Robert Samuel Langer Jr. FREng[1] (born August 29, 1948) is an American biotechnologist, businessman, chemical engineer, chemist, and inventor.

[5] He is a widely recognized and cited researcher in biotechnology, especially in the fields of drug delivery systems and tissue engineering.

[19][20][21] Langer worked with Judah Folkman at Boston Children's Hospital to isolate the first angiogenesis inhibitor, a macromolecule to block the spread of blood vessels in tumors.

[18][22] Macromolecules tend to be broken down by digestion and blocked by body tissues if they are injected or inhaled, so finding a delivery system for them is difficult.

[18][23] Langer also worked with Henry Brem of the Johns Hopkins University Medical School on a drug-delivery system for the treatment of brain cancer, to deliver chemotherapy directly to a tumor site.

[24] In 2019, he and his team developed and patented a technique whereby microneedle tattoo patches could be used to label people with invisible ink to store medical information subcutaneously.

[32] Alongside Daniel G. Anderson, he has contributed bioengineering work to a project involving teams from MIT, Harvard University and other institutions, to produce an implantable device to treat type 1 diabetes by shielding insulin-producing beta cells from immune system attacks.

[33][34] He is also part of a team at MIT that have developed a drug capsule that could be used to deliver oral doses of insulin to people with type 1 diabetes.

[84] Langer has been involved in the founding of many companies,[85] more than twenty in partnership with the venture capital firm Polaris Partners.

[94] He is also a member of the Xconomists, an ad hoc team of editorial advisors for the tech news and media company, Xconomy.