Enhancing surface immobilization of bioactive moleculesviaa silica nanoparticle based coating

Abstract

Surface modification is of significant interest in biomaterials, biosensors, and device biocompatibility. Immobilization of bioactive or biomimetic molecules is a common method of disguising a foreign body as host tissue to decrease the foreign body response (FBR) and/or increase device–tissue integration. For example, in neural interfacing devices, immobilization of L1, a neuron-specific adhesion molecule, has been shown to increase neuron adhesion and reduce inflammatory gliosis on and around the implants. However, the activity of modified surfaces is limited by the relatively low concentration of the immobilized component, in part due to the low surface area of flat surfaces available for modification. In this work, we demonstrate a novel method for increasing the device surface area by attaching a layer of thiolated silica nanoparticles (TNPs). This coating method results in an almost two-fold increase in the immobilized L1 protein. L1 immobilized nanotextured surfaces showed a 100% increase in neurite outgrowth than smooth L1 immobilized surfaces without increasing the adhesion of astrocytes in vitro. The increased bioactivity observed in the cell assay was determined to be mainly due to the higher protein surface density, not the increase in surface roughness. In addition, we tested immobilization of a superoxide dismutase mimic (SODm) on smooth and roughened substrates. The SODm immobilized rough surfaces demonstrated an increase of 145% in superoxide scavenging activity compared to chemically matched smooth surfaces. These results not only show promise in improving biomimetic coating for neural implants, but may also improve surface immobilization efficacy in other fields such as catalysts, protein purification, sensors, and tissue engineering devices.

Nano-Architectural Approaches for Improved Intracortical Interface Technologies

“…The nano-architecture surfaces provide cues to initiate the production of ECM molecules necessary for initial cell attachment to surfaces ( Cui et al, 2018 ). Furthermore, the nano-architecture surface results in an increased adsorption of those ECM molecules necessary for cell attachment ( Salakhutdinov et al, 2008 ; Ereifej et al, 2013b ; Woeppel et al, 2018 ). These surface-cell topographical interactions initiate the cellular response that can lead to decreased inflammation around implanted IME.…”

“…Additionally, Xie et al (2016) found that 47% of neurons seeded on a nano-patterned microseive array with nano-grooves 230 nm wide with a period of 600 nm showed alignment along the direction of the grooves. Recently, Woeppel et al (2018) found that roughening the silicon substrate surface with silica nanoparticles 60 nm in diameter on average, followed by L1 protein adhesion lead to increase neuron outgrowth. Notably, Nissan et al observed an increase in the number of neurites and branching points toward more complicated structures, when neurons were seeded onto silver nano-lines (180–500 nm wide, 160 nm high, and 700 nm apart) made via EBL.…”

Nanoparticle Doped PEDOT for Enhanced Electrode Coatings and Drug Delivery

“…First, the size, porosity, and surface chemistry of silica nanoparticles are modifiable, and can be tuned to specific applications. Incorporation of the thiol‐containing silane mercaptopropyl trimethoxysilane (MTS) produces thiol groups at the particle surface . These thiol groups can be efficiently oxidized to sulfonates under relatively mild hydrogen peroxide oxidation .…”

Engineering bioactive synthetic polymers for biomedical applications: a review with emphasis on tissue engineering and controlled release

“…17,[30][31][32] This straightforward method has proven effective for promoting cell attachment and proliferation and for triggering even more sophisticated responses, such as cell differentiation and tissue maturation. 17,33,34 The recent literature illustrates even more elaborate methods for engineering SyPs with ECM proteins. 17,[35][36][37][38] For instance, Barros et al 17 reported the design of SyP-ECM hydrogels for neural regeneration applications.…”