ABSTRACT
Patients with bone diseases often experience increased bone fragility. When bone injuries exceed the body's natural healing capacity, they become significant obstacles. The global rise in the aging population and the escalating obesity pandemic are anticipated to lead to a notable increase in acute bone injuries in the coming years. Our research developed a novel DLP resin for 3D printing, utilizing poly(ethylene glycol diacrylate) (PEGDA) and various monomers through the PET-RAFT polymerization method. To enhance the performance of bone scaffolds, triply periodic minimal surfaces (TPMS) were incorporated into the printed structure, promoting porosity and pore interconnectivity without reducing the mechanical resistance of the printed piece. The gyroid TPMS structure was the one that showed the highest mechanical resistance (0.94 ± 0.117 and 1.66 ± 0.240 MPa) for both variants of resin composition. Additionally, bioactive particles were introduced to enhance the material's biocompatibility, showcasing the potential for incorporating active compounds for specific applications. The inclusion of bioceramic particles produces an increase of 13% in bioactivity signal for osteogenic differentiation (alkaline phosphatase essay) compared to that of control resins. Our findings highlight the substantial improvement in printing precision and resolution achieved by including the photoabsorber, Rose Bengal, in the synthesized resin. This enhancement allows for creating intricately detailed and accurately defined 3D-printed parts. Furthermore, the TPMS gyroid structure significantly enhances the material's mechanical resistance, while including bioactive compounds significantly boosts the polymeric resin's biocompatibility and bioactivity (osteogenic differentiation).
ABSTRACT
Bone implants or replacements are very scarce due to the low donor availability and the high rate of body rejection. For this reason, tissue engineering strategies have been developed as alternative solutions to this problem. This research sought to create a cellular scaffold with an intricate and complex network of interconnected pores and microchannels using salt leaching and additive manufacturing (3D printing) methods that mimic the hierarchical internal structure of the bone. A biocompatible hydrogel film (based on poly-ethylene glycol) was used to cover the surface of different polymeric scaffolds. This thin film was then exposed to various stimuli to spontaneously form wrinkled micropatterns, with the aim of increasing the contact area and the material's biocompatibility. The main innovation of this study was to include these wrinkled micropatterns on the surface of the scaffold by taking advantage of thin polymer film surface instabilities. On the other hand, salt and nano-hydroxyapatite (nHA) particles were included in the polymeric matrix to create a modified filament for 3D printing. The printed part was leached to eliminate porogen particles, leaving homogenously distributed pores on the structure. The pores have a mean size of 26.4 ± 9.9 µm, resulting in a global scaffold porosity of ~42% (including pores and microchannels). The presence of nHA particles, which display a homogeneous distribution according to the FE-SEM and EDX results, have a slight influence on the mechanical resistance of the material, but incredibly, despite being a bioactive compound for bone cells, did not show a significant increase in cell viability on the scaffold surface. However, the synergistic effect between the presence of the hydrogel and the pores on the material does produce an increase in cell viability compared to the control sample and the bare PCL material.
ABSTRACT
Micrometer-sized double emulsions and antibubbles were produced and stabilized via the Pickering mechanism by colloidal interfacial layers of polymeric nanoparticles (NPs). Two types of nanoparticles, consisting either of polylactic acid (PLA) or polylactic-co-glycolic acid (PLGA), were synthesized by the antisolvent technique without requiring any surfactant. PLA nanoparticles were able to stabilize water-in-oil (W/O) emulsions only after tuning the hydrophobicity by means of a thermal treatment. A water-in-oil-in-water (W/O/W) emulsion was realized by emulsifying the previous W/O emulsion in a continuous water phase containing hydrophilic PLGA nanoparticles. Both inner and outer water phases contained a sugar capable of forming a glassy phase, while the oil was crystallizable upon freezing. Freeze drying the double emulsion allowed removing the oil and water and replacing them with air without losing the three-dimensional (3D) structure of the original emulsion owing to the sugar glassy phase. Reconstitution of the freeze-dried double emulsion in water yielded a dispersion of antibubbles, i.e., micrometric bubbles containing aqueous droplets, with the interfaces of the antibubbles being stabilized by a layer of adsorbed polymeric nanoparticles. Remarkably, it was possible to achieve controlled release of a flourescent probe (calcein) from the antibubbles through heating to 37 °C leading to bursting of the antibubbles.
Subject(s)
Nanoparticles , Emulsions , Glycolates , PolyestersABSTRACT
Objetivo: determinar la tasa de muerte celular al exponer fibroblastos humanos (FBH) a concentraciones de BisGMA: IE-6[M], 6E-5[M], IE-5[M] y 4,8E-4[M], con el fin de determinar la citotoxicidad de BisGMA presente en materiales de uso odontológico. Material y métodos: las concentraciones de BisGMA se aplicaron en el cultivo FBH durante 24, 48 y 96 horas. La viabilidad celular se determinó mediante ensayos de reducción metabólica del Bromuro de 3-(4,5dimetiltiazol-2-ilo)-2,5-difeniltetrazol (MTT). Resultados: las concentraciones de BisGMA generan una disminución en la viabilidad celualr, de una forma dosis y tiempo dependiente. Conclusión: la disminución de la viabilidad celular es dependiente de la concentración de BisGMA presente en los cultivos celulares.
Subject(s)
Humans , Polymethacrylic Acids/toxicity , Fibroblasts , Composite Resins/chemistry , Cell Survival , Materials Testing , Time Factors , Cell Culture Techniques/methodsABSTRACT
El proceso de esterilización de tubos anestésicos se realiza mediante una solución de glutaraldehído activado al 2 por ciento, pero el émbolo o la membrana de goma del tubo anestésico puede permitir una difusión del compuesto esterilizante. El objetivo del estudio es detectar la presencia de glutaraldehído dentro de tubos anestésicos después de aplicar protocolo de esterilización en frío (Normas de Desinfección MINSAL, 2008) mediante espectroscopía de absorción molecular. Al someter los tubos de anestésico al protocolo de esterilización podemos observar que existe una interacción entre el anestésico y la solución esterilizadora de glutaraldehído activado al 2 por ciento, entre los 220 y 250 nm, además se observa una laxitud en la membrana semipermeable después de la exposición por 10 horas al agente esterilizante. El glutaraldehído activado al 2 por ciento toma contacto con el anestésico mediante su filtración por el émbolo o diafragma.
The sterilization process is performed anesthetic tube with a solution of 2 percent activated gluteraldehyde, but the piston or diaphragm anesthetic tube allows a diffusion of sterilizing compound. The objective of this study is to detect the presence of gluteraldehyde into tubes after applying anesthetic cold sterilization protocol (Normas de Desinfección MINSAL) by molecular absorption spectroscopy. By making the pipes of anesthetic to the sterilization protocol we see that there is an interaction between the anesthetic and sterilizing solution of gluteraldehyde to 2 percent , between 220 and 250 nm, in addition there is a laxity in the semipermeable membrane after exposure for 10 hours a sterilizing agent. The activated 2 percent gluteraldehyde made contact with the anesthetic through its filtration by the piston or diaphragm.