An electrochemical aptasensor for detection of prostate-specific antigen-based on carbon quantum dots-gold nanoparticles.

In this work, an electrochemical aptasensor was described for the determination of prostate-specific antigen (PSA). Aptamer chains were decorated on the surface of a glassy carbon electrode (GCE) via carbon quantum dots/Au nanoparticles (Au/CQD). Structural analysis that was used to characterize the prepared materials shows that Au/CQD nanoparticles synthesized in a spherical shape with an average size of 70 nm. Furthermore, the combination of Au nanoparticles with CQD resulted in formation of crystalline the structure of the Au/CQD composite. To study the electrochemical performance of the prepared aptasensor, cyclic voltammetry, square wave voltammetry, and electrochemical impedance spectroscopy were used. The results show that the aptasensor has a good selectivity to PSA over other biomaterials with the time optimized about 30 min. K4 [Fe(CN)6 ] was used as an electrochemical probe with the limit of detection about 2 fg⋅mL-1 . To avoid the hazardous nature of K4 [Fe(CN)6 ], a label-based aptasensor was prepared using methylene blue as an electrochemical signal producer. They provide the capability of electrochemical detection in buffer phosphate solution with high sensitivity.

Prediction of autoimmune connective tissue disease in an at-risk cohort: prognostic value of a novel two-score system for interferon status.

OBJECTIVE: To evaluate clinical, interferon and imaging predictors of progression from 'At Risk' to autoimmune connective tissue diseases (AI-CTDs). METHODS: A prospective observational study was conducted in At-Risk of AI-CTD (defined as antinuclear antibody (ANA) positive; ≤1 clinical systemic lupus erythematosus (SLE) criterion; symptom duration <12 months and treatment-naïve). Bloods and skin biopsy (non-lesional) were analysed for two interferon-stimulated gene expression scores previously described (IFN-Score-A and IFN-Score-B). Forty-nine healthy controls (HCs) and 114 SLE were used as negative and positive controls. Musculoskeletal ultrasound was performed. Progression was defined by meeting classification criteria for AI-CTDs at 12 months. RESULTS: 118 individuals with 12-month follow-up were included. Of these, 19/118 (16%) progressed to AI-CTD (SLE=14, primary Sjogren's=5). At baseline, both IFN scores differed among At-Risk, HCs and SLE groups (p<0.001) and both were elevated in At-Risk who progressed to AI-CTD at 12 months versus non-progressors, to a greater extent for IFN-Score-B (fold difference (95% CI) 3.22 (1.74 to 5.95), p<0.001) than IFN-Score-A (2.94 (1.14 to 7.54); p=0.018). Progressors did not have significantly greater baseline clinical characteristics or ultrasound findings. Fold difference between At-Risk and HCs for IFN-Score-A was markedly greater in skin than blood. In multivariable logistic regression, only family history of autoimmune rheumatic disease, OR 8.2 (95% CI 1.58 to 42.53) and IFN-Score-B, 3.79 (1.50-9.58) increased the odds of progression. CONCLUSION: A two-factor interferon score and family history predict progression from ANA positivity to AI-CTD. These interferon scores may allow stratification of individuals At-Risk of AI-CTD permitting early intervention for disease prevention and avoid irreversible organ damage.

Enhanced DNA binding capacity on up-regulated epidermal wild-type p53 in vitiligo by H2O2-mediated oxidation: a possible repair mechanism for DNA damage.

Vitiligo is characterized by a patchy loss of inherited skin color affecting approximately 0.5% of individuals of all races. Despite the absence of the protecting pigment and the overwhelming evidence for hydrogen peroxide (H(2)O(2))-induced oxidative stress in the entire epidermis of these patients, there is neither increased photodamage/skin aging nor a higher incidence for sun-induced nonmelanoma skin cancer. Here we demonstrate for the first time increased DNA damage via 8-oxoguanine in the skin and plasma in association with epidermal up-regulated phosphorylated/acetylated p53 and high levels of the p53 antagonist p76(MDM2). Short-patch base-excision repair via hOgg1, APE1, and polymerasebeta DNA repair is up-regulated. Overexpression of Bcl-2 and low caspase 3 and cytochrome c levels argue against increased apoptosis in this disease. Moreover, we show the presence of high epidermal peroxynitrite (ONOO(-)) levels via nitrotyrosine together with high nitrated p53 levels. We demonstrate by EMSA that nitration of p53 by ONOO(-) (300 x 10(-6) M) abrogates DNA binding, while H(2)O(2)-oxidized p53 (10(-3) M) enhances DNA binding capacity and prevents ONOO(-)-induced abrogation of DNA binding. Taken together, we add a novel reactive oxygen species to the list of oxidative stress inducers in vitiligo. Moreover, we propose up-regulated wild-type p53 together with p76(MDM2) as major players in the control of DNA damage/repair and prevention of photodamage and nonmelanoma skin cancer in vitiligo.

Self-assembling of graphene oxide on carbon quantum dot loaded liposomes.

This paper describes the design of stimuli-sensitive theranostic nanoparticles, composed of reduced graphene oxide (rGO) self-assembled on thermosensitive liposomes encapsulated doxorubicin (DOX) and carbon quantum dot (CQD) (CQD-DOX-rGO-Tlip). The rGO-Tlip particles have been observed to be flower-shaped objects. The thermoresponsive and theranostic potential of CQD-DOX-rGO-Tlips have been studied using differential scanning calorimetry (DSC), ultraviolet visible spectroscopy (UV-Vis), Raman spectroscopy and photoluminescent assays. The chemo-photothermal potential of rGO-Tlip on MD-MB-231 cells during NIR laser irradiation has been examined using MTT assay. Also, the ability of rGO-Tlip to be taken up by MD-MB-231 cells has been studied using confocal microscopy and flowcytometry. The results indicate that CQD-DOX-rGO-Tlips achieve a synergistic effect between photothermal therapy and chemotherapy for cancer treatment. Furthermore, online monitoring drug release is accomplished by studying the emission intensity of CQD while DOX released.

Plucked hair follicles from patients with chronic discoid lupus erythematosus show a disease-specific molecular signature.

OBJECTIVE: When faced with clinical symptoms of scarring alopecia-the standard diagnostic pathway involves a scalp biopsy which is an invasive and expensive procedure. This project aimed to assess if plucked hair follicles (HFs) containing living epithelial cells can offer a non-invasive approach to diagnosing inflammatory scalp lesions. METHODS: Lesional and non-lesional HFs were extracted from the scalp of patients with chronic discoid lupus erythematosus (CDLE), psoriasis and healthy controls. RNA was isolated from plucked anagen HFs and microarray, as well as quantitative real-time PCR was performed. RESULTS: Here, we report that gene expression analysis of only a small number of HF plucked from lesional areas of the scalp is sufficient to differentiate CDLE from psoriasis lesions or healthy HF. The expression profile from CDLE HFs coincides with published profiles of CDLE from skin biopsy. Genes that were highly expressed in lesional CDLE corresponded to well-known histopathological diagnostic features of CDLE and included those related to apoptotic cell death, the interferon signature, complement components and CD8+ T-cell immune responses. CONCLUSIONS: We therefore propose that information obtained from this non-invasive approach are sufficient to diagnose scalp lupus erythematosus. Once validated in routine clinical settings and compared with other scarring alopecias, this rapid and non-invasive approach will have great potential for paving the way for future diagnosis of inflammatory scalp lesions.

Presence of epidermal allantoin further supports oxidative stress in vitiligo.

Xanthine dehydrogenase/xanthine oxidase (XDH/XO) catalyses the hydroxylation of hypoxanthine to xanthine and finally to uric acid in purine degradation. These reactions generate H(2)O(2) yielding allantoin from uric acid when reactive oxygen species accumulates. The presence of XO in the human epidermis has not been shown so far. As patients with vitiligo accumulate H(2)O(2) up to mm levels in their epidermis, it was tempting to examine whether this enzyme and consequently allantoin contribute to the oxidative stress theory in this disease. To address this question, reverse transcription-polymerase chain reaction, immunoreactivity, western blot, enzyme kinetics, computer modelling and high performance liquid chromatography/mass spectrometry analysis were carried out. Our results identified the presence of XDH/XO in epidermal keratinocytes and melanocytes. The enzyme is regulated by H(2)O(2) in a concentration-dependent manner, where concentrations of 10(-6 )m upregulates the activity. Moreover, we demonstrate the presence of epidermal allantoin in acute vitiligo, while this metabolite is absent in healthy controls. H(2)O(2)-mediated oxidation of Trp and Met in XO yields only subtle alterations in the enzyme active site, which is in agreement with the enzyme kinetics in the presence of 10(-3 )m H(2)O(2). Systemic XO activities are not affected. Taken together, our results provide evidence that epidermal XO contributes to H(2)O(2)-mediated oxidative stress in vitiligo via H(2)O(2)-production and allantoin formation in the epidermal compartment.

Effect of size and chemical composition of graphene oxide nanoparticles on optical absorption cross-section.

Photothermal therapy with various nanoparticles, as photothermal transducers, is a widely researched technique. A continuous wave (CW) laser is employed during this procedure. The therapeutic setup is slightly modified to measure the optical absorption cross-section of the graphene oxide (GO), by mitigating the effects of heat diffusion and light scattering. With an 808-nm CW laser setup modulated by a waveform modulation setup, the effect of nanoparticle size and composition of GO in water on optical absorption cross section is characterized.