Three-Dimensional Hybrid Mesoporous Scaffolds for Simvastatin Sustained Delivery with in Vitro Cell Compatibility

Abstract

The development of scaffolds with suitable physicochemical and mechanical properties allowing for the structural regeneration of injured bone and recovery of the natural biological functionality is still a challenge in the tissue engineering field. Nanostructured materials with added theranostic abilities, together with an interconnected hierarchy of pores, offer the possibility to provide a new generation of bone implants. In this work, scaffolds with highly porous and resistant threedimensional structures have been successfully developed by homogeneously embedding mesoporous silica nanostructures in a bioactive matrix of chitosan/κ-carrageenan. Moreover, magnetite (Fe 3 O 4 ) nanoparticles were also added to the mesoporous scaffold to include additional magnetic functionalities for diagnostic or therapeutic actions. The complete physicochemical characterization shows mesoporous materials with a wide range of interconnected pores, remarkable surface roughness, and large effective surface area, suitable for cell adhesion. In accordance to these properties, a simvastatin loading and release assay showed high loading capacities and sustained release over a long period of time. Together with a suitable resistance against degradation and biocompatible performance assessed by cell viability assays, these scaffolds show interesting features for delivering drugs with activity in bone regeneration processes.

Multifunctional Superparamagnetic Stiff Nanoreservoirs for Blood Brain Barrier Applications

“…The size distribution statistics of these rodlike particles (Figure 7) display an average width of 92 ± 25 nm, and a length in the range between 300 and 540 nm, similar to those found by Johansson [37]. Rod-like morphology can be tailored by controlling the acid mixture (HCl/H 3 PO 4 ), which is a key factor in the production of nanorods [14].…”

“…Structural properties were analyzed by X-ray diffraction at a low angle and wide angle to asses both the small scale order of the mesoporous silica channels and the medium scale order structures, like the magnetite nanoparticles, respectively. Low angle X-ray diffraction patterns of S15N and HMMSN samples, in Figure 2A, show the Bragg diffraction maxima at (100), (110), and (200) planes, corresponding to a highly ordered 2D hexagonal structure (space group P6m), which is characteristic of mesoporous nanostructures [14]. From the position of the (100) diffraction peaks, the unit cell parameters (a 0 ) for the S15N and the hybrid HMMSN nanostructures were calculated and are shown in Table 1.…”

“…Among their advantages, the following have been reported [8,9,10]: Low immune response, chemical resistance to enzymes [11]; prolonged drug release [12,13,14,15]; large surface area for gene transfection [16,17], bone regeneration [18,19], and multimode theranostic actions [20,21,22]; magnetic separators [23]; cell markers [24]; and supports for enzyme immobilization [25].…”

Cytophilic Agarose-Epoxide-Amine Cryogels Engineered with Granulated Microstructures

“…The specific bisepoxide selected for this study is 1,4-butanediol diglycidyl ether (BDDE), a bifunctional epoxide commonly used as a biocompatible crosslinker for collagen, 31−34 hyaluronan, 35−39 polyethylenimine, 40 silk, 41 and chitosan. 42 The polyetheramine used is one with the trade name Jeffamine T403, a water-soluble triamine featuring a poly(propylene oxide) (PPO) structure. The hydrophobicity of PPO helps ensure that the reaction between BDDE and T403 results in LCST polymers exhibiting temperatureinduced phase separation behavior in water.…”

“…The strategy builds on the thermal gelation property of agarose as well as capitalizes on the reaction of bisepoxides and multifunctional polyetheramines in water to in situ form polymers capable of temperature-induced phase separation as exemplified by lower critical solution temperature (LCST) characteristics. − The rationale is that by carrying out this reaction in an agarose solution, we can achieve the dual goals of leveraging both the amine characteristics of the polyetheramines for desired cell affinity and LCST-mediated phase separation behavior of the epoxide-amine-derived polymers to create a microstructured morphology in the final gel products. The specific bisepoxide selected for this study is 1,4-butanediol diglycidyl ether (BDDE), a bifunctional epoxide commonly used as a biocompatible cross-linker for collagen, − hyaluronan, − polyethylenimine, silk, and chitosan . The polyetheramine used is one with the trade name Jeffamine T403, a water-soluble triamine featuring a poly­(propylene oxide) (PPO) structure.…”