Self-assembly of the amphiphilic copolymer into core−shell-like nanoparticles is the new tactic to tailor carriers toward rationalization in the field of drug-delivery systems. Herein, a facile route for examining how the entrapment of a hydrophobic and negative-charge drug affects the micellar structure of a positive-charged copolymer and its biological behavior was developed. In this study, Pluronic F127-grafted chitosan (CF127) was utilized as a positivecharged copolymer for in situ loading of nanocurcumin in a cosolvent condition. Ultrasonication was found to be an effective method to control the self-assembly of phosphocasein and its interaction with curcumin. The superstructure of the incorporated nanoparticles was fabricated in the medium under unimolecular micelles as vesicular structure (SV) at lower ultrasonic condition while large complex micelles (multimicelle aggregates, LCMs) at higher ultrasonic power density. According to transmission electron microscopy, variable UV−visible spectrophotometry, as well as fluorescence spectroscopy, nanocurcumin was not only incorporated into the hydrophobic micelle cores via hydrophobic interaction but also underwent electrostatic interaction with amine groups on chitosan backbone, resulting in micellar aggregation and finally turning in LCMs. Furthermore, regarding dynamic light scattering measurements, correlation coefficients of SV, as well as LCMs, were higher than 0.9, which means that all nanostructures were homogeneous in size under precise control by ultrasonication. Cell-culture studies showed that both unique morphologies endowed fibroblast cell development. Interestingly, the more complex structure as LCM exhibited as a potential candidate in cancer therapy. These corollaries suggest that the morphology of micelles based on cationic amphiphilic block copolymer can be modulated by adding negative-charged/hydrophobic molecules under varying condition of ultrasonication that reinforces their prospective applications as nanocarriers for drug-delivery systems.
Polyamidoamine (PAMAM) dendrimers are extensively researched as potential drug delivery system thanks to their desirable features such as controlled and stable structures, and ease of functionalization onto their surface active groups. However, there have been concerns about the toxicity of full generation dendrimers and risks of premature clearance from circulation, along with other physical drawbacks presented in previous formulations, including large particle sizes and low drug loading efficiency. In our study, carboxyl-terminated PAMAM dendrimer G3.5 was grafted with poly (ethylene glycol) methyl ether (mPEG) to be employed as a nano-based drug delivery system with great cytocompatibility for the delivery of carboplatin (CPT), a widely prescribed anticancer drug with strong side effects so that the drug will be effectively entrapped and not exhibit uncontrolled outflow from the open structure of unmodified PAMAM G3.5. The particles formed were spherical in shape and had the optimal size range (around 36 nm) that accommodates high drug entrapment efficiency. Surface charge was also determined to be almost neutral and the system was cytocompatible. In vitro release patterns over 24 h showed a prolonged CPT release compared to free drug, which correlated to the cytotoxicity assay on malignant cell lines showing the lack of anticancer effect of CPT/mPEG-G3.5 compared with CPT.
In this work, AgNPs/PVA/Cellulose was used as a substrate material for surface Raman scattering enhancement. Silver nanoparticles (AgNPs) was synthesized by Lee and Meisel's method with the average particles size of 15.4 nm. Then, this silver colloid was made a homogenous coating on polyvinyl alcohol and cellulose film and structural characteristics of this material were determined using Scanning Electron Microscopy (SEM). The findings demonstrated that the Raman shifts of the pesticide will be identified by the SERS method at 1660 cm −1 , 2234 cm −1 (strong intensity), and at 3077 cm −1 , 1033 cm −1 , 1457 cm −1 (medium intensity) when using the excited laser with wavelength of 532 nm. Under excited laser, the limit of chlorfenapyr detection is 1 ppm (mg l −1 ), allowing determination of chlorfenapyr residue in food. Potential applications identified food samples containing chlorfenapyr residue for rapid detection, low cost, non-destructive nature and minimal sample preparation.
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