Effect of glass dissolution products on the detection of proteins by silver staining.
The influence of glass dissolution on the silver staining of proteins was investigated by reacting glass microspheres of varying chemical durability in boiling Laemmli sample buffer (LSB) for up to 5 min. All three of the investigated glass compositions leached Na+ ions to varying degrees during boiling in LSB, thereby causing an increase in the pH of the sample buffer. The LSB supernatant from the dissolution tests was mixed with unreacted LSB containing human serum albumin (HSA) and standard one-dimensional SDS-PAGE was performed. Silver staining was then used to visualize protein bands within the gel. The 30 Na2O.70 SiO2 glass exhibited pronounced degradation as shown by scanning electron microscopy. Further experiments employing solutions of neat LSB and reacted LSB (i.e., LSB containing glass dissolution products) mixed at varying ratios demonstrated the apparent significance of sample pH in affecting the inhibition of silver staining. The cause of this behavior may be due to an interference with the fixation stage of the staining protocol, thereby resulting in the loss of protein in subsequent rinsing stages.