Platinum Contamination from Filament-Based Puller and Its Influence on Micro/Nanopipette Properties

This study demonstrates that micro/nanopipettes fabricated using a platinum filament-based P-97/P-1000 puller are subject to surface contamination in the form of Pt⁰ and Pt²⁺ deposits on their outer walls. These platinum residues not only confer catalytic activity toward hydrogen peroxide but also promote the ethanol-mediated reduction of chloroauric acid, resulting in the formation of a gold film on the outer wall. The contaminants are predominantly localized within a confined thermally affected region near the pipet tip. The Pt content increased from 0.58 ± 0.04 pmol to 18.49 ± 0.95 pmol as the heating parameter (HEAT) was raised from 400 to 560 and increased nearly linearly from 0.64 ± 0.08 pmol to 10.61 ± 0.57 pmol when the heating duration was extended from 1 to 11 s. These findings carry dual implications: they highlight an inherent source of contamination in such systems and its impact on performance, challenging the conventional paradigm that overlooks these risks in instrument selection; concurrently, they point to a viable strategy for the controlled functionalization of pipet tips through tailored deposition.