To prepare P/WWW/MEA, the remaining unreacted N-hydroxysuccinimidyl ester was used for conjugation of 2-mercaptoethylamine
hydrochloride (MEA, 1.6 mg, 0.012 mmol, 2% equivalent to the total malyl groups) in the presence of triethylamine (2.4 [micro]L).
First, [F(ab').sub.2] 1-21 antibodies dissolved in buffer (20 mmol/L sodium phosphate buffer, 20 mmol/L NaCl, and 56 g/L saccharose, pH7.4) were reduced to Fab' 1-21 fragments with 2-mercaptoethylamine
hydrochloride (final concentration, 100 mmol/L; final pH, 6.0; Sigma-Aldrich) under final buffer conditions (15 mmol/L sodium phosphate, pH 6, 15 mmol/L NaCl, and 50 g/L saccharose) for 1 h at 37 [degrees]C.
This period may be shortened if mesna (2-mercaptoethylamine
sulfonate sodium) is given, since mesna helps to inactivate the toxic metabolite of cyclophosphamide (Austin & Boumpas, 1996).
The remaining 2-mercaptoethylamine
ligands were considerably smaller than the original ligand, and the electrical characteristics of the device improved due to enhanced contact between the CdSe particles and the polymer (Figure 6).