The death was announced by the Sunrise, Fla.-based biotech company U.S. Stem Cell, where Dr. Murphy had served as chairman until last year. No cause was given.

The two elements at the core of Dr. Murphy’s work — experimentation and therapeutics — were intertwined from his boyhood. As a teenager in a Boston suburb, he built a gasoline-powered snowblower and later sold the design to a company for $1,500, a handsome sum in the late 1930s.

He also was observing the wards of Peter Bent Brigham Hospital (now Brigham and Women’s Hospital) in Boston alongside his father, who shared the 1934 Nobel Prize in medicine for research into diet and red blood cell production.

“I was impressed with the fact that much of what I saw [at the hospital] was antique,” Dr. Murphy recounted in a 2003 interview that touched on some of the medical advances he helped oversee, including expanding uses for heart pacemakers and a device to act as a kidney and filter blood.

The blood bags, however, were the most revolutionary in terms of their sweep across medicine. The initial problem was clear: finding an alternative to the glass bottles used until the 1950s to hold blood for transfusions. The bottles were bulky and breakable, two major challenges for military medics and aid teams dispatched to natural disasters.

Dr. Murphy and Dr. Carl W. Walter, a researcher at Harvard Medical School, studied various plastics for years. The most promising idea came in the early 1950s. A bag made of polyvinyl chloride, a synthetic polymer, was inexpensive to produce, easy to store and extremely durable.

The Korean War became a testing ground. Dr. Murphy, who joined the U.S. Public Health Service as a consultant, went close to the front lines in 1952 to demonstrate the blood bags during treatment of wounded service personnel. The trials went well, but the bags met institutional resistance.

A few medical officers opposed using the vinyl blood bags and the transfusion tubes until more studies were made, according to a historical account by the U.S. military. Military nurses were among the biggest advocates of the new blood bag system. By the 1960s, the bags and use of vinyl — for blood bags, catheters and intravenous drips — became the standard across all corners of medicine.

A component initially used to add flexibility to polyvinyl chlorides, diethylhexyl phthalate, or DEHP, was later linked to possible hormonal disruptions and other potential harmful health effects. DEHP has been banned in children’s products and was gradually phased out of use in blood bags and other medical equipment.

Dr. Murphy’s wartime experience also set other ideas in motion. He took note of how medical instruments were often not fully sterilized before being reused, elevating risks of infection and other complications. Back at his lab, Dr. Murphy devised a single-use kit of sterilized medical equipment and drugs.

At a conference in Miami in 2014, Dr. Murphy described what kept him motivated during a career that touched eight decades: “Learning about anything anybody would show me or teach me.”

Well into his 90s, Dr. Murphy was active in promoting research into stem-cell treatments at U.S. Stem Cell, where he served as chairman. The company lost a landmark case in 2019 when a federal judge ruled in favor of the Food and Drug Administration and ordered a halt to treatment that the FDA said had blinded at least four patients.

The lawsuit stemmed from injections of an extract of a patients’ fat cells into their eyes in attempts to treat macular degeneration, a disease that breaks down part of the retina.

An FDA statement described U.S. Stem Cell as among “clinics that abuse the trust of patients and endanger their health.” U.S. Stem Cell defended the “efficacy of this protocol” but complied with the judge’s order. The company continued to offer other stem-cell treatments.

Drawn to research

William Parry Murphy Jr. was born in Boston on Nov. 11, 1923, and raised in neighboring Brookline. His father was awarded the Nobel along with two other researchers for studies into how eating raw liver can boost red blood cell production and ease pernicious anemia. His mother, the former Harriett Adams, was cited as being the first woman to become a licensed dentist in Massachusetts.

Dr. Murphy graduated from Harvard University in 1946 after studies geared toward medical school. He received his medical degree from the University of Illinois at Chicago the following year. During a year of mechanical engineering studies at the Massachusetts Institute of Technology, Dr. Murphy developed a film projector to display enlarged X-ray images.

He was on the medical staff at Peter Bent Brigham Hospital, the same place he visited often as a boy. In 1957, he founded the Miami-based Medical Development Corp., which became Cordis Corp., involved in developing devices to diagnose and treat heart and vascular diseases.

Dr. Murphy retained top positions including president and chief engineer, overseeing teams that created an advanced pacemaker in the 1980s that could regulate heart rhythms and detect abnormalities such as bleeding or clot formation. He also helped lead research into innovations to check for vascular blockages and the development of a baton-size device that cleaned blood of waste for use by patients with failing kidneys.

Dr. Murphy left Cordis in 1985 and, with a colleague, purchased Hyperion, which created medical laboratory and diagnostic devices. In 2003, joined the board of Bioheart and became its chairman in 2010. Dr. Murphy was inducted into the National Inventors Hall of Fame in 2008.

(In 1988, after Dr. Murphy left Cordis, the company pleaded guilty to federal criminal charges that it had sold pacemakers with potentially defective batteries from 1980 to 1985 and filed false quality-control reports with the FDA. Dr. Murphy was not named in the indictments.)

Dr. Murphy remained a restless tinkerer. He dabbled in projects such as refurbishing an antique organ grinder contraption and making improvements to his 100-ton steam-powered tugboat he used to explore South Florida waters.

His first marriage, to Barbara Eastham, ended in divorce. Survivors include his wife of 50 years, Beverly Patterson; three daughters from his first marriage; two grandchildren; and a great-grandson.

Dr. Murphy described himself as a dreamer and a pragmatist. What’s the point, he once asked, of thinking up an invention that never makes it to the marketplace?

“That’s a waste of time,” he said. “I believe you should follow [an idea] and make it available when it is needed.”