Cristiano De Michele Hierarchical propagation of chirality through reversible polymerization: the cholesteric phase of DNA oligomers Tommaso Bellini Giuliano Zanchetta Elisa Frezza Alberta Ferrarini

OUTLINE MOTIVATION OF THIS WORK MODELS MOLECULAR THEORY PARAMETERIZATION COMPARISON WITH EXPERIMENTS CONCLUSIONS

SHORT DNA DUPLEXES EXPERIMENTAL SYSTEM WATER

Building Block (monomer) Short DNA Duplex (nanoDNA) 6 to 20 bp in length SHORT DNA DUPLEXES Sugar-phosphate backbone Base stacking Base pairing 12 bp Nb=Nb=

nanoDNA SELF-ASSEMBLY semi-flexible reversible polymers

nanoDNA SELF-ASSEMBLY ISOTROPIC CHIRAL NEMATIC semi-flexible reversible polymers

CHOLESTERIC nanoDNA CHOLESTERIC nanoDNA PERIODIC ROTATION OF NEMATIC DIRECTOR PERIOD = CHOLESTERIC PITCH (p) NEMATICCHOLESTERIC

AN ITALIAN THREE-COURSE MEAL AN ITALIAN THREE-COURSE MEAL ISOTROPIC NEMATIC CHOLESTERIC long holed fusilli of Gragnano fusilli helical axis

\ p NEW PITCH MEASUREMENT FOR DICKERSON DODECAMER (CGCGAATTCGCG)

MODELS EXPERIMENTS THEORY SIMULATIONS comparison to optimize input parameteres STRATEGY: MULTISCALE BOTTOM-UP APPROACH Input parameters Comparison to check theoretical predictions NO THEORETICAL OR COMPUTATIONAL APPROACH WHICH ACCOUNTS FOR BOTH SELF-ASSEMBLY AND HELICAL ORDERING

OUTLINE MOTIVATION OF THIS WORK MODELS MOLECULAR THEORY PARAMETERIZATION COMPARISON WITH EXPERIMENTS CONCLUSIONS

Sugar- phosphate backbone Base stacking Base pairing 12 bp OXFORD MODEL CDM, L. Rovigatti, T. Bellini and F. Sciortino, Soft Matter 8, 8388 (2012) rigid body (nucleotide) Nb=Nb= realistic and parameter free

HARD CYLINDERS MODEL Sugar- phosphate backbone Base stacking Base pairing 12 bp K. T. Nguyen, F. Sciortino and CDM, Langmuir 30, 4814 (2014) Nb=Nb= simplistic model to test theory

BENT CYLINDER MODEL K. T. Nguyen, A. Battisti, D. Ancora, F. Sciortino and CDM, Soft Matter 11, 2934 (2015) N b = 12 θbθb accounts for structural bending of short duplexes

STERIC MODEL OF DICKERSON DODECAMER nucleobase sugar phosphate E. Frezza, F. Tombolato and A. Ferrarini, Soft Matter 7, 9291 (2011) WE IGNORE ELECTROSTATICS RIGID STRUCTURE HARD CORE INTERACTIONS

OUTLINE MOTIVATION OF THIS WORK MODELS MOLECULAR THEORY PARAMETERIZATION COMPARISON WITH EXPERIMENTS CONCLUSIONS

FREE ENERGY In our approach: CDM, T. Bellini and F. Sciortino, Macromolecules 45, (2012) Onsager-like theory

FREE ENERGY In our approach: CDM, G. Zanchetta, T. Bellini, E. Frezza and A. Ferrarini, submitted (2015)

OUTLINE MOTIVATION OF THIS WORK MODELS MOLECULAR THEORY PARAMETERIZATION COMPARISON WITH EXPERIMENTS CONCLUSIONS

ESTIMATE OF STACKING FREE ENERGY G ST AND l 0 OXFORD MODEL STACKING FREE ENERGY G ST HARD CYLINDER MODEL l0l0 BENT CYLINDER MODEL PERSISTENCE LENGTH l p STERIC MODEL

OUTLINE MOTIVATION OF THIS WORK MODELS MOLECULAR THEORY PARAMETERIZATION COMPARISON WITH EXPERIMENTS CONCLUSIONS

DICKERSON DODECAMER PHASE DIAGRAM I + N * N*N* I N*N*

THEORETICAL AND EXPERIMENTAL PITCH \ p 20 µm 750 mg/ml, 289 K 750 mg/ml, 301 K 20 µm no fitting/adjustable parameters

OUTLINE MOTIVATION OF THIS WORK MODELS MOLECULAR THEORY PARAMETERIZATION COMPARISON WITH EXPERIMENTS CONCLUSIONS

We developed a parameter free theoretical approach for self-assembly-driven cholesteric liquid crystals Our molecular theory is rather general and it accounts for helical ordering in self-assembly-driven cholesteric phases Hallmark of self-assembly: pitch dependence on ρ and T, which is in good agreement with experiments

THANK YOU FOR YOUR ATTENTION

CHOLESTERIC CONTRIBUTIONS TO FREE ENERGY CHOLESTERIC CONTRIBUTIONS TO FREE ENERGY twist elastic constantchiral strength CDM, G. Zanchetta, T. Bellini, E. Frezza and A. Ferrarini, submitted (2015)

CHOLESTERIC CONTRIBUTIONS TO FREE ENERGY CHOLESTERIC CONTRIBUTIONS TO FREE ENERGY twist elastic constant chiral strength cholesteric (N * ) pitch CDM, G. Zanchetta, T. Bellini, E. Frezza and A. Ferrarini, submitted (2015)

SOME INSIGHT FROM THEORETICAL RESULTS

isoM

SELF-ASSEMBLED CHAINS OF FUSILLI UNBONDED FUSILLI M=1 M=4 THEORETICAL RESULTS FOR STIFF CHAINS

SELF-ASSEMBLED CHAINS OF FUSILLI UNBONDED FUSILLI M=1 M=4 #contacts = 4 #contacts = 1 THEORETICAL RESULTS FOR STIFF CHAINS

SELF-ASSEMBLED CHAINS OF FUSILLI UNBONDED FUSILLI M=1 M=4 #contacts = 4 #contacts = 1 THEORETICAL RESULTS FOR STIFF CHAINS

CHIRAL AND ELASTIC GENERALIZED EXCLUDED VOLUMES CHIRAL AND ELASTIC GENERALIZED EXCLUDED VOLUMES α is the parameter associated to Onsager distribution

CHOLESTERIC CONTRIBUTIONS TO FREE ENERGY CHOLESTERIC CONTRIBUTIONS TO FREE ENERGY CDM, G. Zanchetta, T. Bellini, E. Frezza and A. Ferrarini, submitted (2015) Parsons-Lee factorchain length distribution generalized excluded volumes

CHOLESTERIC CONTRIBUTIONS TO FREE ENERGY CHOLESTERIC CONTRIBUTIONS TO FREE ENERGY CDM, G. Zanchetta, T. Bellini, E. Frezza and A. Ferrarini, submitted (2015) Parsons-Lee factorchain length distribution generalized excluded volumes

HARD CYLINDERS MODEL

ESTIMATE OF BENDING ANGLE θbθb BENDING ANGLE

EFFECTIVE PERSISTENCE LENGTH

G ST ESTIMATE: RB MODEL NO FITTING PARAMETERS

ESTIMATE OF l 0 ESTIMATE OF l 0 no fitting parameters