The immobilization of Chinese herbal medicine onto the surface-modified calcium hydrogenphosphate
Date Issued
2002-07-31
Date
2002-07-31
Author(s)
DOI
902314B002352
Abstract
To accelerate the healing of bone defects or to enable to heal at all, it is often
necessary to fill them with suitable substance. Various artificial materials defects have
been developed. Among these, calcium phosphates and bioactive glass have been
proven to be biocompatibile and bioactive materials that can chemically bond with
bone, and have been successfully used clinically for repair of bone defects and
augmentation of osseous tissue. However, those bioceramics have only the property of
osteoconduction without any osteoinduction.
Many ligands have been physicochemically absorbed onto substrates to enhance
cell-substrate interactions. Although it has been widely developed, it is still limited to
use in long-term implantation because of short half-life period. Thus, some interfacial
modification will be required for enhancing the efficacy of delivery system. These
models involve the immobilization of biologically active ligands of natural and
synthetic origin onto various substrates to produce an interface with stronger chemical
bond between ligand and substrate. The advantage of covalently immobilizing a
ligand is that a chemical bond is present to prevent ligand or medicine from
desorption.
In our study, two-step of chemical immobilization was performed to
surface-modified calcium hydrogenphosphate powders. The first was to modify the
surface of calcium hydrogen-phosphate (CHP) with coupling agent of
hexanmethylene diisocyanate (HMDI). The linkage between CHP and HMDI will be
characterized by FTIR. The second step was to immobilize chemically Gusuibu onto
MCHP. Moreover, the sorption and desorption of Gusuibu was evaluated and
quantitative analyzed by spectrophotometer and HPLC.
From the results, bioceramic CHP was surface-modified by two-step of chemical
immobilization. Firstly, successfully modified the surface of calcium
hydrogen-phosphate (CHP) with coupling agent of hexanmethylene diisocyanate
(HMDI). The first step was also activated the surface of CHP to induce primary amine
terminator. The reaction of this functional group with Gusuibu was the second step.
We confirmed simultaneously that Gusuibu could be immobilized chemically onto the
surface of MCHP. Although some immobilized Gusuibu also released rapidly at the
first 12 hours, the degree of released Gusuibu was lower than both by
Gusuibu-adsorbing MCHP and Gusuibu-adsorbing CHP.
Publisher
臺北市：國立臺灣大學醫學工程學研究所
Type
report
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