Reagent-loaded pencils and methods

A method of preparing a reagent-loaded pencil, comprising:

• mixing a soluble carrier and at least one reagent, said at least one reagent comprising a biologically active substance capable of reacting with a sample, said biologically active substance selected from the group consisting of enzymes, proteins, DNA, RNA, phage, cells, yeast, bacteria, viruses, and antibodies to produce a composition;
• compressing the composition into a pellet or shaft;
• and
• disposing a sheath around at least a portion of the pellet or shaft to produce said reagent-loaded pencil.

A system for performing assays, comprising:

• a reagent-loaded pencil having a plurality of matrices, each matrix comprising a composition comprising:
• (i) a soluble carrier;
• (ii) at least one reagent, said at least one reagent comprising a biologically active substance capable of reacting with a sample, said biologically active substance selected from the group consisting of enzymes, proteins, DNA, RNA, phage, cells, yeast, bacteria, viruses, and antibodies;
• (iii) graphite;
• and
• (iv) a sheath disposed around at least a portion of the composition.