Because of their
high magnetization and suitable biocompatibility,
iron-oxide nanoparticles (IONPs) have been widely employed in various
biomedical applications, including magnetic hyperthermia for cancer
treatment. In many cases, the colloidal stability requirement will
limit the usage of ferromagnetic particles that are usually associated
with good magnetic response. To address this challenge, a stable carrier
for better colloidal stability regardless of the size or shape of
the IONPs while at the same time providing enhanced magnetic hyperthermia
heating performance is required. In this work, IONPs of different
sizes (4, 8, 20, 45, and 250 nm) were engineered to reside in the
graphene oxide (GO) sheet carrier, which were stable in aqueous solution
even in the presence of a strong magnetic field. Out of various IONPs
sizes, highest specific absorption rate (SAR) value of 5020 W g−1 was obtained with 45 nm GO-IONPs nanocomposites at
a frequency and alternating magnetic field of 400 kHz and 32.5 kA
m–1, respectively. The calculated intrinsic loss
power (ILP) was 12.21 nH m2 kg–1, which
is one of the highest ILP values reported for synthesized IONPs to
the best of our knowledge. To enhance the excellent colloidal stability
in biological environment, the GO-IONPs nanocomposites can be further
grafted with polyethylene glycol (PEG) because agglomeration of pristine
GO sheets occurs because of adsorption of cations. High ILP values
could be well maintained even after PEG coating. The PEGylated 45
nm GO-IONP showed excellent antitumor efficacy in 4T1-tumor model
mice by inhibiting tumor progression within a safe dosage range. Overall,
the novel nanocomposite in this workPEG-GO-IONPpossesses
high hyperthermia performance, excellent colloidal stability in biological
environment, and availability of functional groups in GO and can be
utilized for tagging in various biomedical applications.
Wastewater contaminated with heavy metals is a worldwide concern due to the toxicity to human and animals. The current study presents an incorporation of adsorption and low-field dynamic magnetic separation technique for the treatment of heavy-metal-contaminated water. The key components are the eco-fabricated magnetic filter with mesh architectures (constituted of a soft magnetic material (Ni,Zn)FeO) and poly(acrylic acid) (PAA)-coated quasi-superparamagnetic FeO nanoparticles (NPs). PAA-coated FeO NPs possess high adsorption capacity of heavy metal ions including Pb, Ni, Co, and Cu and can be easily regenerated after the adjustment of pH. Moreover, magnetic mesh filter has shown excellent collection ability of quasi-superparamagnetic particles under a magnetic field as low as 0.7 kOe (0.07 T) and can easily release these particles during ultrasonic washing when small magnets are removed. In the end, after one filtration process, the heavy metal concentration can be significantly decreased from 1.0 mg L to below the drinking water standard recommended by the World Health Organization (e.g., less than 0.01 mg L for Pb). Overall, a proof-of-concept adsorption and subsequent low-field dynamic separation technique is demonstrated as an economical and efficient route for heavy metal removal from wastewater.
The present study was carried out to investigate the impact of various types of silk fibroin (SF) scaffolds on human osteoblast-like cell (MG63) attachment and proliferation. SF was isolated from Bombyx mori silk worm cocoons after degumming. Protein concentration in the degummed SF solution was estimated using Bradford method. Aqueous SF solution was used to fabricate three different types of scaffolds, viz, electrospun nanofiber mat, sponge, and porous film. The structures of the prepared scaffolds were characterized using optical microscopy and field emission scanning electron microscopy. The changes in the secondary structure of the proteins and the thermal behavior of the scaffolds were determined by Fourier transform infrared spectroscopy and thermo-gravimetric analysis, respectively. The biodegradation rate of scaffolds was determined by incubating the scaffolds in simulated body fluid for 4 weeks. MG63 cells were seeded on the scaffolds and their attachment and proliferation onto the scaffolds were studied. The MTT assay was carried out to deduce the toxicity of the developed scaffolds. All the scaffolds were found to be biocompatible. The amount of collagen produced by the osteoblast-like cells growing on different scaffolds was estimated.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.