RESUMO
Natural polyphenols like tannic acid (TA) have recently emerged as multifunctional building blocks for designing advanced materials. Herein, we show the benefits of having TA in a dynamic liquid state using low-transition-temperature mixtures (LTTMs) for developing freezing-tolerant glues. TA was combined with betaine or choline chloride to create LTTMs, which direct the self-assembly of guanosine into supramolecular viscoelastic materials with high adhesion. Molecular dynamics simulations showed that the structural properties of the material are linked to strong hydrogen bonding in TA-betaine and TA-choline chloride mixtures. Notably, long-term and repeatable adhesion was achieved even at -196 °C due to the binding ability of TA's catechol and gallol units and the mixtures' glass transition temperature. Additionally, the adhesives demonstrated injectability and low toxicity against fibroblasts in vitro. These traits reveal the potential of these systems as bioadhesives for tissue repair, opening new avenues for creating multifunctional soft materials with bioactive properties.
RESUMO
Diabetes mellitus (DM) is a highly prevalent disease affecting almost 10% of the world population; it is characterized by acute and chronic conditions. Diabetic patients have twenty-five times higher risk of going blind and developing cataracts early than the general population. Alpha-lipoic acid (LA) is a highly valuable natural antioxidant for the prevention and treatment of ophthalmic complications, such as diabetic keratopathy and retinopathy. However, its applicability is limited due to its low solubility in water; therefore, suitable systems are required for its formulation. In this work we developed an erodible insert based on Eudragit E100 (E PO) and Lipoic Acid (LA) for the delivery of this compound for the preventive treatment of ocular diseases especially in diabetic patients. Film evaluation was carried out by mechanical and thermal properties, mucoadhesivity, drug release, dynamic light scattering and corneal permeability as the concentration of LA increased. It was shown that upon LA release, it forms nanoparticles in combination with E PO that favor corneal permeation and LA retention in the cornea. These E PO-LA films also resulted non-irritable hence they are promising for their application in the treatment of ocular diseases.
RESUMO
We describe the functional capability of a cross-linked hydrogel composed of sulfated glycosaminoglycans and a cationic cellulose by conducting trials on experimental animal models using intra-articular implants to treat an articular disease called osteoarthritis. Forty-eight mature New Zealand white rabbits were divided into three experimental groups: A, B, and C. Group A and B underwent unilateral anterior cruciate ligament transection (ACLT) of the right knee. Subsequently, both knees of group A were treated with the injectable formulation under study. Meanwhile, group B was treated with sterile PBS (placebo). The animals of group C were surgically operated in both knees: Commercial hyaluronic acid (HA) was implanted in the left knee, and the formulation under study was implanted in the right knee. After implantation, all specimens underwent several evaluations at 3, 6, and 12 months postoperatively. At 6 months, no significant differences were detected between the right and left knees of the different groups. However, significant differences were observed between both knees at 12 months in group C, with less cartilage damage in the right knees implanted with our hydrogel. Therefore, in vivo studies have demonstrated hydrogel safety, superior permanence, and less cartilage damage for long-term follow up 12 months after implantation for the formulation under study compared with commercial HA.
RESUMO
We reported herein the study and characterization of films obtained by casting of chitosan solutions in perfluorinated acids, trifluoroacetic (TFA), perfluoropropionic (PFPA), and perfluorooctanoic (PFOA). The films were characterized by FTIR, solid state (13)C NMR, X-ray, AFM, contact angle, thermogravimetric effluent analysis by mass spectrometry, and rheology. The results showed a marked influence of chain length of the perfluorinated acids on the hydrophobic/hydrophilic ratio of the modified chitosan films which was evidenced by the different characteristics observed. The material that showed greater surface stability was chitosan-PFOA. Chitosan film with the addition of PFOA modifier became more hydrophobic, thus water vapor permeability diminished compared to chitosan films alone, this new material also depicted bacterial adhesion which, together with the features already described, proves its potential in applications for bioreactor coating.
Assuntos
Ácidos/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Quitosana/farmacologia , Fluorocarbonos/farmacologia , Pseudomonas aeruginosa/fisiologia , Caprilatos/farmacologia , Linhagem Celular Tumoral , Contagem de Colônia Microbiana , Módulo de Elasticidade/efeitos dos fármacos , Humanos , Espectroscopia de Ressonância Magnética , Viabilidade Microbiana/efeitos dos fármacos , Microscopia de Força Atômica , Peso Molecular , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Reologia/efeitos dos fármacos , Termodinâmica , Termogravimetria , Ácido Trifluoracético/farmacologia , Difração de Raios XRESUMO
We investigated the nature and stability of the interactions established between polyquaternium (PQ10) and perfluorodecanoic acid (PFDA) in terms of different variables such as composition, ionic strength, pH and temperature. The PQ10-PFDA complex formation is interpreted in view of electrostatic associations between carboxylic and quaternary amino group. The properties of the systems were characterized by rheology analysis. The adhesive properties of complex were also assessed. One of the macroscopic features of the new material formed in solution was the increase in viscosity from 6 Pas for 1% PQ10 (MW 1.7×10(6) g mol(-1)) to about 1000 Pas by the addition of enough PFDA to reach 1:0.5 ammonium:carboxylic group molar ratio. At this proportion, PQ10 and PFDA form a network structure with a maximum viscosity and storage modulus. This maximum coincides with an increased mucoadhesive work.