Nanoparticles composed of the tea polysaccharide-complexed cationic vitamin B12-conjugated glycogen derivative.

Tea polysaccharides exhibit multiple important bioactivities, but very few of them can be absorbed through the small intestine. To enhance the absorption efficacy of tea polysaccharides, a cationic vitamin B12-conjugated glycogen derivative bearing the diethylenetriamine residues (VB12-DETA-Gly) was synthesized and characterized using FTIR, 1H NMR, and UV-vis spectroscopy. An acidic tea polysaccharide (TPSA) was isolated from green tea. The TPSA/VB12-DETA-Gly complexed nanoparticles were prepared, which showed positive zeta potentials and were irregular spherical nanoparticles in the sizes of 50-100 nm. To enable the fluorescence and UV-vis absorption properties of TPSA, a Congo red residue-conjugated TPSA derivative (CR-TPSA) was synthesized. The interactions and complexation mechanism between the CR-TPSA and the VB12-DETA-Gly derivatives were investigated using fluorescence spectroscopy, resonance light scattering spectroscopy, and UV-vis spectroscopy. The results indicated that the electrostatic interaction could play a major role during the CR-TPSA and VB12-DETA-Gly-II complexation processes. The TPSA/VB12-DETA-Gly nanoparticles were nontoxic and exhibited targeted endocytosis for the Caco-2 cells, and showed high permeation through intestinal enterocytes using the Caco-2 cell model. Therefore, they exhibit potential for enhancing the absorption efficacy of tea polysaccharides through the small intestinal mucosa.

Investigation Of Vitamin B12-Modified Amphiphilic Sodium Alginate Derivatives For Enhancing The Oral Delivery Efficacy Of Peptide Drugs.

PURPOSE: Peptide drugs have been used in therapy various diseases. However, the poor bioavailability of peptide drugs for oral administration has limited their clinical applications, on account of the acidic environment and digestive enzymes inside the human gastrointestinal tract. To enhance stability in the human gastrointestinal tract, bioavailability, and targeted drug delivery of peptide drugs through oral administration, a vitamin B12-modified amphiphilic sodium alginate derivative (CSAD-VB12) was synthesized. MATERIALS AND METHODS: A vitamin B12-modified amphiphilic sodium alginate derivative (CSAD-VB12) was synthesized via the N,N'-dicyclohexylcarbodiimide active method at room temperature, and then characterized using FTIR and 1H NMR spectroscopy. Insulin was used as a model peptide drug and the insulin-loaded CSAD-VB12 (CSAD-VB12/insulin) nanoparticles with negative zeta potentials were prepared in PBS (pH=7.4). Scanning electron microscopy was used to observe CSAD-VB12/insulin as spherical nanoparticles. The CSAD-VB12 derivatives and CSAD-VB12/insulin nanoparticles displayed nontoxicity towards the human colon adenocarcinoma (Caco-2) cells by CCK-8 test. Caco-2 cell model was used to measure the apparent permeability (Papp) of insulin, CSAD/insulin and CSAD-VB12/insulin. Furthermore, confocal was used to confirm the endocytosis of intestinal enterocytes. Type 1 diabetes mice were used to evaluate the intestinal absorption and retention effect of test nanoparticles. RESULTS: They were observed as spherical nanoparticles in the size of 30-50 nm. The CSAD-VB12 derivatives and CSAD-VB12/insulin nanoparticles displayed nontoxicity towards the human colon adenocarcinoma (Caco-2) cells. Comparing with insulin and the CSAD/insulin nanoparticles, the CSAD-VB12/insulin nanoparticles exhibited higher permeation ability through intestinal enterocytes in the Caco-2 cell model. Oral administration of the CSAD-VB12/insulin nanoparticles to Type 1 diabetic mice yields higher intestinal retention effect, targeted absorption, and outstanding efficacy. CONCLUSION: CSAD-VB12 derivatives enhance the small intestinal absorption efficacy and retention of peptide by oral administration, which indicated that it could be a promising candidate for oral peptide delivery in the prospective clinical application.

RGD-Modified Nanocarrier-Mediated Targeted Delivery of HIF-1α-AA Plasmid DNA to Cerebrovascular Endothelial Cells for Ischemic Stroke Treatment.

Studies have shown that the use of proangiogenic genes can improve the prognosis of ischemic stroke by promoting angiogenesis at the injury site. For example, within this study, hypoxia-inducible factor 1-α (HIF-1α) has exhibited an angiogenic effect. Our previous study reported a more stable HIF-1α mutant form (HIF-1α-AA), which was transfected into mesenchymal stem cells to provide neuroprotective effects against ischemic stroke. The safety of nonviral gene vectors has attracted researchers' attention. This study encapsulated the HIF-1α-AA plasmid DNA into a newly synthesized effective nonviral gene vector, a hyperbranched cationic amylopectin derivative (DMAPA-Amyp) nanocarrier. In addition, a targeting strategy was applied to select the RGD peptides and bind to the designed nanocarrier as a molecule targeting endothelial cells. The targeting strategy is used to directly deliver the nanocarriers to the vascular endothelial cells of the brain peri-infarct site. This study emphasizes the targeting ability of nanocarrier and its therapeutic effect on cerebral ischemia. The results showed that RGD-DMAPA-Amyp had good biocompatibility and a high cell uptake rate, indicating that it is a safe nonviral gene vector that can be endocytosed by human cells. In rat models of ischemic stroke, compared with the nontargeted nanocarrier group, more RGD-DMAPA-Amyp nanoparticles aggregated in vascular endothelial cells of the peri-infarct region and significantly improved the recovery of neurological function. It is indicated that the RGD-modified nanomedicine promotes the recovery of nerve function more efficiently. Further study on the mechanism of RGD-DMAPA-Amyp/HIF-1α-AA in the treatment of cerebral ischemia displayed potential to significantly promote the formation of new blood vessels in vivo. Our findings suggest that the RGD-modified nonviral gene vector containing HIF-1α-AA appears to be a safe and promising therapeutic strategy for ischemic stroke gene therapy.

Magnetic Cationic Amylose Nanoparticles Used to Deliver Survivin-Small Interfering RNA for Gene Therapy of Hepatocellular Carcinoma In Vitro.

Amylose is a promising nanocarrier for gene delivery in terms of its good biocompatibility and high transfection efficiency. Small interfering RNA against survivin (survivin-siRNA) can cause tumor apoptosis by silencing a hepatocellular carcinoma (HCC)-specific gene at the messenger RNA level. In this study, we developed a new class of folate-functionalized, superparamagnetic iron oxide (SPIO)-loaded cationic amylose nanoparticles to deliver survivin-siRNA to HCC cells. The cellular uptake of nanocomplexes, cytotoxicity, cell apoptosis, and gene suppression mediated by siRNA-complexed nanoparticles were tested. The results demonstrated that folate-functionalized, SPIO-loaded cationic amylose nanoparticles can mediate a specific and safe cellular uptake of survivin-siRNA with high transfection efficiency, resulting in a robust survivin gene downregulation in HCC cells. The biocompatible complex of cationic amylose could be used as an efficient, rapid, and safe gene delivery vector. Upon SPIO loading, it holds a great promise as a theranostic carrier for gene therapy of HCC.

Superparamagnetic Iron Oxide Nanoparticles-Complexed Cationic Amylose for In Vivo Magnetic Resonance Imaging Tracking of Transplanted Stem Cells in Stroke.

Cell-based therapy with mesenchymal stem cells (MSCs) is a promising strategy for acute ischemic stroke. In vivo tracking of therapeutic stem cells with magnetic resonance imaging (MRI) is imperative for better understanding cellular survival and migrational dynamics over time. In this study, we develop a novel biocompatible nanocomplex (ASP-SPIONs) based on cationic amylose, by introducing spermine and the image label, ultrasmall superparamagnetic iron oxide nanoparticles (SPIONs), to label MSCs. The capacity, efficiency, and cytotoxicity of the nanocomplex in transferring SPIONs into green fluorescence protein-modified MSCs were tested; and the performance of in vivo MRI tracking of the transplanted cells in acute ischemic stroke was determined. The results demonstrated that the new class of SPIONs-complexed nanoparticles based on biodegradable amylose can serve as a highly effective and safe carrier to transfer magnetic label into stem cells. A reliable tracking of transplanted stem cells in stroke was achieved by MRI up to 6 weeks, with the desirable therapeutic benefit of stem cells on stroke retained. With the advantages of a relatively low SPIONs concentration and a short labeling period, the biocompatible complex of cationic amylose with SPIONs is highly translatable for clinical application. It holds great promise in efficient, rapid, and safe labeling of stem cells for subsequent cellular MRI tracking in regenerative medicine.