Fig. 1

Effect of glycerol co-solvent concentration (a–c) and PVA molecular weight (d, e) on cryogel transparency. Light transmission quantified in the near-infrared (a, d), and overall photosynthetic wavelength ranges (b, e) in 10% w/v PVA cryogel after 1 freeze–thaw cycle. PVA samples in cuvettes frozen at −20 °C show changes in opacity relating to glycerol concentration (c). Light transmission in 5% Ca-alginate gel films included in panel e for comparison from Pereira et al. 2013 [37]. Data shown is the average of 4 samples, with error bars representing SD. Statistical significance for one-way ANOVA with Tukey’s multiple comparison indicated by ****p < 0.0001; *p < 0.05