The LAMP reaction was carried out on a scale of 25 µl based on reference 1. Briefly, a forward inner primer (FIP) and a backward inner primer (BIP) at a final concentration of 1. The LAMP primers (Sigma Genosis Japan K.K., HPLC purification grade) were as follows. The hyphens were added between F1c or B1c and F2 or B2. The LAMP reaction for Lambda DNA was used as a LAMP reaction for a basic investigation to clarify the fundamental characteristics of the reaction that occurs between the LAMP product and PEI. A well-established LAMP product [1] for mRNA of prostate-specific antigen (PSA) was used as a LAMP reaction product unrelated to the three LAMP reaction products above. A solution was prepared by serially diluting a LAMP reaction solution with a known concentration (28 µg DNA/25 µl) using LAMP reaction buffer in order to systematically investigate the reaction between the LAMP product and PEI. The concentration of DNA synthesized by the LAMP reaction was determined according to the attached protocol using a PicoGreen dsDNA Quantitation Kit (Molecular Probes, Inc.). The spectrofluorophotometer used was the RF-5000 spectrofluorophotometer (Shimadzu Scientific Instruments, Inc.).