Abstract
Event Abstract Back to Event A universal aqueous-based antifouling coating for multi-material devices Sharon Goh1*, Yafei Luan2, Xiaojing Wang2*, Hong Chen2*, John L. Brash1 and Qiyin Fang1* 1 McMaster University, School of Biomedical Engineering, Canada 2 Soochow University, Polymer Science and Engineering, China Introduction: Preventing unwanted protein adsorption is important to improve implant biocompatibility, reduce biofouling, and control cell adhesion. A typical approach involves grafting polymers to alter surface chemistry. However, many surface modification protocols require harsh chemical conditions and solvents which may not be suitable for some materials. Thus, antifouling protocols need to consider the chemical stability of the substrate and, consequently, their applicability may be limited. This is of importance for biomedical devices which are composed of multiple classes of materials. Therefore, antifouling methods suitable for whole device modification are highly desirable [1],[2]. An aqueous-based polyethylene glycol (PEG) antifouling coating was previously developed using polydopamine (PDA) as a spacer [1]. PDA has been demonstrated to polymerize strongly onto virtually all material classes and readily forms covalent bonds with free amino groups.[3] However PEG grafting from solution may be sterically limited, leading to areas of exposed PDA available for protein binding. We sought to improve this method by backfilling the PDA-PEG coating with a non cell-adhesive protein, bovine serum albumin (BSA). A previous study on PDA-BSA coated substrates reportedly reduced cell adhesion compared to PDA [4]. We hypothesized that the combination of PEG and BSA may reduce fouling to a greater degree than PEG alone. Materials and Methods: Polydimethyl siloxane (PDMS), hydrophilic porous polycarbonate membranes (PC; 0.01 μm pore diameter), and borosilicate glass cover slips were incubated for 3 h with stirring in 2 mg/mL dopamine solution prepared in PBS, pH 8.5. The PDA coated surfaces were then incubated for 24 h in either (a): 10 mg/mL BSA (PBS, pH 7.4) at room temperature or (b): 5 mg/mL NH2-PEG-NH2 (MW 5000), (PBS, pH 8.5) at 37ºC or (c): (a) followed by (b) or (d): (b) followed by (a). Fibrinogen (Fg) was radiolabeled with I-125 using the ICl method and passed through an ion exchange resin column to remove free iodide. The surfaces were incubated in 1 mg/mL Fg solution in PBS (5% labelled) for 2 h, and rinsed with buffer. Adsorption was quantified from radioactivity measurements. Results and Discussion: Fg was used as a model protein to evaluate resistance to non-specific protein adsorption of the modified PDMS, glass, and PC. Adsorption data are shown in Figure 1. Consistent with previous reports [4], the PDA coated surfaces showed enhanced protein adsorption due to their ability to bind covalently to amino groups in Fg. Compared to the unmodified materials PEG modification was effective in reducing Fg adsorption only on PC. Interestingly, the PDA-PEG modified surfaces showed significantly higher Fg adsorption than the PDA-BSA, possibly due to the larger BSA molecules giving greater surface coverage. For all three substrates there was no significant difference in adsorption between PDA-BSA and PDA-BSA/PEG, possibly due to blockage of PEG attachment by the BSA. The lowest adsorption was seen on the PDA-PEG surfaces that were “backfilled” with BSA. These PDA-PEG/BSA surfaces showed reductions in Fg adsorption of 89%, 63%, and 55% for PC, glass, and PDMS, respectively. Figure 1. Fg adsorption on different substrates. SEM ± mean for n=6 replicates and two trials. Protein concentration = 1 mg/mL. Conclusions: Attachment of passivating moieties to a variety of material types using polydopamine as a bonding agent has been demonstrated. Backfilling PDA-PEG layers with albumin was shown to improve their antifouling properties. The modification was demonstrated on various types of materials, suggesting its utility as a universal antifouling coating. This strategy should be applicable to biomedical devices required to be non-fouling including implants and sensors. Mitacs Globalink; Government of Ontario
Highlights
AND OBJECTIVESPreventing unwanted protein adsorption on biomedical devices is important to improve biocompatibility, reduce biofouling, and control cell adhesion
Since heat has been reported to activate Perfluorophenyl azides (PFPAs) [106,111,112], we investigated whether increasing the drying temperature would reduce the reaction efficiency due to activation of PFPA-PEG while the sample is still wet
After two treatments there was no significant difference between the drying temperatures (p=0.11). These results indicate that drying the samples at 60°C for 3 h does not materially reduce the coupling efficiency of PFPA-PEG to the substrate
Summary
AND OBJECTIVESPreventing unwanted protein adsorption on biomedical devices is important to improve biocompatibility, reduce biofouling, and control cell adhesion. Patterned surfaces can be achieved with PFPAs using a photomask [104], since PFPAs show virtually no coupling to surfaces in the dark, allowing non-activated material to be washed away with water [24] This is useful in developing biological platforms for single-cell analysis where researchers are interested in studying individual cell interactions and functions, including cell geometry, morphology, differentiation and proliferation [27]. Another advantage is that PFPAs are highly soluble in water, eliminating the need for harsh solvents and reaction conditions [24]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
