Ultra-low fouling and functionalizable zwitterionic coatings grafted onto SiO2 via a biomimetic adhesive group for sensing and detection in complex media.
ABSTRACT Non-specific protein binding from human plasma and serum has severely hindered the full capabilities of biosensors concerned with cancer biomarker detection. Currently, there is a strong desire for developing new materials which allow for the convenient attachment of an ultra-low fouling and functionalizable surface coating which can be used for highly sensitive and label-free detection of target analytes directly from complex media. In this work, a short 20 min in situ "graft to" protocol using Tris pH 8.5 buffer was developed for zwitterionic carboxybetaine methacrylate (CBMA) polymer conjugates containing the adhesive biomimetic moiety, 3,4-dihydroxy-L-phenylalanine (DOPA), on SiO(2) substrates. Using a surface plasmon resonance (SPR) biosensor, different buffers, pH values, salt concentrations, and temperatures were investigated for determining the "graft to" conditions that yield dense polymer films which both minimize non-specific protein adsorption and maximize antibody immobilization. The optimized surface coatings were shown to be highly protein resistant to 100% human blood plasma and serum. Subsequent antibody functionalized surfaces without any blocking agents enabled the specific detection of the cancer biomarker ALCAM directly from undiluted human serum down to 64 ng/mL. The successful use of this zwitterionic surface coating for detection from complex media on SiO(2) surfaces indicates its potential for broad impacts in the development of implantable medical devices, in vivo diagnostics, and nano-scale biosensors.
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ABSTRACT: Catechols represent an important and versatile building block for the design of mussel-inspired synthetic adhesives and coatings. Indeed, their ability to establish large panoply of interactions with both organic and inorganic substrates has promoted catechol as a universal anchor for surface modifications. In addition to its pivotal role in adhesive interfaces, the catechol unit recently emerged as a powerful building block for the preparation of a large range of polymeric materials with intriguing structures and fascinating properties. The importance of catechols as efficient anchoring groups has been highlighted in recent excellent reviews partly dedicated to the characterization of their adhesive mechanisms onto surfaces and to their applications. The aim of this paper is to review for the first time the main synthetic approaches developed for the design of novel catechol-based polymer materials. We will also highlight the importance of these groups as versatile platforms for further functionalization of the macromolecular structures, but also surfaces. This will be illustrated by briefly discussing some advanced applications developed from these catechol-modified polymers. The review is organized according to the chemical structure of the functionalized catechol polymers. Chapter 1 discusses polymers bearing catechols embedded into the polymer main chain. Chapter 2 focuses on the attachment of catechol moieties as pendant groups and Chapter 3 describes the different approaches for incorporation of the catechol unit at the extremity of well-defined polymers.Progress in Polymer Science. 01/2013; 38(1):236–270.
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ABSTRACT: A polymeric platform for immunodiagnostic bioassay was constructed based on biostable polymeric support and two functional monomers, low-fouling methacryloyloxyethyl phosphorylcholine (MPC) and acrylic acid (AAc), by a photografting polymerization approach. Covalent binding of antibody to pAAc chains was achieved by activating carboxyl with NHS/EDC partner. The resultant surface showed obvious suppression of nonspecific protein adsorption and platelet adhesion relative to the control sample, exhibiting good anti-bioadhesion performances. Based on the polymer-supported matrix, a highly sensitive antibody–antigen specific recognition was confirmed in both native plasma and diluted human plasma due to the enhanced antibody loading capacity and lowered bioadhesion as compared to the reference.Materials Science and Engineering: C. 01/2014; 36:57–64.
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ABSTRACT: Rapid diagnosis of infectious diseases and timely initiation of appropriate treatment are critical determinants that promote optimal clinical outcomes and general public health. Conventional in vitro diagnostics for infectious diseases are time-consuming and require centralized laboratories, experienced personnel and bulky equipment. Recent advances in biosensor technologies have potential to deliver point-of-care diagnostics that match or surpass conventional standards in regards to time, accuracy and cost. Broadly classified as either label-free or labeled, modern biosensors exploit micro- and nanofabrication technologies and diverse sensing strategies including optical, electrical and mechanical transducers. Despite clinical need, translation of biosensors from research laboratories to clinical applications has remained limited to a few notable examples, such as the glucose sensor. Challenges to be overcome include sample preparation, matrix effects and system integration. We review the advances of biosensors for infectious disease diagnostics and discuss the critical challenges that need to be overcome in order to implement integrated diagnostic biosensors in real world settings.Expert Review of Molecular Diagnostics 02/2014; · 4.09 Impact Factor