ix

Or, how physical science methods help us under­

stand “life”

And the whole is greater than the part.

Euclid elements, Book I, Common Notion 5, ca. 300 BC

This book concerns one simple question:

What is life?

If only the answer were as simple! In this book, you

will find a comprehensive discussion of the experi­

mental and theoretical tools and techniques of bio­

physics, which can be used to help us address that most

innocuous question.

The creation of this second edition was guided mainly

by two imperatives: include the feedback from students

and teachers made in the classroom, tutorial offices,

practical labs, and lecture theaters from the first edition,

and to freshen up some key areas and include some

new emergent ones in light of recent developments in

Physics of Life research. So, a number of sections have

been reorganized, condensed, and expanded as appro­

priate, and the narrative improved in response to reader

comments. Several additional worked examples and

problem questions are now included. The title has been

marginally revised to reflect the intersection of “bio­

physics” and “biological physics” into a single discipline

of the “Physics of Life.”

“Interdisciplinary” research between the physical and

biological sciences is now emerging as one of the fastest

growing fields within both the physical and biosciences—​

a typical search for “biophysics” in any major Internet

search engine now generates several million hits. The

trend toward greater investment in this interfacial area

is reflected in the establishment of centers of excellence

across the world dedicated to interdisciplinary science

research and graduate student training that combine the

elements of both physical and life sciences. Biophysics/​

biological physics is now a standard teaching compo­

nent option in undergraduate biochemistry and physics

courses, and the significant direction of change over the

past few years in terms of research direction has been

a shift toward a smaller length scale and a far greater

physiological realism to highly challenging bioscience

experiments—​experiments are getting better at imaging

molecular processes. On the other hand, there are some

theorists who feel that we need biophysical concepts

and theories at higher length scales to combat the some­

times suffocating reductionism of modern biology.

Physical science methods historically have been

key to providing enormous breakthroughs in our

understanding of fundamental biology—​stemming

from the early development of optical microscopy for

understanding the cellular nature of life to complex

structural biology techniques to elucidate the shape

of vital biomolecules, including essential proteins and

DNA, the coding molecule of genes. More recently,

physical science developments have involved methods

to study single cells in their native context at the single-​

molecule level, as well as providing ground-​breaking

developments in areas of artificial tissue bioengineering

and synthetic biology, and biosensing and disease diag­

nosis. But there is also a tantalizing theme emerging for

many of the researchers involved to, in effect, reframe

their questions across the interface between the phys­

ical and life sciences, through a process of “co-creation”;

biologists and physicists interacting to generate trans­

formative ways of studying living matter that neither

in isolation could achieve. The tools and techniques

described in this book resonate with those chords.

This book concisely encompasses the full, modern

physical science “toolbox” of experimental and analytical

techniques that are in active use. There is an enormous

demand for literature to accompany both active research

and taught courses, and so there is a compelling, timely

argument to produce a concise handbook summarizing

the essential details in this broad field, but one which

will also focus on core details of the more key areas. This

book can be used to complement third-​ and fourth-​year

undergraduate courses in physical science departments

involving students who are engaged in physical/​life

sciences modules—​there are several of these inter­

nationally involving biological physics/​biophysics, bio­

engineering, bionanotechnology, medical/​healthcare

physics, biomedical sciences, natural sciences, com­

putational biology, and mathematical biology. Similar

stage undergraduates in life sciences departments doing

physical/​life science interfacial courses will also benefit

from this text, to accompany lectures covering bio­

physics, bionanotechnology, systems biology, and syn­

thetic biology. Also, PhD and master’s students engaged

in physical/​life sciences courses and/​or research will

find significant utility for structuring and framing their

study, and expert academics will find this text to be an

Preface