Control of Protein Affinity of Bioactive Nanocellulose and Passivation Using Engineered Block and Random Copolymers

Abstract

We passivated TEMPO-oxidized cellulose nanofibrils (TOCNF) toward human immunoglobulin G (hIgG) by modification with block and random copolymers of poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) and poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA). The block copolymers reversibly adsorbed on TOCNF and were highly effective in preventing nonspecific interactions with hIgG, especially if short PDMAEMA blocks were used. In such cases, total protein rejection was achieved. This is in contrast to typical blocking agents, which performed poorly. When an anti-human IgG biointerface was installed onto the passivated TOCNF, remarkably high affinity antibody-antigen interactions were observed (0.90 ± 0.09 mg/m(2)). This is in contrast to the nonpassivated biointerface, which resulted in a significant false response. In addition, regeneration of the biointerface was possible by low pH aqueous wash. Protein A from Staphylococcus aureus was also utilized to successfully increase the sensitivity for human IgG recognition (1.28 ± 0.11 mg/m(2)). Overall, the developed system based on TOCNF modified with multifunctional polymers can be easily deployed as bioactive material with minimum fouling and excellent selectivity.

Paper-based diagnostics in the antigen-depletion regime: High-density immobilization of rcSso7d-cellulose-binding domain fusion proteins for efficient target capture

“…(Credou and Berthelot, 2014; Nery and Kubota, 2016; Shen et al, 2016; Yu et al, 2012; Zhao et al, 2016) These chemical pre-processing methods limit production throughput, and require efficient surface passivation steps following binder immobilization in order to prevent the non-specific adsorption of patient proteins and free detection reagents. (Vuoriluoto et al, 2016; Zhu et al, 2014) Additionally, stochastic chemical conjugation methods result in the non-oriented immobilization of the binding species, which can reduce the solvent accessibility of the target-binding paratope and result in an inactive sub-population of immobilized binder. (Song et al, 2012)…”

Characterization of Covalently Bound Anti‐Human Immunoglobulins on Self‐Assembled Monolayer Modified Gold Electrodes

“…It may be noted that in order to avoid nonspecific adsorption of antibodies on the gold electrode treatment of the functionalized surface with blocking reagents such as bovine albumin serum, polyethylene glycol derivatives, casein, tween 20, etc. may be employed to enhance the selectivity and sensitivity of the sensor …”

“…All the above reveal the importance of investigating the surface chemistry of biomodified materials, including noble metals, nanoparticles, metal oxides, polymers etc., for the optimization of the incorporation of biomolecules in miniaturized electronic sensors. Especially, the incorporation of biorecognition sites on inert metal surfaces such as gold gives rise to biosensors taking advantage of different physical quantifiable signals including electrochemical sensing, surface plasmon resonance (SPR), or the lately gaining significant attention electrolyte gated thin film transistors (EG‐TFTs) based biosensors. Biorecognition elements (e.g., proteins, DNA, cells, etc.)…”

A Label-Free and Ultrasensitive Immunosensor for Detection of Human Chorionic Gonadotrophin Based on Graphene FETs

“…Finally, hCG solution with concentrations ranging from 1 pg·mL −1 to 100 ng·mL −1 were prepared by diluting 1 µg·mL −1 stock solution with PBS buffer and then incubated on graphene channel at 4 °C for 4 h to ensure the strong antibody/antigen binding. Finally, the samples were treated with 100 mM ethnolamine for 30 min and washed with DIW for 5 min to remove non-specific passivation followed by vacuum dry at 30 Torr for an hour before characterization [ 25 ].…”