Neo4j is very specific Graph database. I don't see any reason to spend time writing such specific things.
You can use php lib which provide good interface - https://github.com/jadell/neo4jphp
In one of my project I thought to use Neo4j for store nodes/relations and search via them. I used this lib. But in that time I thought about c-extension for that.
Now there is a zephir - and you can write a own c-extension for neo4 :)