Environmental stability and cytotoxicity of layered black phosphorus modified with Polyvinylpyrrolidone and Zeolitic Imidazolate Framework-67.

Layered black phosphorus (LBP) is regarded as a promising two-dimensional nanomaterial in various application fields. As bare LBP is unstable in humid environment, many modification methods have been developed recently. However, environmental risks of modified LBP nanomaterials are largely unknown. Herein, by sonication and in-situ surface-confined synthesis, polyvinylpyrrolidone (PVP) coated LBP (LBP/PVP), and zeolitic imidazolate framework-67 (ZIF-67) modified LBP (LBP/PVP-ZIF-67) nanomaterials were synthesized. Environmental stability and toxicity of the modified nanomaterials were compared with bare LBP. Results show that LBP/PVP-ZIF-67 exhibits excellent photothermal performance, and higher potential in electrochemical hydrogen evolution than bare LBP or LBP/PVP. Characteristic visible light absorbance at 593 nm was introduced into the nanomaterial by ZIF-67. LBP/PVP has stability in aqueous environment or cytotoxicity similar to LBP. LBP/PVP-ZIF-67 is completely stable in water within 120 h, in contrast to over 30% degradation of LBP or LBP/PVP. More than 50% of LBP in the LBP/PVP-ZIF-67 can degrade to dissolvable phosphorus in oxygenated water after 17 days, indicating the nanomaterial will not be persistent in the environment. Moreover, modification with ZIF-67 can reduce cytotoxicity of LBP. Therefore, this study develops a safe strategy to modify LBP and provides basic information for ecological risk assessment of LBP based materials.

MOF-derived novel porous Fe3O4@C nanocomposites as smart nanomedical platforms for combined cancer therapy: magnetic-triggered synergistic hyperthermia and chemotherapy.

Multifunctional nanomedical platforms have broad prospects in imaging-guided combination therapy in cancer precision medicine. In this work, metal-organic framework (MOF)-derived novel porous Fe3O4@C nanocomposites were developed as an intelligent cancer nanomedical platform for combined cancer therapy with MRI-guided magnetic-triggered hyperthermia and chemotherapy functions. The magnetic behavior, porous character and good surface modification endowed this smart nanoplatform with favorable biocompatibility, high-efficiency MRI imaging, magnetic-triggered on-demand DOX release function, and synergistic therapy of magnetic hyperthermia and chemotherapy, which proposed an all-in-one platform for cancer therapy. Additionally, in vivo animal experiments verified the significant suppression of malignant tumor growth with negligible side effects, which were attributed to the consecutive 13 day synergistic therapy of magnetic hyperthermia and chemotherapy in one. To be specific, Fe3O4@C-PVP@DOX significantly decreases the volume (2.5 to 0.44 of tumor volume ratio) and weight (0.49 g to 0.10 g) of tumors after magnetic-triggered hyperthermia and chemotherapy treatments. Moreover, no big difference of body weight and associated damage was observed among all major organs. Therefore, owing to its high-efficiency combined therapy of magnetic-triggered hyperthermia and chemotherapy, this smart nanoplatform holds great potential application in the precise treatments of clinical cancer.

Synthesis and characterization of pectin/PVP hydrogel membranes for drug delivery system.

The purpose of the present study was to develop and design pectin and polyvinyl pyrrolidone (PVP) blended hydrogel membranes (PEVP), with different pectin: PVP ratios (1:0.2, 1:0.4, 1:0.6, 1:0.8 and 1:1 w/w), which were prepared by using a conventional solution casting technique. An attempt has been made to characterize the hydrogel membranes by various instrumental techniques like, FTIR (Fourier transform infrared) spectroscopy, X-ray diffraction (XRD), Differential scanning calorimetry (DSC), tensile strength test and scanning electron microscopy (SEM). The release patterns of the drug (salicylic acid) from the hydrogel membrane were done in three different release mediums (pH 1.4, pH 7.4 and distilled water) and samples were analyzed spectrophotometrically at 294 nm wavelength on a UV Vis spectrophotometer. MTT assay was done to ensure cytocompatibility of the pectin/PVP hydrogel membranes using B16 melanoma cells. FTIR spectroscopy indicated the presence of secondary amide (I) absorption bands. The XRD study shows decrease in crystallinity of the hydrogel membranes with increase in PVP ratio. DSC study shows an increase in T(g) of pectin after blending with PVP. It was found that tensile strength increases with increasing PVP ratios in the hydrogel membranes. The prepared hydrogel membranes were found to be biocompatible with B16 melanoma cells.

The targeting of anionized polyvinylpyrrolidone to the renal system.

We reported that the co-polymer composed of vinylpyrrolidone and maleic acid selectively distributed into the kidneys after i.v. injection. To further optimize the renal drug delivery system, we assessed the renal targeting capability of anionized polyvinylpyrrolidone (PVP) derivatives after intravenous administration in mice. The elimination of anionized PVP derivatives from the blood decreased with increasing anionic groups, and the clearance of carboxylated PVP and sulfonated PVP from the blood was almost similar. But carboxylated PVP efficiently accumulated in the kidney, whereas sulfonated PVP was rapidly excreted in the urine. The renal levels of carboxylated PVP were about five-fold higher than sulfonated PVP. Additionally, carboxylated PVP was effectively taken up by the renal proximal tubular epithelial cells in vivo after i.v. injection. These anionized PVP derivatives did not show any cytotoxicity against renal tubular cells and endothelial cells in vitro. Thus, these carboxylated and sulfonated PVPs may be useful polymeric carriers for drug delivery to the kidney and bladder, respectively.