Stereoselective Voltammetric Biosensor for Myo-Inositol and D-Chiro-Inositol Recognition

A novel dual-impedance-analysis EQCM system—investigation of bovine serum albumin adsorption on gold and platinum electrode surfaces

Kinetics of Adsorption of Lysozyme and Bovine Serum Albumin at the Air–Water Interface from a Binary Mixture

Adsorption of bovine serum albumin at the air/water interface and its effect on the formation of DPPC surface film

Cibacron Blue F3GA was covalently coupled with poly(ethylene glycoldimethacrylate-2-hydroxyethylmethacrylate) [poly(EGDMA-HEMA)] microbeads via the nucleophilic substitution reaction between the chloride of its triazine ring and the hydroxyl groups of the HEMA molecules under alkaline conditions. The affinity sorbent carrying 16.5 μmol Cibacron Blue F3GA/g polymer was then used for bovine serum albumin (BSA) adsorption from aqueous protein solutions and from human plasma in a packed-bed column. The BSA adsorption capacity of the microbeads decreased with an increase in the recirculation rate. High adsorption rates were observed at the beginning, then equilibrium was gradually achieved in about 60 min. The BSA concentration in the mobile phase was also effective on adsorption. BSA adsorption was first increased with BSA concentration, then reached a plateau that was about 57.3 mg BSA/g. Higher BSA adsorption was observed at lower ionic strength. The maximum adsorption was observed at pH 5.0, which is the isoelectric pH of BSA. Higher human serum albumin adsorption was achieved from human plasma (109.6 mg HSA/g). High desorption ratios (over 94% of the adsorbed albumin) were achieved by using 1.0M NaSCN (pH 8.0) in 30 min. It was observed that albumin could be repeatedly adsorbed and desorbed without a significant loss in adsorption capacity.

Sequential and competitive adsorption of bovine serum albumin and β-lactoglobulin, and their resistance to exchange with α-lactalbumin and β-casein

Protein adsorption on crosslinked polydimethylsiloxane using total internal reflection fluorescence

The electrochemical monitoring of (i) label‐free and (ii) indicator based DNA hybridization related to Microcystis spp. (MYC) DNA was explored in this study via multiwalled carbon nanotube (MWCNT) based screen printed graphite electrodes (SPEs). The effect of CNT modification onto SPE was firstly investigated by measuring the oxidation signals of guanine and adenine before/after DNA immobilization onto the surfaces of bare SPE, MWCNT‐SPE and SWCNT‐SPE in combination with differential pulse voltammetry. MYC‐DNA hybridization was monitored by following two procedures and measuring the guanine oxidation signal and the reduction signal of cobalt‐phenanthroline Co(phen)33+. Voltammetric results were complemented with electrochemical impedance spectroscopy (EIS).

Competitive adsorption of bovine serum albumin and n-dodecyl-β-d-maltoside in foam films

Albumin adsorption on oxide thin films studied by spectroscopic ellipsometry

In this work, we examined adsorption of bovine serum albumin (BSA) and lysozyme (LYZ) on carboxylated (CM), hydroxylated (HM), and graphitized (GM) multiwall carbon nanotubes (CNTs). All adsorption isotherms were fitted well with the Langmuir model. The maximum adsorption capacities (mg/g) followed the order HM > CM > GM for both BSA and LYZ, which positively related to the surface areas of the three CNTs. However, after surface area normalization, adsorption capacities (mg/m2) followed the order HM > GM > CM for BSA and GM > CM > HM for LYZ, indicating that functional groups and hydrophobicity of CNTs also contributed to protein adsorption. In addition, adsorption of LYZ (81 800–90 700 mg/g) was at least 300 times higher than that of BSA (132–266 mg/g) for all the three CNTs. BSA molecules on CNTs surface mainly showed a monolayer adsorption while LYZ adsorption was through multilayers. Moreover, BSA at the tested concentrations was able to disperse the three CNTs. However, no significant dispersion was observed for all the three CNTs in the presence of LYZ at the same concentrations. The results revealed that α-helix structure of both the proteins diminished after interacting with the three CNTs. This research will be helpful to clarify the mechanism of protein adsorption on functionalized CNTs and would be of importance for using CNTs in biomedical and pharmaceutical fields.

Understanding the mechanism of protein adsorption and designing materials with high sensitivity, high specificity and fast response are critical to develop the next-generation biosensing and diagnostic platforms. Mesoporous materials with high surface area, tunable pores, and good thermal/hydrostatic stabilities are promising candidates in this field. Because of the excellent biocompatibility, titanium dioxide has received an increasing interest in the past decade for biomedical applications. In this work, we synthesized mesoporous titanium dioxide with controlled pore sizes (7.2-28.0 nm) and explored their application for bovine serum albumin (BSA) adsorption. Scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and nitrogen adsorption/desorption experiments were performed to characterize the mesoporous TiO2 samples before and after BSA adsorption. Isothermal microcalorimetry was applied to measure both the adsorption heat and conformation rearrangement heat of BSA in those mesopores. We also carried out thermogravimetry measurements to qualitatively estimate the concentration of hydroxyl groups, which plays an important role in stabilizing BSA in-pore adsorption. The adsorption stability was also examined by leaching experiments. The results showed that TiO2 mesopores can host BSA adsorption when their diameters are larger than the hydrodynamic size of BSA (∼9.5 nm). In larger mesopores studied, two BSA molecules were adsorbed in the same pores. In contrast to the general understanding that large mesopores demonstrate poor stabilities for protein adsorptions, the synthesized mesoporous TiO2 samples demonstrated good leaching stabilities for BSA adsorption. This is probably due to the combination of the mesoporous confinement and the in-pore hydroxyl groups.

Microcalorimetric study of the adsorption of native and mono-PEGylated bovine serum albumin on anion-exchangers

Accelerated synthesis of gold nanoparticles (AuNPs) in charged microdroplets produced by electrospray ionization (ESI) was exploited to modify the surface of graphite screen-printed electrodes (GSPEs). The deposited AuNPs were then functionalized by the charged microdroplets deposition of 6-ferrocenyl-hexanethiol (6Fc-ht) solutions that act as reducing and stabilizing agents and provide electrochemical properties for the modified electrodes. The morphology and composition of the AuNPs were characterized by scanning electron microscopy (SEM). Cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) were used to investigate the electrochemical behavior of the modified electrodes. The results showed that the ESI microdroplets deposition technique produces uniform and well-dispersed AuNPs on GSPE, and optimal conditions for deposition were identified, enhancing GSPE electrocatalytic performance. Further functionalization by ESI microdroplets of AuNPs with 6Fc-ht demonstrated improved redox properties compared with the conventional self-assembled monolayer (SAM) method, highlighting the technique’s potential for the easy and fast functionalization of electrochemical sensors.

Adsorption and desorption behavior of bovine serum albumin (BSA) and gelatin on the surface of stainless steel particles are studied. The amount of BSA adsorbed increases significantly with temperature above 60°C whereas that of gelatin decreases slightly with increasing temperature. Results of adsorption experiments with S-carboxymethylated BSA show that the thermal aggregation of BSA molecules at the surface through intermolecular thiol-disulfide interchange reactions plays an important role in the adsorption of BSA at elevated temperatures. Furthermore, the initial desorption rate constants and residual amounts of the two proteins during caustic and enzymatic cleanings of the fouled particles are compared under various conditions. As a result, a large difference is found in the temperature dependence of the initial desorption rate constant in caustic cleaning, suggesting different modes of adsorption of the proteins.

Adsorption of bovine serum albumin on CoCrMo surface: Effect of temperature and protein concentration