In this article, research trend of biomaterials for spinal disease was summarized with an emphasis on molecular therapy for spinal cord injury. Cytokines, cell therapy and biomaterials are future perspectives for treatment of spinal cord injury. But there is no promising result in clinical trial setting so far. Adult stem cells, embryonal stem cells and recently iPS(induced pluripotent stem) cells are widely investigated for cell therapy of spinal cord injury. But ideal cell is not yet determined. Research of biomaterials for cord injury is in the beginning. There is no conclusive data of stem cell therapy in cord injury in terms of effectiveness of improving neurologic deficits. But results of clinical trial showed the feasibility and safety of cell therapy. The combined treatments with cytokines, cells, and biomaterials will be a new modality of biological treatment in spinal cord injury.

Chronic low back pain is a common cause of disability causing major socioeconomic consequences. Recent advances in disc biology and tissue engineering techniques enable a new emerging field of biologic treatments for degenerative disc disease. These new treatment modalities aim to achieve structural and functional restoration of the degenerated discs by introducing protein, cells, genetic modifications of resident disc cells or exogenous cultured cells, and use of biomaterials. So far, these techniques have been successfully applied to treat degenerated discs in preclinical setting, including in vitro or in animal studies. Application of these treatment modalities for degenerative disc disease should be individualized according to the degree of disc degeneration. For the successful application in clinical field, the biologic treatment should achieve the functional restoration of the disc, resulting in pain regulation.

Introduction
Degenerative change of the vertebral disc is known to be caused by inherited factors, aging and mechanical and environmental factors and it progresses due to the decreasing amount of proteoglycan in the vertebral disc. Resolving the imbalance between the synthesis and break down of proteoglycan is an important strategy for slowing additional degeneration and increasing regeneration of the disc. Body: To regenerate vertebral discs, many attempt have been made to get curative value such as direct injection of growth factors like BMP-2, BMP-7, IGF-1, TGF-β1, GDF-5 and FGF into the disc or transplantation of cytokine for improving the composition of proteoglycan. But these proteins have a short acting time and so repeated transplantation is necessary even if transplantation into the disc is done. So, much research has been done on genetic transplantation, which may improve certain proteins. Other trials of transplantation of nucleus pulposus cells, combinations of stem cells with scaffold and amalgamation with genetic care have also been done. But the safety of these therapies has not yet been completely established.
Conclusion
Biological therapy for degenerative disc disease has many benefits compared with the conventional therapies. Hereafter, according to additional research, the clinical indications for biological therapies are expected to increase. Clinical applications should be performed after securing enough results for establishing the safety and effectiveness of these new procedures.