# Manipulation of Bacterial Metabolism: A New Approach to Develop Smart Dental Composites

> **NIH NIH R01** · OREGON STATE UNIVERSITY · 2020 · $433,091

## Abstract

Proposal Summary
In the oral cavity, metabolic lactic acid production by bacteria and the associated change in pH are suspected
to play a key role in the longevity and integrity of dental composite restorations. We propose gathering
fundamental knowledge about the chemical microenvironment created by bacterial metabolites at the dental
material interface to design next-generation dental composites. Our central hypothesis is that metal ion (Ca2+,
Mg2+)-releasing composites can be engineered to influence bacterial metabolism and manipulate the chemical
microenvironment to inhibit tooth demineralization. To quantify these bacterial chemical microenvironments, we
will apply our newly developed unique electrochemical sensors (pH, lactate, H2O2, metal ions) to measure
major bacterial metabolites such as lactate and H2O2 in real time. Aim 1: Determine the effects of metal ions on
bacterial metabolism and the chemical microenvironment. We will determine the effects of metal ions on
bacterial metabolism with dental plaque-derived microcosm biofilms such that the local pH is 5.5 or higher. To
create a genetically amendable and reproducible biofilm model, we will extend our study to replicate local pH,
lactate, and H2O2 concentrations with different ratios of three model organisms: Streptococcus mutans (lactate
producing, pH lowering), Veillonella parvula (lactate consuming), and Streptococcus gordonii (H2O2 producing).
We will use pH, lactate, and H2O2 microsensors as scanning electrochemical microscope (SECM) probes to
determine the local rate of lactate and H2O2 production and the corresponding local pH change above the
biofilms in real time in the presence of metal ions. Aim 2: Quantify the local pH above the bacterial biofilms
grown on metal ion-releasing BAG composites. We will use SECM to measure pH at 20 µm above the dental
plaque microcosm and above three-species biofilm (Sm/Sg/Vp) grown on different metal ion-releasing
composites (similar concentration ranges as in Aim 1). This will help us determine whether metal ions released
from BAG composites can influence bacterial metabolism such that the local pH is >5.5. We will also use Ca2+-
and Mg2+-sensing SECM probes to quantify the local concentration of metal ions released from BAG
composites to determine the ion concentration to which bacteria will be exposed while growing on these
composites. Aim 3: Measure pH and H2O2 at the biofilm–composite interface in real time. Innovative flexible
wire sensors (pH, H2O2, metal ions) will be placed at the highly dynamic material–biofilm interface to monitor it
and answer a crucial question: How do bacterial metabolites influence biomaterial integrity and how do metal
ions released from biomaterials affect bacterial metabolites? The proposed research provides a significant step
towards identifying next-generation “smart” dental composites that can control biofilm composition to maintain
a local pH of 5.5 or higher, thus inhibiting adjacent tooth demineralizat...

## Key facts

- **NIH application ID:** 9965888
- **Project number:** 5R01DE027999-03
- **Recipient organization:** OREGON STATE UNIVERSITY
- **Principal Investigator:** Dipankar Koley
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $433,091
- **Award type:** 5
- **Project period:** 2018-08-01 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9965888

## Citation

> US National Institutes of Health, RePORTER application 9965888, Manipulation of Bacterial Metabolism: A New Approach to Develop Smart Dental Composites (5R01DE027999-03). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/9965888. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*