Parts-per-Million of Polyethylene Glycol as a Non-Interfering Blocking Agent for Homogeneous Biosensor Development

Abstract

Abstract.Many homogeneous assays are complicated by the adsorption of probe molecules by the surface of reaction vessels, which are often made of polypropylene or polystyrene-based plastics. To solve this problem, many protein and surfactant-based blocking agents are used. However, these blockers may interfere with intended assays by sequestering transition metal ions, inducing protein denaturing, generating air bubbles or making pores in membranes. Coating surfaces with polyethylene glycol (PEG) through covalent linkages have been proven to be an effective method to minimize protein adsorption.However, this method is more difficult to apply on plastic surfaces and is quite expensive. While unmodified PEG is often considered as a non-adsorbing polymer, in this Technical Note, we report that PEG at very low ppm can still effectively block plastic surfaces. This method works for DNA, protein and liposome-based assays as long as the molecular weight of PEG is larger than 2000. PEG works due to multivalent hydrophobic interaction from its repeating methylene units. This Technical Note will not only facilitate biosensor development, but also enhance our understanding of the interaction between various molecules and plastic surfaces.3

Prevention of doxorubicin sorptive losses in drug delivery studies using polyethylene glycol

“…[17][18][19] PEG effect on sorptive loss of DOX Currently, there are several established agents used for surface blocking including BSA and the surfactants Tween and Triton X-100, which are efficacious in preventing sorptive losses in various bioassays. 20 However, these traditional blocking methods have limitations such as additional and timeconsuming plate treatment steps (e.g., 0.5-12 h for BSA blocking), generating air bubbles in the sample solution during mixing, and potential for interference with DOX loading onto nanomaterials. All these technical issues can be overcome by using low concentrations of PEG as the blocking agent.…”

Silicon Nanowire Biosensor for Highly Sensitive and Multiplexed Detection of Oral Squamous Cell Carcinoma Biomarkers in Saliva

“…In this work, amino-PEG was used to passivate any unreacted aldehydic groups so as to reduce non-specific protein bindings due to any multivalent hydrophobic interaction from PEG's repeating methylene units. 37 After specific proteins are bound to these antibodyfunctionalized SiNW surfaces, the charges exhibited by these bound protein molecules in the measuring the buffer of a certain pH value can then directly affect the magnitude of current flow through the SiNW. 20 The isoelectric point (pI) of IL-8 is predicted to be 9.02, and the pI of TNF-α is within the range from 5.3 to 8.0.…”

Centrifugal microfluidics for sorting immune cells from whole blood

“…4a). Both PEG and PLL-PEG have been commonly used as blockers, given the multivalent hydrophobic interactions from its repeating methylene units in PEG [22, 23], and the polycationic PEG grafted copolymer with a PLL backbone which strongly adsorbs onto negatively charged surfaces in aqueous solution [24]. Detailed explanation as how exactly trypsin, which is commonly used for detaching adherent cells, interact with PDMS to prevent blood cell adhesion will require an in-depth investigation and is beyond the scope of this work.…”