Fabrication of Polymeric Coatings with Controlled Microtopographies Using an Electrospraying Technique

Abstract

Surface topography of medical implants provides an important biophysical cue on guiding cellular functions at the cell-implant interface. However, few techniques are available to produce polymeric coatings with controlled microtopographies onto surgical implants, especially onto implant devices of small dimension and with complex structures such as drug-eluting stents. Therefore, the main objective of this study was to develop a new strategy to fabricate polymeric coatings using an electrospraying technique based on the uniqueness of this technique in that it can be used to produce a mist of charged droplets with a precise control of their shape and dimension. We hypothesized that this technique would allow facile manipulation of coating morphology by controlling the shape and dimension of electrosprayed droplets. More specifically, we employed the electrospraying technique to coat a layer of biodegradable polyurethane with tailored microtopographies onto commercial coronary stents. The topography of such stent coatings was modulated by controlling the ratio of round to stretched droplets or the ratio of round to crumped droplets under high electric field before deposition. The shape of electrosprayed droplets was governed by the stability of these charged droplets right after ejection or during their flight in the air. Using the electrospraying technique, we achieved conformal polymeric coatings with tailored microtopographies onto conductive surgical implants. The approach offers potential for controlling the surface topography of surgical implant devices to modulate their integration with surrounding tissues.

Parts‐per‐million polyhedral oligomeric silsesquioxane loading induced mechanical reinforcement in polyethylene nanocomposites. When small and well‐dispersed yields big

“…The R groups are designed to promote solubilization of POSS into a polymeric matrix or integration by wetting, London forces, hydrogen bonding, or covalent and ionic bonding when the R groups are reactively functionalized 1,2 . The modification of physical properties promoted by POSS, tethered, or untethered, has been gradually recognized and the applications are growing in diverse high‐technology fields like electronics, 3‐5 smart medical devices, 6‐15 coatings, 16 templates for lithography and nonlinear optics, 17,18 and sensors 19,20 …”

Co‐(POSS#‐styrene) nanocomposites reduced the glass‐transition temperature, rubbery modulus, and melt viscosity of entangled polystyrene

“…Hence, POSS is finding multiple applications when copolymerized with other monomers, or when molecularly dispersed as untethered nanoparticles, acting as additive [1][2][3][4][5]. The applications continue growing and cover multiple fields, for example, electronics [6][7][8][9][10], biomedical [11][12][13][14][15][16][17], shape memory materials [18][19][20][21][22], electronic and architectural coatings [23][24][25][26], templates for lithography [27][28][29], nonlinear optics [30], and sensors for precise molecular recognition [31,32]. The reader is referred to several reviews on POSS synthesis, polymerization, and applications [1,2,33].…”

Development of a Bioactive Polymeric Drug Eluting Coronary Stent Coating Using Electrospraying

“…2 Other imperfections that have previously been reported with stent coatings, such as polymer webbing between struts, buckling and coating fragmentation, for example, were not evident in any of the coatings produced in the present study. 2 Recent work by Guo et al, 10 demonstrated that polymer deposition on to coronary stents by means of ES can be fine-tuned to allow control over the polymer surface topography at a micro scale, which may allow for recapitulation of the topographical features of tissue and therefore promote integration of the device in vivo. 10 We applied this method to produce coatings using a polymer that has been designed such that it mimics RGD.…”

“…2 Recent work by Guo et al, 10 demonstrated that polymer deposition on to coronary stents by means of ES can be fine-tuned to allow control over the polymer surface topography at a micro scale, which may allow for recapitulation of the topographical features of tissue and therefore promote integration of the device in vivo. 10 We applied this method to produce coatings using a polymer that has been designed such that it mimics RGD. The RGD peptide sequence is found on proteins present in the basement membrane of native arteries, and is required for cell adhesion, which is a crucial step in cellular interaction with the substrate.…”

“…By tuning the fabrication parameters, the resulting micro-topography of the polymer surface could be optimised. 10 Ultrasonic atomisation is a very widely used method for applying stent coatings, with many manufacturers of clinically used DES making use of this technology. 8 However, in-depth analysis of the topographical features of clinically used DES coatings produced in this way, has gone largely unreported in the literature.…”