# pH-sensitive materials responding to metabolic activities of cariogenic plaque

> **NIH NIH R21** · ADA SCIENCE AND RESEARCH INSTITUTE LLC · 2020 · $233,618

## Abstract

Abstract: In today’s microbiome era, it is well-recognized that dental caries, one of the most prevalent and costly
chronic infectious diseases world-wide, results from dysbiosis of the oral microbiota and the oral environmental
changes that cause tooth damage. Specifically, frequent intake of fermentable carbohydrates promotes a
progressive shift in microbial composition toward acidogenic and acid-tolerant species. The continual acid-
induced demineralization eventually overcomes the buffering capacity and anti-microbial properties of saliva,
leading to irreversible tooth destruction. The goal of this proposed research is to develop pH-responsive
materials capable of targeted treatment of acid-producing bacteria (t-TAB) and antifouling. Our central
hypothesis is that the combination of pH-responsive protein adsorption and acid-enhanced antimicrobial (AM)
efficacy will inhibit the attachment and growth of acid-producing bacteria, consequently prevent the accumulation
of cariogenic plaque. We propose three specific aims to design, develop, and evaluate the pH-responsive
materials capable of altering protein-adsorption and achieving t-TAB. In Specific Aim 1, we will design and
prepare Azo-QPS-containing materials that have pH-responsive surface properties. The Azo-QPS compounds
have pH-sensitive AM efficacy and t-TAB functions in solution. We will covalently bond Azo-QPS functional
groups onto surfaces in the form of single-molecule monolayer or Azo-QPS-polymers, which will produce variant
amount of Azo-QPS functional groups/surface area. In addition, by bonding Azo-QPS with a clinically tested AM
agent, chlorhexidine (CHX), we will enhance the new materials’ pH-responsive AM efficacy. In Specific Aim 2,
we will evaluate the new materials’ performance in terms of pH-responsive reversible protein-adsorption and
antifouling. We will enhance our understanding of the correlation between the surface chemical and physical
properties and the antifouling performance. Specifically, we will focus on the correlation of hydrophilicity and
charge density with the protein-adsorption in response to the pH variation between pH 4-8, a biological relevant
pH range in oral environments. In Specific Aim 3, we will assess on-site antifouling and t-TAB efficacy of the new
materials in a multispecies biofilm model that simulates oral microbial community. These will be performed in the
presence and absence of sucrose—the cariogenic dietary carbohydrate. Strategy will entail evaluating biomass,
analyzing microbial profiles and determining environmental pH. The successful completion of the proposed
research will yield pH-responsive materials that are antifouling and obtain t-TAB in response to environmental
changes autonomously. The material design may find extended utility in dental resin-restoratives, denture, and
implant. As an exploratory research, the knowledge/results gained from this study will serve as preliminary data
for an R01 application.

## Key facts

- **NIH application ID:** 10043261
- **Project number:** 1R21DE029925-01
- **Recipient organization:** ADA SCIENCE AND RESEARCH INSTITUTE LLC
- **Principal Investigator:** Xuesong He
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $233,618
- **Award type:** 1
- **Project period:** 2020-09-01 → 2021-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10043261

## Citation

> US National Institutes of Health, RePORTER application 10043261, pH-sensitive materials responding to metabolic activities of cariogenic plaque (1R21DE029925-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10043261. Licensed CC0.

---

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