# In Situ Synthesis of a Hydroxyapatite and Reduced Graphene Oxide Composite for Potential Electrochemical Biosensing Applications

## TL;DR

This paper describes a new method to create a composite material combining hydroxyapatite and reduced graphene oxide, which could be used in biosensors.

## Contribution

A novel microwave hydrothermal-assisted coprecipitation method is introduced for in situ synthesis of HA/rGO composites.

## Key findings

- The HA/rGO composite exhibited a hexagonal crystalline phase with a mean crystallite size of 28.1 nm.
- HA nanorods were uniformly distributed on rGO layers, averaging 75 nm in length.
- FTIR and STXM confirmed the successful reduction of graphene oxide and composite formation.

## Abstract

Hydroxyapatite/reduced
graphene oxide (HA/rGO) composites are extensively
used in numerous applications, including tissue engineering, energy
storage, catalysis, and electrochemical sensing. In this study, a
novel microwave hydrothermal-assisted coprecipitation method was implemented
to synthesize an in situ HA/rGO composite for potential electrochemical
biosensing applications. The structural, optical, and morphological
properties were thoroughly analyzed using XRD, Raman spectroscopy,
FTIR, STXM, and SEM. Rietveld refinement confirmed the presence of
a hexagonal crystalline phase in the HA/rGO composite with a mean
crystallite size of 28.1 nm. Raman spectroscopy revealed characteristic
vibrational modes of each precursor, while STXM spectra displayed
electronic transitions corresponding to rGO (C 1s to π* and
σ* levels) as well as Ca L-edge and O and P K-edge transitions
of HA, confirming a composite material. FTIR analysis confirmed the
reduction of GO to rGO by tracking the presence and disappearance
of oxygen-functional groups in the graphitic structure. Electron microscopy
revealed that HA nanorods, averaging 75 nm in length, were uniformly
distributed along the surface and edges of the rGO layers.