Nanoporous Silicon as Drug Delivery Systems for Cancer Therapies

Figure 2

Mechanism of pore formation. (1) F ion attacks the hydrogen saturated silicon surface; (2) Si–F bond is formed by nucleophilic attack on a Si–H by a F ion; (3) the second F ion attack replaces the remaining hydrogen bond; (4) HF or H₂O attacks the Si–Si back bond due to the reduced the electron density; (5) the tetrafluoride molecule reacts with HF producing the highly stable SiF₆ fluoroanion.