pH sensitive Laponite/alginate hybrid hydrogels: swelling behaviour and release mechanism

Li, Yulin; Maciel, Dina; Tomás, Helena; Rodrigues, João; Ma, Hui; Shi, Xiangyang

doi:10.1039/c1sm05345k

Cited by 75 publications

(77 citation statements)

References 28 publications

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“…Laponite clay, a disk-shaped synthetic silicate Na + 0.7 [Si 8 Mg 5.5 Li 0.3 H 4 O 24 ] − 0.7 with dimensions of 25 nm in diameter and 0.92 nm in thickness, is readily available, low-cost and is generally regarded as safe (GRAS) by the FDA as a natural clay product; the nanomaterial also exhibits some favorable bioactive properties [29]. Recent studies have demonstrated that laponite can induce osteogenic differentiation of stem cells and develop microenvironments that support tissue regeneration [30, 31].…”

Section: Introductionmentioning

confidence: 99%

Tunable staged release of therapeutics from layer-by-layer coatings with clay interlayer barrier

2014

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In developing new generations of coatings for medical devices and tissue engineering scaffolds, there is a need for thin coatings that provide controlled sequential release of multiple therapeutics while providing a tunable approach to time dependence and the potential for sequential or staged release. Herein, we demonstrate the ability to develop a self-assembled, polymer-based conformal coating, built by using a water-based layer-by-layer (LbL) approach, as a dual-purpose biomimetic implant surface that provides staggered and/or sustained release of an antibiotic followed by active growth factor for orthopedic implant applications. This multilayered coating consists of two parts: a base osteoinductive component containing bone morphogenetic protein-2 (rhBMP-2) beneath an antibacterial component containing gentamicin (GS). For the fabrication of truly stratified composite films with the customized release behavior, we present a new strategy—implementation of laponite clay barriers—that allows for a physical separation of the two components by controlling interlayer diffusion. The clay barriers in a single-component GS system effectively block diffusion-based release, leading to approximately 50% reduction in bolus doses and 10-fold increase in the release timescale. In a dual-therapeutic composite coating, the top GS component itself was found to be an effective physical barrier for the underlying rhBMP-2, leading to an order of magnitude increase in the release timescale compared to the single-component rhBMP-2 system. The introduction of a laponite interlayer barrier further enhanced the temporal separation between release of the two drugs, resulting in a more physiologically appropriate dosing of rhBMP-2. Both therapeutics released from the composite coating retained their efficacy over their established release timeframes. This new platform for multi-drug localized delivery can be easily fabricated, tuned, and translated to a variety of implant applications where control over spatial and temporal release profiles of multiple drugs is desired.

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Section: Introductionmentioning

confidence: 99%

Tunable staged release of therapeutics from layer-by-layer coatings with clay interlayer barrier

2014

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“…The process is simple and allows for technical grade components in water. Potentially, using Laponite nanoparticles versatile adsorption capabilities, many other functional molecules [16,18,26,41,42], and enzymes [15,43], could be entrapped in the silk membrane.…”

Section: Discussionmentioning

confidence: 99%

Fabrication and Optimization of Stable, Optically Transparent, and Reusable pH-Responsive Silk Membranes

Toytziaridis

Dicko

2016

IJMS

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The fabrication of silk-based membranes that are stable, optically transparent and reusable is yet to be achieved. To address this bottleneck we have developed a method to produce transparent chromogenic silk patches that are optically responsive to pH. The patches were produced by blending regenerated silk fibroin (RSF), Laponite RD (nano clay) and the organic dyes neutral red and Thionine acetate. The Laponite RD played a central role in the patch mechanical integrity and prevention of dye leaching. The process was optimized using a factorial design to maximize the patch response to pH by UV absorbance and fluorescence emission. New patches of the optimized protocol, made from solutions containing 125 μM neutral red or 250 μM of Thionine and 15 mg/mL silk, were further tested for operational stability over several cycles of pH altering. Stability, performance, and reusability were achieved over the tested cycles. The approach could be extended to other reporting molecules or enzymes able to bind to Laponite.

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“…To simulate body fluids, three pHs were selected, pH 2.0, 7.4, and 9.0, representing the microenvironments of the stomach, colon, and pancreatic juice, respectively . The loading and release behaviors of the system were studied in the above pH solutions.…”

Section: Methodsmentioning

confidence: 99%

“…It has pH‐dependent edge surface charges and a large specific surface area as high as 370 m 2 /g, which offer a high loading capacity and pH‐controllable release for a Lap‐based drug delivery system. One research group concentrated on the preparation and application of the Lap‐based drug delivery system in cancer therapy. They found that Lap showed high biocompatibility and enhanced encapsulation efficiency for drugs.…”

Section: Introductionmentioning

confidence: 99%

Influence of laponite on the drug loading and release performance of LbL polyurethane/poly(acrylic acid) multilayers

Shi

Zhang

Feng

et al. 2018

J of Applied Polymer Sci

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A facile way to fabricate clay-based multilayers was introduced. Compared to other works, poly(acrylic acid)-laponite nanocomposites (PAA-Lap) were used as a membrane component instead of Lap alone. Coupled with water-soluble polyurethane (PU), a series of PU/PAA-Lap multilayer films were fabricated via layer-by-layer assembly containing different contents of Lap. The effect of clay content on the loading and release behavior of PU/PAA-Lap multilayers was investigated in various pH solutions with cationic methylene blue as the indicator. It was found that the introduction of Lap can influence the charge density, swelling rate, and pH stability of the film. When the content of Lap in the film was increased to a certain degree, the main adsorption mechanism changed from chemical to physical adsorption, but the releasing mechanism had no change. We hope this method can be used as a model for the fabrication of clay-based polymer drug delivery systems in low-pH environments.

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pH sensitive Laponite/alginate hybrid hydrogels: swelling behaviour and release mechanism

Cited by 75 publications

References 28 publications

Tunable staged release of therapeutics from layer-by-layer coatings with clay interlayer barrier

Tunable staged release of therapeutics from layer-by-layer coatings with clay interlayer barrier

Fabrication and Optimization of Stable, Optically Transparent, and Reusable pH-Responsive Silk Membranes

Influence of laponite on the drug loading and release performance of LbL polyurethane/poly(acrylic acid) multilayers

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