Study of the stability of functionalized gold nanoparticles for the colorimetric detection of dipeptidyl peptidase IV

In this report, we investigated three stabilization strategies of gold nanoparticles and their practical application for the visual detection of dipeptidyl peptidase IV (DPP-IV). Citrate-capped gold nanoparticles (Au NPs) are generally unstable in high-ionic-strength samples. Au NPs are easily tagged with various proteins and biomolecules rich in amino acids, leading to important biomedical applications including targeted drug delivery, cellular imaging, and biosensing. The investigated assays were based on different modes of stabilization, such as the incorporation of polyethylene glycol (PEG) groups, stabilizer peptide, and bifunctionalization. Although all approaches provided highly stable Au NP platforms demonstrated by zeta potential measurements and resistance to aggregation in a high-ionic-strength saline solution, we found that the Au NPs modified with a separate stabilizer ligand provided the highest stability and was the only platform that demonstrated sensitivity to the addition of DPP-IV, whilst PEGylated and peptide-stabilized Au NPs showed no significant response

Optimization of gold nanoparticle-based real-time colorimetric assay of dipeptidyl peptidase IV activity

Dipeptidyl peptidase IV (DPP-IV also referred to as CD-26) is a serine protease enzyme with remarkable diagnostic and prognostic value in a variety of health and disease conditions. Herein, we describe a simple and real-time colorimetric assay for DPP-IV/CD-26 activity based on the aggregation of gold nanoparticles (AuNPs) functionalized with the peptide substrates: Gly-Pro-Asp-Cys (GPDC) or Val-Pro-ethylene diamine-Asp-Cys (VP-ED-DC). Cleavage of the substrates by DPP-IV resulted in aggregation of the AuNPs with accompanying color change in the solution from red to blue that was monitored using either a UV–visible spectrophotometer or by the naked eye. Factors, such as time course of the reaction, stability of the functionalized AuNPs and the structure of the substrate that influence the cleavage reaction in solution were investigated. The effects of potential interference from serum proteins (lysozyme, thrombin and trypsin) on the analytical response were negligible. The detection limits when GPDC or VP-EN-DC functionalized AuNPs were used for DPP-IV assay were 1.2 U/L and 1.5 U/L, respectively. The VP-EN-DC method was preferred for the quantitative determination of DPP-IV activity in serum because of its wide linear range 0–30 U/L compared to 0–12 U/L for the GPDC assay. Recoveries from serum samples spiked with DPP-IV activity, between 5 and 25 U/L, and using the VP-EN-DC modified AuNPs method ranged between 83.6% and 114.9%. The two colorimetric biosensors described here are superior to other conventional methods because of their simplicity, stability, selectivity and reliability

Lipidomic UPLC-MS/MS Profiles of Normal-Appearing White Matter Differentiate Primary and Secondary Progressive Multiple Sclerosis

Multiple sclerosis (MS) is a neurodegenerative inflammatory disease where an autoimmune response to components of the central nervous system leads to a loss of myelin and subsequent neurological deterioration. People with MS can develop primary or secondary progressive disease (PPMS, SPMS) and differentiation of the specific differences in the pathogenesis of these two courses, at the molecular level, is currently unclear. Recently, lipidomics studies using human biofluids, mainly plasma and cerebrospinal fluid, have highlighted a possible role for lipids in the initiation and progression of MS. However, there is a lack of lipidomics studies in MS on CNS tissues, such as normal-appearing white matter (NAWM), where local inflammation initially occurs. Herein, we developed an untargeted reverse phase ultra-performance liquid chromatography time of flight tandem mass spectrometry (RP-UPLC-TOF MSE)-based workflow, in combination with multivariate and univariate statistical analysis, to assess significant differences in lipid profiles in brain NAWM from post-mortem cases of PPMS, SPMS and controls. Groups of eight control, nine PPMS and seven SPMS NAWM samples were used. Correlation analysis of the identified lipids by RP-UPLC-TOF MSE was undertaken to remove those lipids that correlated with age, gender and post-mortem interval as confounding factors. We demonstrate that there is a significantly altered lipid profile of control cases compared with MS cases and that progressive disease, PPMS and SPMS, can be differentiated on the basis of the lipidome of NAWM with good sensitivity, specificity and prediction accuracy based on receiver operating characteristic (ROC) curve analysis. Metabolic pathway analysis revealed that the most altered lipid pathways between PPMS and SPMS were glycerophospholipid metabolism, glycerophosphatidyl inositol (GPI) anchor synthesis and linoleic acid metabolism. Further understanding of the impact of these lipid alterations described herein associated with progression will provide an increased understanding of the mechanisms underpinning progression and highlight possible new therapeutic targets

Gold nanoparticle-based colorimetric biosensors

Gold nanoparticles (AuNPs) provide excellent platforms for the development of colorimetric biosensors as they can be easily functionalised, displaying different colours depending on their size, shape and state of aggregation. In the last decade, a variety of biosensors have been developed to exploit the extent of colour changes as nano-particles (NPs) either aggregate or disperse, in the presence of analytes. Of critical importance to the design of these methods is that the behaviour of the systems has to be reproducible and predictable. Much has been accomplished in understanding the interactions between a variety of substrates and AuNPs, and how these interactions can be harnessed as colorimetric reporters in biosensors. However, despite these developments, only a few biosensors have been used in practice for the detection of analytes in biological samples. The transition from proof of concept to market biosensors requires extensive long-term reliability and shelf life testing, and modification of protocols and design features to make them safe and easy to use by the population at large. Developments in the next decade will see the adoption of user friendly biosensors for point-of-care and medical diagnosis as innovations are brought to improve the analytical performances and usability of the current designs. This review discusses the mechanisms, strategies, recent advances and perspectives for the use of AuNPs as colorimetric biosensors. Keywords: biosensors, colloids, gold nanoparticles, nanotechnology, surface plasmon resonance, enzymes, quantification

The use of vibrational spectroscopy to study the pathogenesis multiple sclerosis and other neurological conditions

Spectroscopy techniques are valuable tools in biomedical research and have been used extensively in the study of disease. However, neurological conditions such as multiple sclerosis (MS) have received little attention and the available spectroscopy studies are limited, both in overall numbers of patients studied and the disease samples considered. MS is a complex immune-mediated disease, with variable clinical courses and limited therapeutic options. This review aims to summarize current literature in the area, demonstrating how spectroscopy techniques can provide valuable information to inform and advance research into the most common neurological condition affecting young adults

Effects of an exercise and hypocaloric healthy eating intervention on indices of psychological health status, hypothalamic-pituitary-adrenal axis regulation and immune function after early-stage breast cancer : a randomised controlled trial

INTRODUCTION: Many women experience emotional distress, depression and anxiety after a diagnosis of breast cancer. Psychological stress and depression have been associated with hypothalamic-pituitary-adrenal (HPA) axis dysregulation that may adversely affect immune system functioning and impact upon survival. This study investigated the effects of a lifestyle intervention on indices of psychological health status, HPA axis regulation and immune function in overweight women recovering from early-stage breast cancer treatment. METHODS: A total of 85 women treated for breast cancer 3 to 18 months previously were randomly allocated to a 6-month exercise and hypocaloric healthy eating program plus usual care or usual care alone (control group). Women in the intervention group received three supervised exercise sessions per week and individualized dietary advice, supplemented by weekly nutrition seminars. Depressive symptoms (Beck Depression Inventory version II: BDI-II), perceived stress (Perceived Stress Scale: PSS), salivary diurnal cortisol rhythms; inflammatory cytokines (IL-6 and Tumor necrosis factor-α), leukocyte phenotype counts, natural killer (NK) cell cytotoxicity and lymphocyte proliferation following mitogenic stimulation were assessed at baseline and 6-month follow up. RESULTS: Compared with the control group, the intervention group exhibited a reduction in depressive symptoms (adjusted mean difference, 95% confidence intervals (95% CI): -3.12, -1.03 to -5.26; P = 0.004) at the 6-month follow-up but no significant decrease in PSS scores (-2.07, -4.96 to 0.82; P = 0.16). The lifestyle intervention also had a significant impact on diurnal salivary cortisol rhythm compared with usual care alone, as evidenced by an increase in morning salivary cortisol at the 6-month follow-up (P <0.04), indicating a change in HPA axis regulation. Women in the control group had higher total leukocyte, neutrophil and lymphocyte counts in comparison to the intervention group at the 6-month follow-up (P ≤0.05), whereas there was no difference in NK cell counts (P = 0.46), NK cell cytotoxicity (P = 0.85) or lymphocyte proliferation responses (P = 0.11) between the two groups. CONCLUSION: Our results show that the lifestyle intervention resulted in a reduction in depressive symptoms and a normalisation of HPA axis regulation. Such changes could have important implications for long-term survival in women recovering from early-breast cancer treatment. TRIAL REGISTRATION: Current Controlled Trials: ISRCTN08045231

Pragmatic intervention for increasing self-directed exercise behaviour and improving important health outcomes in people with multiple sclerosis : a randomised controlled trial

Background: Exercise programmes that can demonstrate evidence of long-lasting clinical effectiveness are needed forpeople with multiple sclerosis (PwMS). Objective: The objective of this study was to assess the effects of a practically implemented exercise programme onself-directed exercise behaviour and important health outcomes in PwMS to nine months of follow-up. Methods: We conducted a parallel-arm, randomised controlled trial: 120 PwMS (Expanded Disability Status Scale (EDSS) 1.0-6.5) randomised to a three-month exercise intervention plus usual care, or usual care only. Two supervised plus one homeexercisesession (weeks 1-6) were followed by one supervised and two home-exercise sessions (weeks 7-12). Cognitivebehaviouraltechniques promoted long-term exercise behaviour change. Outcomes were blindly assessed at baseline and atthree and nine months after randomisation. The primary outcome was self-reported exercise behaviour (Godin Leisure TimeExercise Questionnaire (GLTEQ)). Secondary outcomes included fatigue and health-related quality of life (HRQoL). Results: The intervention increased self-reported exercise (9.6 points; 95% CI: 2.0 to 17.3 points; p = 0.01) andimproved fatigue (p<0.0001) and many HRQoL domains (p≤0.03) at three months. The improvements in emotionalwell-being (p = 0.01), social function (p = 0.004) and overall quality of life (p = 0.001) were sustained for nine months. Conclusion: This pragmatic approach to implementing exercise increases self-reported exercise behaviour, improves fatigue and leads to a sustained enhancement of HRQoL domains in PwMS

Family-focused campus-based university event increases perceived knowledge, science capital and aspirations across a wide demographic

Creative ways of delivering informal science events in community settings are viewed as key to engaging new audiences and participants whom scientists find hard to reach, however, the impact of ‘formal’ setting events is often overlooked. Here, through a mixed-methods approach, we analyse a large-scale family-focused public engagement event hosted within a university campus setting. We aimed to explore the profile of visitors attending together with the impact and perceived knowledge gained. Analysis from two consecutive years of data collection found that the university-based event attracted new visitors annually, with almost half having not attended other science events/attractions within the last year. An increase in perceived knowledge was shown amongst all study participants, being significantly amplified in those from low progression to higher education postcode areas. Both immediate and longer-term positive impact was reported by participants with increases in components of science capital observed as well as enhanced positive perception of the university and its students. This data exemplifies the benefit of university-hosted events in widening participation and public understanding of science

Qualitative investigation of exercise perceptions and experiences in people with multiple sclerosis before, during, and after participation in a personally tailored exercise program

Objective To undertake a qualitative investigation of exercise perceptions and experiences in people with multiple sclerosis (PwMS) before, during, and after participation in a personally tail ored program designed to promote long-term maintenance of self-directed exercise. Design Focus groups and semistructured telephone interviews. Setting University exercise science department close to the recruiting hospital. Participants PwMS (N=33; mean age ± SD, 47.6±7.9y). Interventions Participants were recruited after participation in a randomized controlled exercise trial; all had been allocated to a 12-week exercise program comprising supervised and self-directed exercise sessions. Main Outcome Measures Exercise perceptions and experiences before, during, and after participation in the program. Results Four themes emerged from the analysis: (1) the transition to inactivity; (2) lack of knowledge and confidence; (3) positive exercise experiences; and (4) perspectives on exercise adherence. Conclusions Lack of confidence and exercise knowledge, coupled with negative perceptions about physical capabilities after an MS diagnosis, are clear barriers to exercise participation in PwMS. These issues are not being adequately addressed as part of the health care pathway or in community settings. Perceptions of improved posture, ability to overcome everyday difficulties, acute mood enhancements during and after exercise, and increased opportunities for social interaction were among the reported benefits of exercise participation. Despite the provision of a personally tailored exercise plan and use of cognitive behavioral strategies, self-directed exercise continued to present challenges to PwMS, and the importance of seeking cost-effective ways to maintain motivational support was implicit in participant responses