such as environmental detection and hazardous materials detection. The substrate showed excellent SERS activity against malachite green (MG) and crystal violet (CV) with limits of detection of 1.18 × 10-13 M and 7.17 × 10-12 M, respectively. The usability of the proposed SERS substrate was demonstrated by detecting the above contaminants in aquatic water. This work not only utilizes a cost-effective method for mass production but also provides a reliable and convenient platform for the preparation of other noble metal flexible substrates.

Preparation of cellulose-based flexible SERS and its application for rapid and ultra-sensitive detection of thiram on fruits and vegetables.

In response to the prevalent issue of thiram as a common pesticide residue on the surface of fruits and vegetables, our research team employed an acidic hydrated metal salt low co-fusion solvent to dissolve cellulose lysis slurry. Subsequently, a regenerated cellulose membrane (RCM) was successfully prepared via sol-gel method. Uniformly sized Ag nanoparticles (NPs) were deposited on RCM utilizing the continuous ion layer adsorption and reaction (SILAR) technique. The resulting Ag NPs/RCM flexible surface-enhanced Raman spectroscopy (SERS) substrates exhibited a minimum detection limit of 5 × 10-9 M for Rhodamine 6G (R6G), demonstrating good uniformity (RSD = 4.86 %) and reproducibility (RSD = 3.07 %). Moreover, the substrate displayed a remarkable sensitivity of 10-10 M toward thiram standard solution. Given its inherent flexibility, the substrate proves advantageous for the detection of three-dimensional environments such as fruit and vegetable surfaces, and its practicality has been confirmed in the detection of thiram residue on apples, tomatoes, pears, and other fruits and vegetables.

Ultra-sensitive detection of tumor necrosis factor alpha based on silver-coated gold core shell and magnetically separated recognition of SERS aptamer sensors.

A highly sensitive tumor necrosis factor α (TNF-α) detection method based on a surface-enhanced Raman scattering (SERS) magnetic patch sensor is reported. Magnetic beads (MNPs) and core shells were used as the capture matrix and signaling probe, respectively. For this purpose, antibodies were immobilized on the surface of magnetic beads, and then Au@4-MBN@Ag core-shell structures coupled with aptamers and TNF-α antigen were added sequentially to form a sandwich immune complex. Quantitative analysis was performed by monitoring changes in the characteristic SERS signal intensity of the Raman reporter molecule 4-MBN. The results showed that the limit of detection (LOD) of the proposed method was 4.37 × 10-15 mg·mL-1 with good linearity (R2 = 0.9918) over the concentration range 10-12 to 10-5 mg·mL-1. Excellent assay accuracy was also demonstrated, with recoveries in the range 102% to 114%. Since all reactions occur in solution and are separated by magnetic adsorption of magnetic beads, this SERS-based immunoassay technique solves the kinetic problems of limited diffusion and difficult separation on solid substrates. The method is therefore expected to be a good clinical tool for the diagnosis of the inflammatory biomarker THF-α and in vivo inflammation screening.

Bacterial cellulose loaded with silver nanoparticles as a flexible, stable and sensitive SERS-active substrate for detection of the shellfish toxin DTX-1.

Diarrheal shellfish toxins are considered one of the most lethal red tide algae toxins in the worldwide. In this work, we propose an Ag NPs-loaded bacterial cellulose membrane (BCM) surface-enhanced Raman scattering (SERS) sensor based on an aptamer (Apt) for the ultrasensitive detection of dinophysistoxin (DTX-1), a type of diarrheal shellfish toxin. During drying, Ag NPs can be further densified on "gel-like" BCM to form high-density SERS "hot spots". We developed the "Apt-SH@Ag NPs@BCM" SERS sensor and used the competition of DTX-1 and complementary base (Cob) in the process of base complementary pairing to achieve SERS detection of DTX-1, with a minimum detection limit of 9.5 × 10-10 mol/L. Sample assays showed DTX-1 recovery rates ranging from 95.8% and 108.2% and the detection results were comparable to those obtained by LC-MS. Therefore, this work holds great potential for detecting of toxic substances in shellfish products, especially for the oyster (portuguese oyster) and mussel (blue mussel).

Preparation of SERS substrate with 2D silver plate and nano silver sol for plasticizer detection in edible oil.

As a widely used industrial additive of plastic products, phthalate ester (PAE) plasticizers can easily migrate into food, threatening human health. In this work, we proposed a rapid, precise, and reliable method to detect PAE plasticizers in edible oils by using surface-enhanced Raman spectroscopy (SERS) technology. A two-dimensional (2D) silver plate synergizing with a nanosilver sol was prepared as a substrate for SERS to detect potassium hydrogen phthalate (PHP), a hydrolysate of a PAE plasticizer. Detection conditions, such as pH values, drying times, and hydrolysate interference, were optimized. The working curve was well fitted with a linear parameter R2 of 0.9994, and the minimum detection limit was evaluated as 10-9 mol/L. Furthermore, the detection accuracy was supported by five edible oil samples. Therefore, using SERS technology to detect PHP is expected to provide an avenue for PAE plasticizer detection in oils and fats, and it features promising potential applications in food safety.

Label-Free SERS Analysis of Serum Using Ag NPs/Cellulose Nanocrystal/Graphene Oxide Nanocomposite Film Substrate in Screening Colon Cancer.

Label-free surface-enhanced Raman scattering (SERS) analysis shows tremendous potential for the early diagnosis and screening of colon cancer, owing to the advantage of being noninvasive and sensitive. As a clinical diagnostic tool, however, the reproducibility of analytical methods is a priority. Herein, we successfully fabricated Ag NPs/cellulose nanocrystals/graphene oxide (Ag NPs/CNC/GO) nanocomposite film as a uniform SERS active substrate for label-free SERS analysis of clinical serum. The Ag NPs/CNC/GO suspensions by self-assembling GO into CNC solution through in-situ reduction method. Furthermore, we spin-coated the prepared suspensions on the bacterial cellulose membrane (BCM) to form Ag NPs/CNC/GO nanocomposite film. The nanofilm showed excellent sensitivity (LOD = 30 nM) and uniformity (RSD = 14.2%) for Nile Blue A detection. With a proof-of-concept demonstration for the label-free analysis of serum, the nanofilm combined with the principal component analysis-linear discriminant analysis (PCA-LDA) model can be effectively employed for colon cancer screening. The results showed that our model had an overall prediction accuracy of 84.1% for colon cancer (n = 28) and the normal (n = 28), and the specificity and sensitivity were 89.3% and 71.4%, respectively. This study indicated that label-free serum SERS analysis based on Ag NPs/CNC/GO nanocomposite film combined with machine learning holds promise for the early diagnosis of colon cancer.

[Benefits of community-based reproductive health service to middle-aged and elderly men].

OBJECTIVE: To explore the role of community-based reproductive health service in improving male reproductive health-related knowledge, behavior and psychology in middle-aged and elderly men. METHODS: We recruited 136 men aged 40－69 years from 5 community health service centers in Xuzhou for this self-control study from July to August 2019. We carried out a 4-item health education among the subjects concerning reproductive health knowledge, reproductive system diseases, healthy life, and enjoying health. Before and at 6 months after education, we evaluated the effects of intervention using the General Condition Questionnaire, Reproductive System Symptoms Questionnaire, Male Reproductive Health-Related Knowledge, Attitude and Behavior Questionnaire, and the Chinese version of Connor-Davidson Resilience Scale. RESULTS: At 6 months after intervention, the subjects showed significantly increased scores on healthy eating habits, male reproductive health cognation and psychological resilience, and decreased unhealthy behaviors and positive rate of reproductive system symptoms as compared with those before intervention (all P < 0.05). The cost-effectiveness ratio of the study was 7.75. CONCLUSIONS: Community-based reproductive health service can effectively improve the reproductive health-related knowledge and psychology, eating habits and healthy behaviors of middle-aged and elderly men. And it has a high cost-effectiveness ratio and is worthy of promotion in other communities.

Hypertonic saline improves brain edema resulting from traumatic brain injury by suppressing the NF-κB/IL-1ß signaling pathway and AQP4.

Although hypertonic saline (HS) has been extensively applied to treat brain edema in the clinic, the precise mechanism underlying its function remains poorly understood. Therefore, the aim of the present study was to investigate the therapeutic mechanism of HS in brain edema in terms of aquaporins and inflammatory factors. In the present study, traumatic brain injury (TBI) was established in male adult Sprague-Dawley rats, which were continuously administered 10% HS by intravenous injection for 2 days. In addition, brain edema and brain water content were detected by MRI and wet/dry ratio analysis and histological examination, respectively. Immunohistochemical staining for albumin and western blotting for occludin, zonula occludens-1 and claudin-5 was performed to evaluate the integrity of the blood-brain barrier. Aquaporin 4 (AQP4) expression was also analyzed using western blotting and reverse transcription-quantitative PCR, whilst interleukin (IL)-1ß and NF-κB levels were measured using ELISA. It was demonstrated that HS treatment significantly reduced brain edema in TBI rats and downregulated AQP4 expression in cerebral cortical tissues around the contusion site. In addition, IL-1ß and NF-κB levels were found to be downregulated after 10% HS treatment. Therefore, results from the present study suggested that HS may protect against brain edema induced by TBI by modulating the expression levels of AQP4, NF-κB and IL-1ß.

Study on the Adhesion Force Between Ga-Doped ZnO Thin Films and Polymer Substrates.

Flexible Ga doped ZnO (GZO) transparent conductive thin films were prepared on polycarbonate (PC) substrates at room temperature by magnetron sputtering. The adhesive property between the GZO film and the PC substrate was investigated quantitatively by the scratch test, which is designed for the quantitative assessment of the mechanical integrity of coated surfaces. The effect of the sputtering pressures on the adhesion forces for the GZO films was investigated. When the sputtering pressure varied from 0.2 to 0.5 Pa, no obvious adhesion force alteration was observed. However, when the sputtering pressure was increased to 0.7 Pa, the adhesion force was decreased. The lowest square resistance of the GZO film was 18.6 Ω/sq. Regardless of the sputtering pressure, the transmittance in the visible light was about 90%. When the sputtering pressure was 0.4 Pa, the optimal figure of merit (ΦTC) was 2.5×10-2 Ω-1, indicating that the optimal pressure was 0.4 Pa.

Tirofiban combined with urokinase selective intra-arterial thrombolysis for the treatment of middle cerebral artery occlusion.

The aims of the present study were to establish a model of embolic stroke in rabbits and to evaluate the efficacy and safety of intra-arterially administered tirofiban combined with urokinase thrombolysis. The middle cerebral artery occlusion model (MCAO) of embolic stroke was established in New Zealand rabbits via an autologous clot. The model rabbits were allocated at random into four groups: Tirofiban group (T group), urokinase group (UK group), tirofiban and urokinase group (T + UK group) and the control group (C group). The recanalization rate, relative-apparent diffusion coefficient (rADC) and neurological function deficit score (NFDS) values were compared among the four groups. The recanalization rate, rADC and NFDS values were improved in the T + UK group compared with the other groups. In summary, the intra-arterial administration of tirofiban combined with urokinase thrombolysis was a more effective intervention in an MCAO model compared with intra-arterial urokinase alone, and may promote reperfusion and reduce infarct volume.