Determination of the Serum Concentrations of the Monoclonal Antibodies Bevacizumab, Rituximab, and Panitumumab Using Porous Membranes Containing Immobilized Peptide Mimotopes

Effective monoclonal antibody (mAb) therapies require a threshold mAb concentration in patient serum. Moreover, the serum concentration of the mAb Bevacizumab should reside in a specific range to avoid side effects. Methods for conveniently determining the levels of mAbs in patient sera could allow for personalized dosage schedules that lead to more successful treatments. This work utilizes microporous nylon membranes functionalized with antibody-binding peptides to capture Bevacizumab, Rituximab, or Panitumumab from diluted (25%) serum. Modification of the capture-peptide terminus is often crucial to creating the affinity necessary for effective binding. The high purity of eluted mAbs allows for their quantitation using native fluorescence, and membranes are effective in spin devices that can be used in any laboratory. The technique is effective over the therapeutic range of Bevacizumab concentrations. Future work aims at further modifications to develop rapid point-of-care devices and decrease detection limits.

Antifouling, antibacterial and non-cytotoxic transparent cellulose membrane with grafted zwitterion and quaternary ammonium copolymers

Copolymer brushes with different ratios of sulfobetaine methacrylate (SBMA) and [2-(Acryloyloxy)ethyl]trimethylammonium chloride (DAC) were grafted from transparent cellulose membrane (CM) via surface-initiated atom transfer radical polymerization (SI-ATRP) method for improving its antifouling and antibacterial performance. Surface concentrated copolymer grafting on the cellulose membranes can be obtained without significantly sacrificing the transparency and mechanical properties. The zwitterionic PSBMA chains of the copolymers can lead to an extremely hydrophilic surface with significantly reduced non-specific protein adsorption and bacterial attachment, therefore, leading to satisfying antifouling and antibacterial property. While the PDAC chains of the copolymers improved antibacterial performance against both Gram-positive and Gram-negative bacteria due to the presence of quaternary ammonium groups, the PDAC modified CM (CM-1) possessed best antibacterial performance, reaching to 95.1 % against S. aureus and 90.5 % against E. coli, respectively. More importantly, the biocompatibility of all grafted CM was retained, leading to over 100 % cell viability.

Specific purification of a single protein from a cell broth mixture using molecularly imprinted membranes for the biopharmaceutical industry

A surface imprinting method is presented herein for the development of a highly selective yet highly permeable molecularly imprinted membrane for protein separation and purification. The resultant protein imprinted membrane was shown to exhibit great potential for the efficient separation of the template protein from a binary mixture and a cell lysate solution, while maintaining high transport flux for complementary molecules. Bovine Serum Albumin (BSA) and Lysozyme (Lys) were individually immobilized on a cellulose acetate membrane as template molecules. In situ surface crosslinking polymerization was then used for protein imprinting on the membrane for a controlled duration. Both membranes showed high adsorption capacity towards template proteins in the competitive batch rebinding tests. In addition, the adsorption capacity could be greatly enhanced in a continuous permeation procedure, where the resultant membrane specifically adsorbed the template protein for more than 40 h. Moreover, this is the first report of purification of a specific protein from the cell broth mixture using a molecularly imprinted membrane. The protein imprinted membrane enables the transport of multiple non-template proteins with high permeation rate in a complex system, thus opening the way for high efficiency protein separation at a low cost for the industry.

Trypsin electrochemical sensing using two-dimensional molecularly imprinted polymers on 96-well microplates

Molecular imprinting is an efficient technology to create artificial receptors with antibody-like binding properties for a variety of applications such as separation and sensing. In this work, a new sensing method was introduced by combining a two-dimensional molecularly imprinted polymer (2D-MIP) film with copper oxide nanoparticles (CuO NPs) labeling for signal conversion and amplification. CuO labeling can effectively monitor the thickness of 2D-MIPs to achieve the best imprinting effect. Trypsin imprinted polymer based electrochemical sensor on 96-well microplates was constructed and a good dynamic response was observed in the range of 0.5-500 ng/mL. Furthermore, detections of trypsin in fetal bovine serum were demonstrated using the imprinted polymer thin films. Our electrochemical sensors possess an excellent specificity, fast kinetics, high sensitivity and low cost, which have great potential in biological analysis.