RESUMEN
Conjugated polymers with strong absorption in the second near-infrared (NIR-II) window have multiple applications. However, the development of new type of NIR-II conjugated polymers via facile and green methods remains challenging. Herein, this work reports a mild and convenient transition-metal-free method to synthesize near-infrared absorbing quinoidal conjugated polymers containing para-azaquinodimethane (AQM) moieties. The AQM quinoidal conjugated polymers with unique molecular structures and tunable optoelectronic properties can be synthesized by combining the Knoevenagel polycondensation of aromatic dialdehyde monomers with commercially available 1,4-diacetyl-2,5-piperazinedione and the following alkylation reaction. The resultant polymer PQ-DPP shows remarkable NIR-II absorption with a narrow band gap of about 1.08 eV. PQ-DPP nanoparticles exhibit high photothermal conversion efficiency of up to 48% under 1064 nm laser irradiation (1 W cm-2) endowing this polymer with potential in bio-related applications.
Asunto(s)
Nanopartículas , Elementos de Transición , Polímeros/química , Nanopartículas/química , DiacetilRESUMEN
Descending propriospinal neurons (DPSN) are known to establish functional relays for supraspinal signals, and they display a greater growth response after injury than do the long projecting axons. However, their regenerative response is still deficient due to their failure to depart from growth supportive cellular transplants back into the host spinal cord, which contains numerous impediments to axon growth. Here we report the construction of a continuous growth-promoting pathway in adult rats, formed by grafted Schwann cells overexpressing glial cell line-derived neurotrophic factor (GDNF). We demonstrate that such a growth-promoting pathway, extending from the axonal cut ends to the site of innervation in the distal spinal cord, promoted regeneration of DPSN axons through and beyond the lesion gap of a spinal cord hemisection. Within the distal host spinal cord, regenerated DPSN axons formed synapses with host neurons leading to the restoration of action potentials and partial recovery of function.
Asunto(s)
Factor Neurotrófico Derivado de la Línea Celular Glial/metabolismo , Regeneración Nerviosa/fisiología , Recuperación de la Función/fisiología , Células de Schwann/fisiología , Células de Schwann/trasplante , Traumatismos de la Médula Espinal/fisiopatología , Traumatismos de la Médula Espinal/cirugía , Animales , Biotina/análogos & derivados , Recuento de Células , Dextranos , Modelos Animales de Enfermedad , Estimulación Eléctrica , Potenciales Evocados/fisiología , Femenino , Lateralidad Funcional/fisiología , Factor Neurotrófico Derivado de la Línea Celular Glial/genética , Proteína Ácida Fibrilar de la Glía/metabolismo , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Regeneración Tisular Guiada Periodontal , Técnicas In Vitro , Microscopía Electrónica de Transmisión , Proteínas Asociadas a Microtúbulos/metabolismo , Actividad Motora/fisiología , Proteína P0 de la Mielina/metabolismo , Vías Nerviosas/metabolismo , Vías Nerviosas/patología , Ratas , Ratas Sprague-Dawley , Médula Espinal/metabolismo , Médula Espinal/patología , Estilbamidinas , Sinaptofisina/metabolismo , Factores de Tiempo , Transducción Genética/métodosRESUMEN
The free membrane of Eudragit L100/S100 which is pH-sensitive, colon-specific was prepared by plane casting films. The film humidity, species and amount of plasticizers, the ratio of membrane material was investigated. The rate of membrane permeability and mechanical properties were used as indicators of orthogonal experiment, and its related properties were studied. The results show that the mechanical properties of the membrane and phragmoid capacity are the best when 30% TEC was used as plasticizer; the ratio of membrane material have little effect on the rate of membrane permeability and mechanical properties. By adjusting the species and amount of plasticizers, the ratio of Eudragit L100/S100, the free membrane which is colon-specific can be obtained.