Novel stable cytokine delivery system in physiological pH solution: chitosan oligosaccharide/heparin nanoparticles

Abstract

Background Cell therapy is a promising strategy for tissue regeneration. Key to this strategy is mobilization and recruitment of exogenous or autologous stem/progenitor cells by cytokines. However, there is no effective cytokine delivery system available for clinic application, in particular for myocardial regeneration. The aim of this study was to develop a novel cytokine delivery system that is stable in solution at physiological pH. Methods Four groups of self-assembled chitosan oligosaccharide/heparin (CSO/H) nanoparticles were prepared with various volume ratios of chitosan oligosaccharide to heparin (5:2, 5:4, 4:15, 1:5) and characterized by laser diffraction, particle size analysis, and transmission electron microscopy. The encapsulation efficiency and loading content of two cytokines, ie, stromal cell-derived factor (SDF)-1α and vascular endothelial growth factor (VEGF) were quantified using an enzyme-linked immunosorbent assay. The biological activity of the loaded SDF-1α and VEGF was evaluated using the transwell migration assay and MTT assay. The dispersion profiles for the cytokine-loaded nanoparticles were quantified using fluorescence molecular tomography. Results CSO/H nanoparticles were prepared successfully in solution with physiological pH. The particle sizes in the four treatment groups were in the range of 96.2–210.5 nm and the zeta potential ranged from −29.4 mV to 24.2 mV. The loading efficiency in the CSO/H nanoparticle groups with the first three ratios was more than 90%. SDF-1α loaded into CSO/H nanoparticles retained its migration activity and VEGF loaded into CSO/H nanoparticles continued to show proliferation activity. The in vivo dispersion test showed that the CSO/H nanoparticles enabled to VEGF to accumulate locally for a longer period of time. Conclusion CSO/H nanoparticles have a high cytokine loading capacity and allow cytokines to maintain their bioactivity for longer, are stable in an environment with physiological pH, and may be a promising cytokine delivery system for tissue regeneration.

Sustained dual release of placental growth factor-2 and bone morphogenic protein-2 from heparin-based nanocomplexes for direct osteogenesis

“…the osteogenic effects is complex, mainly owing to the reversible, noncovalent interactions between heparin and heparin-binding GFs, which ensure minimal impact on GF structure. 13,30,37,39,43,44,[48][49][50][51][52] We demonstrated that the nanocomplexes in our study not only effectively loaded and sustained release of PlGF-2/BMP-2, but also maintained their bioactivities for bone regeneration. A key result in this study was the bioactivity of the released PlGF-2 being comparable to that of the released BMP-2, despite its dose being half that of BMP-2.…”

“…29,30 To prepare heparin-HTCC nanocomplexes, heparin and HTCC powder were first dissolved in deionized water to obtain a final concentration of 2 mg/mL of each. Then, the two aqueous solutions were sterilized by passing them through 0.22 μm syringe filters, followed by adding the heparin solution dropwise to the HTCC solution (volume ratio of heparin:HTCC =3:5) with continuous stirring.…”

“…The supernatant was collected to determine the amount of GF (PlGF-2 and/or BMP-2) loaded using ELISA kits (according to the manufacturer's instructions). In each case, the GF loading efficiency was determined by applying the following equation: 30 Loading efficiency (%) Total amount of GF Free GF Total amount of GF = -a added ×100% .…”

“…In this study, heparin acts as a "sandwich" or "double duty" component and interacts with HTCC to form highly stable polyelectrolyte complexes 37 that have been demonstrated to effectively load GFs and maintain their bioactivities. 13,30,44,46 The minimal initial release may be attributed to the release of GFs that were physically adsorbed onto the heparin-HCCT nanocomplexes. The degradation test proved the stability of the nanocomplexes (Table 4, Figure 4), and its results matched the sustained release pattern.…”

Heparin-Based Nanoparticles: An Overview of Their Applications

“…It was used to target drugs in vivo to the sciatic nerve, and such system showed no inflammation issues and good biocompatibility, although the authors mention that nerve regeneration is the topic that will be a follow-up to this research [95]. Bone and tissueoriented studies have been worked on, too, for example, bone formation [96] and scaffold [97]; tissue engineering [98]; and regeneration [99]. Some other potential applications that are understudied are as follows: antimicrobial activity [100,101], glucose biosensing [102], analyte detection in solution using a colorimetric approach [103], and surface enhanced Raman spectroscopy [104].…”