Medical-grade polycaprolactone scaffolds made by melt electrospinning writing for oral bone regeneration - a pilot study in vitro

BACKGROUND

The spectrum of indications for the use of membranes and scaffolds in the field of oral and maxillofacial surgery includes, amongst others, guided bone regeneration (GBR). Currently available membrane systems face certain disadvantages such as difficult clinical handling, inconsistent degradation, undirected cell growth and a lack of stability that often complicate their application. Therefore, new membranes which can overcome these issues are of great interest in this field.

METHODS

In this pilot study, we investigated polycaprolactone (PCL) scaffolds intended to enhance oral wound healing by means of melt electrospinning writing (MEW), which allowed for three-dimensional (3D) printing of micron scale fibers and very exact fiber placement. A singular set of box-shaped scaffolds of different sizes consisting of medical-grade PCL was examined and the scaffolds' morphology was evaluated via scanning electron microscopy (SEM). Each prototype sample with box sizes of 225 μm, 300 μm, 375 μm, 450 μm and 500 μm was assessed for cytotoxicity and cell growth by seeding each scaffold with human osteoblast-like cell line MG63.

RESULTS

All scaffolds demonstrated good cytocompatibility according to cell viability, protein concentration, and cell number. SEM analysis revealed an exact fiber placement of the MEW scaffolds and the growth of viable MG63 cells on them. For the examined box-shaped scaffolds with pore sizes between 225 μm and 500 μm, a preferred box size for initial osteoblast attachment could not be found.

CONCLUSIONS

These well-defined 3D scaffolds consisting of medical-grade materials optimized for cell attachment and cell growth hold the key to a promising new approach in GBR in oral and maxillofacial surgery.

Preparation and physiological properties of alkyl esters of 2,3-dihydroxypropionic acid

In order to investigate the physiological behavior of alkyl esters of 2,3-dihydroxypropionic acid two such compounds have been synthesized. One of them, the 1-dodecylester of 2,3-ditetradecyloxypropionic acid was subjected to digestion by pancreatic lipase. The substance remained unaffected. For an in vivo experiment a doubly labelled homolog, the [1'-14C]decyl ester of 2,3-di[1'-3H]hexadecyloxypropionic acid was synthesized. This compound was fed by stomach tube to three groups of male albino rats. The experimental animals were killed after 2,4 and 6 h, those of the control groups after 6 h. Blood, urine, small intestines and livers were examined for radioactivity. From the recovery rates it could be derived that the molecule had been metabolized and absorbed. Obviously, the alkyl chain labelled with 14C was split off first and the alkyl chains labelled with 3H were split off thereafter. As the substance is metabolized in vivo it cannot be utilized as a 'non-fattening fat'.

[A new contrast medium emulsion for lymphography (author's transl)]

A new contrast medium for lymphography has been developed. It is suitable for direct, such as bi-pedal, lymphangiography, and has certain advantages compared with the commercially available contrast medium Ethiodol, such as absence of a lipogranulomatous reaction and less extensive oil emboli in the lungs. It is also possible to use the substance for indirect, retrosternal lymphography. The substance is indirect, retrosternal lymphography. The substance is an emulsion of triglycerides of iodinated poppy seed oil. The method of preparation of the emulsion is described.

[Solubility of phospholipids in oilseeds depending on the extraction conditions (author's transl)]

The results of the determination of oil content depend on the method and on the solvent used. Extractions by the Twisselmann method give increasing yields in the order n-pentane, hexane, and n-heptane. Using the Soxhlet extraction, much lower yields were obtained with n-heptane than with the other two solvents. In both methods, the phospholipid content in the extracts depends only on the solvent and not on the method used. The yield and composition of the mixture of phospholipids vary in the different methods of extraction.