Aggregation-resistant nanozyme containing accessible magnetite nanoparticles immobilized in monodisperse-porous silica microspheres for colorimetric assay of human genomic DNA

A new multimodal magnetic nanozyme and a reusable peroxymonosulfate oxidation catalyst: Manganese oxide coated-monodisperse-porous and magnetic core-shell microspheres

Monodisperse-porous, polydopamine and manganese oxide coated, core-shell type, magnetic SiO2 (MagSiO2@PDA@MnO2) microspheres 6.4 μm in size were synthesized for the first time, using magnetic, monodisperse-porous SiO2 (MagSiO2) microspheres 6.2 μm in size as the starting material. MagSiO2 microspheres were obtained by a recently developed method namely "staged shape templated hydrolysis and condensation protocol". In the synthesis, MagSiO2 microspheres were consecutively coated by polydopamine (PDA) and then by a MnO2 layer in the aqueous medium. The pore volume and the specific surface area of monodisperse-porous MagSiO2@PDA@MnO2 microspheres were measured as 0.59 cm3 g-1 and 154 m2 g-1, respectively. Their Mn and Fe contents were determined as 66 ± 1 mg g-1 and 165 ± 5 mg g-1 respectively. MagSiO2@PDA@MnO2 microspheres exhibited multimodal enzyme mimetic behavior with highly superior catalase-like, oxidase-like and peroxidase-like activities. The effective production of singlet oxygen (1O2) and superoxide anion (O2-*) radicals in MagSiO2@PDA@MnO2-peroxymonosulfate (PMS) system was demonstrated by ESR spectroscopy. By evaluating this property, MagSiO2@PDA@MnO2 microspheres were tried as a reusable catalyst for dye removal via peroxymonosulfate (PMS) activation in batch experiments for the first time. The degradation runs were made with, rhodamine B (Rh B), methyl orange (MO) and methylene blue (MB) as the pollutant. The core-shell type design allowing the deposition of porous MnO2 layer onto a large surface area provided very fast, instant removals with all dyes, via both physical adsorption and degradation via PMS activation. In the reusability experiments, the removal yields of MO and Rh B decreased 1.8% and 8.9% over five consecutive runs in batch fashion. MagSiO2@PDA@MnO2 microspheres exhibited very good functional and structural stability in consecutive dye degradations. No significant change was observed in Fe content of microspheres while Mn content exhibited a decrease of 7.4% w/w over 5 consecutive degradation runs.

Cibacron Blue F3GA ligand dye-based magnetic silica particles for the albumin purification

Dye-ligand affinity chromatography is among the increasingly popular affinity chromatography based on molecular recognition for the purification of albumin. This study focuses on the binding of Cibacron Blue F3GA ligand dye with magnetic silica particles and purification by separation. Mono-disperse silica particles with bimodal pore size distribution were employed as a high-performance adsorbent for human serum albumin (HSA) protein purification under equilibrium conditions. The synthesized ligand-dye affinity based magnetic silica particles were characterized by electron spin resonance, Fourier-transform infrared spectroscopy, scanning electron microscopy, vibrating sample magnetometer, elemental analysis, and dispersive X-ray analysis. The HSA purification performance of the proposed material in the presence of a magnetic field was relatively investigated using magnetic-based particles with similar morphologies. The maximum adsorption capacity for HSA in an artificial plasma medium was defined as 48.6 mg/g magnetic silica particle. By using the designed magnetic silica particles, 1.0 M NaCl solution was successfully utilized for obtaining quantitative desorption with HSA. However, continued HSA purification performances of magnetic-based particles were significantly lower concerning the ligand-dye magnetic silica particles. The purity of the removed albumin was about 97%. The magnetic silica particles could be utilized many times without decreasing their protein adsorption capacities remarkably.

3D-Printed Functional Hydrogel by DNA-Induced Biomineralization for Accelerated Diabetic Wound Healing

Chronic wounds in diabetic patients are challenging because their prolonged inflammation makes healing difficult, thus burdening patients, society, and health care systems. Customized dressing materials are needed to effectively treat such wounds that vary in shape and depth. The continuous development of 3D-printing technology along with artificial intelligence has increased the precision, versatility, and compatibility of various materials, thus providing the considerable potential to meet the abovementioned needs. Herein, functional 3D-printing inks comprising DNA from salmon sperm and DNA-induced biosilica inspired by marine sponges, are developed for the machine learning-based 3D-printing of wound dressings. The DNA and biomineralized silica are incorporated into hydrogel inks in a fast, facile manner. The 3D-printed wound dressing thus generates provided appropriate porosity, characterized by effective exudate and blood absorption at wound sites, and mechanical tunability indicated by good shape fidelity and printability during optimized 3D printing. Moreover, the DNA and biomineralized silica act as nanotherapeutics, enhancing the biological activity of the dressings in terms of reactive oxygen species scavenging, angiogenesis, and anti-inflammation activity, thereby accelerating acute and diabetic wound healing. These bioinspired 3D-printed hydrogels produce using a DNA-induced biomineralization strategy are an excellent functional platform for clinical applications in acute and chronic wound repair.

Recent advances in colorimetric sensors based on nanozymes with peroxidase-like activity

Nanozymes have been widely used to construct colorimetric sensors due to their advantages of cost-effectiveness, high stability, good biocompatibility, and ease of modification. The emergence of nanozymes greatly enhanced the detection sensitivity and stability of the colorimetric sensing platform. Recent significant research has focused on designing various sensors based on nanozymes with peroxidase-like activity for colorimetric analysis. However, with the deepening of research, nanozymes with peroxidase-like activity has also exposed some problems, such as weak affinity and low catalytic activity. In view of the above issues, existing investigations have shown that the catalytic properties of nanozymes can be improved by adding surface modification and changing the structure of nanomaterials. In this review, we summarize the recent trends and advances of colorimetric sensors based on several typical nanozymes with peroxidase-like activities, including noble metals, metal oxides, metal sulfides/metal selenides, and carbon and metal-organic frameworks (MOF). Finally, the current challenges and prospects of colorimetric sensors based on nanozymes with peroxidase-like activity are summarized and discussed to provide a reference for researchers in related fields.

Highly Specific Colorimetric Probe for Fluoride by Triggering the Intrinsic Catalytic Activity of a AgPt-Fe3O4 Hybrid Nanozyme Encapsulated in SiO2 Shells

Current colorimetric probes for fluoride (F^-) primarily rely on organic chromophores that often suffer from unsatisfactory selectivity, complex organic synthesis, and low aqueous compatibility. Herein, we proposed a highly specific colorimetric method for F^- with 100% aqueous compatibility by triggering the intrinsic peroxidase-like activity of a AgPt-Fe₃O₄ nanozyme encapsulated in SiO₂ shells. The excellent catalytic performance of the AgPt-Fe₃O₄ nanozyme serves as an ideal platform for sensitive colorimetric sensing. After being encapsulated in SiO₂, the enzyme-like activity of AgPt-Fe₃O₄ is inhibited and only F^- can exclusively etch the SiO₂ shell to expose the active site of the nanozyme, thereby inducing color changes via oxidation of the chromogenic substrate. The limit of detection of the proposed method can reach as low as 13.73 μM in aqueous solution, which is lower than the maximum allowable concentration (79 μM) stipulated in the World Health Organization drinking water regulation. More importantly, this method is highly specific toward F^- over other types of anions commonly found in environmental water, making it capable of analyzing sewage samples with very complex matrices. Finally, the nanoprobe is embedded into a test strip by electrostatic spinning to enable the rapid, visual, and on-site detection of F^-.

Recent trends in sorbents for bioaffinity chromatography

Isolation or enrichment of biological molecules from complex biological samples is mostly a prerequisite in proteomics, genomics, and glycomics. Different techniques have been used to advance the efficiency of the purification of biological molecules. Bioaffinity chromatography is one of the most powerful technique that plays an important role in the isolation of target biological molecules by the specific interactions with ligands that are immobilized on different support materials. This review examines the recent developments in bioaffinity chromatography particularly over the past 5 years in the literature. Also properties of supports, immobilization techniques, types of binding agents, and methods used in bioaffinity chromatography applications are summarized.

Glutathione detection in human serum using gold nanoparticle decorated, monodisperse porous silica microspheres in the magnetic form

A nanozyme for glutathione (GSH) detection in a broad concentration range was synthesized. GSH is usually detected up to an upper limit of 100 μM using current noble metal nanozymes due to the sharp decrease in the colorimetric response with the increasing GSH concentration. Strong inhibition of colorimetric reactions by GSH adsorbed onto noble metal based nanozymes in the form of non-porous, nanoscale particulate materials dispersed in an aqueous medium is the reason for the sharp decrease in the colorimetric response. In the present study, a new magnetic nanozyme synthesized by immobilization of Au nanoparticles (Au NPs) on magnetic, monodisperse porous silica microspheres (>5 μm) obtained by a "staged-shape templating sol-gel protocol" exhibited peroxidase-like activity up to a GSH concentration of 5000 μM. A more controlled linear decrease in the peroxidase-like activity with a lower slope with respect to that of similar nanozymes was observed with the increasing GSH concentration. The proposed design allowed the GSH detection in a broader concentration range depending on the adsorption of GSH onto the Au NPs immobilized on magnetic, monodisperse porous silica microspheres. A calibration plot allowing the detection of GSH in a broad concentration range up to 3300 μM was obtained using the magnetic nanozyme. The GSH concentration was also determined in human serum by elevating the upper detection range and adjusting the sensitivity of detection via controlling the nanozyme concentration.

Polymeric template assisted synthesis of monodisperse-porous manganese oxide microspheres: a new nanozyme with oxidase-like activity allowing biomolecule determination via bimodal sensing

New template assisted synthesis of monodisperse-porous MnO₂ microspheres and their usage as a nanozyme in the first bimodal sensing of ascorbic acid.