Chemometrics-Assisted Raman Spectroscopy Characterization of Tunable Polymer-Peptide Hybrids for Dental Tissue Repair

Abstract

The interfaces that biological tissues form with biomaterials are invariably defective and frequently the location where failure initiates. Characterizing the phenomena that lead to failure is confounded by several factors including heterogeneous material/tissue interfaces. To seamlessly analyze across these diverse structures presents a wealth of analytical challenges. This study aims to develop a molecular-level understanding of a peptide-functionalized adhesive/collagen hybrid biomaterial using Raman spectroscopy combined with chemometrics approach. An engineered hydroxyapatite-binding peptide (HABP) was copolymerized in dentin adhesive and dentin was demineralized to provide collagen matrices that were partially infiltrated with the peptide-functionalized adhesive. Partial infiltration led to pockets of exposed collagen—a condition that simulates defects in adhesive/dentin interfaces. The spectroscopic results indicate that co-polymerizable HABP tethered to the adhesive promoted remineralization of the defects. The spatial distribution of collagen, adhesive, and mineral as well as crystallinity of the mineral across this heterogeneous material/tissue interface was determined using micro-Raman spectroscopy combined with chemometrics approach. The success of this combined approach in the characterization of material/tissue interfaces stems from its ability to extract quality parameters that are related to the essential and relevant portions of the spectral data, after filtering out noise and non-relevant information. This ability is critical when it is not possible to separate components for analysis such as investigations focused on, in situ chemical characterization of interfaces. Extracting essential information from complex bio/material interfaces using data driven approaches will improve our understanding of heterogeneous material/tissue interfaces. This understanding will allow us to identify key parameters within the interfacial micro-environment that should be harnessed to develop durable biomaterials.

Engineered Peptides Enable Biomimetic Route for Collagen Intrafibrillar Mineralization

“…For intact dentin, the characteristic peaks associated with PO 4 3− and CO 3 2− are observed at 960 cm −1 and 1070 cm −1 , respectively. The intensity of these mineral bands was decreased in the demineralized dentin, whereas the spectral signatures reflecting type I collagen became clearer: 1667 cm −1 (amide I), 1460 cm −1 (CH 2 ), and the doublet observed from 1215 cm −1 to 1310 cm −1 (amide III) [ 3 , 46 , 47 ]. The chemical signatures observed in both intact and demineralized dentin were compared to spin-coated (SC) rat tail type 1 collagen on glass using RAMAN microscopy.…”

“…This multivariate analysis method was integrated into the LabSPEC 6 analysis software as a Multivariate Analysis (MVA) module (powered by Eigenvector Research Inc., HORIBA Jobin Yvon, NJ, USA). A rectangular area of the surface was imaged and submitted to this multivariate analysis where a statistical pattern determined derived independent clusters to present chemically distinct regions [ 3 , 4 ]. Average spectra are calculated per cluster which were used to provide information on particular peak parameters and component distribution in the resulting spectra.…”

“…Polymeric restorative materials have revolutionized the treatment of dental caries by allowing clinicians a “one-of-a kind” in situ tissue engineering approach afforded by resin–dentin bonding [ 1 , 2 , 3 , 4 , 5 ]. Despite significant advances in composite resins for treating teeth, the low durability of the current dental adhesives continues to be a major health burden.…”

“…Adhesion and adhesive performance on dentin are especially challenging due to the complexity of dentin, a mineralized dynamic biological composite tissue composed of 70% hydroxyapatite (HA), 30% type I collagen, multiple non-collagenous proteins, and water [ 12 , 13 , 14 ]. Due to the multi-scaled and multi-faceted events taking place at this complex resin–dentin adhesive interface, strategies developed so far have been slow to address the short lifespan of resin–dentin bonding and subsequently prevent the repeated failure of composite resin restorations [ 3 , 15 ]. Composite restorations will substantially benefit from the next generation of approaches based upon bioactive and biohybrid pathways that address the ongoing multifaceted events at this complex interface [ 2 , 15 , 16 , 17 , 18 ].…”

Engineering peptide-polymer hybrids for targeted repair and protection of cervical lesions

“…Despite dental adhesive polymers possessing broad and versatile properties, they lack biological functionalities such as remineralization and antimicrobial. Building on our prior research (46)(47)(48)(49)(50)(51)(52)(53)(54)(55), we developed a multipronged strategy to both repair and protect exposed dentin (50). This multi-pronged strategy: (a) remineralizes damaged dentin; (b) inhibits bacterial attack; and (c) provides durable protection.…”