Drug delivery with a pH-sensitive star-like dextran-graft polyacrylamide copolymer

Hydrazone-functionalized nanoscale covalent organic frameworks as a nanocarrier for pH-responsive drug delivery enhanced anticancer activity

Nanoscale covalent organic frameworks (NCOFs) as emerging drug-delivery nanocarriers have received much attention in biomedicine in recent years. However, there are few reports on the application of pH-responsive NCOFs for drug delivery nanosystems. In this work, hydrazone-decorated NCOFs as pH-triggered molecular switches are designed for efficient cancer therapy. These functionalized NCOFs with hydrazone groups on the channel walls (named NCOFs-NHNH2) are obtained via a post-synthetic modification strategy. Subsequently, the anticancer drug doxorubicin (DOX) as the model molecule is loaded through covalent linkage to yield NCOFs-NN-DOX. Finally, soybean phospholipid (SP) is coated on the surface of HNTs-NN-DOX, named NCOFs-NN-DOX@SP, to further enhance the dispersibility, stability and biocompatibility of HNTs in physiological solution. NCOFs-NN-DOX@SP showed an excellent and intelligent sustained-release effect with an almost sixfold increase at pH = 5.2 than at pH = 7.4. In vitro cell toxicity and imaging assays of NCOFs-NN-DOX@SP exhibited an enhanced therapeutic effect on Lewis lung carcinoma (LLC) cells, demonstrating that the fabricated NCOFs have a great potential in cancer therapy. Thus, this work provides a new way toward designing stimulus-responsive functionalized NCOFs and promotes their potential application as an on-demand drug delivery system in the field of cancer treatment.

Advanced Nano-Drug Delivery Systems in the Treatment of Ischemic Stroke

In recent years, the frequency of strokes has been on the rise year by year and has become the second leading cause of death around the world, which is characterized by a high mortality rate, high recurrence rate, and high disability rate. Ischemic strokes account for a large percentage of strokes. A reperfusion injury in ischemic strokes is a complex cascade of oxidative stress, neuroinflammation, immune infiltration, and mitochondrial damage. Conventional treatments are ineffective, and the presence of the blood-brain barrier (BBB) leads to inefficient drug delivery utilization, so researchers are turning their attention to nano-drug delivery systems. Functionalized nano-drug delivery systems have been widely studied and applied to the study of cerebral ischemic diseases due to their favorable biocompatibility, high efficiency, strong specificity, and specific targeting ability. In this paper, we briefly describe the pathological process of reperfusion injuries in strokes and focus on the therapeutic research progress of nano-drug delivery systems in ischemic strokes, aiming to provide certain references to understand the progress of research on nano-drug delivery systems (NDDSs).

Hemocompatibility of dextran-graft-polyacrylamide/zinc oxide nanosystems: hemolysis or eryptosis?

Aim. In this study, blood compatibility of ZnO nanoparticles-polymer nanocomplex (D-PAA/ZnONPs(SO42-)) synthesizedin situinto dextran-graft-polyacrylamide (D-PAA) using zinc sulphate as a precursor was tested using hemolysis, osmotic fragility and eryptosis assays.Materials and methods. Dose-dependent ability to induce eryptosis was assessed following 24 h incubation at concentrations of 0-800 mg l-1analyzing hallmarks of eryptosis (cell shrinkage and phosphatidylserine externalization), as well as reactive oxygen species generation. Hemolysis was detected spectrophotometrically based on hemoglobin release following exposure to the D-PAA/ZnONPs(SO42-) nanocomplex. Osmotic fragility test (OFT) involved detection of hemolysis of red blood cells exposed to 0.2% saline solution following incubation with the D-PAA/ZnONPs(SO42-) nanocomplex. Additional incubation of the nanocomplex in the presence or absence of either ascorbic acid or EGTA was used to reveal the implication of oxidative stress- or Ca2+-mediated mechanisms in D-PAA/ZnONPs(SO42-) nanocomplex-induced erythrotoxicity.Results. Hemocompatibility assessment of the D-PAA/ZnONPs(SO42-) nanocomplex revealed that it induced hemolysis and reduced resistance of erythrocytes to osmotic stress at concentrations of above 400 and 200 mg l-1, respectively. Oxidative stress- or Ca2+-mediated mechanisms were not involved in D-PAA/ZnONPs(SO42-) nanocomplex-induced hemolysis. Strikingly, the D-PAA/ZnONPs(SO42-) nanocomplex did not promote cell membrane scrambling, cell shrinkage and oxidative stress in red blood cells following the direct exposure for 24 h. Thus, the D-PAA/ZnONPs(SO42-) nanocomplex did not induce eryptosisin vitro. Eryptosis is generally considered to occur earlier than hemolysis in response to stress in order to prevent hemolytic cell death. Counterintuitively, our data suggest that hemolysis can be triggered by nanomaterials prior to eryptosis indicating that eryptosis and hemolysis assays should be used in combination for testing blood compatibility of nanomaterials.Conclusions. The D-PAA/ZnONPs(SO42-) nanocomplex has a good hemocompatibility profile at low concentrations. Hemocompatibility testing in nanotoxicology should include both eryptosis and hemolysis assays.

Combined Dextran-Graft-Polyacrylamide/Zinc Oxide Nanocarrier for Effective Anticancer Therapy in vitro

Introduction

Cancer chemotherapy faces two major challenges - high toxicity of active substances and tumor resistance to drugs. Low toxic nanocarriers in combination with anticancer agents can significantly increase the effectiveness of therapy. Modern advances in nanotechnology make it easy to create materials with the necessary physical and chemical properties.

Methods

Two hybrid nanosystems of dextran-polyacrylamide/ zinc oxide nanoparticles (D-PAA/ZnO NPs) were synthesized in aqueous solution with zinc sulphate (D-PAA/ZnO NPs (SO42-)) and zinc acetate (D-PAA/ZnO NPs (-OAc)). The light absorption, fluorescence, dynamic light scattering and transmission electron microscopy for nanocomposite characterization were used. MTT, neutral red uptake and scratch assays were selected as fibroblasts cytotoxicity assays. Cytotoxicity was tested in vitro for normal fibroblasts, MAEC, prostate (LNCaP, PC-3, DU-145) and breast (MDA-MB-231, MCF-7) cancer cells lines. Immunocytochemical methods were used for detection of Ki-67, p53, Bcl-2, Bax, e-cadherin, N-cadherin and CD44 expression. Acridine orange was used to detect morphological changes in cells.

Results

The radius of ZnO NPs (SO42-) was 1.5 nm and ZnO NPs (-OAc) was 2 nm. The nanosystems were low-toxic to fibroblasts, MAEC. Cells in the last stages of apoptosis with the formation of apoptotic bodies were detected for all investigated cancer cell lines. Proapoptotic proteins expression in cancer cells indicates an apoptotic death. Increased expression of E-cadherin and N-cadherin was registered for cancer cells line LNCaP, PC-3, DU-145 and MCF-7 after 48 h incubation with D-PAA/ZnO NPs (SO42-).

Conclusion

The nanosystems were low-toxic to fibroblasts, MAEC. The D-PAA/ZnO NPs nanosystem synthesized using zinc sulphate demonstrates high cytotoxicity due to destruction of various types of cancer cells in vitro and potentially increases adhesion between cells. Thus, our findings indicate the selective cytotoxicity of D-PAA/ZnO NPs against cancer cells and can be potentially used for cancer treatment.