Real-Time Biosensing Bacteria and Virus with Quartz Crystal Microbalance: Recent Advances, Opportunities, and Challenges.

Continuous monitoring of pathogens finds applications in environmental, medical, and food industry settings. Quartz crystal microbalance (QCM) is one of the promising methods for real-time detection of bacteria and viruses. QCM is a technology that utilizes piezoelectric principles to measure mass and is commonly used in detecting the mass of chemicals adhering to a surface.

Selective isolation and sensitive detection of lysozyme using aptamer based magnetic adsorbent and a new quartz crystal microbalance system.

Magnetic chitosan beads and quartz crystal microbalance chip were decorated with lysozyme specific aptamer for isolation and detection of lysozyme, respectively. The lysozyme specific aptamer was immobilized on poly (dopamine) coated magnetic chitosan beads and the chip via Schiff base reaction. The percentage of the removal efficiency and purity of the isolated lysozyme from egg white were 87.

Surface plasmon resonance aptasensor for Brucella detection in milk.

A Surface Plasmon Resonance (SPR) aptasensor was developed for the detection of Brucella melitensis (B. melitensis) in milk samples. Brucellosis is a bacterial zoonotic disease with global distribution caused mostly by contaminated milk or their products.

Immobilization of Candida rugosa lipase on magnetic chitosan beads and application in flavor esters synthesis.

In this work, magnetic chitosan (MCH) beads were synthesized by phase-inversion method, and grafted with polydopamine (PDA) and then used for direct immobilization of Candida rugosa lipase by Schiff base reaction. The amount of immobilized enzyme and the retained activity were found to be 47.3 mg/g and 72.

Strong and weak cation-exchange groups generated cryogels films for adsorption and purification of lysozyme from chicken egg white.

Here, the macroporous poly(hydroxylmethyl methacrylate/glycidyl methacrylate [p(HEMA-GMA)] cryogels with large porous surface were prepared, and then the epoxy groups of the p(HEMA-GMA) cryogels were systematically modified into strong and weak cationic groups. The effects of initial protein concentrations, adsorption time, pH, salt concentrations and temperatures on adsorption efficiency of cation exchange cryogels for lysozyme were determined. The maximum lysozyme adsorption capacities of strong and weak cation exchange cryogels were found to be 188.

Fibrous polymer functionalized magnetic biocatalysts for improved performance.

Although enzymes are known for their excellent catalytic performance, industrial, medical or biotechnological applications should overcome some drawbacks like long-term stability under specific conditions of the application. Immobilized enzymes have offered advantages over soluble counterparts in many industrial and laboratory scale applications by increasing operational stability and reusability. When the immobilization matrix has magnetic properties, an additional advantage is obtained as simpler processing.

Catalytic Activity of Immobilized Chymotrypsin on Hybrid Silica-Magnetic Biocompatible Particles and Its Application in Peptide Synthesis.

In this work, novel silica hybrid magnetic particles with biocompatible surface were designed as a support for enzyme immobilization, and the immobilized chymotrypsin (CT) performance was clarified as a model biocatalyst. CT is used in food technology for drink clarification and protein hydrolysis. The enzyme was directly immobilized onto polydopamine-grafted magnetic silica particles (MNP@SiO@PDA-CT) via the Schiff base reaction.

Rapid and label-free detection of Brucella melitensis in milk and milk products using an aptasensor.

In this work, a novel quartz crystal microbalance (QCM) aptasensor is designed for the diagnosis of Brucella melitensis bacteria, which affects the Mediterranean fever (brucellosis) from the zoonotic diseases that are very common in the Middle East Countries. The method is based on the selection of B. melitensis bacterium from solutions using B.

Biodegradation of Cibacron Blue 3GA by insolubilized laccase and identification of enzymatic byproduct using MALDI-ToF-MS: Toxicity assessment studies by Daphnia magna and Chlorella vulgaris.

The presented paper describes a detailed study on the use of immobilized laccase for effective degradation of Cibacron Blue 3GA dye. The amount of laccase loading on the cyclic carbonate groups containing poly(hydroxyethyl methacrylate-co-vinylene carbonate), p(HEMA-co-VC), microbeads was 27.8 mg g, and the retained immobilized enzyme activity was 73% compared to free enzyme.

Design of an aptamer-based magnetic adsorbent and biosensor systems for selective and sensitive separation and detection of thrombin.

An aptasensor was designed for sensitive detection of thrombin using in biological fluids by integrating a magnetic aptamer-microbeads. To achieve this goal, the surface of gold plated QCM crystals was coated with L-cysteine and a thrombin binding DNA aptamer was immobilized on the L-cysteine coated QCM crystals surface via glutaraldehyde coupling. The binding interactions of thrombin to QCM crystals were characterized.

Fast and Sensitive Detection of in Milk Samples Using Aptamer-Functionalized Magnetic Silica Solid Phase and MCM-41-Aptamer Gate System.

General detection methods for include PCR analysis, immunologic methods, solid culturing techniques, and various microscopic studies. Milk and other food samples demonstrate an especially difficult challenge for direct detection, resulting from high biological contents. In this report, we aimed for fast detection of pathogen cells through an efficient magnetic capture and subsequent quick detection based on aptamer affinity.

Improvement stability and performance of invertase via immobilization on to silanized and polymer brush grafted magnetic nanoparticles.

In this study, magnetic nanoparticles (FeO) were modified sequentially with silica (FeO@SiO), glycidyl methacrylate (GMA) by surface initiated atom transfer radical polymerization (SI-ATRP) and hexamethylene diamine (as a spacer arm). The p(GMA) grafted and SA modified form (i.e.

Aminopyridine modified Spirulina platensis biomass for chromium(VI) adsorption in aqueous solution.

Chemical modification of Spirulina platensis biomass was realized by sequential treatment of algal surface with epichlorohydrin and aminopyridine. Adsorptive properties of Cr(VI) ions on native and aminopyridine modified algal biomass were investigated by varying pH, contact time, ionic strength, initial Cr(VI) concentration, and temperature. FTIR and analytical analysis indicated that carboxyl and amino groups were the major functional groups for Cr(VI) ions adsorption.

Staphylococcus aureus detection in blood samples by silica nanoparticle-oligonucleotides conjugates.

A fast, specific and sensitive homogeneous assay for Staphylococcus aureus detection was developed by measuring the activity of secreted nuclease from the bacteria via a modified DNA oligonucleotide. As biosensor format, an effective system, Nanokeepers as previously reported, were used for triggered release of confined fluorophores, and hence specific detection of S. aureus on nuclease activity was obtained.

Removal of bisphenol A from aqueous medium using molecularly surface imprinted microbeads.

The aim of this study is to prepare bisphenol A (BPA) imprinted polymers, which can be used for the selective removal of BPA from aqueous medium. The BPA-imprinted (MIP) and non-imprinted (NIP) microbeads were synthesized, and characterized by Zeta-sizer, FTIR, SEM and BET method. Bisphenol A was determined in solutions using liquid chromatography-mass spectroscopy (LC-MS).

A facile and efficient method of enzyme immobilization on silica particles via Michael acceptor film coatings: immobilized catalase in a plug flow reactor.

A novel method was developed for facile immobilization of enzymes on silica surfaces. Herein, we describe a single-step strategy for generating of reactive double bonds capable of Michael addition on the surfaces of silica particles. This method was based on reactive thin film generation on the surfaces by heating of impregnated self-curable polymer, alpha-morpholine substituted poly(vinyl methyl ketone) p(VMK).

Study of polyethyleneimine- and amidoxime-functionalized hybrid biomass of Spirulina (Arthrospira) platensis for adsorption of uranium (VI) ion.

This study investigates the potential application of the polyethyleneimine- (PEI) and amidoxime-modified Spirulina (Arthrospira) platensis biomasses for the removal of uranium ion in batch mode using the native biomass as a control system. The uranium ion adsorption was also characterized by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectra, zeta potential analysis, and surface area measurement studies. The effects of pH, biomass amount, contact time, initial uranium ion concentration, and ionic strength were evaluated by using native and modified algal biomass preparations.

Fibrous polymer grafted magnetic chitosan beads with strong poly(cation-exchange) groups for single step purification of lysozyme.

Lysozyme is an important polypetide used in medical and food applications. We report a novel magnetic strong cation exchange beads for efficient purification of lysozyme from chicken egg white. Magnetic chitosan (MCHT) beads were synthesized via phase inversion method, and then grafted with poly(glycidyl methacrylate) (p(GMA)) via the surface-initiated atom transfer radical polymerization (SI-ATRP).

Pathogen detection in complex samples by quartz crystal microbalance sensor coupled to aptamer functionalized core-shell type magnetic separation.

A quartz crystal microbalance sensor (QCM) was developed for sensitive and specific detection of Salmonella enterica serovar typhimurium cells in food samples by integrating a magnetic bead purification system. Although many sensor formats based on bioaffinity agents have been developed for sensitive and specific detection of bacterial cells, the development of robust sensor applications for food samples remained a challenging issue. A viable strategy would be to integrate QCM to a pre-purification system.

NanoKeepers: stimuli responsive nanocapsules for programmed specific targeting and drug delivery.

Bacterial resistance is a high priority clinical issue worldwide. Thus, an effective system that rapidly provides specific treatment for bacterial infections using controlled dose release remains an unmet clinical need. Herein, we report on the NanoKeepers approach for the specific targeting of S.

Development of a paper-type tyrosinase biosensor for detection of phenolic compounds.

A low-cost, portable, and disposable paper-type tyrosinase biosensor was developed for determination of phenolic compounds, using a paper-strip absorption method. Tyrosinase and a chromophore (3-methyl-2-benzothiazolinone hydrazone) were immobilized on paper strips to manufacture the biosensor, which was tested on a nontoxic substrate (l-dopamine). The biosensor was responsive to phenolic compounds such as 4-chlorophenol, catechol, m-cresol, and p-cresol.

Examination of fabrication conditions of acrylate-based hydrogel formulations for doxorubicin release and efficacy test for hepatocellular carcinoma cell.

The objective of the present study was to develop 2-hydroxypropyl methacrylate-co-polyethylene methacrylate [p(HPMA-co-PEG-MEMA)] hydrogels that are able to efficiently entrap doxorubicin for the application of loco-regional control of the cancer disease. Systemic chemotherapy provides low clinical benefit while localized chemotherapy might provide a therapeutic advantage. In this study, effects of hydrogel properties such as PEG chains length, cross-linking density, biocompatibility, drug loading efficiency, and drug release kinetics were evaluated in vitro for targeted and controlled drug delivery.

Pathogen detection by core-shell type aptamer-magnetic preconcentration coupled to real-time PCR.

The presence of pathogenic bacteria is a major health risk factor in food samples and the commercial food supply chain is susceptible to bacterial contamination. Thus, rapid and sensitive identification methods are in demand for the food industry. Quantitative polymerase chain reaction (PCR) is one of the reliable specific methods with reasonably fast assay times.