Viability of plant spore exine capsules for microencapsulation

Barrier, Sylvain; Diego‐Taboada, Alberto; Thomasson, Matthew J.; Madden, Leigh A.; Pointon, Joanna C.; Wadhawan, Jay D.; Beckett, Stephen T.; Atkin, Stephen L.; Mackenzie, Grahame

doi:10.1039/c0jm02246b

Cited by 85 publications

(130 citation statements)

References 33 publications

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“…Figs 3D, 3E, 3F, 3G, and 3H show treated LSs that are filled with sulforhodamine (558 Da), dextran (4 kDa), OVA (45 kDa), bovine serum albumin (67 kDa), and dextran (2000 kDa), respectively. This result is consistent with a recent study that successfully encapsulated oils, fats and proteins such as β-galactosidase (540 kDa) and horseradish peroxidase (100 kDa) in LSs [23]. Thus, a wide range of molecules can be filled in to LS core demonstrating the flexibility of the platform for vaccine delivery.…”

Section: Resultssupporting

confidence: 91%

“…Indeed, using this conceptual framework LSs have recently been proposed for oral drug delivery. It has been shown that proteins as large as 540 kDa, a magnetic resonance imaging contrast agent, food oils including cod liver oil can be filled into LSs [19-23]. While these in vitro studies demonstrate the flexibility of filling LSs with different molecules, in vivo demonstrations on the effectiveness of pollens for oral drug and vaccine delivery are lacking.…”

Section: Introductionmentioning

confidence: 99%

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Pollen grains for oral vaccination

Atwe¹,

Ma²,

Gill³

2014

Journal of Controlled Release

147

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Oral vaccination can offer a painless and convenient method of vaccination. Furthermore, in addition to systemic immunity it has potential to stimulate mucosal immunity through antigen-processing by the gut-associated lymphoid tissues. In this study we propose the concept that pollen grains can be engineered for use as a simple modular system for oral vaccination. We demonstrate feasibility of this concept by using spores of Lycopodium clavatum (clubmoss) (LSs). We show that LSs can be chemically cleaned to remove native proteins to create intact clean hollow LS shells. Empty pollen shells were successfully filled with molecules of different sizes demonstrating their potential to be broadly applicable as a vaccination system. Using ovalbumin (OVA) as a model antigen, LSs formulated with OVA were orally fed to mice. LSs stimulated significantly higher anti-OVA serum IgG and fecal IgA antibodies compared to those induced by use of cholera toxin as a positive-control adjuvant. The antibody response was not affected by pre-neutralization of the stomach acid, and persisted for up to seven months. Confocal microscopy revealed that LSs can translocate in to mouse intestinal wall. Overall, this study lays the foundation of using LSs as a novel approach for oral vaccination.

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Section: Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Pollen grains for oral vaccination

Atwe¹,

Ma²,

Gill³

2014

Journal of Controlled Release

147

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show abstract

“…This study also described the encapsulation of polar materials, such as enzymes (amylase, galactosidase, alkaline phosphatase and sHRP (horseradish peroxidase)) with loading around 20% (drug:drug and exine) but most significantly these experiments showed that the enzymes kept most of their catalytic activity when they were re-extracted from the shells [62]. …”

Section: Encapsulation and Release Of An Activementioning

confidence: 99%

“…Examples of this technique can be found in studies by Barrier et al , including encapsulating a solution of alkaline phosphatase in glycerol at 4 °C with a 20% loading [62]. …”

Section: Encapsulation and Release Of An Activementioning

confidence: 99%

Hollow Pollen Shells to Enhance Drug Delivery

et al. 2014

Self Cite

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Pollen grain and spore shells are natural microcapsules designed to protect the genetic material of the plant from external damage. The shell is made up of two layers, the inner layer (intine), made largely of cellulose, and the outer layer (exine), composed mainly of sporopollenin. The relative proportion of each varies according to the plant species. The structure of sporopollenin has not been fully characterised but different studies suggest the presence of conjugated phenols, which provide antioxidant properties to the microcapsule and UV (ultraviolet) protection to the material inside it. These microcapsule shells have many advantageous properties, such as homogeneity in size, resilience to both alkalis and acids, and the ability to withstand temperatures up to 250 °C. These hollow microcapsules have the ability to encapsulate and release actives in a controlled manner. Their mucoadhesion to intestinal tissues may contribute to the extended contact of the sporopollenin with the intestinal mucosa leading to an increased efficiency of delivery of nutraceuticals and drugs. The hollow microcapsules can be filled with a solution of the active or active in a liquid form by simply mixing both together, and in some cases operating a vacuum. The active payload can be released in the human body depending on pressure on the microcapsule, solubility and/or pH factors. Active release can be controlled by adding a coating on the shell, or co-encapsulation with the active inside the shell.

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“…[ 14 ] Recent studies have demonstrated the use of processed L. clavatum shells for encapsulation, [15][16][17][18][19] however, the production of L. clavatum sporopollenin capsules requires the prolonged processing of natural spores with harsh chemical treatments at elevated temperatures, so as to isolate the sporopollenin exine shell. [20][21][22][23][24] In many applications, this extensive processing may be unnecessary and potential therapeutic benefi ts may be lost. For applications in medicine, cosmetics, and food, enhanced effects may be obtained through the encapsulation of synergistic compounds, [ 25 ] and overall, the use of natural unprocessed spores provides signifi cant benefi ts in terms of processing complexity and costs for a wide range of applications.…”

Section: Introductionmentioning

confidence: 99%

Lycopodium Spores: A Naturally Manufactured, Superrobust Biomaterial for Drug Delivery

Mundargi

Potroz

Park

et al. 2015

Adv Funct Materials

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Herein, the exploration of natural plant‐based “spores” for the encapsulation of macromolecules as a drug delivery platform is reported. Benefits of encapsulation with natural “spores” include highly uniform size distribution and materials encapsulation by relatively economical and simple versatile methods. The natural spores possess unique micromeritic properties and an inner cavity for significant macromolecule loading with retention of therapeutic spore constituents. In addition, these natural spores can be used as advanced materials to encapsulate a wide variety of pharmaceutical drugs, chemicals, cosmetics, and food supplements. Here, for the first time a strategy to utilize natural spores as advanced materials is developed to encapsulate macromolecules by three different microencapsulation techniques including passive, compression, and vacuum loading. The natural spore formulations developed by these techniques are extensively characterized with respect to size uniformity, shape, encapsulation efficiency, and localization of macromolecules in the spores. In vitro release profiles of developed spore formulations in simulated gastric and intestinal fluids have also been studied, and alginate coatings to tune the release profile using vacuum‐loaded spores have been explored. These results provide the basis for further exploration into the encapsulation of a wide range of therapeutic molecules in natural plant spores.

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Viability of plant spore exine capsules for microencapsulation

Cited by 85 publications

References 33 publications

Pollen grains for oral vaccination

Pollen grains for oral vaccination

Hollow Pollen Shells to Enhance Drug Delivery

Lycopodium Spores: A Naturally Manufactured, Superrobust Biomaterial for Drug Delivery

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