Modulation of Foreign Body Reaction against PDMS Implant by Grafting Topographically Different Poly(acrylic acid) Micropatterns

Abstract

The surface of poly(dimethylsiloxane) (PDMS) is grafted with poly(acrylic acid) (PAA) layers via surface‐initiated photopolymerization to suppress the capsular contracture resulting from a foreign body reaction. Owing to the nature of photo‐induced polymerization, various PAA micropatterns can be fabricated using photolithography. Hole and stripe micropatterns ≈100‐µm wide and 3‐µm thick are grafted onto the PDMS surface without delamination. The incorporation of PAA micropatterns provides not only chemical cues by hydrophilic PAA microdomains but also topographical cues by hole or stripe micropatterns. In vitro studies reveal that a PAA‐grafted PDMS surface has a lower proliferation of both macrophages (Raw 264.7) and fibroblasts (NIH 3T3) regardless of the pattern presence. However, PDMS with PAA micropatterns, especially stripe micropatterns, minimizes the aggregation of fibroblasts and their subsequent differentiation into myofibroblasts. An in vivo study also shows that PDMS samples with stripe micropatterns polarized macrophages into anti‐inflammatory M2 macrophages and most effectively inhibits capsular contracture, which is demonstrated by investigation of inflammation score, transforming‐growth‐factor‐β expression, number of macrophages, and myofibroblasts as well as the collagen density and capsule thickness.

Pathological Change and Whole Transcriptome Alternation Caused by ePTFE Implantation in Myocardium

“…These findings may help in uncovering new therapeutic targets for prevention and intervention of ePTFE-related complications [ 30 ]. For example, we found that both innate and adaptive immune responses might be involved in the ePTFE-related adverse reactions, which extended previous observations that only innate immune responses existed in FBR caused by artificial material implantation [ 17 , 19 , 44 , 45 ]. Many molecules and signal pathways were involved in the mechanisms underlying the ePTFE-related adverse reactions, and they might interact with each other in multiple ways, which increased the difficulty of learning the underlying mechanisms.…”

“…Accordingly, many efforts have tried to improve the anticoagulant properties of ePTFE and they include heparin coating [1], endothelial cell coverage [6], antibody or peptide coating the ePTFE [11][12][13], and others [14,15]. Similarly, several methods have been developed to prevent intimal hyperplasia or inhibit the FBR [16][17][18][19]. However, their efficacy and stability are unsatisfactory and far away from clinical application [20,21].…”

Assessment of human adipose‐derived stem cell on surface‐modified silicone implant to reduce capsular contracture formation

“…PDMS was prepared by mixing the base and curing agent at 10:1 (w/w), which was reported as the best ratio for biological application 46 , 47 and has been used as a model of silicone implants in several studies. 48 , 49 , 50 , 51 , 52 We chemically modified the surface of PDMS with 150 mM IA (Figure 1 ). This concentration was selected because previously, it was reported to result in the excellent enhancement of biocompatibility and reduction in capsular contracture formation of the PDMS surface, similar to results with the 0.50 wt% IA‐GT polymer but with an easier preparation method than the latter.…”

“…These results were consistent with those of previous studies, which showed that hydrophilic surfaces were better at preventing protein adsorption than hydrophobic surfaces. 21 , 50 , 59 , 60 Figure 2d shows cell cytotoxicity results using the 3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5‐diphenyltetrazolium bromide (MTT) assay. The PDMS and IA‐PDMS samples showed significantly lower absorbance than cells on a plate at Days 1, 3, and 7 ( p < 0.05).…”

Recent Advances in Anti-inflammatory Strategies for Implantable Biosensors and Medical Implants

“…Three types of drugs that inhibit the FBR include glucocorticoids, anti-fibrotic agents, and gene silencing 55 . First, glucocorticoids are widely adopted drugs which serve as a regulator of the inflammatory reaction 56 . Glucocorticoids target immune cells, which are associated with the FBR, including macrophages, neutrophils, and lymphocytes.…”