Thromboelastography (TEG) Cups and Pins with Different PECVD Coatings: Effect on the Coagulation Cascade in Platelet‐poor Blood Plasma

Abstract

Thromboelastography uses cups and pins made of CyroliteW plastic to analyze the rate of fibrin clot formation in blood samples. In this study, TEG cups and pins were modified by 4 distinct coating types using plasma-enhanced chemical vapor deposition (PECVD): carboxylated, amine-rich, hydrophobic, SiO 2 , and analyzed for surface chemistry and wettability. We tested the hypothesis that the coagulation kinetics of recalcified citrated blood plasma is controlled by surface chemistry, in the absence of clot activator. Only carboxylated surfaces became negatively charged upon wetting, and accelerated clot formation in a highly reproducible manner, whereas Cyrolite W and the other coatings had delayed and unpredictable clotting times. These data are consistent with a model whereby carboxylated surfaces selectively adsorb and activate factor XII while repelling other more abundant anionic blood proteins, resulting in reproducible clot kinetics.

Fusion peptide P15‐CSP shows antibiofilm activity and pro‐osteogenic activity when deposited as a coating on hydrophilic but not hydrophobic surfaces

“…Caco‐2 epithelial cells were found to attach and proliferate to a similar extent on traditional cell culture plastic and PECVD‐deposited poly(2‐hydroxyethyl methacrylate) (pHEMA) films with a 1:1:1.1 ratio of carbonyl:hydroxyl:ester groups . Data in this study extend these findings to show that L‐PPE:O films with 1:1:1.9 carbonyl:hydroxyl:ester groups and 6.7% carboxylic acid support human MSC cell attachment and osteogenesis. This study also revealed that primary human MSCs colonize and commit to early osteoblast differentiation on both HMDSO surfaces (92.3° WCA) and L‐PPE:O surfaces (41.8° WCA), but after 3 weeks of osteogenic culture, end‐stage differentiation and biomineralization only takes place on L‐PPE:O surfaces, an effect enhanced by adsorption of L‐PPE:O with P15‐CSP or P15.…”

“…Hydrophobic thin films with a poorly wettable surface were generated by plasma‐polymerized hexamethyldisiloxane (HMDSO) . In previous studies, L‐PPE:O but not HMDSO surfaces were shown to reproducibly initiate contact activation of the blood coagulation enzyme cascade; these data serve as proof‐of‐concept that L‐PPE:O thin films present anionic surfaces that can form bioactive complexes with proteins such as FXII. Thus, we analyzed the effect of P15‐CSP, P15, CSP coatings on surfaces with distinct wettability, including highly anionic (L‐PPE:O), anionic (TC‐treated), and hydrophobic (HMDSO).…”

“…PECVD was used to generate nanocoatings of hydrophobic and hydrophilic/anionic surfaces on 35 mm TC‐treated Petri dishes (Corning). As previously reported, hydrophobic surfaces were generated by plasma‐polymerized HMDSO vapors at 50 W, 60 mTorr, 20 sccm flow of HMDSO, and 2‐min deposition. Hydrophilic carboxylated surfaces (L‐PPE:O) with negative charges were created by C 2 H 4 + Ar/O 2 mixture at 10 W, 600 mTorr, 20 sccm flow of C 2 H 4 and 15 sccm flow of O 2 /Ar (10/90 v/v) for 60 min.…”

“…The HMDSO and L‐PPE:O surfaces maintained the same WCA after sterilization by exposure to UV light under a laminar flow hood for 1 h (data not shown). Previous experiments suggested that these thin films are stable during at least 1 h of incubation with human blood plasma; therefore, it was assumed that the plasma‐modified surfaces retained their hydrophobic and hydrophilic/anionic character during the dry‐coating step with the peptides described below and in TC medium.…”

Monitoring of blood coagulation with non‐contact drop oscillation rheometry

“…Chief among these is the need for contact containment and manipulation of the blood sample. Blood contact with container walls has a strong effect on initiation of the coagulation cascade, even in the presence of calcium chloride (CaCl 2 ), resulting in sensitivity of coagulation tests to the types of material and surface treatment used for the containment cup . These effects also lead to widely variable clot rigidity and variations in the quality of clot adhesion to the cup walls .…”