Table 1.

Ratio of Ti vs. elements abundant in biological samples shows different accumulation of nanoparticles in different tissues when nanoparticle delivery by IV vs. IC is done. As a type of internal control ratio of Ti vs. Fe is shown as well. Due to the core–shell structure of nanoparticles these two elements have a constant ratio, and show no variation from sample to sample or tissue to tissue.

Elemental Content Ratio		Mean			SD
		IC	IV	p	IC	IV
VX2	Ti/P *	0.01711	0.02127	0.26872	0.00297	0.00476
	Ti/S	0.01528	0.01383	0.84901	0.00224	0.01217
	Ti/Zn	0.64011	0.65397	0.89887	0.14092	0.10773
	Ti/Fe	0.12339	0.1504	0.27581	0.02431	0.02803
	$\text{Ti **}$	$370.5783$	$394.69696$	$0.91055$	$261.26612$	$231.72104$
	$\text{Fe}$	$3362.35601$	$2735.3082$	$0.75481$	$2800.07347$	$1643.73117$
Liver	Ti/P	0.01262	0.02182	0.03075 ***	0.00373	0.00313
	Ti/S	0.00736	0.0137	0.00965	0.0023	0.00052
	Ti/Zn	0.26631	0.45213	0.02825	0.08716	0.03959
	Ti/Fe	0.06452	0.09442	0.0991	0.02088	0.01223
	$\text{Ti}$	$590.53869$	$953.44229$	$0.08483$	$48.8673$	$271.3826$
	$\text{Fe}$	$9580.52357$	$\mathrm{10,107.78307}$	$0.7948$	$1985.14$	$2617.5$
Spleen	Ti/P	0.0149	0.03427	0.0403	0.00564	0.00969
	Ti/S	0.01895	0.04221	0.04122	0.00697	0.01165
	Ti/Zn	0.85428	2.125	0.03773	0.50079	0.51691
	Ti/Fe	0.04296	0.08506	0.13063	0.0064	0.0379
	$\text{Ti}$	$891.72723$	$1807.40153$	$0.09733$	$445.70119$	$445.70119$
	$\text{Fe}$	$\mathrm{20,612.158}$	$\mathrm{22,297.20167}$	$0.81604$	$\mathrm{10,397.89461}$	$5469.26885$
Lung	Ti/P	0.02079	0.02239	0.8848	0.01005	0.01489
	Ti/S	0.00803	0.01081	0.28208	0.00107	0.00373
	Ti/Zn	0.44638	0.61228	0.4479	0.1362	0.31355
	Ti/Fe	0.07881	0.08918	0.77821	0.04038	0.04388
	$\text{Ti}$	$575.33695$	$490.11802$	$0.64474$	$143.85801$	$259.27169$
	$\text{Fe}$	$8816.3227$	$8795.4073$	$0.99758$	$4989.00812$	$\mathrm{10,081.30602}$
Kidney	Ti/P	0.01028	0.0146	0.11988	0.00219	0.0031
	Ti/S	0.00568	0.0087	0.10969	0.0018	0.0018
	Ti/Zn	0.20283	0.40091	0.03195	0.05167	0.09277
	Ti/Fe	0.07926	0.13716	0.06617	0.02248	0.03306
	$\text{Ti}$	$374.46392$	$691.11448$	$0.04831$	$126.5038$	$148.62759$
	$\text{Fe}$	$4679.936$	$5062.48907$	$0.24386$	$266.53554$	$405.51323$

* White, elemental ratios; ** gray, mean femtograms per pixel, based on Figure 5; *** bold, statistically significant difference between IC and IV NPs delivery, p < 0.05.