1. A composition comprising: (a) a fiber comprising “m” types of proteins of differing molecular weight, wherein each protein in said “m” proteins comprises, independently, “n” repeats of a repetitive sequence of a major ampullate spidroin (MaSp) protein, wherein m and n are, independently, an integer between 2 to 70, said protein are of differing molecular weight and a different number of said repetitive sequence, said repetitive sequence comprises an amino acid sequence as set forth in SEQ ID NO: 1: (X₁)_ZX₂GPGGYGPX₃X₄X₅GPX₆GX₇GGX₈GPGGPGX₉X₁₀, wherein X₁ is, independently, at each instance A or G wherein at least 50% of (X₁)Z is A, Z is an integer between 5 to 30; X₂ is S or G; X₃ is G or E; X₄ is G, S or N; X₅ is Q or Y; X₆ is G or S; X₇ is P or R; X₈ is Y or Q; X₉ is G or S; and X₁₀ is S or G; and (b) a biocompatible material, cell culture media, cells, or any combination thereof.