Schematic drawing for the sample preparation and visualization under the light microscopy observation and AFM-based nanoindentation analysis.

<p>Schematic drawing for the sample preparation and visualization under the light microscopy observation and AFM-based nanoindentation analysis.</p

FTIR and micro-FTIR analysis of demineralized and remineralized dentin.

<p>A-D) selected individual spectra obtained from area as indicated by arrows, showing peaks associated with phosphate groups at 1020–1160 cm^-1 and around 1660 cm^-1 for amide-I; E) micro-FTIR map of cross section through the demineralized dentin lesion (DE), plotted as area of intensity between 1020–1160 cm^-1; F) micro-FTIR map for range 1020–1160 cm^-1 of DEpi sample and G) micro-FTIR map of same sample (DEpi) but plotted for intensity of peak at 1110 cm^-1. Bar shows false color scale to indicate intensity with red being highest and blue lowest.</p

Optical images and shrinkage of dried cross sections exposing the lesion depths.

<p>A) demineralized lesion (DE) with nail varnish shown protecting the unexposed surface; B) shrinkage was greatly decreased when demineralized in the present of PI (DEpi) and and was almost undetectable at C) DE-REM; D) DE-REMpi; and E) DEpi-REMpi. Solid red line = original surface location, black dotted line = lesion depth.</p

Average shrinkage measurement.

<p>Average shrinkage measurement.</p

Using Biomimetic Polymers in Place of Noncollagenous Proteins to Achieve Functional Remineralization of Dentin Tissues

In calcified tissues such as bones and teeth, mineralization is regulated by an extracellular matrix that includes noncollagenous proteins (NCP). This natural process has been adapted or mimicked to restore tissues following physical damage or demineralization by using polyanionic acids in place of NCPs, but the remineralized tissues fail to fully recover their mechanical properties. Here, we show that pretreatment with certain amphiphilic peptoids, a class of peptide-like polymers consisting of N-substituted glycines that have defined monomer sequences, enhances ordering and mineralization of collagen and induces functional remineralization of dentin lesions in vitro. In the vicinity of dentin tubules, the newly formed apatite nanocrystals are coaligned with the <i>c</i>-axis parallel to the tubular periphery, and recovery of tissue ultrastructure is accompanied by development of high mechanical strength. The observed effects are highly sequence-dependent with alternating polar and nonpolar groups leading to positive outcomes, whereas diblock sequences have no effect. The observations suggest aromatic groups interact with the collagen while the hydrophilic side chains bind the mineralizing constituents and highlight the potential of synthetic sequence-defined biomimetic polymers to serve as NCP mimics in tissue remineralization