Biophysicsisaninterdisciplinarysciencethatusesthemethodsofphysicalsciencetostudybiologicalsystems.[1]Studiesincludedunderthebranchesofbiophysicsspanalllevelsofbiologicalorganization,fromthemolecularscaletowholeorganismsandecosystems.Biophysicalresearchsharessignificantoverlapwithbiochemistry,nanotechnology,bioengineering,agrophysicsandsystemsbiology.

　　Molecularbiophysicstypicallyaddressesbiologicalquestionsthataresimilartothoseinbiochemistryandmolecularbiology,butthequestionsareapproachedquantitatively.Scientistsinthisfieldconductresearchconcernedwithunderstandingtheinteractionsbetweenthevarioussystemsofacell,includingtheinteractionsbetweenDNA,RNAandproteinbiosynthesis,aswellashowtheseinteractionsareregulated.Agreatvarietyoftechniquesisusedtoanswerthesequestions.

　　Fluorescentimagingtechniques,aswellaselectronmicroscopy,x-raycrystallography,NMRspectroscopyandatomicforcemicroscopy(AFM)areoftenusedtovisualizestructuresofbiologicalsignificance.Conformationalchangeinstructurecanbemeasuredusingtechniquessuchasdualpolarisationinterferometryandcirculardichroism.DirectmanipulationofmoleculesusingopticaltweezersorAFMcanalsobeusedtomonitorbiologicaleventswhereforcesanddistancesareatthenanoscale.Molecularbiophysicistsoftenconsidercomplexbiologicaleventsassystemsofinteractingunitswhichcanbeunderstoodthroughstatisticalmechanics,thermodynamicsandchemicalkinetics.Bydrawingknowledgeandexperimentaltechniquesfromawidevarietyofdisciplines,biophysicistsareoftenabletodirectlyobserve,modelorevenmanipulatethestructuresandinteractionsofindividualmoleculesorcomplexesofmolecules.

　　Inadditiontotraditional(i.e.molecularandcellular)biophysicaltopicslikestructuralbiologyorenzymekinetics,modernbiophysicsencompassesanextraordinarilybroadrangeofresearch,frombioelectronicstoquantumbiology.Itisbecomingincreasinglycommonforbiophysiciststoapplythemodelsandexperimentaltechniquesderivedfromphysics,aswellasmathematicsandstatistics(seebiomathematics),tolargersystemssuchastissues,organs,populationsandecosystems.