Membrane-Based Nanotechnology and Drug Delivery - Membrane Biophysics, Biological and Medical Physics, Biomedical Engineering - page 141

Fig. 6.11 Nanoparticles that are reluctant to interact with lipids naturally diffuse through the type
of toroidal pores where the opening region inside the pore consists of no pore-inducing agents.
The absence of pore-inducing agents in the opening regions helps nanoparticles to experience no
considerable direct interactions with the agents. We have observed such a type of pore to be induced
by chemotherapy drugs (e.g. TCC, TXL, etc.). In addition to chemotherapy drugs, a possible search
for a better set of agents, e.g., any natural or synthetic antimicrobial peptides or biomolecules which
might create the type of pore as mentioned here, should be worth pursuing. This is hoped to generate
a combination therapy with low cytotoxicity

can easily diffuse to the cellular interior regions. From the comparable analysis on
nanoparticle interactions with membranes presented in the last section, it is clear that
silica nanoparticles and similar ones that show poor or no binding with lipids may
emerge as good candidates for drug delivery through the lipid lined toroidal pores.
The proposed novel nanotechnology heavily depends on considerations involving
charge and geometry of nanoparticles, as well as the dimension and stability of the
nanoparticle-transporting pores. As the proposed pore is a 'lipid-lined' type, the
lowest possible value of the cross-section of a pore is as small as 0. From there,
the cross-section can increase to an arbitrary value. The triangular nature of the
discrete conductance events (see Fig. 6.10 ) clearly suggests that the cross-sectional
dimension either increases, decreases, or follows a back-and-forth oscillation pattern.
This ensures the possibility of free transport of nanoparticles with any dimension,
which can even be as low as the dimension of the order of a lipid head group ( 6nm

diameter). This can provide the freedom of choice of nanoparticles of any size for
drug delivery into the cellular interior. Smaller size drug-carrying nanoparticles will
require induction of smaller pores, and the particle diffusion may also be faster

∼ 0 .