*2.1. Intracellular Method*

This method includes synthesis of NPs inside the fungal cells by transporting ions during the exposure of enzymes [62,63]. First, the mycelia cultures are treated with a metal precursor and then they are incubated in the dark for 24 h. For intracellular identification, mycelia are resuspended in phosphate buffer saline (PBS, pH 7.4) and homogenized with a sonicator. NPs formed by the intracellular technique have a smaller size when compared with the NPs fabricated by the extracellular method [64,65]. Nucleation of particles inside the fungus could be the cause behind the variation in sizes. This technique is slower when compared with the extracellular method for synthesizing metal NPs [64]. As the NPs synthesis starts within the cell, their downstream processing becomes complicated, increasing cost of synthesizing NPs [66–68]. However, this type of synthesis technique is suitable for making composite films [69].
