Silicone Surface with Drug Nanodepots for Medical Devices

Abstract

An ideal surface of poly(dimethylsiloxane) (PDMS) medical devices requires sustained drug release to combat various tissue responses and infection. At present, a noncovalent surface coating with drug molecules using binders possesses a detachment problem, while covalently linking drug molecules to the surface provides no releasable drug. Here, a platform that allows the deposition of diverse drugs onto the PDMS surface in an adequate quantity with reliable attachment and a sustained-release character is demonstrated. First, a PDMS surface with carboxyl functionality (PDMS-COOH) is generated by subjecting a PDMS piece to an oxygen plasma treatment to obtain silanol moieties on its surface, then condensing the silanols with (3-aminopropyl)triethoxysilane molecules to generate amino groups, and finally reacting the amino groups with succinic anhydride. The drug-loaded carriers with hydroxyl groups on their surface can then be esterified to PDMS-COOH, resulting in a PDMS surface covalently grafted with drug-filled nanocarriers so that the drugs inside the securely grafted carriers can be released. Demonstrated here is the covalent linking of the surface of a PDMS endotracheal tube with budesonide-loaded ethylcellulose nanoparticles. A secure and high drug accumulation at the surface of the tubes (0.025 mg/cm2) can be achieved without changes in its bulk property such as hardness (Shore-A), and sustained release of budesonide with a high release flux during the first week followed by a reduced release flux over the subsequent 3 weeks can be obtained. In addition, the grafted tube possesses more hydrophilic surface and thus is more tissue-compatible. The grafted PDMS pieces show a reduced in vitro inflammation in cell culture and a lower level of in vivo tissue responses, including a reduced level of inflammation, compared to the unmodified PDMS pieces, when implanted in rats. Although demonstrated with budesonide and a PDMS endotracheal tube, this platform of grafting a PDMS surface with drug-loaded particles can be applied to other drugs and other devices.

Nondestructive tissue analysis for ex vivo and in vivo cancer diagnosis using a handheld mass spectrometry system

“…The probe tip material, the conduit tubes, and the chemical used were PDMS, PTFE, and water, respectively. PDMS and PTFE are widely recognized as biocompatible materials and have a long history of utilization in medical devices including catheters and long-term implants (37). Our experiments demonstrate that the low volume (10 μl or less) of high-purity water used caused no effect to the tissues analyzed in vivo and ex vivo.…”

Nanoscience‐Based Strategies to Engineer Antimicrobial Surfaces

“…Most in vitro antimicrobial tests use a static “closed” testing system,[9b,34b,42] whereas in vivo the implant has to face a dynamic, continuously changing, mechanically unstable, and predominantly fluid environment. [9b,12,34a,43] To date, there is no widely accepted methodology available to precisely and reproducibly evaluate the antimicrobial efficiency of new nano‐based solutions proposed for antimicrobial surfaces . In this respect, controlled and standardized testing conditions that closely mimic the human in vivo environment need to be developed for the evaluation of antimicrobial efficiency.…”

“…A large variety of surfaces are obtained, depending on the modification of the solid support (physical, chemical, or both) and the supplementary association with antibacterial components (bio‐, synthetic molecules, membranes, and assemblies). Antibacterial surfaces based on nanoscience approaches include: i) hydrogels or hydrogel‐like films with temporal release of active agents, ii) solid supports decorated with: polymer brushes, nanoparticles, nanocarriers, nanostructures, and nanoreactors, which are catalytically active nanocompartments, which produce reactive agents in situ, and iii) micro‐ and nanopatterned surface structures . Nanoscience‐based strategies to design antimicrobial surfaces have the advantage of being bottom‐up approaches, which allow combination of different biosynthetic, and synthetic compounds and assemblies at molecular level.…”

Layer-by-Layer Nanocoating of Antiviral Polysaccharides on Surfaces to Prevent Coronavirus Infections

“…The IOL can, however, allow adhesion of many kinds of bacteria and lead to post-operative infections with catastrophic effects in some patients. LbL nanocoating of the lenses with hyaluronic and chitosan had significant anti-adhesion and bactericidal effects that reduced the risk of postoperative infections [ 83 , 84 ].…”