Modifications of Ganoderma lucidum spores into digestive-tissue highly adherent porous carriers with selective affinity to hydrophilic or hydrophobic drugs

Ganoderma lucidum spores (GLSs) have been suggested to provide optimal structures for transporting orally bioavailable drugs. However, the double-layer wall and cavities of GLSs are naturally closed. This study aimed to modify GLSs into porous carriers by opening the layers and internal cavity with iturin A (IA) followed by potassium hydroxide (KOH) or hydrochloric acid (HCl). The (IA + KOH)- and (IA + HCl)-treated GLS carriers exhibited a high loading rate of 301.50 ± 2.33 and 268.18 ± 7.72 mg/g for the hydrophilic methylene blue (MB) and hydrophobic rifampicin (RF), respectively. The mechanisms underlying the modification involved the enhancement of the specific surface area with IA and the exposure of hydrophilic groups or hydrophobic groups of the GLSs with KOH or HCl. The sustained 48-h molecule-release profiles of the MB- and RF-loaded GLS carriers were best fitted using a first-order kinetics model in simulated gastric (or intestinal) fluid compared with other models. In mice, the designed GLS carriers had high adhesion capacities onto the mucosa of the digestive tract and long retention times (120 h), and even promoted the secretion of mucus and expression of several key intestinal barrier proteins. This study provided a new method to modify GLSs into oral carriers with selective drug affinity, high loading capacity, sustained drug release, and high adhesion to the digestive tract.

Preparation of three-dimensional palygorskite based carrier

Palygorskite is a kind of crystalline hydrated magnesium aluminum silicate mineral with micro-fibrous morphology. Due to the large specific surface area, moderate cationic exchange capacity and pronounced adsorption properties, it has been widely used in many fields. In order to enhance the loading capacity and adjust the microstructure of palygorskite (Pal) crystal, series of three-dimensional palygorskite carriers (3D Pal) with different pore size were fabricated through grafting from or grafting onto method. Due to the functional and cross-linked molecules act as upholder reagents, the specific surface of individual palygorskite is fully utilized and the load capacity is greatly improved. The porosity and pore size of 3D palygorskite based carrier also can be regulated by the length of organic molecular chain segments. The successful preparation of 3D Pal-based carrier provides a new way for surface grafting, modification or preparing 3D carrier of palygorskite and other minerals.•

The developed method allows fabricating three-dimensional palygorskite based carriers by covalent bonding method.

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The pore size of the as-prepared carriers can be conveniently adjusted by length of the bonded molecular chain.

Hyaluronic acid concentration-mediated changes in structure and function of porous carriers for corneal endothelial cell sheet delivery

In this study, the effects of hyaluronic acid (HA) concentrations (0.05-1.25wt.%) on the properties of porous carriers for corneal endothelial tissue engineering were investigated. The pore size and porosity gradually increased with decreasing solid content. However, at relatively low HA concentration (i.e., 0.05wt.%), the material samples contained small interior pores and a dense surface skin layer, probably due to no gas bubble effect on the stirring processing of porous microstructures of freeze-dried polysaccharide hydrogels. The carriers prepared from 0.25wt.% HA solution had the highest freezable water content and oxygen and glucose permeability among the samples evaluated. Results of cell viability assays and quantitative real-time reverse transcription polymerase chain reaction analyses showed that the HA concentration-related alteration of porous microstructure dictates the compatibility of biopolymer carriers with corneal endothelial cell (CEC) cultures. In vivo studies demonstrated that the CEC sheet/HA carrier construct implants are therapeutically efficacious in the reconstruction of endothelial scrape-wounded corneas. It is concluded that the polysaccharide concentration is the major factor for affecting the processing of carriers and their structure and function. Porous hydrogels prepared from 0.25wt.% HA solution are capable of delivering bioengineered CEC sheets to the posterior surface of cornea.