Injectable biomaterials for stem cell delivery and tissue regeneration

ABSTRACT

Introduction: Organ dysfunction and failure are major health issues affecting millions of patients, many of whom are desperate for organ transplantation. Tissue regeneration aims at providing alternative solutions through innovative application of cell biology and materials engineering to clinical practice. Biomaterials play a critical role in tissue engineering, which interface with both cell biology and surgical procedures. Injectable stem cell carriers represent a promising platform to harvest the therapeutic effects of cells and to simplify the surgical process.

Areas covered: This review is focused on injectable cell carriers which are not only expected to improve therapeutic outcomes, but also to facilitate easy surgical process. Such cell carriers include in situ gelling hydrogel, injectable supramolecular hydrogels, and microcarriers.

Expert opinion: The current design of hydrogels and microcarriers can achieve biocompatibility, biodegradability, and provide desirable features to enhance biological response. Overall, more systematic understanding of stem cell behaviors in a synthetic microenvironment, as well as advancement in materials sciences, are needed to design injectable biomaterials that can provide all critical guidance for the full course of tissue regeneration.

KEYWORDS:

• Drug delivery
• hydrogel
• microcarriers
• stem cells
• tissue engineering

Article highlights

• Hydrogels responsive to physiological stimuli (temperature, pH, ionic strength, etc.) can be utilized as in situ gelling carriers for stem cell delivery

• The design of polymers capable of thermally-induced gelling needs to maintain a delicate balance in molecular design to achieve a Tgel near body temperature and prolonged physical and mechanical stability

• Microcarriers represent a promising injectable stem cell carrier, which provide excellent control of cell microenvironments

• The physical and chemical structure of microspheres can be tailored to improve cell-microsphere interactions

• Nanofibrous microspheres with various chemical and physical features can be synthesized, which demonstrated excellent performance as stem cell carriers for various tissue regenerations

This box summarizes key points contained in the article.

Declaration of interest

Z Zhang is an employee of Otonomy Inc. He has no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Additional information

Funding

This manuscript has not been funded.