No, the police cannot take DNA in PA unless you have been convicted of certain sexual and violent crimes or if the Police get a search warrant.
While the Pennsylvania DNA Act requires collection of DNA samples from persons who are convicted of felonies and serious misdemeanors there is no right to collect DNA prior to conviction.
Nevertheless, Bensalem Township Police Department and others are requesting that persons arrested permit a mouth swab for DNA. This requires your voluntary consent. It is your right to decline to consent to a DNA swab upon arrest.
While the Federal Government and 28 other States authorize obtaining DNA samples from people who are merely arrested for serious crimes, Pennsylvania does not.
There is a bill pending in PA to change that but it has not yet passed the legislature.
The Bensalem Police Department is the first in the Nation to use a new device allowing them to analyze DNA samples without sending the sample out to a lab. They can do so in-house in about 90 minutes. The samples are then collected and put into a database. The DNA evidence in the database is used in the current case for which one is arrested and to solve cold cases.