Cellulose supported promising magnetic sorbents for magnetic solid-phase extraction: A review

Covalent-Organic Frameworks for Selective and Sensitive Detection of Antibiotics from Water

As the consumption of antibiotics rises, they have generated some negative impacts on organisms and the environment because they are often unable to be effectively degraded, and seeking effective detection methods is currently a challenge. Covalent-organic frameworks (COFs) are new types of crystalline porous crystals created based on the strong covalent interactions between blocked monomers, and COFs demonstrate great potential in the detection of antibiotics from aqueous solutions because of their large surface area, adjustable porosity, recyclability, and predictable structure. This review aims to present state-of-the-art insights into COFs (properties, classification, synthesis methods, and functionalization). The key mechanisms for the detection of antibiotics and the application performance of COFs in the detection of antibiotics from water are also discussed, followed by the challenges and opportunities for COFs in future research.

Magnetic composite microspheres with a controlled mesoporous shell for highly efficient DNA extraction and fragment screening

Rapid extraction and screening of high-purity DNA fragments is an indispensable technology in advanced molecular biology. In this article, mesoporous magnetic composite microspheres (MSP@mTiO2) with tunable pore sizes were successfully fabricated for high-purity DNA extraction and fragment screening. Owing to the strong complexation ability of Ti ions with DNA phosphate groups and the high specific surface area of mesoporous microspheres, the MSP@mTiO2 microspheres possess excellent adsorption performance, where the saturated loading capacity of MSP@mTiO2 with a specific surface area of 122 m2 g-1 is as high as 575 μg mg-1 for a salmon sperm specimen. ITC experiments demonstrated that DNA adsorption on MSP@mTiO2 microspheres is mainly driven by entropy, which gives us more potential ways to regulate the balance of adsorption and desorption. Meanwhile, the mesoporous MSP@mTiO2 microspheres exhibit a much higher extraction efficiency compared with non-porous MSP@TiO2 for whole genome DNA from Arabidopsis thaliana plants. Interestingly, DNA fragments with different lengths could be screened by simply regulating the pore size of MSP@mTiO2 or the concentration of Na3PO4 in the eluent. A small pore size and low phosphate concentration are advantageous for the extraction of short-stranded DNA fragments, and DNA fragments (≤1000 bp) can be efficiently extracted when the mesopore size of MSP@mTiO2 is lower than 7.6 nm. The extraction results from the mesoporous composite microspheres provide new promising insights into the purification and screening of DNA from complex biological samples.

Synthesis of composite materials combining magnetic metal-organic frameworks and conjugated organic frameworks for selective extraction of carbendazim and thiabendazole residues from Chinese herbal medicine samples

A magnetic metal-organic framework MIL-68(Al) and a covalent organic framework were used as magnetic solid-phase extraction (MSPE) adsorbents in combination with high-performance liquid chromatography ultraviolet detection (HPLC-UV) to detect carbendazim (CBZ) and thiabendazole (TBZ). The main parameters affecting the extraction in the MSPE process were studied and optimized. Fe3O4@MIL-68(Al) coated with 1,3,5-tris(4-aminophenyl)benzene and terephthaldehyde (Fe3O4@MIL-68(Al)@TAPB-PDA-COF) was analyzed and verified. The material was proven to be suitable for adsorbing CBZ and TBZ. Various adsorption models were used to study its adsorption mechanism. The adsorption results were in good agreement with the pseudo-second-order kinetic model and Langmuir isotherm model. The maximum adsorption capacities of Fe3O4@MIL-68(Al)@TAPB-PDA-COF over CBZ and TBZ were 54.24 and 67.87 mg g-1, respectively, and the equilibrium adsorption time was 200 min. Fe3O4@MIL-68(Al)@TAPB-PDA-COF with excellent recyclability showed higher adsorption capacity and selectivity. A method based on Fe3O4@MIL-68(Al)@TAPB-PDA-COF combined with HPLC-UV was established under the optimal extraction conditions and used to separate and detect trace imidazole drugs in Chinese herbal samples, achieving a low limit of detection (0.65-1.30 μg L-1) with excellent linear correlation (r > 0.999). The recovery rate and relative standard deviation were 86.05-99.78 % and 0.15-4.90 %, respectively. Therefore, the Fe3O4@MIL-68@TAPB-PDA-COF can be regarded as an effective adsorbent for the pretreatment of CBZ and TBZ drugs in Chinese herbal samples.

Investigation of Gelation Techniques for the Fabrication of Cellulose Aerogels

Because of the pronounced degradation of the environment, there has been an escalated demand for the fabrication of eco-friendly and highly efficient products derived from renewable sources. Cellulose aerogels have attracted significant interest attributable to their structural characteristics coupled with biodegradability and biocompatibility. The features of the molecular structure of cellulose allow for the use of various methods in the production of gels. For instance, the presence of hydroxyl groups on the cellulose surface allows for chemical crosslinking via etherification reactions. On the other hand, cellulose gel can be procured by modulating the solvent power of the solvent. In this study, we investigate the impact of the gelation methodology on the structural attributes of aerogels. We present methodologies for aerogel synthesis employing three distinct gelation techniques: chemical crosslinking, cryotropic gelation, and CO2-induced gelation. The outcomes encompass data derived from helium pycnometry, Fourier-transform infrared spectroscopy, nitrogen porosimetry, and scanning electron microscopy. The resultant specimens exhibited a mesoporous fibrous structure. It was discerned that specimens generated through cryotropic gelation and CO2-induced gelation manifested higher porosity (93-95%) and specific surface areas (199-413 m2/g) in contrast to those produced via chemical crosslinking (porosity 72-95% and specific surface area 25-133 m2/g). Hence, this research underscores the feasibility of producing cellulose-based aerogels with enhanced characteristics, circumventing the necessity of employing toxic cross-linking agents. The process of gel formation through chemical crosslinking enables the creation of gels with enhanced mechanical properties and a more resilient structure. Two alternative methodologies prove particularly advantageous in applications necessitating biocompatibility and high porosity. Notably, CO2-induced gelation has not been hitherto addressed in the literature as a means to produce cellulose gels. The distinctive feature of this approach resides in the ability to combine the stages of obtaining an aerogel in one apparatus.

Immobilization of Multivalent Titanium Cations on Magnetic Composite Microspheres for Highly Efficient DNA Extraction and Amplification

Magnetic-assisted DNA testing technology has attracted much attention in genetics, clinical diagnostics, environmental microbiology, and molecular biology. However, achieving satisfying DNA adsorption and desorption efficiency in real samples is still a big challenge. In this paper, a new kind of high-quality magnetic composite microsphere of MM@PGMA-PA-Ti4+ was designed and prepared for DNA extraction and detection based on the strong interaction of Ti4+ and phosphate groups. By taking the advantages of high magnetic susceptibility and high Ti4+ content, the MM@PGMA-PA-Ti4+ microspheres possessed remarkable extraction capacity for mimic biological samples (salmon sperm specimens) with saturated loadings up to 533.0 mg/g. When the DNA feeding amount was 100 μg and the MM@PGMA-PA-Ti4+ dosage was 1 mg, the adsorption and desorption efficiencies were 80 and 90%, respectively. The kinetic and equilibrium extraction data were found to fit well with the pseudo-second-order model and Freundlich isotherm model. Furthermore, the MM@PGMA-PA-Ti4+ microspheres were successfully employed for DNA extraction from mouse epithelial-like fibroblasts. The extraction ability (84 ± 4 μg/mg) and DNA purity were superior to the comparative commercial spin kits, as evaluated by electrophoresis assays and qPCR analysis. The experimental results suggest that the MM@PGMA-PA-Ti4+ microspheres possess great potential as an adsorbent for DNA purification from complex biological samples.

Synthesis of a novel magnetic nanomaterial for the development of a multielemental speciation method of lead, mercury, and vanadium via HPLC-ICP MS

A new magnetic functionalized material based on graphene oxide magnetic nanoparticles named by us, M@GO-TS, was designed and characterized in order to develop a magnetic solid-phase extraction method (MSPE) to enrich inorganic and organic species of lead, mercury, and vanadium. A flow injection (FI) system was used to preconcentrate the metallic and organometallic species simultaneously, while the ultra-trace separation and determination of the selected species were achieved by high-performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC-ICP MS). Therefore, preconcentration and separation/determination processes were automated and conducted separately. To the best of our knowledge, this is the first method combining an online MSPE and HPLC-ICP MS for multielemental speciation. Under the optimized conditions, the enrichment factor obtained for Pb^II, trimethyllead (TML), Hg^II, methylmercury (MetHg), and V^V was 27. The calculated LOD for all studied species were as follows: 5 ng L^-1, 20 ng L^-1, 2 ng L^-1, 10 ng L^-1, and 0.4 ng L^-1, respectively. The RSD values calculated with a solution containing 0.5 μg L^-1 of all species were between 2.5 and 4.5%. The developed method was validated by analyzing Certified Reference Materials TMDA 64.3 for total concentration and also by recovery analysis of the species in human urine from volunteers and a seawater sample collected in Málaga. The t statistical test showed no significant differences between the certified and found values for TMDA 64.3. All the recoveries obtained from spiked human urine and seawater samples were close to 100%. All samples were analyzed using external calibration. The developed method is sensitive and promising for routine monitoring of the selected species in environmental waters and biological samples.

Cellulose supported magnetic nanohybrids: Synthesis, physicomagnetic properties and biomedical applications-A review

Cellulose and its forms are widely used in biomedical applications due to their biocompatibility, biodegradability and lack of cytotoxicity. It provides ample opportunities for the functionalization of supported magnetic nanohybrids (CSMNs). Because of the abundance of surface hydroxyl groups, they are surface tunable in either homogeneous or heterogeneous solvents and thus act as a substrate or template for the CSMNs' development. The present review emphasizes on the synthesis of various CSMNs, their physicomagnetic properties, and potential applications such as stimuli-responsive drug delivery systems, MRI, enzyme encapsulation, nucleic acid extraction, wound healing and tissue engineering. The impact of CSMNs on cytotoxicity, magnetic hyperthermia, and folate-conjugates is highlighted in particular, based on their structures, cell viability, and stability. Finally, the review also discussed the challenges and prospects of CSMNs' development. This review is expected to provide CSMNs' development roadmap in the context of 21st-century demands for biomedical therapeutics.