Electrospun zein nanofibers loaded with curcumin as a wound dressing: enhancing properties with PSS and PDADMAC layers.

Development of wound dressings with enhanced therapeutic properties is of great interest in the modern healthcare. In this study, a zein-based nanofibrous wound dressing containing curcumin as a therapeutic agent was fabricated through electrospinning technique. In order to achieve desirable properties, such as antibacterial characteristics, reduced contact angle, and enhanced mechanical properties, the layer-by-layer technique was used for coating the surfaces of drug-loaded nanofibers by sequentially incorporating poly (sodium 4-styrene sulfonate) as a polyanion and poly (diallyldimethylammonium chloride) (PDADMAC) as a polycation. Various analyses, including scanning electron microscopy, Fourier transform infrared spectroscopy, drug release assessment., and mechanical tests were employed to assess the characteristics of the prepared wound dressings. Based on the results, coating with polyelectrolytes enhanced the Young's modulus and tensile strength of the electrospun mat from 1.34 MPa and 4.21 MPa to 1.88 MPa and 8.83 MPa, respectively. The coating also improved the controlled release of curcumin and antioxidant activity, while the outer layer, PDADMAC, exhibited antibacterial properties. The cell viability tests proved the appropriate biocompatibility of the prepared wound dressings. Moreover, our findings show that incorporation of the coating layers enhances cell migration and provides a favorable surface for cell attachment. According to the findings of this study, the fabricated nanofibrous wound dressing can be considered a promising and effective therapeutic intervention for wound management, facilitating the healing process.

Influence of Ionic Additives in the PEDOT:PSS Hole Transport Layers for Efficient Blue Perovskite Light Emitting Diodes.

Ruddlesden-Popper (RP) perovskites have been gaining traction in the development of high-efficiency or blue-emitting perovskite light emitting diodes (PeLEDs) due to the unique energy funneling mechanism, which enhances photoluminescence intensity, and dimensional control, which enables spectral tuning. In a conventional p-i-n device structure, the quality of RP perovskite films, including grain morphology and defects, as well as device performance can be significantly influenced by the underlying hole-transport layer (HTL). Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is commonly used in several PeLEDs as an HTL because of its high electrical conductivity and optical transparency. Nonetheless, the energy level mismatch and exciton quenching caused by PEDOT:PSS often compromises PeLED performance. Herein, we investigate the mitigation of these effects through addition of work-function-tunable PSS Na to the PEDOT:PSS HTL and assess the impact on blue PeLED performance. Surface analysis of the modified PEDOT:PSS HTLs reveals a PSS-rich layer that alleviates exciton quenching at the HTL/perovskite interface. At an optimal concentration of 6% PSS Na addition, an improvement in the external quantum efficiency is observed, with champion blue and sky-blue PeLEDs achieving 4% (480 nm) and 6.36% (496 nm), respectively, while operation stability is prolonged by fourfold.

Atomic force microscopy characterization of polyethylene terephthalate grafting with poly(styrene sulfonate).

Polyethylene terephthalate (PET) is widely used to elaborate biomaterials and medical devices in particular for long-term implant applications but tuning their surface properties remains challenging. We investigate surface functionalization by grafting poly(sodium 4-styrene sulfonate, PNaSS) with the aim of enhancing protein adhesion and cellular activity. Elucidating the topography and molecular level organization of the modified surfaces is important for understanding and predicting biological activity. In this work, we explore several grafting methods including thermal grafting, thermal grafting in the presence of Mohr's salt, and UV activation. We characterize the different surfaces obtained using atomic force microscopy (AFM), contact angle (CA), and x-ray photoelectron spectroscopy (XPS). We observe an increase in the percentage of sulfur atoms (XPS) that correlates with changes in (CA), and we identify by AFM characteristic features, which we interpret as patches of polymers on the PET surfaces. This work demonstrates tuning of biomaterials surface by functionalization and illustrates the capability of AFM to provide insights into the spatial organization of the grafted polymer.

Gold-nanoparticle based electrochemical DNA sensor for the detection of fish pathogen Aphanomyces invadans.

Epizootic ulcerative syndrome (EUS) is a devastating fish disease caused by the fungus, Aphanomyces invadans. Rapid diagnosis of EUS is needed to control and treat this highly invasive disease. The current diagnostic methods for EUS are labor intensive. We have developed a highly sensitive and specific electrochemical genosensor towards the 18S rRNA and internal transcribed spacer regions of A. invadans. Multiple layers of latex were synthesized with the help of polyelectrolytes, and labeled with gold nanoparticles to enhance sensitivity. The gold-latex spheres were functionalized with specific DNA probes. We describe here the novel application of this improved platform for detection of PCR product from real sample of A. invadans using a premix sandwich hybridization assay. The premix assay was easier, more specific and gave higher sensitivity of one log unit when compared to the conventional method of step-by-step hybridization. The limit of detection was 0.5 fM (4.99 zmol) of linear target DNA and 1 fM (10 amol) of PCR product. The binding positions of the probes to the PCR amplicons were optimized for efficient hybridization. Probes that hybridized close to the 5' or 3' terminus of the PCR amplicons gave the highest signal due to minimal steric hindrance for hybridization. The genosensor is highly suitable as a surveillance and diagnostic tool for EUS in the aquaculture industry.

Carbon nanotubes for delivery of small molecule drugs.

In the realm of drug delivery, carbon nanotubes (CNTs) have gained tremendous attention as promising nanocarriers, owing to their distinct characteristics, such as high surface area, enhanced cellular uptake and the possibility to be easily conjugated with many therapeutics, including both small molecules and biologics, displaying superior efficacy, enhanced specificity and diminished side effects. While most CNT-based drug delivery system (DDS) had been engineered to combat cancers, there are also emerging reports that employ CNTs as either the main carrier or adjunct material for the delivery of various non-anticancer drugs. In this review, the delivery of small molecule drugs is expounded, with special attention paid to the current progress of in vitro and in vivo research involving CNT-based DDSs, before finally concluding with some consideration on inevitable complications that hamper successful disease intervention with CNTs.