Chitosan nanoparticles in drug therapy of infectious and inflammatory diseases

Chitosan-based nanoparticles as drug delivery systems: a review on two decades of research

Chitosan (CS) is one of the most functional natural biopolymer widely used in the pharmaceutical field due to its biocompatibility and biodegradability. These privileges lead to its application in the synthesis of nanoparticles for the drug during the last two decades. This article gives rise to a general review of the different chitosan nanoparticles (CSNPs) preparation techniques: Ionic gelation, emulsion cross-linking, spray-drying, emulsion-droplet coalescence method, nanoprecipitation, reverse micellar method, desolvation method, modified ionic gelation with radial polymerisation and emulsion solvent diffusion, from the point of view of the methodological and mechanistic aspects involved. The physicochemical behaviour of CSNPs including drug loading, drug release, particles size, zeta potential and stability are briefly discussed. This review also directs to bring an outline of the major applications of CSNPs in drug delivery according to drug and route of administration. Finally, derivatives of CSNPs and CS nano-complexes are also discussed.

Bone biomaterials and interactions with stem cells

Bone biomaterials play a vital role in bone repair by providing the necessary substrate for cell adhesion, proliferation, and differentiation and by modulating cell activity and function. In past decades, extensive efforts have been devoted to developing bone biomaterials with a focus on the following issues: (1) developing ideal biomaterials with a combination of suitable biological and mechanical properties; (2) constructing a cell microenvironment with pores ranging in size from nanoscale to submicro- and microscale; and (3) inducing the oriented differentiation of stem cells for artificial-to-biological transformation. Here we present a comprehensive review of the state of the art of bone biomaterials and their interactions with stem cells. Typical bone biomaterials that have been developed, including bioactive ceramics, biodegradable polymers, and biodegradable metals, are reviewed, with an emphasis on their characteristics and applications. The necessary porous structure of bone biomaterials for the cell microenvironment is discussed, along with the corresponding fabrication methods. Additionally, the promising seed stem cells for bone repair are summarized, and their interaction mechanisms with bone biomaterials are discussed in detail. Special attention has been paid to the signaling pathways involved in the focal adhesion and osteogenic differentiation of stem cells on bone biomaterials. Finally, achievements regarding bone biomaterials are summarized, and future research directions are proposed.

Synthesis of methylprednisolone loaded ibuprofen modified dextran based nanoparticles and their application for drug delivery in acute spinal cord injury

To improve the therapeutic efficacy of spinal cord injury (SCI), the methylprednisolone was incorporated into nanoparticles based on the ibuprofen modified dextran. The ibuprofen modified dextran was synthesized using a direct esterification linkage between the carboxylic acids of hydrophobic drug and the hydroxyl groups of the polymer backbone. The morphology of methylprednisolone loaded nanoparticles was evaluated by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The therapeutic efficacy of the prepared nanoparticles on the acute SCI model rats was assessed. It is demonstrated that methylprednisolone loaded ibuprofen modified dextran based nanoparticles (MP-loaded NPs) could promote the recovery of neurological deficits, enhance growth of neurons, decrease degeneration of injuried neurons and reduce the tissue tumor necrosis factor alpha (TNF-α) levels significantly in the SCI rats. Subsequently, the study indicates that synthesis of methylprednisolone loaded ibuprofen modified dextran based nanoparticles has a great potential in the synergetic effect treatment for spinal cord injury and nanoparticles based drug delivery system will become a powerful weapon of human conquest of disease.