selfCastingObject.ps1

$deserialized = [psobject][ordered]@{
'string' = 'this is a string'
'double' = [double]::MaxValue
'fileInfo' = 'C:\'
'__castme' = {
    param($myself)
  switch (($myself|Get-Member -MemberType NoteProperty).Name)
  {
     'string'   {$myself.string = $myself.string }
     'double'   {$myself.double = [double]($myself.double) }
     'fileInfo' {$myself.fileInfo =  [System.IO.FileInfo]($myself.fileInfo) }
     '__castme'   { $myself.__castme = [scriptblock]::create($myself.__castme) }
  }
  $myself
 }.ToString()
} | convertTo-Json | convertfrom-json

$casted = [scriptblock]::Create($deserialized.__castme).invoke($deserialized)

"string is of type $($casted.string.GetType().ToString())"
"Double is of type $($casted.double.GetType().ToString())"
"FileInfo is of type $($casted.fileInfo.GetType().ToString())"
"__castme is of type $($casted.__castme.GetType().ToString())"

#This is a simple example, you can use the castme to also 'reload' script method,
# or PSTypeName
# I usually wrap this up into a New-something function, that allows to create such
# serializable object with strongly typed parameters, and to also allow piping
# deserialized object to it...