**Biological Molecules, Proteins and Polymers**

84 Atomic Force Microscopy Investigations into Biology – From Cell to Protein

Zhang, Y.; Zhou, H. & Ou-Yang, Z. C. (2001) Stretching Single-Stranded DNA: Interplay of

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Electrostatic, Base-Pairing, and Base-Pair Stacking Interactions, *Biophys. J.*, Vol. 81,

self-sensing measuring head, *Sensors and actuators A-physical*, Vol.167, N°2, pp. 267-

**4** 

*Italy* 

**AFM Measurements to Investigate** 

**Biological Macromolecules** 

*Innovative Materials, University of Perugia* 

L. Latterini and L. Tarpani

**Particulates and Their Interactions with** 

*Department of Chemistry, Center of Excellence for Nanostructured and* 

In recent years much attention has been paid to the development of metrology methods to investigate particulate matter and its interaction with bio-molecules. This interest is triggered by the potential applications of nanoparticle-biomolecule hybrid systems in different areas such as bio-sensing, catalysis, target delivery, selective recognition, etc. (Amelia et al., 2010; Bellezza et al., 2009; Latterini & Amelia, 2009; Joralemon et al., 2005; Nehilla et al., 2005; Rosi & Mirkin, 2005). Furthermore, a better understanding of the interactions between particles and biomolecules could help to optimize the ability to reduce

In the last decade AFM methods based on a vibrating tip to explore a surface topography experienced a significant transformation which allowed them to reach nm-resolution imaging and become sensitive tools to investigate tip-sample interactions down to sub-nm resolution (García & Pérez, 2002). Hence the chance is to develop quantitative procedures to study material properties with high spatial resolution even without affecting the softest samples. These achievements have shown that AFM methods can be used as a valid alternative to other well established techniques (such as electron microscopies) in the study of nanostructured materials. The good spatial resolution of AFM measurements can be achieved without any sample pre-treatments thus overcoming the limitations in the sample preparation involved in electron microscopies. AFM imaging appears particularly attractive to characterize particulate matter based on organic materials with high spatial resolution without any concerns about scattering cross sections and sample treatment procedures. Extremely interesting in this context is the possibility to use AFM to characterize particles conjugated to biological macromolecules. Indeed, AFM scanning showed a good accuracy to obtain size distributions for colloidal particle samples comparable to dynamic light scattering techniques or even better if the samples were polydispersed (Hoo et al., 2008)

In the present contribution, particulate matter, either intentionally prepared with designed dimensional, morphological and chemical properties or produced in working environments during the phases of metal processing or combustion processes, were dimensionally characterized and information on their surface morphology were obtained.

the exposure to particulate matter in working environments.

**1. Introduction** 
