Self‐healing injectable hydrogel biomaterials uniquely enable precise therapeutic deposition and deployment at specific bodily locations through versatile and minimally invasive processes that can preserve cargo integrity and cell viability. Despite the distinct advantages that injectable hydrogels offer in tissue engineering and therapeutic delivery, exceptionally few have been created using components naturally present in the cellular niche. In this work, we introduce a shear‐thinning hydrogel based on guest‐host complexation of gelatin. As a biocompatible, biodegradable, and nonimmunogenic biopolymer derived from the most abundant extracellular matrix protein (collagen), gelatin offers great utility as the structural component of biomaterials. Taking advantage of reversible guest‐host interactions between β‐cyclodextrin (CD) and adamantane (AD) on modified gelatins, we report the first strategy to afford a self‐healing material based solely on a functionalized extracellular matrix protein. By varying the initial material formulation, hydrogels were synthesized with variable moduli and shear‐thinability across a broad range. Gels were demonstrated to exhibit shear‐thinning and self‐healing properties, supporting protection of clinically relevant stem‐cell‐derived cardiomyocytes during injection. These materials are expected to expand clinical opportunities in cell delivery for in vivo tissue regeneration.

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Protein and cell interactions on implanted, blood-contacting medical device surfaces can lead to adverse biological reactions. Medical-grade poly­(vinyl chloride) (PVC) materials have been used for decades, particularly as blood-contacting tubes and containers. However, there are numerous concerns with their performance including platelet activation, complement activation, and thrombin generation and also leaching of plasticizers, particularly in clinical applications. Here, we report a surface modification method that can dramatically prevent blood protein adsorption, human platelet activation, and complement activation on commercial medical-grade PVC materials under various test conditions. The surface modification can be accomplished through simple dip-coating followed by light illumination utilizing biocompatible polymers comprising zwitterionic carboxybetaine (CB) moieties and photosensitive cross-linking moieties. This surface treatment can be manufactured routinely at small or large scales and can impart to commercial PVC materials superhydrophilicity and nonfouling capability. Furthermore, the polymer effectively prevented leaching of plasticizers out from commercial medical-grade PVC materials. This coating technique is readily applicable to many other polymers and medical devices requiring surfaces that will enhance performance in clinical settings.