Figure 1. Physico-chemical characterization of TAP NPs.

A-B) Dynamic light scattering analysis of TAP NPs: stability over 1-week and in different pH solutions. 50 µL of TAP NPs were added to 1 mL of ultrapure water or pH solutions and probe sonicated for 30 s and particle size was measured using Zetasizer (Nano ZS, Malvern Instruments, Malvern, UK) at 25 °C. A) TAP NPs exhibited particle size of 102.22±14.05 nm. Inset: representative particle size of TAP NPs stored at 25 °C for 1-week, demonstrating stability and no significant change in size. B) Stability of TAP NPs in HEPES buffer solutions (pH 6, 7, 7.4 and 8). Data presented as mean ± standard error of the mean (n = 3). C) A representative transmission electron microscopic (TEM) image of TAP NPs. UranyLess EM Stain solution was used to achieve a better contrast purpose for nanoparticles. Image was acquired by using JEOL 200EX TEM at a direct magnification of 100,000× (scale = 100 nm). D) Fourier-transform Infrared (FTIR) spectral analysis of TA, PTX and TAP NPs acquired on a Universal Attenuated Total Reflectance (UATR) accessory plate by a Spectrum 100 FTIR spectrophotometer (Waltham, MA), between 4000 and 650 cm⁻¹ at a scanning speed of 4 cm⁻¹ for 32 scans. TAP NPs show characteristic TA peaks at 1603 and 1700 cm⁻¹ and PTX peaks at 3350 and 1650 cm^–1, confirming the presence of functional moieties of TA and PTX in TAP NPs. E) Thermogravimetric analysis (TGA) was recorded for TA, PTX and TAP NPS from 50 to 500 °C by a Rigaku D/Max-B diffractometer (Rigaku Americas Corp, Woodlands, TX) with cobalt-alpha radiation (k = 1.5 Å). There is no significant change in thermograms of TAP NPs in comparison to TA and PTX. F) X-ray diffraction (XRD) was acquired at 2θ range of 25 – 70 ^oC suggesting TAP NPs has both TA and PTX present in amorphous or dissolution state.