Cellular Interactions with Lubricin and Hyaluronic Acid–Lubricin Composite Coatings on Gold Electrodes in Passive and Electrically Stimulated Environments

Abstract

In the field of bionics, the long-term effectiveness of implantable bionic interfaces depends upon maintaining a “clean” and unfouled electrical interface with biological tissues. Lubricin (LUB) is an innately biocompatible glycoprotein with impressive antifouling properties. Unlike traditional antiadhesive coatings, LUB coatings do not passivate electrode surfaces, giving LUB coatings great potential for controlling surface fouling of implantable electrode interfaces. This study characterizes the antifouling properties of bovine native LUB (N-LUB), recombinant human LUB (R-LUB), hyaluronic acid (HA), and composite coatings of HA and R-LUB (HA/R-LUB) on gold electrodes against human primary fibroblasts and chondrocytes in passive and electrically stimulated environments for up to 96 h. R-LUB coatings demonstrated highly effective antifouling properties, preventing nearly all adhesion and proliferation of fibroblasts and chondrocytes even under biphasic electrical stimulation. N-LUB coatings, while showing efficacy in the short term, failed to produce sustained antifouling properties against fibroblasts or chondrocytes over longer periods of time. HA/R-LUB composite films also demonstrated highly effective antifouling performance equal to the R-LUB coatings in both passive and electrically stimulated environments. The high electrochemical stability and long-lasting antifouling properties of R-LUB and HA/R-LUB coatings in electrically stimulating environments reveal the potential of these coatings for controlling unwanted cell adhesion in implantable bionic applications.

Novel Boundary Lubrication Mechanisms from Molecular Pillows of Lubricin Brush-Coated Graphene Oxide Nanosheets

“…22−25 The biocompatibility of LUB has previously been demonstrated in a recent investigation toward the application of LUB surface coatings for in vivo bioionics, where the antifouling properties of LUB tethered to Au substrates were observed against human primary fibroblasts and chondrocytes. 26 The results of this study show that LUB surface coatings not only mitigate cell attachment and proliferation but also do not harm or damage the cell types investigated, highlighting the excellent biocompatibility of LUB in vivo.…”

“…The self-assembly mechanism of LUB is unique with respect to traditional end-grafted polymers and is derived from the intrinsic triblock structure of the molecule, − which consists of a heavily glycosylated mucin domain flanked by two adhesive end domains. Once bound to a surface via the highly adhesive end domains, the LUB molecule takes on a “loop” orientation, with the glycosylated portion of the biomolecule exposed to the bulk solution, creating a dense and uniform brush layer once the substrate is sufficiently populated. , The surface-bound LUB brush layer is well established as one of the primary boundary lubrication mechanisms within the cartilage/joints of mammals, and its function as a boundary lubricant is well documented throughout the literature. − The biocompatibility of LUB has previously been demonstrated in a recent investigation toward the application of LUB surface coatings for in vivo bioionics, where the antifouling properties of LUB tethered to Au substrates were observed against human primary fibroblasts and chondrocytes . The results of this study show that LUB surface coatings not only mitigate cell attachment and proliferation but also do not harm or damage the cell types investigated, highlighting the excellent biocompatibility of LUB in vivo.…”

Rapid Point-of-Care Electrochemical Sensor for the Detection of Cancer Tn Antigen Carbohydrate in Whole Unprocessed Blood

“…When in contact with a solid surface, LUB rapidly self-assembles into a telechelic brush. , This brush has properties that have direct applications in electrochemical sensing for two main reasons: (1) it is fully extended even at a relatively low grafting density (∼9 nm between end domains) and (2) the diffuse architecture of the LUB brush (>95% water) creates a flexible brush, , which is highly desirable for electrochemical sensors relying on electron transfer between tethered redox species and the electrode surface. LUB has been used successfully as an antifouling coating while still preserving the electrochemical properties of the underlying electrode surface in question. ,,,− Thus, the use of LUB can facilitate development and fabrication and enhance functionality of sensing platforms for point-of-care clinical applications. It drives rapid self-assembly, enables assembly on different electrode materials, acts as a linker for tethering the biorecognition element, generates a dynamic harmonic motion, prevents fouling, and does not passivate the electrode.…”