The following polymeric materials were used to prepare corresponding 3×3 MN arrays (dimensions 600 μm in height, 300 μm in width, and an interspacing of 300 μm): PVA, alginic acid, Carbopol® 971 and Gantrez® AN-139. A 30% w/w aqueous solution of PVA was prepared by adding the required mass of PVA to deionised water, followed by heating at 80.0°C for 4.0 h, until a clear gel was formed. Upon cooling, the blend was then readjusted to the final concentration of 30% w/w by addition of an appropriate amount of deionised water. A 10% w/w aqueous solution of alginic acid was prepared by adding the required mass of alginic acid to deionised water, followed by heating at 70°C for 30 min and readjusting to the final concentration of 10%w/w with deionised water. A 10% w/v aqueous Carbopol® 971-P NF blend was prepared by adding the required amount of polymer to distilled water with constant stirring at 800.0 rpm. Once a homogenous gel was formed, it was neutralised using 10 M NaOH to pH6, thus increasing the viscosity of the gel. A 20% w/w aqueous solution of Gantrez® AN-139 was prepared by adding the required mass of Gantrez® AN-139 to ice-cold deionised water, followed by vigorous stirring and heating at 95°C until a clear gel was obtained, due to hydrolysis of the anhydride form of the copolymer to the corresponding acid. Upon cooling, the blend was then readjusted to the final concentration of 20% w/w by addition of an appropriate amount of deionised water. In each case, the resultant solutions were then poured into the silicone micromoulds, centrifuged for 15 min at 3,500 rpm, and allowed to dry under ambient conditions for 24 h.