# The Effect of Human Blood Plasma Conditioning Films on Platelet Tungsten Bag Surface Properties
## 3 Results
### Physicochemistry
marcscens_ followed the same trend as _S. epidermidis_, where an initial slight reduction was observed after 1 h (45.5 mJ/m\({}^{2}\)) but then a further reduction to 38.7 mJ/m\({}^{2}\) was \begin{table}
\begin{tabular}{c c c c c c c} \hline  & \(\Delta G\) & \(\gamma_{s}\) & \(\gamma_{s}\)_LW_ & \(\gamma_{s}\)_AB_ & \(\gamma_{s}\)+_ & \(\gamma_{s}\)\(-\) \\  & **m/m\({}^{2}\)** & **m/m\({}^{2}\)** & **m/m\({}^{2}\)** & **m/m\({}^{2}\)** & **m/m\({}^{2}\)** & **m/m\({}^{2}\)** & **m/m\({}^{2}\)** \\ \hline Rough & \(-53.0\pm 6.1\) & \(52.4\pm 1.2\) & \(48.9\pm 0.1\) & \(3.5\pm 1.1\) & \(0.4\pm 0.2\) & \(7.3\pm 1.5\) \\ \hline Rough 1 h Plasma & \(-28.5\pm 7.1\) & \(52.7\pm 4.1\) & \(46.0\pm 1.1\) & \(6.7\pm 3.7\) & \(1.0\pm 0.7\) & \(16.8\pm 3.5\) \\ \hline Rough 24 h Plasma & \(-6.0\pm 6.1\) & \(52.0\pm 4.0\) & \(43.4\pm 2.3\) & \(8.6\pm 3.2\) & \(1.0\pm 0.5\) & \(27.2\pm 3.4\) \\ \hline Rough 1 h Plasma + Se & \(-43.3\pm 9.6\) & \(45.7\pm 0.3\) & \(44.0\pm 0.6\) & \(1.7\pm 0.4\) & \(0.2\pm 0.1\) & \(11.0\pm 3.5\) \\ \hline Rough 24 h Plasma + Se & \(-31.3\pm 2.2\) & \(46.1\pm 1.1\) & \(44.6\pm 0.9\) & \(1.5\pm 0.5\) & \(0.1\pm 0.0\) & \(14.9\pm 0.8\) \\ \hline Rough 1 h Plasma + Sm & \(-21.5\pm 9.2\) & \(48.4\pm 1.1\) & \(45.4\pm 0.8\) & \(3.0\pm 1.4\) & \(0.1\pm 0.1\) & \(21.5\pm 5.0\) \\ \hline Rough 24 h Plasma + Sm & \(-43.1\pm 5.0\) & \(45.3\pm 0.8\) & \(43.2\pm 0.9\) & \(2.1\pm 0.5\) & \(0.2\pm 0.1\) & \(10.1\pm 1.9\) \\ \hline \end{tabular}
\end{table} 
Table 1: Physicochemistry of the rough surface after applying 1 h or 24 h conditioning films of the bacteria alone, human plasma alone or a combination of bacteria and human plasma. Se denotes the bacteria _Staphylococcus epidermidis_ and Sm denotes _Serratia marcscens_ (\(n=5\)). Statistical differences were considered below the \(p<0.05\) confidence level and are highlighted in grey with bold text. \begin{table}
\begin{tabular}{c c c c c c} \hline  & \(\Delta G\) & \(\gamma_{s}\) & \(\gamma_{s}\)_LW_ & \(\gamma_{s}\)_AB_ & \(\gamma_{s}\)+_ & \(\gamma_{s}\)\(-\) \\  & **m/m\({}^{2}\)** & **m/m\({}^{2}\)** & **m/m\({}^{2}\)** & **m/m\({}^{2}\)** & **m/m\({}^{2}\)** & **m/m\({}^{2}\)** \\ \hline Smooth & \(-50.1\pm 6.1\) & \(49.6\pm 1.2\) & \(45.7\pm 0.2\) & \(4.0\pm 1.1\) & \(0.5\  
observed after 24 h. Finally, the basic energy did not have a significant change after 1 h, but after 24 h was significantly increased from 9.7 mJ/m\({}^{2}\) to 32.2 mJ/m\({}^{2}\). In summary, the physicochemical results (Tables 1-3) demonstrated that on all the three surface types (rough, smooth and flat) that when the one and 24 h results were compared for all three conditioning films (human plasma, _S. epidermidis_ and human plasma and _Ser. marcescens_ and human plasma) that the Gibbs Free energy (\(\Delta G\)) decreased in all instances with the exception of the _Ser. marcescens_ and human plasma on the rough surface which became more hydrophobic after 24 h (\(-\)21.5 mJ/m\({}^{2}\) to \(-\)4.3 mJ/m\({}^{2}\)). On the smooth and flat surfaces when the one and 24 h results were compared for all three conditioning films (human plasma, _S. epidermidis_ and human plasma and _Ser. marcescens_ and human plasma) were compared, the values for the \(\gamma_{\mathrm{s}}\), \(\gamma_{\mathrm{lw}}\), \(\gamma_{\mathrm{s}}\)\({}^{+}\), all the values decreased, but this was not evidenced on the rough surface, suggesting that the surface topography was having an effect on the physicochemical properties even in the presence of a conditioning film. The _Ser. marcescens_ and human plasma results were generally different to those seen with the human plasma, _S. epidermidis_ and human plasma conditioning films since \(\gamma_{\mathrm{s}}\)\({}^{\mathrm{AB}}\) and \(\gamma_{\mathrm{s}}\)\({}^{-}\) values increased for all the surfaces between 1 and 24 h.