Osteoarthritis is a degenerative disease characterized by the progressive deterioration of articular cartilage. Electrospun scaffolds have shown promise in the regeneration of degraded areas due to their highly interconnected and extracellular matrix-mimicking structures. However, current electrospun scaffold-based therapies are limited by the constraints of 2D cell culture. In this study, a novel wet-electrospinning technique to generate polycaprolactone (PCL) porous 3D scaffolds was developed. The wet-electrospun yarns were collected via vortex, allowing for loosely interconnected yarns, thereby enhancing cell infiltration. Sodium hydroxide (NaOH) treatment was used to introduce carboxyl groups on PCL fibres, followed by gelatin conjugation via N-hydroxysuccinimide (NHS) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) crosslinking. Comparative analysis between conventional electrospun 2D dense and wet-electrospun 3D porous scaffolds revealed significant advantages in porosity, reaching up to 99.5 % in the 3D matrices. Subsequent in vitro evaluations demonstrated full-thickness cell infiltration in the 3D high-porosity scaffold after 7 days, as confirmed by SEM and confocal images. Further analysis on day 14 revealed the deposition of glycosaminoglycans (GAGs) and collagen. This research introduces a novel technique for fabricating high-porosity scaffolds that facilitate full-thickness 3D cell culture. These novel high-porosity, gelatin-conjugated scaffolds enhance cell colonisation and deposition. Overall, these high-porosity scaffolds overcome the limitations of conventional electrospinning, enabling 3D cell culture and offering new opportunities for cartilage regeneration and reconstruction.

Polysorbate 80 is a commonly used excipient in the food, cosmetics and pharmaceutical industries. In pharmaceutical formulations, the only requirement in the British Pharmacopeia and US Pharmacopeia is for the composition to be ≥ 58% oleic acid ester. However, there is a tendency for companies to prefer more refined materials. This study focused on whether this is necessary, and whether less refined materials could be used instead. To this end, we probed the chemical stability of four different polysorbate 80 samples and then explored the stability of the active ingredients in formulations of biologics containing the different polysorbate 80s. No chemical degradation could be identified by nuclear magnetic resonance or IR spectroscopy over storage for 44 weeks in the fridge or under accelerated aging conditions (30 °C/65% RH; 40 °C/75% RH). All the samples contain some water, with the water content greater than stated in the supplier datasheet (possibly because of adsorption upon storage at the supplier sites). No change in water content is noted upon the storage of polysorbate 80. With the super-refined grades, autoxidation can be seen to occur upon storage, with hydrogen peroxide, aldehydes and ketones produced. This is less noticeable with the less refined grades, likely because these already contain autoxidation products and there is an equilibrium in place. Increasing the temperature and humidity of the aging conditions causes an increase in the rate of autoxidation. We find that the grade of polysorbate 80 used as excipient does not affect the stability of biologic formulations, with no differences observed in terms of activity after combination with any of the polysorbates. It hence appears that less-refined polysorbates could be used in place of the more-expensive super-refined materials, reducing the cost and providing wider access to medicines.

Peripheral Arterial Disease (PAD) is a cause of significant morbidity and mortality in the Western world. Risk factor modification and endovascular and surgical revascularisation are the main treatment options at present. However, a significant number of patients still require major amputation. There is evidence that nitric oxide (NO) and its endogenous inhibitor asymmetric dimethylarginine (ADMA) play significant roles in the pathophysiology of PAD. This paper reviews experimental work implicating the ADMA-DDAH-NO pathway in PAD, focussing on both the vascular dysfunction and effects within the ischaemic muscle, and examines the potential of manipulating this pathway as a novel adjunct therapy in PAD.