Functional Amino Research Articles

Enhanced adsorption of cadmium from aqueous solution by amino modification biochar and its adsorption mechanism insight

Cadmium (Cd) in industrial wastewater can accumulate in organisms in the aquatic environment, posing a severe threat to human health. Therefore, effective remediation of cadmium-contaminated water is necessary for public health and environmental sustainability. In this study, the amino groups were modified on the corn stalks biochar (CSBC) surface to prepare a highly selective Cd(Ⅱ) adsorbent (NH2-CSBC) by nitrification and reduction. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis demonstrated that amino groups were modified on the surface of CSBC. The adsorption capacity of NH2-CSBC for Cd(Ⅱ) was 4 times that of the original CSBC. The adsorption kinetics results showed that the Cd(Ⅱ) adsorption process by NH2-CSBC can be well described by the pseudo-second-order kinetic model. The maximum adsorption capacity obtained by the Sips model fitting reached 375.58 mg/g. The adsorption thermodynamic results indicated that Cd(Ⅱ) adsorption by NH2-CSBC was a spontaneous endothermic process. The analysis results based on FTIR and XPS before and after Cd(Ⅱ) adsorption showed that the amino functional groups on the surface of NH2-CSBC have strong complexation with Cd(Ⅱ). In summary, it is feasible to modify amino groups on the surface of biochar, and the obtained amino-modified biochar could adsorb Cd(Ⅱ) quickly and efficiently, showing great potential in the treatment of heavy metal wastewater.

Biocompatible polymer functionalized magnetic nanoparticles for antimicrobial and anticancer activities

Polymer functionalized transition metal oxide (TMO)-NPs are the future of cancer therapy and antimicrobial activities. Present study was related to synthesis of pure, chitosan (CH) and polyethylene glycol (PEG) coated Fe3O4-NPs via co-precipitation method. The XRD analysis represents the cubic lattice structure and crystallite size varies from 11 to 21 nm. The SEM micrograph shows that the irregular and dendrimer like surface morphology by using the (PEG and CH) coating agents. To investigate the different functional groups carboxyl, hydroxyl, amino groups, FeO and CH2 in pure and coated spectrum of Fe3O4-NPs by using FTIR. The VSM analysis shows that the coercivity increase Hci (m = 0) 11.281 Oe, 45.135 Oe, 51.127 Oe and magnetization decrease (Ms) 7.5001E-3 emu, 5.2432E-3 emu and 4.7801E-3 of polymer coated Fe3O4-NPs. In-vitro bioassay, the antimicrobial activities were observed against Escherichia coli (E.coli), Bacillus cereus (B.cereus) and Fusarium avenaceum (F.avenaceum), these results shows that the inhibition zone increase from 9 to 14 mm. The biotoxicity was tested against hepatocellular carcinoma (HepG2) cell lines via MTT assay. The overall assessment indicated that the PEG coated Fe3O4-NPs give the significant results against antimicrobial and anticancer activities. In future, surface functionalized magnetic nanomaterials will be playing the central role for hyperthermia therapy and wound healing purpose.

Strategy Based on Michael Addition Reaction for the Development of Bioinspired Multilayered and Multiphasic 3D Constructs.

The high incidence of osteochondral defects has increased the interest in the development of improved repairing alternatives, with tissue engineering being considered a promising approach. The hierarchical, complex structure of osteochondral tissue requires the design of a biomimetic multilayered scaffold. Here, a multilayered and multiphasic 3D macroporous structure was achieved at subzero temperature by the Michael addition reaction of amino functionalities of collagen with acryloyl groups of a bifunctionalized poly(ε-caprolactone). This green approach has been successfully applied to crosslink layers of different composition, both for their efficient sequential formation and connection. Polyethylenimine functionalized nano-hydroxyapatite (nHApLPEI) was added to the bottom layer. The resulting hybrid cryogels were characterized by morphology, equilibrium swelling ratios, compressive strength analysis, and MTS assay. They presented good stability, integrity, and biocompatibility. The results revealed that the properties of the prepared constructs may be tuned by varying the composition, number, and thickness of the layers. The Young modulus values were between 3.5 ± 0.02 and 10.5 ± 0.6 kPa for the component layers, while for the multilayered structures they were more than 7.3 ± 0.2 kPa. The equilibrium swelling ratio varied between 4.6 and 14.2, with a value of ~10.5 for the trilayered structure, correlated with the mean pore sizes (74-230 µm).

Potential application of Curtobacterium sp. GX_31 for efficient biosorption of Cadmium: Isotherm and kinetic evaluation

In this study, the adsorption capacity and mechanism of Cd2+ by both live and dead Curtobacterium sp. GX_31 biomasses were evaluated using a batch experiment, adsorption isotherm and kinetic models, scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) analysis. The optimal pH, dosage, and contact time were 6.0, 1.0 g/L, and 60 min, respectively. Under optimal conditions, the removal efficiency was >90% for the live biomass and close to 100% for the dead biomass at an initial Cd2+ concentration of ≤10 mg/L, and the maximum adsorption capacities were 37.04 and 40.16 mg/g for the live and dead biosorbents with 200 mg/L Cd2+. The R2 values of the isotherm models indicated that the Temkin isotherm model was best fitted for both the live and dead biomass. The parameters KL (0.3998 vs. 5.1066), n (4.0177 vs. 6.0205), and bT (507.7947 vs. 675.3512) implied that the dead cells had a higher affinity, stronger adsorption, and higher binding energy than the live cells. The kinetic study showed that the pseudo-second-order model was more suitable for depicting the biosorption process, demonstrating that the rate-limiting step might be chemisorption and more than one step, which was confirmed by the intra-particle diffusion model. SEM analysis identified Cd2+ adsorbed onto the cell surface. FT-IR spectra suggested that hydroxyl, amino, carboxyl, sulphate and carbonyl functional groups might be involved in Cd2+ adsorption. Based on the results obtained, Curtobacterium sp. GX_31 might be a promising novel biosorbent for Cd2+-contaminated soil or water, especially at lower concentrations.

Some Nanocarrier’s Properties and Chemical Interaction Mechanisms with Flavones

Flavones such as 7,8-dihydroxyflavone (tropoflavin), 5,6,7-trihydroxyflavone (baicalein), 3',4',5,6-tetrahydroxyflavone (luteolin), 3,3',4',5,5',7-hexahydroxyflavone (myricetin), 4',5,7-trihydroxyflavone (apigenin), and 5,7-dihydroxyflavone (chrysin) are important both for their presence in natural products and for their pharmacological applications. However, due to their chemical characteristics and their metabolic processes, they have low solubility and low bioavailability. Knowledge about the physicochemical properties of nanocarriers and the possible mechanisms of covalent and non-covalent interaction between nanoparticles (NPs) and drugs is essential for the design of nanocarriers to improve the bioavailability of molecules with pharmacological potential, such as tropoflavin, baicalein, luteolin, myricetin, apigenin, and chrysin. The parameters of characterization of some NPs of these flavones, such as size, polydispersity index (PDI), zeta potential, encapsulation efficiency (EE), and % release/time, utilized in biomedical applications and the covalent and non-covalent interactions existing between the polymeric NPs and the drug were analyzed. Similarly, the presence of functional groups in the functionalized carbon nanotubes (CNTs), as well as the effect of pH on the % adsorption of flavonoids on functionalized multi-walled carbon nanotubes (MWCNT-COOH), were analyzed. Non-covalent interaction mechanisms between polymeric NPs and flavones, and covalent interaction mechanisms that could exist between the NPs and the amino and hydroxyl functional groups, are proposed.

Preparation and potential application of amino-functionalized titanosilicates to removal of Th(IV) in aqueous solutions: optimization using response surface methodology (RSM)

Abstract Mesoporous titanosilicates (TiSil) with a size of almost 25 nm were prepared by an alkali-assisted hydro-thermal route, as an choice for developing efficient adsorbents of Th(IV) ions. TiSil were functionalized with the amino functional group (-NH2) from 3-aminopropyltriethoxysilane (APTES) by post-preparation method. The obtained amino-grafted titanosilicates (TiSilNH2) were characterized by Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller (BET), X-ray Diffraction (XRD) and Fourier-Transform Infrared Spectroscopy (FTIR) techniques. Adsorption of Th(IV) ions on TiSilNH2 was examined in aqueous solution. Response surface methodology (RSM) based on central composite design (CCD) was applied to optimize the four essential process variables namely initial pH and initial concentration of Th(IV) ions of aqueous solution, amount of adsorbent, and adsorption process temperature for the Th(IV) removal. The adequacy of the model was investigated, and it was deemed to be statistically significant. The optimal predicted adsorption capacity of TiSilNH2 for Th(IV) ions was 83.04 mg/g and the actual value was 84.8 mg/g. The equilibrium adsorption data were fitted to Langmuir, Freundlich, Dubinin–Radushkevich and Temkin isotherm models. The equi-librium data were best re-presented by Langmuir isotherm model, showing maximum monolayer adsorption capacity of 87.71 mg/g. The thermodynamic parameters indicated that the Th(IV) adsorption on the TiSilNH2 was a spontaneous, and endo-thermic process at the studied temperatures and occurred via physisorption. Adsorbent recovery by using 0.5 M HNO3 solution for adsorbent reuse indicated that the adsorbent was regenerable and could be employed frequently.

Enantioselective Synthesis of [b]‐Annulated Azepane Scaffolds

AbstractCyclopenta‐, benzo‐, and cyclohepta[b]‐annulated azepane scaffolds were prepared in two steps from optically active cyclic α‐allyl‐β‐oxoesters. The first step was ruthenium‐catalyzed olefin cross metathesis with acrylonitrile. The second step was palladium‐catalyzed dihydrogenation which consists of three consecutive processes: The hydrogenation of the C−C double and C−N triple bonds was followed by the reductive amination via the iminium ion formed in situ from the primary amino function and the endocyclic carbonyl group. This last step gave, stereoselectively, the annulated azepanes with relative trans‐configuration. The amino function and the ester group define two points for further diversification of the scaffolds. The trifluoroacetyl derivatives allowed to establish the enantiopurity of the products to be 97–98 % ee by GLC on a chiral phase. The relative trans‐configurations and in one case also the absolute (R,R)‐configuration was established by X‐ray crystallography.

Examining Interactions of Uranyl(VI) Ions with Amino Acids in the Gas Phase

Gas-phase experiments, using electrospray ionization quadrupole ion trap mass spectrometry (ESI-QIT/MS), were conducted to probe basic interactions of the uranyl(VI) ion, UO22+, with selected natural amino acids, namely, L-cysteine (Cys), L-histidine (His), and L-aspartic acid (Asp), which strongly bind to metal ions. The simplest amino acid, glycine (Gly), was also studied for comparison. Cys, His, and Asp have additional potentially coordinating groups beyond the amino and carboxylic acid functional groups, specifically thiol in Cys, imidazole in His, and a second carboxylate in Asp. Gas-phase experiments comprised collision-induced dissociation (CID) of uranyl–amino acid complexes and competitive CID to assess the relative binding strength of different amino acids in the same uranyl complex. Reactivity of selected uranyl–amino acid complexes with water provided further insights into relative stabilities. In positive ion mode, CID and ensuing reactions with water suggested that uranyl–neutral AA binding strength decreased in the order His > Asp > Cys > Gly, which is similar to amino acid proton affinities. In negative ion mode, CID revealed a decreasing dissociation tendency in the order Gly >> His ≈ Cys > Asp, presumably reflecting a reverse enhanced binding to uranyl of the doubly deprotonated amino acids formed in CID.

Adsorption of BSA Protein in Aqueous Medium Using Vegetable Tannin Resin from Acacia mearnsii (Mimosa) and Modified Lignocellulosic Fibers from the Bark of Eucalyptus citriodora.

Proteins are abundant biomolecules found in human cells, as well as pathogenic bacteria and viruses. Some of them become pollutants when released into water. Adsorption is an advantageous method for separating proteins in aqueous media since proteins are already immobilized on solid surfaces. Adsorbents with surfaces rich in tannins are efficient due to their affinity for strong interactions with the various amino acids that make up proteins. This work aimed to develop an adsorbent for protein adsorption in aqueous medium using lignocellulosic materials modified from eucalyptus bark and vegetable tannins. A more efficient resin was prepared containing 10% eucalyptus bark fibers and 90% tannin mimosa by condensation with formaldehyde, and it was characterized by UV–Vis, FTIR-ATR spectroscopy and determinations of degree of swelling, bulk and bulk density and specific mass. For UV–Vis spectroscopy the percentage of condensed and hydrolysable tannins in the extracts of fibers of the dry husks of Eucalyptus Citriodora was estimated and it was also determined your soluble solids. The study of bovine serum albumin (BSA) adsorption was carried out in batch with quantification by UV–Vis spectroscopy. The most efficient prepared resin obtained 71.6 ± 2.78% removal in a solution of 260 mg L−1 of BSA working in a better pH range of the aqueous solution of BSA in its isoelectric point, ~ 5, 32 ± 0.02, under these conditions, the synthesized resin can reach a maximum BSA adsorption capacity of ~ 26.7 ± 0.29 mg g−1 in 7 min. The new synthesized resin presents good prospects for adsorption of proteins or species that in their structure have higher percentages of amino functional groups or amino acids with aliphatic, acidic and/or basic hydrophilic characteristics.

Colorimetric and Fluorescent Sensing of Copper Ions in Water through o-Phenylenediamine-Derived Carbon Dots.

Fluorescent nitrogen and sulfur co-doped carbon dots (NSCDs) were synthesized using a simple one-step hydrothermal method starting from o-phenylenediamine (OPD) and ammonium sulfide. The prepared NSCDs presented a selective dual optical response to Cu(II) in water through the arising of an absorption band at 660 nm and simultaneous fluorescence enhancement at 564 nm. The first effect was attributed to formation of cuprammonium complexes through coordination with amino functional groups of NSCDs. Alternatively, fluorescence enhancement can be explained by the oxidation of residual OPD bound to NSCDs. Both absorbance and fluorescence showed a linear increase with an increase of Cu(II) concentration in the range 1-100 µM, with the lowest detection limit of 100 nM and 1 µM, respectively. NSCDs were successfully incorporated in a hydrogel agarose matrix for easier handling and application to sensing. The formation of cuprammonium complexes was strongly hampered in an agarose matrix while oxidation of OPD was still effective. As a result, color variations could be perceived both under white light and UV light for concentrations as low as 10 µM. Since these color changes were similarly perceived in tap and lake water samples, the present method could be a promising candidate for simple, cost-effective visual monitoring of copper onsite.

Carbon Nanostructures-Silica Aerogel Composites for Adsorption of Organic Pollutants.

Silica aerogels are a class of materials that can be tailored in terms of their final properties and surface chemistry. They can be synthesized with specific features to be used as adsorbents, resulting in improved performance for wastewater pollutants' removal. The purpose of this research was to investigate the effect of amino functionalization and the addition of carbon nanostructures to silica aerogels made from methyltrimethoxysilane (MTMS) on their removal capacities for various contaminants in aqueous solutions. The MTMS-based aerogels successfully removed various organic compounds and drugs, achieving adsorption capacities of 170 mg⋅g-1 for toluene and 200 mg⋅g-1 for xylene. For initial concentrations up to 50 mg⋅L-1, removals greater than 71% were obtained for amoxicillin, and superior to 96% for naproxen. The addition of a co-precursor containing amine groups and/or carbon nanomaterials was proven to be a valuable tool in the development of new adsorbents by altering the aerogels' properties and enhancing their adsorption capacities. Therefore, this work demonstrates the potential of these materials as an alternative to industrial sorbents due to their high and fast removal efficiency, less than 60 min for the organic compounds, towards different types of pollutants.

Chitosan-modified magnetic carbon nanomaterials with high efficiency, controlled motility, and reusability-for removal of chromium ions from real wastewater.

Hexavalent chromium Cr(VI) is one of the most hazardous oxygen-containing anions to human health and the environment. Adsorption is considered to be an effective method for the removal of Cr(VI) from aqueous solutions. Based on an environmental perspective, we used renewable biomass cellulose as carbon source and chitosan as functional material to synthesize chitosan-coated magnetic carbon (MC@CS) material. The synthesized chitosan magnetic carbons were uniform in diameter (~ 20nm) and contain a large number of abundant hydroxyl and amino functional groups on the surface, meanwhile owning excellent magnetic separation properties. The MC@CS exhibited high adsorption capacity (83.40mg/g) at pH 3 and excellent cycling regeneration ability when applied to Cr(VI) removal in water, removal rate of Cr(VI) (10mg/L) was still over 70% after 10 cycles. FT-IR and XPS spectra showed that electrostatic interaction and reduction with Cr(VI) are the main mechanisms of Cr(VI) removal by MC@CS nanomaterial. This work provides an environment-friendly adsorption material that could be reused for the removal of Cr(VI) in multiple cycles.

Biocompatibility and Biological Effects of Surface-Modified Conjugated Polymer Nanoparticles.

Semiconductiong polymer nanoparticles (Pdots) have a wide range of applications in biomedical fields including biomolecular probes, tumor imaging, and therapy. However, there are few systematic studies on the biological effects and biocompatibility of Pdots in vitro and in vivo. The physicochemical properties of Pdots, such as surface modification, are very important in biomedical applications. Focusing on the central issue of the biological effects of Pdots, we systematically investigated the biological effects and biocompatibility of Pdots with different surface modifications and revealed the interactions between Pdots and organisms at the cellular and animal levels. The surfaces of Pdots were modified with different functional groups, including thiol, carboxyl, and amino groups, named Pdots@SH, Pdots@COOH, and Pdots@NH2, respectively. Extracellular studies showed that the modification of sulfhydryl, carboxyl, and amino groups had no significant effect on the physicochemical properties of Pdots, except that the amino modification affected the stability of Pdots to a certain extent. At the cellular level, Pdots@NH2 reduced cellular uptake capacity and increased cytotoxicity due to their instability in solution. At the in vivo level, the body circulation and metabolic clearance of Pdots@SH and Pdots@COOH were superior to those of Pdots@NH2. The four kinds of Pdots had no obvious effect on the blood indexes of mice and histopathological lesions in the main tissues and organs. This study provides important data for the biological effects and safety assessment of Pdots with different surface modifications, which pave the way for their potential biomedical applications.

Influence of DNA Type on the Physicochemical and Biological Properties of Polyplexes Based on Star Polymers Bearing Different Amino Functionalities

The interactions of two star polymers based on poly (2-(dimethylamino)ethyl methacrylate) with different types of nucleic acids are investigated. The star polymers differ only in their functionality to bear protonable amino or permanently charged quaternary ammonium groups, while DNAs of different molar masses, lengths and topologies are used. The main physicochemical parameters of the resulting polyplexes are determined. The influence of the polymer' functionality and length and topology of the DNA on the structure and properties of the polyelectrolyte complexes is established. The quaternized polymer is characterized by a high binding affinity to DNA and formed strongly positively charged, compact and tight polyplexes. The parent, non-quaternized polymer exhibits an enhanced buffering capacity and weakened polymer/DNA interactions, particularly upon the addition of NaCl, resulting in the formation of less compact and tight polyplexes. The cytotoxic evaluation of the systems indicates that they are sparing with respect to the cell lines studied including osteosarcoma, osteoblast and human adipose-derived mesenchymal stem cells and exhibit good biocompatibility. Transfection experiments reveal that the non-quaternized polymer is effective at transferring DNA into cells, which is attributed to its high buffering capacity, facilitating the endo-lysosomal escape of the polyplex, the loose structure of the latter one and weakened polymer/DNA interactions, benefitting the DNA release.

Towards Quantum-Chemical Level Calculations of SARS-CoV-2 Spike Protein Variants of Concern by First Principles Density Functional Theory.

The spike protein (S-protein) is a crucial part of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with its many domains responsible for binding, fusion, and host cell entry. In this review we use the density functional theory (DFT) calculations to analyze the atomic-scale interactions and investigate the consequences of mutations in S-protein domains. We specifically describe the key amino acids and functions of each domain, which are essential for structural stability as well as recognition and fusion processes with the host cell; in addition, we speculate on how mutations affect these properties. Such unprecedented large-scale ab initio calculations, with up to 5000 atoms in the system, are based on the novel concept of amino acid-amino acid-bond pair unit (AABPU) that allows for an alternative description of proteins, providing valuable information on partial charge, interatomic bonding and hydrogen bond (HB) formation. In general, our results show that the S-protein mutations for different variants foster an increased positive partial charge, alter the interatomic interactions, and disrupt the HB networks. We conclude by outlining a roadmap for future computational research of biomolecular virus-related systems.

Reductive Cleavage of C(sp2)–CF3 Bonds in Trifluoromethylpyridines

A reductive detrifluoromethylation protocol has been developed making use of an earth-abundant alkoxide base and silicon hydride species. A variety of pyridine and quinoline substrates bearing alkyl, aryl, and amino functional groups are reduced in moderate to high yields. The reaction is chemoselective for C(sp2)-CF3 groups located at the 2-position on the pyridine ring, leaving trifluoromethyl groups located elsewhere on the molecule intact. Preliminary mechanistic studies demonstrate that the combination of silane and base generates a strongly reducing system that may transfer an electron to electron-deficient π systems.

Preparation of molecularly imprinted silica particles with amino functionality for chiral separation of (±)-naproxen.

Herein is the synthesis and effective use of an S-naproxen (S-NP) enantioselective adsorbent material with amino functionality for the enantioseparation of a (±)-NP racemic mixture. To begin, the S-NP enantiomer of (3-aminopropyl)triethoxysilane was used to create an amide derivative (S-NP-Si-NH2 ). In order to incorporate the S-NP enantiomeric species into the cross-linked material, the developed S-NP-Si-NH2 derivative was combined with tetraethoxysilane (TEOS) and subjected base-catalyzed sol-gel condensation polymerization procedure. The S-NP is released from the cross-linked matrix by alkaline hydrolysis and subsequent acidification, creating an enantioselective gap filled with cationic ions that are compatible with the S-NP during recombination. With the use of elemental analysis, nuclear magnetic resonance (NMR), and Fourier transform infrared (FTIR) spectroscopy, it was verified that the performed chemical processes on the monomeric precursor and the resulting S-NP molecularly imprinted material (S-NP-Sil) were successful. Furthermore, the morphology alterations were analyzed using scanning electron microscopy images of the sorbent surface. The produced adsorbent particles were also used in the chiral separation of a (±)-NP racemic combination utilizing a column approach, with encouraging separation results shown in both the first loading run (59% ee of R-NP) and the second elution run (85% ee of S-NP).

Enhanced activity of Fe/Mn nanoparticles using a response surface methodology and mechanism for removing oxytetracycline and copper ion

As feed additives, oxytetracycline (OTC) and copper ion (Cu(II)) are often detected in livestock and poultry farming wastewater. To address this issue, firstly, the synthesis conditions of Fe/Mn nanoparticles (Fe/Mn NPs) were initially optimized using a response surface methodology (RSM) to yield highly active Fe/Mn NPs, where the application of RSM significantly increased the Fe/Mn NPs’ efficiency in removing co-contamination OTC and Cu(II),respectively, from 45.8 to 86.2% and 14.9–67.2%. Secondly, scanning electron microscope and Nitrogen adsorption-desorption isotherms results showed that Fe/Mn NPs were composed of elliptic particles between 20 and 40 nm, a specific surface area of 59.5 m2 g−1, and a mean pore diameter of 5.27 nm. Fourier infrared spectrometer and X-ray photoelectron spectroscopy analysis revealed that amino, carboxyl and hydroxyl functional groups existed on the surface. Zeta potential indicated that Fe/Mn NPs maintained a high negative charge density between pH 1 and 11. These surface properties possessed by the green synthesized Fe/Mn NPs resulted in high adsorption efficiency for co-contamination OTC and Cu(II). Based on this, a removal mechanism based on a combination of complex-bridging effect, pore-filling, hydrogen bonding, surface complexation, ion exchange and electrostatic attraction was proposed. Finally, the assessment of Fe/Mn NPs used in swine wastewater demonstrated that both 99.9% OTC and 55.6% Cu(II) were removed.

A Sensitive Immunochromatographic Test Strip Based on Hydrophobic Quantum Dots Incorporated into Mg/Fe Nanoflowers for HCG Detection

As the most widely used disposable paper-based diagnostic tool in the world, immunochromatographic test strips (ICTS) have occupied more and more positions in the field of rapid diagnosis due to their ease of operation and affordability. Therefore, the development of an easily prepared, sensitive, and accurate signal reporter is of great significance for the detection of some low-abundance biomarkers in clinical diagnosis. Herein, Mg/Fe layered double hydroxide nanoflowers (MF NFs) were selected as adsorption templates and sulfhydryl-functionalized, followed by one-step loading of hydrophobic CdSe/ZnS quantum dots in the organic phase via a metal-thiol covalent bond. After coating the reporter with branched polyethyleneimine (PEI), a novel ICTS fluorescent reporter was prepared. The modification of PEI not only improved the hydrophilicity of MF@CdSe/ZnS NFs but also introduced amino functional groups on the surface of the reporter for subsequent conjugation with antibodies. X-ray photoelectron spectroscopy, UV-vis absorption, X-ray diffraction, fluorescence spectroscopy, and infrared spectroscopy were used to characterize the composition of MF@CdSe/ZnS NFs. Under the optimal experimental conditions, the detection range of MF@CdSe/ZnS@PEI-ICTS for the model analyte HCG was 0.1–500 mIU/mL, and the limit of detection (LOD) reached was 0.1 mIU/mL. The potential for practical application was validated by the detection of HCG in spiked healthy human serum, showing overall recoveries between 90.48 and 116.1% with coefficients of variation that ranged from 3.66 to 12.91%.

Construction of Amino‐Functionalized Molecularly Imprinted Silica Particles for (±)‐Ofloxacin Chiral Separation

AbstractTo enantioselectively separate a (±)‐ofloxacin (OFX) racemic mixture, we describe the production and successful use of an S‐ofloxacin (S‐OFX) enantio‐selective sorbent with amino functional groups. An amide derivative was first synthesized by reacting the S‐OFX enantiomer with 3‐aminopropyltriethoxysilane (S‐OFX‐Si‐NH2). The generated S‐OFX‐Si‐NH2 derivative was then mixed with tetraethoxysilane (TEOS) and put through a base‐catalyzed sol‐gel condensation polymerization process to insert the S‐OFX enantiomeric species into the cross‐linked material. To facilitate recombination involving S‐OFX, an enantioselective gap is created by alkaline hydrolysis followed by acidification, freeing the S‐OFX from the crosslinked matrix and filling the resulting gaps with cationic ions compatible with the S‐OFX. Our chemical transformations of the monomeric precursor and the ensuing S‐OFX molecularly imprinted material (S‐OFX‐Sil) were confirmed by elemental analysis, nuclear magnetic resonance (NMR), and Fourier transform infrared spectroscopy (FTIR). In addition, scanning electron microscopy images of the sorbent surface were employed to comprehend the morphological adjustments. Both the first loading run (60 % ee of R‐OFX) and the second elution run (83 % ee of S‐OFX) using the manufactured adsorbent particles showed promising separation results.