In 1944 Ling won the biology slot of the sixth Boxer Indemnity Scholarship, a nationwide competitive examination that allowed Chinese science and engineering students full scholarship to study in a United States university. In 1947 he co-developed the Gerard-Graham-Ling microelectrode, a device that allows scientists to more accurately measure the electrical potentials of living cells. In 1962 he proposed the Association induction hypothesis, which claims to be unifying, general theory of the living cell, and is an alternative and controversial hypothesis to the membrane and steady-state membrane pump theories, and three years later added the Polarized-Oriented Multilayer (PM or POM) theory of cell water.
From 1950-1953 Ling worked as an instructor at the Medical School of the Johns Hopkins University in Baltimore. His research and experiments led him to the conclusion that the mainstream membrane pump theory of the living cell was not correct. This early embryonic version of the Association induction hypothesis was called Ling's Fixed Charge Hypothesis (LFCH).
From 1953-1957 he continued full-time research at the Neuropsychiatric institute at the University of Illinois Medical School in Chicago. Beginning as an Assistant Professor, he was promoted two years later to (tenured) Associate Professor-ship.
In 1962 his first book entitled "A Physical Theory of the Living State: the Association-Induction Hypothesis." was published. At this time Ling became director of a research laboratory at the Pennsylvania Hospital in Philadelphia.
Ling in 1962 after publication of his first book
In 1984, Ling published his second book "In Search of the Physical Basis of Life,".
From 1982 to 1985 he was a co-Editor-in-chief of the Physiological Chemistry & Physics and Medical NMR journal and since 1986, has been its sole Editor-in-Chief.
In 1992 Ling published his third book, "A Revolution in the Physiology of the Living Cell."
In 2001 his fourth book "Life at the Cell and Below-Cell Level"  was published and has been translated to Russian and Chinese.
In 2011 his wife of 60 years, Shirley Wang Ling, died from incurable pancreatic cancer.
In 2014 at the age of 94 he published his fifth book, a reply to Erwin Schrödinger's 1944 book What is Life? called What is Life Answered
He has published over 200 scientific papers, although much of his later work has been largely ignored by the scientific community.
John Eccles applied the microelectrode to studies of activity of individual units within the spinal cord and brain and Andrew Huxley used it in muscle cells.
In 1963, Hodgkin with Huxley, won the Nobel Prize in Physiology or Medicine for their work on the basis of nerve "action potentials," the electrical impulses which enable the activity of an organism to be coordinated by a central nervous system. Hodgkin and Huxley shared the prize that year with John Eccles, who was cited for his research on synapses.
Worldwide use of this new microelectrode spread rapidly after this and has subsequently proven to be one of the most important devices applied to the study of cellular physiology.
The microelectrode in use today is essentially the same as this, except that it usually contains a concentrated salt solution, and is commonly referred to as the glass capillary.
In 1950 Gerard was nominated for the Nobel Prize for helping to develop the microelectrode as used in Electrophysiology.
Ling wrote books describing his hypothesis in 1962 and 1984; and later self-published other books.
Polarized-oriented multilayer theory
In 1965, Ling added his Polarized-Oriented Multilayer (PM or POM) theory of cell water to the Association Induction Hypothesis. The theory argues that cell water is polarized and oriented and thus dynamically structured.
More recent studies by Gerald Pollack (2001, 2013) and Mae-Wan Ho (2008, 2012) have confirmed the structured nature of cell water and
some scientists such as Vladimir Matveev (2012) continue to explore the ideas that Ling introduced in the 1960s.
^Harold, Franklin M (2002). "Book Review of Life at the Cell and Below-Cell Level: The Hidden History of a Fundamental Revolution in Biology". Cell Biology International. 26 (11): 1007–1009. doi:10.1006/cbir.2002.0948.
^Ling, Gilbert; Gerard, R. W. (December 1949). "The normal membrane potential of frog sartorius fibers". Journal of Cellular and Comparative Physiology. 34 (3): 383–396. doi:10.1002/jcp.1030340304. PMID15410483.
^Ling, Gilbert Ning (16 December 2006). "THE PHYSICAL STATE OF WATER IN LIVING CELL AND MODEL SYSTEMS*". Annals of the New York Academy of Sciences. 125 (2): 401–417. doi:10.1111/j.1749-6632.1965.tb45406.x.
Gilbert N. Ling. A Physical Theory of the Living State: the Association-Induction Hypothesis. Blaisdell Publishing Company, A Division of Random House, Inc., London. 1962. 682 pages. Library of Congress Catalogue Number: 62-11835
Gilbert N. Ling. In Search of the Physical Basis of Life. Plenum Press, New York and London. 1984. 791 pages. ISBN0-306-41409-0
Gilbert N. Ling. A Revolution in the Physiology of the Living Cell. Krieger Publishing Company, Malabar, Florida. 1992. 378 pages. ISBN0-89464-398-3
Gilbert N. Ling. Life at the Cell and Below-Cell Level: The Hidden History of a Fundamental. Revolution in Biology. New York: Pacific Press. 2001. 373 pages. ISBN0-9707322-0-1
Gilbert N. Ling. What is Life Answered. Cushing Malloy Inc., Ann Arbor, Michigan. 2013. 120 pages. ISBN978-0-615-94793-8