Is it sin for Brahmins if they eat artifical meat (Cultured meat )? Does scriptures scriptures say anything about this?
Although, this does "seem" to be like a newly discovererd loophole. Since, the hiṃsā (violence) part, explicitly seems to be missing, which in the otherwise natural case involves - killing the animal itself. And in that way, one may argue that yes, since no kind of violence is involved and no jīvātman seems to be harmed, thus, we are allowed to eat the "Cultured Meat". However, a meat is a meat, even if lab grown. Anything derived, for the purpose of eating and based on a living creature is called as meat.
As discussed appropriately in this answer, hiṃsā is to be avoided:
According to Bhishma there are four ways to follow Ahimsa Dharma. By Mana (mind), by Speech , by Karma and not eating flesh . So all these are part of Ahimsa Dharma and not eating flesh is one of them.
चतुर्विधेयं निर्द्रिष्टा ह्यहिन्सा ब्रह्मवादिभि : | एकैकतोSपि विभ्रष्टा न भवत्यरिसूदन ||4||
"Bhishma said, 'Utterers of Brahma have said that there are four kinds of compassion or abstention from injury.
i.e. even by mentally mentally committing an act of slaughter, one becomes guilty of it. So those who are wise avoid it because to follow Ahimsa Dharma.
Further, it's very important to know, that the restrictions are not just de-limited to violence based foods, but, what to eat and what not to eat, is largely prescribed and defined by the three guṇas - sāttvika, rājasika, tāmasika modes of the material nature. You may refer, to this answer, for the three categories of food attributes.
Any kind of meat (derived by whatsoever methodology), will unequivocally and definitely fall under the tamasic category, and as such is to be restricted for Brahmins and in general, also forbidden/not recommended for anyone on a spiritual path.
Further, the argument deriving its basis on the fact that -
" cultured meat is not hiṃsā (even though it's a living mass of cells derived from the live body of an animal, but grown in a lab). This is similar to just like one may consider plants are living and thus why do we eat that? "
You may refer to this excellent QnA to resolve that doubt - Why can we eat 'living' plants but not 'living' animals?.
And thus, to conclude for the question posed - No, a Brahmnin is recommended to not eat any kind of meat.