Normally ‘针对’ is used when you want to pinpoint a specific matter for discussion, and usually not directed to any person. In this example, '针对‘ is a more appropriate term, as it's aimed at a specific research the scientists are doing. '科学家都针对人体发光的现象'
(1) 我们应该针对这次的失误做检讨 - We should look into the reason we failed this time
(2) 针对刚才的方案，你有什么想法 - What do you think about the proposal
'向‘ is usually used if the subject is a person, For example,
(1) 我向他借钱 - I borrowed money from him
(2) 学生应该向老师行礼 - Students should greet their teachers
(3) 我向你道歉 - I apologized to you