Device and method for observing and filter for capturing a minute substance

A minute substance capturing method comprising:

• introducing a solution or a suspension comprising a minute substance with a 10 to 500 nm average particle diameter to a porous glass substrate having a plurality of pores;
• and
• separating and capturing the minute substance by the glass substrate,
• wherein
• the porous glass substrate comprises phase-separated glass formed through a spinodal decomposition,
• the plurality of pores has an average pore diameter ranging from 30 to 500% of the average particle diameter of the minute substance, and a pore diameter ranging from 60 to 140% of a pore diameter corresponding to a maximum value in a pore diameter distribution of the plurality of pores occupies 90% or more of total pore volume of the plurality of pores.

A minute substance observation method comprising:

• introducing a solution or a suspension comprising a minute substance with a 10 to 500 nm average particle diameter to a porous glass substrate having a plurality of pores;
• separating and capturing the minute substance by the glass substrate;
• and
• observing the minute substance captured by the glass substrate,
• wherein
• an average pore diameter ranging from 30 to 110% of the average particle diameter of the minute substance,
• each of the plurality of pores has a surface pore diameter on a main surface of the porous glass substrate, and a standard deviation of the surface pore diameter on an uppermost surface of the glass substrate is 60% or less of the average particle diameter of the minute substance, and
• a pore with a pore diameter ranging from 60 to 140% of a pore diameter corresponding to a maximum value in a pore diameter distribution of the plurality of pores occupies 90% or more of total pore volume of the plurality of pores.