4 research outputs found
Degradable Thermoresponsive Nanogels for Protein Encapsulation and Controlled Release
Reversible addition–fragmentation chain transfer
(RAFT)
polymerization technique was used for the fabrication of stable core
cross-linked micelles (CCL) with thermoresponsive and degradable cores.
Well-defined poly(2-methacryloyloxyethyl phosphorylcholine), poly(MPC) <i>macro</i>RAFT agent, was first synthesized with narrow molecular
weight distribution via the RAFT process. These CCL micelles (termed
as nanogels) with hydrophilic poly(MPC) shell and thermoresponsive
core consisting of poly(methoxydiethylene glycol methacrylate) (poly(MeODEGM)
and poly(2-aminoethyl methacrylamide hydrochloride) (poly(AEMA) were
then obtained in a one-pot process by RAFT polymerization in the presence
of an acid degradable cross-linker. These acid degradable nanogels
were efficiently synthesized with tunable sizes and low polydispersities.
The encapsulation efficiencies of the nanogels with different proteins
such as insulin, BSA, and β-galactosidase were studied and found
to be dependent of the cross-linker concentration, size of protein,
and the cationic character of the nanogels imparted by the presence
of AEMA in the core. The thermoresponsive nature of the synthesized
nanogels plays a vital role in protein encapsulation: the hydrophilic
core and shell of the nanogels at low temperature allow easy diffusion
of the proteins inside out and, with an increase in temperature, the
core becomes hydrophobic and the nanogels are easily separated out
with entrapped protein. The release profile of insulin from nanogels
at low pH was studied and results were analyzed using bicinchoninic
assay (BCA). Controlled release of protein was observed over 48 h
Biodegradable and Nontoxic Nanogels as Nonviral Gene Delivery Systems
The development of polymeric systems with tailored properties
as
nonviral gene carriers continues to be a challenging and exciting
field of research. We report here the synthesis and characterization
of biodegradable, temperature- and pH-sensitive carbohydrate-based
cationic nanogels as effective gene delivery carriers to Hep G2 cells.
The temperature-sensitive property of the nanogels allows their facile
complexation of DNA, while the pH-sensitive property allows the degradation
of nanogels followed by the release of plasmid in the endosome. The
nanogels are synthesized via reversible addition–fragmentation
chain transfer polymerization (RAFT) technique and are evaluated for
their DNA condensation efficacy. The gene delivery efficacies of these
nanogels are subsequently studied and it is found that these cationic
glyconanogels can serve as potent gene delivery vectors in hepatocytes.
It is found that the gene delivery efficacies of this system are similar
to that of branched poly(ethyleneimine), which is used as a positive
control. Moreover, these nanogels show desirable properties for systemic
applications including low toxicity and degradation in acidic environment
Bismuth trichloride–mediated cleavage of phenolic methoxymethyl ethers
<p>A simple and efficient method for removal of phenolic methoxymethyl ethers in the presence of 30 mol% of bismuth trichloride in acetonitrile/water is described. Notable features of the cleavage protocol entail use of an ecofriendly bismuth reagent, ease of handling, low cost, operational simplicity, and good functional group compatibility. A number of structurally varied phenolic methoxymethyl ethers were cleaved in good to excellent yields.</p
Cationic Poly(2-aminoethylmethacrylate) and Poly(<i>N</i>‑(2-aminoethylmethacrylamide) Modified Cellulose Nanocrystals: Synthesis, Characterization, and Cytotoxicity
Cellulose nanocrystals (CNCs) continue
to gain increasing attention
in the materials community as sustainable nanoparticles with unique
chemical and mechanical properties. Their nanoscale dimensions, biocompatibility,
biodegradability, large surface area, and low toxicity make them promising
materials for biomedical applications. Here, we disclose a facile
synthesis of poly(2-aminoethylmethacrylate) (poly(AEM)) and poly(<i>N</i>-(2-aminoethylmethacrylamide) (poly(AEMA)) CNC brushes
via the surface-initiated single-electron-transfer living radical
polymerization technique. The resulting modified CNCs were characterized
for their chemical and morphological features using a combination
of analytical, spectroscopic, and microscopic techniques. Zeta potential
measurements indicated a positive surface charge, and further proof
of the cationic nature was confirmed by gold deposition as evidenced
by electron microscopy. The cytotoxicity of these cationic modified
CNCs was evaluated utilizing a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium
bromide (MTT) assay in two different cell lines, J774A1 (mouse monocyte
cells) and MCF-7 (human breast adenocarcinoma cells). The results
indicated that none of the cationic modified CNCs decreased cell viability
at low concentrations, which could be suitable for biomedical applications