There is a constellation of features that mark off early Christian manuscripts in the book-culture of the time. I have proposed that these comprise our earliest evidence of an emerging early Christian “visual and material culture”. Some of these manuscripts are dated as early as the late second century CE, making them perhaps the earliest (and certainly among the earliest) physical artifacts of early Christianity.
The early Christian preference for the codex, the curious scribal devices known as “nomina sacra”, the various features that comprise what appear to be “readers’ aids” (e.g., early forms of punctuation, wide line-spacing, use of spaces to mark off sense-units) all are noteworthy features of early Christian book-production.
The only example I can provide at the moment is this image from the first page of the Gospel of John in P66 about 200 CE. Here we can see wide line spacing, and several high dots, the first in line 2 after ὁ λόγος and the second is in line 3 before the καὶ. There is also a blank space in line 7 marking off a sense unit between verse 5 and verse 6 beginning Ἐγένετο ἄνθρωπος. There is a diaresis over the "I" at the beginning of John's name, Ἰωάννης, in line 9 ad in line 2 there is a nomen sacrum for God, a theta and sigma with a line above.
PS Click on the image to enlarge it. Right click to open it in its own window.