Assessment of Cutaneous Parameters and Sympathetic Skin Response as a Non-Invasive Complementary Diagnostic Tool in Psoriasis: An Exploratory Study.

Background: Various diagnostic tools are used to assess cutaneous psoriasis, but most of it were subjective. Sympathetic skin response (SSR), skin PH and temperature objectively measure the skin barrier functions that could aid clinicians to evaluate accurately and predict skin disease incidence even before the onset of clinical symptoms. Aim and Objectives: The study's objective was to assess the utility of cutaneous parameters (skin temperature and pH) and SSRs influencing psoriatic patients' diagnosis management and treatment compared to controls. Materials and Methods: A total of 40 healthy participants and 40 psoriasis patients aged 18 to 65 years were recruited for this study. SSR, skin temperature and pH were assessed. The psoriasis disability index (PDI) was recorded from all the patients. Data analysis was carried out using SPSS version 20.0. Results: The results shows significantly increased skin temperature, prolonged SSR latency (bilaterally) and decreased SSR amplitude (bilaterally) among patients affected with psoriasis compared to control subjects. There is a positive correlation between SSR latency with PDI and a negative correlation between SSR amplitude and PDI in psoriasis patients. Conclusion: SSR reveals sympathetic sudomotor dysfunction and increased skin temperature in psoriasis. Furthermore, there is a link between increased SSR latency and PDI, which shows that local nervous system impairment significantly contributes to the inflammatory process in psoriasis. Thus, SSR can be used as a complementary tool for the early identification and assessment of epidermal barrier integrity in psoriasis patients, along with the clinician's standard protocols.

Closing the green gap of photosystem I with synthetic fluorophores for enhanced photocurrent generation in photobiocathodes.

One restriction for biohybrid photovoltaics is the limited conversion of green light by most natural photoactive components. The present study aims to fill the green gap of photosystem I (PSI) with covalently linked fluorophores, ATTO 590 and ATTO 532. Photobiocathodes are prepared by combining a 20 µm thick 3D indium tin oxide (ITO) structure with these constructs to enhance the photocurrent density compared to setups based on native PSI. To this end, two electron transfer mechanisms, with and without a mediator, are studied to evaluate differences in the behavior of the constructs. Wavelength-dependent measurements confirm the influence of the additional fluorophores on the photocurrent. The performance is significantly increased for all modifications compared to native PSI when cytochrome c is present as a redox-mediator. The photocurrent almost doubles from -32.5 to up to -60.9 µA cm-2. For mediator-less photobiocathodes, interestingly, drastic differences appear between the constructs made with various dyes. While the turnover frequency (TOF) is doubled to 10 e-/PSI/s for PSI-ATTO590 on the 3D ITO compared to the reference specimen, the photocurrents are slightly smaller since the PSI-ATTO590 coverage is low. In contrast, the PSI-ATTO532 construct performs exceptionally well. The TOF increases to 31 e-/PSI/s, and a photocurrent of -47.0 µA cm-2 is obtained. This current is a factor of 6 better than the reference made with native PSI in direct electron transfer mode and sets a new record for mediator-free photobioelectrodes combining 3D electrode structures and light-converting biocomponents.

Scalable Three-Dimensional Photobioelectrodes Made of Reduced Graphene Oxide Combined with Photosystem I.

Photobioelectrodes represent one of the examples where artificial materials are combined with biological entities to undertake semi-artificial photosynthesis. Here, an approach is described that uses reduced graphene oxide (rGO) as an electrode material. This classical 2D material is used to construct a three-dimensional structure by a template-based approach combined with a simple spin-coating process during preparation. Inspired by this novel material and photosystem I (PSI), a biophotovoltaic electrode is being designed and investigated. Both direct electron transfer to PSI and mediated electron transfer via cytochrome c from horse heart as redox protein can be confirmed. Electrode preparation and protein immobilization have been optimized. The performance can be upscaled by adjusting the thickness of the 3D electrode using different numbers of spin-coating steps during preparation. Thus, photocurrents up to ∼14 µA/cm2 are measured for 12 spin-coated layers of rGO corresponding to a turnover frequency of 30 e- PSI-1 s-1 and external quantum efficiency (EQE) of 0.07% at a thickness of about 15 µm. Operational stability has been analyzed for several days. Particularly, the performance at low illumination intensities is very promising (1.39 µA/cm2 at 0.1 mW/cm2 and -0.15 V vs Ag/AgCl; EQE 6.8%).