## 2 Materials and Methods
### Synthesis of TSNP  
The TSNP solution method was adapted from a previously reported seed-mediated approach [50], consisting of a step for seed production and a subsequent step for TSNP growth. Briefly, 5 mL of TSC (2.5 mM), 0.25 mL of PSSS (500 mg/L), and 0.3 mL of NaBH4 (10 mM) were mixed, followed by the addition of 5 mL of AgNO3 (0.5 mM) at a rate of 2 mL/min on constant stirring for the formation of the seed solution. For the TSNP growth, 4 mL of distilled water, 0.075 mL of AA (10 mM), and 0.35 mL of seed solution were mixed, followed by the addition of 3 mL of AgNO3 (0.5 mM) at a rate of 1 mL/min with constant stirring. Finally, 0.5 mL of TSC (25 mM) was added, for a TSNP solution with a final Ag concentration of 21.34 ppm. The chemical reaction occurs as follows [51]:  
\[\text{AgNO}_{3}+\text{NaBH}_{4}\rightarrow\text{Ag}+1/2\text{H}_{2}+1/2\text{ B}_{2}\text{H}_{6}+\text{NaNO}_{3}.\]  
Afterwards, in the growth step, the spherical Ag seeds can react with new Ag\({}^{+}\) ions in the presence of ascorbic acid and citrate ions, forming the TSNP. The chemical reaction can be explained as follows [52]:  
\[(Spherical\ NPs)+Ag^{+}+C_{6}H_{8}O_{6}\overset{C_{6}H_{8}Na_{9}O_{7}}{ \rightarrow}\text{ TSNP}.\]  
TSC was added at the end of the synthesis to stabilize the nanoplates.  
Increased concentration of NPs is desired to aid treatment for the intended TSNP-polymer processing. A reduction of 20% of water for the synthesis was successfully achieved without negatively affecting the results. Different volumes ranging between 0.2 and 0.7 mL were used until 0.35 mL eventually became the standard. Consequently, the adapted method consists of mixing 4 mL of water, 0.075 mL of AA (10 mM), and 0.35 mL of seed solution (25.56 ppm of Ag), followed by the addition of 3 mL of AgNO3 (0.5 mM) at a rate of 1 mL/min. Finally, 0.5 mL of TSC (25 mM) are added when the reaction is finished, resulting in a final Ag concentration of 21.34 ppm and a volume of 8 mL. Noticeably, upon adding AgNO3, the color starts changing from yellow to shades of orange, then shades of red, then purple, and finally takes on a dark blue color, as demonstrated in Figure 1.  
Scale-Up of TSNP Production  
Unlike the original method where a smaller pump was used, the LP-BT100-1F Peristaltic Dispensing Pump with a YZIII15 pump head and Tygon LMT-55 Tubing (SC0375T), provided by Drifton, were used for the addition of AgNO3. The production of TSNP solution was scaled up to a final volume of 300 mL. To achieve this without affecting the synthesis reaction and the final properties of the TSNP, all the volumes and the ratefor addition of AgNO\({}_{3}\) were increased proportionally for both the seed solution and the TSNP growth reaction. Thus, to prepare 20 mL of seeds: 8.53 mL of water, 0.95 mL of TSC (25 mM), 0.47 mL of PSSS (500 mg/mL), and 0.57 mL of NaHB\({}_{4}\) (10 mM) are mixed, followed by the addition of 9.48 mL of AgNO\({}_{3}\) (0.5 mM) at a rate of 3.79 mL/min. After 4 h, the seeds can be used in the second step of the reaction, mixing 150 mL of water, 2.81 mL of AA (10 mM), and 13.12 mL of seed solution (25.56 ppm), followed by the addition of 112.5 mL of AgNO\({}_{3}\) (0.5 mM) at the rate of 37.5 mL/min, then 18.75 mL of TSC (25 mM) was added after reaction was finished.  
A method of water evaporation was used to further increase the concentration of TSNP in the produced solution. A total of 300 mL of the TSNP solution were kept inside the oven at 40 \({}^{\circ}\)C for 8 days, until approximately 50% of the water volume was evaporated. UV-Vis spectrum of the solution was recorded before and after heat treatment to monitor the stability of the geometry and optical properties of the TSNP through LSPR. Estimated concentration of the solution after evaporation was 42.64 ppm of atomic silver.